University of Nevada Reno in and Distribution of Soil Nitrates on The

Home , Yucca Flat

University of Nevada Reno

in and Distribution of Soil Nitrates on the Nevada Test Site

A thesis submitted in partial fulfillment of the

requirements for the degree of

Master of Science in Hydrology

by Stacey Leatham HI

December 1982 1 M)N«3 LI8«a RY Thesis 1733

The thesis of Stacey Leathain is approved:

University of Nevada

Reno

December 1982 11

ACKNOWLEDGMENT

I would like to acknowledge and thank everyone in Water

Resources Center for their kindness and support throughout

the last two years. Many people were instrumental in the

completion of not only my thesis research but my M.S degree.

I would like to thank Dr. Michael E. Campana for his

foresight in encouraging me to pursue a degree in Hydrogeol- ogy. His exceptional instruction and personal involvement were the foundations for the knowledge I gained.

I also thank Dr. Clinton Case for the honor of having worked with him for the past two years. His enthusiasm and support were invaluable.

Dr. Roger L. Jacobson, my Committee Chairman and Re- search Advisor, was instrumental in my thesis research,

analysis, and writing. I thank him for his personal and professional commitment and help in every aspect of my thesis and research.

I would also like to thank Dr. Watkins Miller and Dr.

Glenn W. Bedelle for their input and suggestions regarding my research and analysis as well as for serving on my committee .

Mary Miller's expert advice and help were crucial for the success of all aspects of my laboratory experiments. I 1X1 also thank James Heidker for all his help and for his dedi- cation in getting my samples analyzed.

Alan McKay, Bert Elliott, Alice Smith, Walter Lombardo, and Doug Zimmerman are all commended and thanked for their fortitude in braving the wind, cold, and snow and making it possible for me to collect as many samples as I did.

I am also greatly indebted to Carol Hackney, Babs Salmon, and Karla Cosens for not only their assistance in fi nal manuscript preparation but for all the help and enthusiasm they showed throughout the course of my thesis.

In conclusion, I would like to thank all the graduate students and professionals for their enthusiasm and moral support. IV

ABSTRACT

Unusually high nitrate concentrations were found in soils of Yucca and Frenchman Flats. A maximum concentration of 11,100 mg/kg was found within the 2-6 inch soil depth on

Frenchman playa. Maximum nitrate concentrations in the playa soils generally occurred within the 6 inch to 2 foot soil depth. The maxima for all playa sampling sites averaged 4,693 mg/kg nitrate. Soils from the bajada had lower nitrate concentrations, with an average maximum concentration of 588 mg/kg.

Nitrogen fixation by blue-green algae was found to occur at 79 percent of the randomly chosen sample sites.

Under optimum laboratory conditions nitrogen fixation ranged from 4.1 to 46,100g N2/acre/day. Average nitrogen fixation in soil cores was 359g N2/acre/day whereas, the average fixation by algal crusts was 5,527g N2/acre/day. Where nitrate was found to accumulate there was generally an associated decrease in the pH of the soil (from about 9.0 to 7.0) possibly indicating the oxidation of atmospheric nitrogen fixed by algae to nitrate by Nitrosomonas and Nitrobacter. V

TABLE OF CONTENTS ABSTRACT

ACKNOWLEDGMENTS

INTRODUCTION 1 Purpose of Study 1

Previous Work 1

Biological Nitrogen Fixation 4 Nitrogen Fixation by Microorganisms 6 Nitrogen Fixation by Free-Living Blue- 7 Green Algae and Lichen Symbionts Physical Inputs of Nitrogen to Desert 9 Ecosystems Precipitation and Dry Fallout 9 Nitrogen in Rocks 10

STUDY AREA 1 3 Regional Setting 13

Geology of the Nevada Test Site 13

Geomorphology of Playas 17 Hydrology 21

Climate 21

Vegetation 24

METHODOLOGY 27 Soil Sample Collection 27

Measurement of Soil Nitrate 29 Soil Moisture 32 Water Sample Collection and Analysis 33

Acetylene Reduction Assay - Gas Chromatograph Analysis 33 vi

Nitrogen Fixation Experiment 35

Soil Samples 35 Crust and Soil Core Assays 37 Nitrogen Fixation Calculations 37

Sample Preparation for Soil i5N Analysis 39 Bacteria Growth Study 40

RESULTS AND DISCUSSION 42

Potential Sources of Nitrate in Playa Soils 42

Nitrate in Precipitation and Dry Fallout 42 Nitrate in Runoff Water 46 Nitrate in Water Ponded on the Playa 48 Nitrate in Water Issuing from Bedrock 51

Soil Nitrate 52

Nitrate vs. TDS 52 Nitrate vs. Chloride 55 Nitrate in the Soil Profile 61 Nitrate Accumulation vs. pH 63

Acetylene Reduction Assay 70 Acetylene Reduction by 0-2 inch Soil Samples 72 Acetylene Reduction by Crust Samples 73 Acetylene Reduction by Cores 80

Bacteria Growth Study 81

Isotope Analysis 84

CONCLUSIONS 86

REFERENCES 88

APPENDIX I - Bacteria Growth Mediums 93 APPENDIX II - Percent Moisture of 0-2 inch (0-5 cm) and 2-6 inch (5-15 cm) Soil Samples 101

APPENDIX III - Percent Nitrate to TDS in Soil Profiles 103 vxx

APPENDIX IV - Chemical Data for Soil Profiles 121 APPENDIX V - Variation of Nitrate with Depth at Different Sample Sites 133 viii

TABLES

1. Fixed Ammonium Nitrogen in Igneous Rocks 12

2. 10-Year Climatological Summary (1962-1971) Yucca Flat, Nevada— Nevada Test Site 25

3. Water Sample Analyses 43

4. Soil Sample Analysis for Soils Analyzed for Chloride 45

5. Water Sample Analysis (Springs) 53

6. Crust Assay (1 day and 7 day incubation) 66

7. Core Assay 82

8. Bacterial Growth Study 83

9. Isotope Analysis 85 IX

FIGURES

1. Desert Nitrogen Cycle 3

2. Location of Nevada Test Site 14

3. Location of Study Site Areas on NTS 15

4. Block Diagram Showing Geomorphic Setting and Sedimentary Framework of Idealized Fine-Grained Playa 20

5. Normal and Means of Monthly Precipitation on NTS 23

6. Vegetation Types of the Nevada Test Site 26 7. Water Ponded on Yucca Playa 28

8. Frenchman Flat Sample Site Locations 30

9. Yucca Flat Sample Site Locations 31 10. Runoff Water Collected in a Sump near Frenchman Flat 47 11. Nitrate and Total Dissolved Solids versus Depth at Station Yucca Lake #3 56

12. Nitrate and Total Dissolved Solids versus Depth at Station Frenchman Flat #5 57 13. Nitrate and Total Dissolved Solids versus Depth at Station Frenchman Flat #6 58

14. Nitrate and Total Dissolved Solids versus Depth at Station Frenchman Flat #13 59

15. Nitrate versus pH at Soil Depths of 0-2 inches 67

16. Nitrate versus pH at Soil Depths of 1.0-1.5 feet 68

17. Nitrate versus pH at Soil Depths of 2.0-2.5 feet 69 18. Algal Crusts from Bajada Around Frenchman Flat 74

19. Algal Mat on Playa Surface 76 1

INTRODUCTION

PURPOSE OF STUDY

Although nitrogen is a necessary component to most biologic systems, when present in the wrong forms and amounts, it can also be detrimental. For example, the cri- teria for NO3-N in drinking water is 10 mg/1 and waters above this concentration are known to cause infant methemo- globinemia (EPA, 1976). Additionally, different forms and amounts of the nitrogen species are known to be toxic to fish. On the other hand, nitrate deposits found in the playas of arid regions have proven economically mineable in terms of their nitrate salts.

The purpose of this study was to investigate the origin and distribution of nitrate concentrations found in and around two playas on the Nevada Test Site (NTS). In trying to determine their origin and distribution emphasis was placed on biological nitrogen fixation. Potential contribu- tions by precipitation, erosional transfer of soil nitrate to the playa by wind and water, and the weathering of parent rock materials were also considered.

PREVIOUS WORK Unusually high nitrate levels (up to 50 percent by weight) have been observed in the arid environments characteristic of Chilean solars (Ericksen, 1981) and in the soils 2 of the Nevada Test Site (Wallace, 1978; Hansen, 1978). Nitrate in the soil profile under aerated and arid conditions is unlikely as susceptible to denitrification as nitrate in more moderate environments (Westerman, 1978). Additionally, denitrifiers require organic carbon as an energy source necessary for the denitrification process. Carbon:nitrogen ratios of approximately 2:1 appear to provide the greatest denitrification rate (Westerman, 1978).

Hence, it is feasible that once the nitrate is formed in arid environments with low organic carbon content, it could remain stable indefinitely (Hunter, 1975). Limited research concerning nitrogen inputs to desert ecosystems has concentrated on individual mechanisms, ignor- ing the complexity of the total system. Research has been directed primarily towards influence of the biological components of the ecosystem as opposed to the combined effects of both physical and biological processes. As presented in Figure 1, nitrogen budgets in desert ecosystems are highly complex and by limiting investigation to one aspect of the total cycle would give an incomplete represen- tation of factors affecting nitrogen accumulation as well as losses. In order to understand the origin and distribution of nitrate in a given ecosystem, it is first necessary to delineate the various components in the system and make a few basic assumptions as to the main input sources of nitrogen 3

N2“ fixing bacteria and algae (roots) Denitrifying bacteria

N2-fixing ' * bacteria (soil) _ . NHoin soil Protein D e ^ r r fa n 9 - / w a t e r synthesis and soil fauna / N 03 by Soil (decomposing) nitrate bacteria nitrification bacteria I N 0 2 by nitrite bacteria

Figure 1. Desert Nitrogen Cycle (after West, 1981) 4 for the ecosystem in question.

Atmospheric nitrogen fixation by algal crusts is thought to be a major contributing source of nitrogen into desert ecosystems (Rychert, 1975). Possible additional sources of nitrogen include: precipitation and dry fallout, decomposition of plant and animal biomass, and contribution by parent rock material (West, 1975) .

As previously mentioned this investigation focused on nitrogen inputs via biological nitrogen fixation, precipitation, erosional transfer, and the weathering of parent rock material.

Biological Nitrogen Fixation

The biologic component of desert ecosystem is sensitive to environmental fluctuations and operates optimally within narrow environmental ranges (Wallace, 1978). Most of the research done has been related to deserts with standing biomass. Little has been done in "sterile" desert systems where no source of organic carbon is readily available (Ericksen, 1981). In relation to playas this poses a problem in that most research, in situ as well as laboratory studies show a direct correlation between the amount of biologically produced nitrogen and the amount of available carbon. It appears that the lower limit of available carbon necessary to support heterotrophic nitrogen fixing bacteria is approximately 3 percent (West, 1978). As previously 5 stated the low organic carbon content would also inhibit losses of nitrogen by heterotrophic denitrifying bacteria.

Other factors such as percent moisture and temperature are also extremely critical to the biological component of the system. Laboratory experiments have shown varying levels of optimum temperature and moisture for algal nitrogen fixation. It appears that optimum temperature ranges from 19- 23°C and moisture -1/3 bars or greater than 10 percent moisture by weight (Rychert, 1975; Sorensen, 1975).

Although the biological component functions optimally within narrow environmental ranges, it is also capable of withstanding extreme conditions by becoming dormant. R.E. Cameron (1966) found that a common species of blue-green algae (Nostoc) was easily revived with limited amounts of water after 100 years of dessication. He also found this species was capable of photosynthesis at -30°C. His study concluded that neither the population number nor the individual number of six different algal species common to desert soils were affected by continuous freezing for one to 48 hours at -79 to -195°C. Cameron found the same thing when subjecting these species to diurnal freeze thaw cycles at

-79 or -195°C for 24 or 168 hours. After such treatment Cameron found that all six species were capable of growth and reproduction when cultured in up to a 5 percent salt solution plus desert soil extract solution. 6

Nitrogen Fixation by Microorganisms Nitrogen fixation by desert algal-lichen crusts could constitute a major input of nitrogen into desert ecosystems.

Until recently the environmental and ecological parameters affecting.the biological fixation of nitrogen in arid ecosystems had never been assessed. Most research was conducted in mesoenvironments where factors such as temperature, moisture and organic carbon content were not limiting.

Nitrogen fixation in association with legume root nodules by Rhizobium is an important source of soil nitrogen. However, native legumes are seldom found in deserts and when present rarely have nodules associated with their roots. It is speculated that temperature, moisture, and available soil nutrients in deserts are limiting to nodule formation (Tchan and Beadle, 1955) .

Nitrogen fixation by free-living heterotrophic bacterial like Azotobacter and Clostridium is limited by the amount of soil moisture and available organic carbon. Low temperatures also inhibit population growth and hence, nitrogen fixation. Blue-green algae are the most important contributors of fixed nitrogen in desert ecosystems (Rychert, 1975). They possess the enzyme nitrogenase which is chemically responsible for the fixation of atmospheric nitrogen within the algal cell structure. Anabaena and Plectonema are nonheterocystous, filamentous blue-greens which may fix nitrogen 7 micro-aerophilically. Gloecapsa is a unicellular, nonheterocystous species capable of nitrogen fixation under aerobic and micro-aerophilic conditions. Nitrogen Fixation by Free-Living Blue-Green Algae and Lichen Symbionts

The majority of blue-green algae capable of fixing atmospheric nitrogen are heterocystous. An exception to this is Plectonema which is nonheterocystous and capable of fixing nitrogen micro-aerophilically but not in the presence of air. Algal species that fix nitrogen do so more effi- ciently in micro-environments where oxygen tension is reduced. This is the basis of the symbiotic relationship between the algae and lichen desert soil crusts. These cryptogramic crusts when wet provide a situation where the mycobiant respiration reduces the oxygen tension thus en- hancing the algae's ability to fix nitrogen. Algal-lichen crusts grow best on desert soils that are neutral to slightly alkaline. Mayland et al. (1966) found that algal crusts from the Sonoran Desert were capable of fixing nitrogen at a rate of 0.18 lb./acre/day under continuous wet conditions and were capable of producing 0.11 lb./acre/day under cycl- ing wet-dry conditions. Further studies showed that Sonoran Desert algal crusts from southern Arizona could produce detectable etheylene from acetylene three hours after moist- ening. Premoistened crusts were able to produce 78±5 nmoles of etheylene/cm2/hr based on the first hour of incubation. This leads to an estimation that algal-lichen crusts could

produce 3 to 4 grams nitrogen/ha/hr after a rainfall. Not- ing that approximately 4 percent of the desert's grassland

had crust formation, this is a substantial amount of nitrogen produced (MacGregor and Johnson, 1971).

Skujins (1974) found a peak value of 1Og nitrogen fixed/ha/hr between 0800 and 1000 hours in algal lichen

crusts of the Great Basin Desert. These values were recorded in the spring and suggest that the morning dew condensing

on the crust was sufficient moisture for nitrogen fixation.

As previously mentioned, N-fixation by moistened crusts drops rapidly when the water potential is below -1/3 bars. This suggests that N-fixation is maximum during summer rains

in the Sonoran Desert and in the fall and spring in the Great Basin Desert. Because the crust is capable of retain-

ing moisture longer than the rainy season, it is likely that

maximum fixation extends for longer periods of time.

Algal crusts act to reduce erosion, increase soil fer-

tility, and improve soil structure, hence, improve infiltra-

tion. In the Sonoran Desert algal crusts contain 400 percent more nitrogen than the soil below (Fletcher and Martin,

1948). Observed nitrogen levels in Nevada desert crusts in

the first 1.2 cm (0.5 inches) were twice as high as areas with no lichen crusts (West, 1978).

Atmospheric nitrogen fixation is optimal at about 200 y

einsteins/m2/sec of incandescent light intensity (Sorensen, 9

1975). While incandescent light is not directly comparable to natural sunlight, results indicate that N-fixation is optimal at low light intensities. Natural light with a heavy gray cloud cover exhibits light intensities of 50 to

300 y einsteins which is comparable to 200 y einsteins of incandescent light or 240-260 foot-candle flourescent light (Rychert, 1974; Sorensen, 1974).

Physical Inputs of Nitrogen to Desert Ecosystems Precipitation and Dry Fallout

Limited research has been done on the quantitative significance of these physical inputs of nitrogen to desert ecosystems (West, 1975). The following information has been derived from more general studies in urban and agricultural areas.

Eriksson (1952) reported 0.6 mg N/l of precipitation in the form of ammonium and 0.1 mg/1 as nitrate at Tashkent, USSR. Yaalon (1964) found the concentration of ammonium at a desert station in Israel varied from 0.16 epm (2.9 mg/1) in winter to 0.68 epm (12.0 mg/1) in the spring. He postu- lated that most of the ammonia evolved from high pH soils, when warmer temperatures stimulated the ammonification process. Junge (1958) found more ammonia coming from regions of alkaline soils over the United States, with more nitrate in rainfall over regions with acidic soils. The aforementioned studies are based only on precipitation and are probably 10

underestimations due to omission of the dry fallout component (West, 1975). Junge (1958) estimates that 70 percent of the atmospheric nitrogen contribution in arid climates comes from dry-fallout.

Skujins (1974) found that about 75 percent of the total nitrogen was in the particulate matter collected in automatic wet and dry gauges at Culew Valley, Utah. The heaviest input was as nitrate after a spring storm. He calculated the total nitrogen input via precipitation and dry fallout to be approximately 12 kg nitrogen per hectare per year. Similarly, Hunter (1976) estimated that precipitation in the northern Mojave Desert to contribute about 1 kg N/ha per year.

Nitrogen in Rocks

A considerable amount of nitrogen in sedimentary and igneous rocks occurs as ammonium ions held within the lat- tice structure of silicate minerals. Analyses indicate that the majority of nitrogen in igneous rocks and from 10 percent to 67 percent in sedimentary rocks (shales) occurs as fixed ammonium (Stevenson, 1962).

It was originally believed that nitrogen in rocks was in the form of NH^Cl or metallic nitrides (Urey, 1952), however, this is inconsistent with the finding that much of the nitrogen in rocks is in the form of nonexchangeable NH4+ 11

held within the silicate structure and can only be removed by drastic chemical treatment (Stevenson, 1959). Table 1 gives a summary of the amount of fixed NHtt+-N in igneous rocks. Table 1 Fixed Ammonium Nitrogen in Igneous Rocks Total KCl-extractable Fixed N NH,^ + nitrogen N H i, nitrogeen Loca t ion Description ___

14 82 • 1 Gran ite A Mt. Washington, New Hampshire Highly weathered 78 15 55-9 Granite B Desert Island, Maine Slightly weathered 34 3 89* 3 Granite C Graniteville, Vermont Unwea the red 28 6 8 1*8 Gran ite D Vermilion County, Illinois Pleistocene boulder, 33 moderately weathered

86*4 Granite E Vermilion County, Illinois Pleistocene boulder, 22 3 moderately weathered

2 90 • 0 Granite F Vermilion County, Illinois Pleistocene boulder, 20 moderately weathered

64 • 7 Granite G Stone Mountain, Georgia Muscovite-biotite granite 17 6 unweathered

77-2 Gran ite H Stone Mountain, Georgia Muscovite-biotite granite 57 13 weathered

80 • 8 Mica peridotite A Saline County, Illinois Native rock 104 20 8 6 1-9 Mica peridotite B Tompkins County, New York 2 1 1 9 5*2 Pegma t i te Black Hills, South Dakota 2 1 6 70 • 0 Basalt Vermilion County, Illinois Glacial drift 20 7 84 • 8 Porphyry Red Lodge, Montana 46 4 8 1*0 Gabbro Vermilion County, Illinois Glacial drift 2 1 1 90 • 9 Dun ite Jackson County, North Carolina Pre-Cambrian 1 1

From Stevenson, 1962

K) 13

STUDY AREA

REGIONAL SETTING

The Nevada Test Site (NTS) encompasses 1 ,350 square miles in the basin and range province in south-central Neva- da, approximately 70 miles northwest of Las Vegas (Figure

2) . The site was established to allow nuclear testing, both underground and atmospheric.

NTS consists primarily of three large valleys, Yucca,

Frenchman and Jackass Flats. These valleys are bordered by mountains and hills of relatively substantial relief (Figure

3) . Jackass Flat is associated with and receives drainage from the Forty-Mile Canyon and has an outlet to the southwest at an elevation of 2,688 ft. (815 m) above mean sea level (the lowest elevation on NTS). Frenchman and Yucca

Flats are closed basins with no outlets for surface water runoff or gravitational air flow at night. Both valleys contain terminal playas or dry lake beds (O'Farrell, 1976).

The smaller valleys, Mercury, Rock, Mid and Tonopah are subunits of the major drainage basins and are considered

"open" drainages (O'Farrell, 1976).

GEOLOGY OF THE NEVADA TEST SITE The geology of NTS is structurally complex owing to acute crustal deformation, significant folding, two thrust fault systems, and many normal faults (Eckel, 1968). NTS 14

100 200 SCALE, MILES

Figure 2. Location of Nevada Test Site (from O'Farrell, 1976) 15

Figure 3. Location of Study Site Areas on NTS (Modified from O'Farrell, 1976) 16 lies within the miogeosyncline belt of the Cordilleran geosyncline in which 37,000 (1120m) feet of marine sediments accumulated during the Precambrian and Paleozoic. During this time the Test Site was part of an elongated subsiding trough (Cordilleran geosyncline), the eastern part of which is characterized by carbonates and clastic sediments and is referred to as the miogeosyncline (Winograd, 1975).

The miogeosyncline sediments are fairly uniform with approximately seventeen Paleozoic formations and one of

Tertiary age. The Paleozoic formations consist primarily of limestone, dolomite, quartzite, shale and conglomerates. Approximately 30 percent of the outcrops on NTS are sedimentary in origin with the remainder being Tertiary volcanics

(O'Farrell, 1976). Two major thrust fault systems occurred during the

Mesozoic era in the eastern and southeastern parts of the region where most of the pre-Tertiary rocks are exposed. The thrust fault systems accompanied by massive uplifting and folding of the region were followed by volcanic deposition during the Tertiary. The central and western portions of the area were characterized by numerous volcanic centers which gave rise to five calderas (O'Farrell, 1976). The volcanic rocks are comprised of pyroclastics and lava flows of several rock types (Winograd, 1975). The Tertiary formations have a composite cross-section of more than 30,000 feet (9000 m) and represents the most widespread formation 17 on NTS (Eckel, 1968). During the middle to late Cenezoic another period of deformation occurred caused by normal block faulting which produced the basin and range topography.

Quaternary deposits are primarily mixtures of alluvium material (derived from bedrock areas), caliche, siltstone, and fanglamerates. The detrital material is washed downslope from the mountains and hills into the basins forming extensive bajadas (coalescing alluvial fans merging with the valley floor) which often terminate in a playa. Quaternary sediments range between 800 to 1500 feet (240 to 450 m) deep; however, in Yucca Flat they exceed 3800 feet (1150 m) in depth. The playas are characterized, almost entirely, by relatively impermeable fine silts and clays. The alluvium- filled basins comprise about 30 percent of the land area of

NTS (O'Farrell, 1976).

GEOMORPHOLOGY OF PLAYAS Playas and closed valleys are geologically unique in that they receive the entire interior drainage of both groundwater and surface water runoff. Because most playas are enclosed by topographic divides, they are the ultimate receptors of all chemical and suspended constituents carried by surface water runoff. Consequently, playas are important areas for the study of geomorphology and sedimentation, especially studies related to deposition (Motts, 1970).

Playas have four basic characteristics: (1) the area 18 occupies a basin or topographic valley of interior drainage;

(2) the area contains standing water infrequently and occurs in arid regions where evaporation exceeds precipitation; (3)

the playa surface is barren, smooth, flat and has a shallow

gradient; and (4) the size is usually large (usually more

than 2000 to 3000 feet [600-900m] in diameter)(Motts, 1970) .

Playas occupy the lowest part of topographically en-

closed valleys. A true playa is dry most of the time.

However, if the flooding ratio— the length of time water

remains in the valley per year— is greater than 0.66 the playa is considered a dry lake or lake, depending upon the

observer. Similarly, if the flooding ratio is 0.33 or less,

the valleys are referred to as playas (Motts, 1965).

The flooding ratio is more important than just defining

a playa because the amount of erosion and deposition is a

direct function of precipitation and runoff, hence, the potential amount of nitrogen brought to the playa.

The geomorphology of playas typical of the basin and

range province can be divided into three categories: allu-

vial slopes, desert flats, and playas. Alluvial slopes generally have gradients between 2° to 3°, however, some-

times they range to 7° (Thornbury, 1956). Alluvial slopes originate at the base of the mountain bedrock and grade to

the smoother slopes of the desert flats. Alluvial slopes

can be further subdivided into: (1) pediments, which are bedrock overlain by a thin (0-2 ft, 0-60cm) cover of alluvi- 19 um; or (2) bajadas, which are a series of coalescing fans underlain by thick alluvium. However, it is common for pediments to gradually merge into bajadas with little change in slope (Motts, 1970). The slopes of desert flats range from 13 to 100 feet per mile (2.5 to 19 meters per kilometer) with an average of 15 feet per mile (2.8 meters per kilometer) for larger flats and 50 feet (9.5 meters) for smaller flats (Clements, 1957). Desert flats extend from the base of the alluvial slopes to the edge of the playa and are usually underlain by thick bajada sediments. Desert flat sediments are composed of gravel and fine sands and vegetation characteristic of the desert biome is present. Playas unlike the desert flats are characteristically barren of vegetation and are categorized as "fine grained playas" and "coarse grained playas" (Figure 4). Fine grained playas are characterized by sediments ranging from medium silts to fine clays. These sediments were primarily deposited during the wet periods of the Pleistocene when considerable precipitation resulted in runoff bringing the finer grain sizes to the base of the valleys (Motts, 1970).

Frenchman and Yucca playas are "fine grained playas" which do not have elevated water tables (shallow depth to groundwater) due to thd characteristics of the sediments.

Usually the fine grained sediments are underlain by coarse grain alluvial aquifers and in the case of Yucca and French- man deeper carbonate aquifers. Figure 4. Block Diagram Showing Geomorphic Setting and Sedimentary Framework of Idealized Fine-Grained Playa (after Motts, 1970) 21

HYDROLOGY

In general, groundwater movement within the valley fill aquifers of intermontane basins in the Southwest is de- scribed as moving laterally from recharge areas in the mountains and flanks toward discharge areas in the playas, streams or adjacent valleys. The bedrock that flanks and underlies the valley fill is generally considered relatively impermeable compared to the valley fill. The valley-fill aquifers of Frenchman and Yucca Flats are bordered by rocks of Tertiary and older age; however, these valleys do not culminate in discharging or "wet" playas. Depth to the water table varies from 700 to 2000 ft (210 to 610 m) below the valley floors (Winograd, 1975).

Test drilling on Yucca and Frenchman Flats has revealed hydraulic communication between the valley-fill aquifer system and the deeper carbonate aquifer. The great depth to water in Frenchman and Yucca is due primarily to the drainage of water from the valley-fill aquifers downward to the underlying carbonate aquifers (Winograd, 1975). Meizner (1923) defines this condition as semi-perched groundwater,

Groundwater may be said to be semi-perched if it has greater pressure head than the underlying body of groundwater from which it is however not separated by an unsaturated rock...

CLIMATE The average annual precipitation on NTS ranges from about 4 inches at 2500 ft (760 m) on an average of less than 22

30 days a year to approximately 12 inches for 50 days a year at 7500 ft (2300 m). Precipitation varies markedly with the season and the frequency and amount vary as a direct function of elevation. Figure 5 shows a characteristic bimodal curve with peaks in the winter and a secondary peak in the middle to late summer. Winter precipitation originating from the Pacific is usually associated with low pressure systems which move over large areas and account for about 65 percent of the average annual precipitation at Yucca Flat

(Quiring, 1965). Summer precipitation is due mainly to moist convective air brought by southeasterly winds from the

Gulf of Mexico or from localized cyclonic lows developing over the Great Basin (Houghton, 1969).

Temperatures on the site are also primarily a function of elevation and topography with daytime temperatures increasing with decreasing elevation. The influence is exert- ed through the effect of wind on large exposed areas and drainage flow on sloping terrain. The effect of elevation and topography on temperature is reflected by average daily temeprature ranges of 6°C in January and 11°C in July at the

Rainier Mesa Station (elevation 7480 ft, 2270 m) compared to temperatures of 17°C in January and 22°C in July at Yucca

Flat (3924 ft, 1190 m). The Yucca station is at the edge of the playa in a closed basin with no outlet for gravitational air flow at night therefore, the air stagnation at night maximizes the effect of radiational cooling (Quiring, 1968). Figure 5. Normal and Means of Monthly Precipitation on Precipitation of Monthly and Means Normal 5.Figure

PRECIPITATION, IN INCHES 0.4 0.2 0.6 0. 1.0 1.2 8 - - - uc Flt att e ft 4 2 9 3 de (altitu lat F Yucca T (after1975)Winograd, NTS 64 (mean) 4 -6 8 5 9 1

764 3 stations) (3 4 57-6 9 1 Ne aa et Site Test vada

Jackass Flats (altitu de 3 6 1 0 ft) 0 1 6 3 de (altitu Flats Jackass 764 (mean) 4 57-6 9 1

At Yucca Flat the average daily maximum is 22°C with record extremes of 43°C. Temperatures in excess of 38°C are common between June and September. The average annual daily minimum is 3°C, however, record extremes of -26°C have been recorded. Temperatures at or around freezing have been recorded in all months except July and August (Quiring,

1968). A ten year climatological summary (1962-1971) for Yucca Flat is presented in Table 2.

VEGETATION

Variation in precipitation and temperature due to changes in elevation causes distinct differences in plant life. Creosote bush, burrow bush, and a variety of Yuccas are the dominant plants on the bajadas below 4000 ft (1200 m). Blackbush and Joshua trees are dominant at slightly higher elevations. Sagebrush, pinion pine and Juniper trees are the dominant flora at 6000 ft (1800 m) and are replaced by white fir and yellow pine above 7500 ft (2300 m) (Brad- ley, 1964). Figure 6 is a vegetation map of the Nevada Test Si te. Table 2 10-Year Climatological Summary (1962-1971) Yucca Plat, Nevada— Nevada Test Site

Temperature P recipitation (b) ( ® F) ( inches) M u u a) a) Averages Snow > (Ji o

t ise to Sun. D a ily Maximum D a ily Minimum M o n th ly G r e a t e s t A v e ra g e h M o n th ly IL e a st [M onthly (G r e a teD s t a ily A v e ra g e G r e a t eM s o t n th ly G r e a t eD s a t ily Average S u Sky n r Co-

J a n 52.1 20.8 36.5 .53 4.02 T 1.25 0.9 4.3 4.3 4.9 Feb 56.1 25.8 4 1.3 .84 3.55 T 1.16 1.9 17.4 6.2 5.0 Mar 60.9 27.7 44.3 .29 .60 .02 .38 2.0 7.5 4.5 4.8 Apr 67.8 34.4 5 1.1 .45 2.57 T 1.08 0.7 3.0 3.0 4.5 May 78.9 43.5 6 1.2 .24 1.62 T .86 0 T T 4.3 Jun 87.6 49.9 68.8 .2 1 1.13 T .45 0 0 0 3.0 Jul 96.1 57.0 76.6 .52 1.34 0 .77 0 0 0 3.0 Aug 95.0 58.1 76.6 .34 1.04 0 .35 0 0 0 3.0 Sep 86.4 46.7 6 6.5 .68 2.38 0 2.13 0 0 0 2 . 1 Oc t 76.1 36.9 56.5 . 1 3 .45 0 .42 0 T T 2.9 Nov 6 1.8 27.6 44.7 .7 1 3.02 0 1.10 0.5 4.8 2.3 4.8 Dec 50.7 19.9 35.3 .79 2.66 T 1.31 2.3 9.9 7.4 4.6

Ann 72.5 37.4 54.9 5.73 4.02 0 2.13 8.3 17.4 7.4 3.9

Modified from O'Farrell, 1967. T Trace, an amount too small to measure ( b) Sky cover is expressed in the range from 0 for no clouds to 10 when the sky is completely covered with clouds. Clear, partly cloudy are defined as average daytime to cloudiness of 0-3, 4-7, and 8-10 tenths, respectively. Ln i Figure 6. Vegetation Tyoes of the I-Ievada test >ite (f rora O'Farrell, 1976) 27

METHODOLOGY

SOIL SAMPLE COLLECTION

Soil samples from Frenchman and Yucca Flats were col-

lected on March 5 and 6, 1981. Samples were collected with

a hand auger or gasoline powered auger at 6 inch (15 cm)

intervals except for 0-1 inch (2.5 cm) or 0-2 inch (5.0 cm) surface samples. All samples were double bagged in heavy duty plastic soil collection bags. Upon collection all surface and 2-6 inch (5-15 cm) samples were placed in a cooler on ice. This was done to prevent any possible changes in the nitrogen species present since the majority of the samples were moist. Samples were stored in the laboratory at 4°C until analysis. At each site soil temperature was measured with a soil thermometer and air temperature noted. Soil temperatures ranged from 6.5 to 11°C and air temperature was approximately 11°C.

At the time of sample collection it was raining and snowing and water had been ponded on Yucca playa approximately 2-3 months. Frenchman Flat had standing water only in cracks present on the playa surface which made access out onto the playa possible. Yucca had water several inches in depth on the majority of the playa which limited sample collection to the fringes (Figure 7).

Samples were collected with respect to location on the fan with emphasis placed on trying to locate areas within

stream channels and between channels. However-, it was very difficult delineating the majority of the channels because

they were extremely shallow (i.e., 0.5 inch - 1.5 cm) and

the topography of the area had changed considerably since

1960 the most recent U.S.G.S. maps of the area. Additional

sampling problems on NTS occur due to the fact that in a large portion of the area is "offroad" travel is prohibited.

The eastern one-half of Frenchman Flat is part of the Nellis

Bombing range— no samples were collected from this area.

See Figures 8 and 9 for sample site locations. In addition

to soil profile samples, a soil core 0.75 inches (1.9 cm) in

diameter and 2.4 inches (6 cm) long was taken at each site.

Cores were corked with rubber stoppers on the bottom and

injectable serum bottle stoppers on the top. Cores were

collected for acetylene reduction analysis in the labora-

tory. At sites where algal crusts were apparent a crust

sample was taken and placed in double plastic bags. All

cores and crusts were placed on ice until return to the laboratory where they were frozen until analysis (Rychert, 1975).

Two distinct unweathered volcanic tuff samples from N-

Tunnels were also collected for laboratory nitrate analysis.

MEASUREMENT OF SOIL NITRATE

To analyze the soil samples for nitrate 25 grams of thoroughly mixed soil was weighed and diluted with 125 ml of distilled water. Samples were placed on a shaker tray and

\ / A Soil crust sample \ / • Soil profile sample V Stream channel

1 i—------i----- 1 0 1 Mile 0 1 Kilometer

Figure 9. Yucca Flat Sample Site Locations 32

agitated for thirty minutes. Soil—water extracts were then

centrifuged in a Sorvall SS-4 for 45 minutes at about 8300xG

and the supernatant was decanted. At this time the extract

was cooled to room temperature (22°C ± 2°C) and electrocon-

ductivity and pH readings were taken. Electroconductivity

standards were run with all the samples. The remaining

extract was frozen and submitted to the laboratory for nitrate analysis.

Laboratory analysis for nitrate was determined either

manually using the Brucine—Sulfanilic acid colorimetric procedure (EPA, method 352.1, 1979), or with the Coulter

Kem-O-Lab Automated colorimeter (EPA, method 354.1, 1979)

which utilizes a hydrozine reduction to produce nitrite with

subsequent diazotizing with sulfanilamide and coupling with

N-( Inaphythyl)-Etheylene Diamine to give a red Diazo dye

(personal communication, James Heidker).

Nitrite was analyzed colorimetrically with either the manual or automated Diazotization procedure. EPA controls

and 10 percent duplicates and spikes were run with each group of samples for quality control.

Data reduction was accomplished with either the Apple

II computer or the PDP 1103 computer utilizing a standard polynomial regression analysis program (personal communication, James Heidker).

SOIL MOISTURE

Percent moisture was determined on all 0-2 inch (0-5 33

cm) and 2-6 (5-15 cm) soil samples. Crucibles and soil

samples were weighed and placed in the drying oven for five

days at 104 C. Samples were then reweighed and the percent moisture calculated by weight difference.

WATER SAMPLE COLLECTION AND ANALYSIS

Water ponded on Yucca and Frenchman playas was collect-

ed in March of 1981 and frozen until submitted to the laboratory for analysis. Subsequent runoff water, playa ponded water, snow, precipitation, lysimeter water and natural leaks water from N-Tunnels were collected in January of 1982 and likewise frozen until analysis.

Analyses consisted of nitrate (Brucine Method, EPA, method 352.1, 1979), chloride (Coulter Kem-O-Lab, EPA, method 350.3, 1979), electroconductivity, and total dissolved solids (Standard Methods, 15th ed., method 209-B).

ACETYLENE REDUCTION ASSAY - GAS CHROMATOGRAPH ANALYSIS

Acetylene reduction is probably the best in situ technique for measuring nitrogen fixation. In the process of biologic fixation the enzyme nitrogenase catalyzes the reduction of N2 to 2NH3 or acetylene to etheylene. The reduction of N2 to 2NH3 requires the transfer of six electrons whereas, the reduction of acetylene to ethylene requires the transfer of two electrons. Therefore, the reduction of acetylene to ethylene occurs three times as fast as the reduction from N2 to 2NH3 and the molar ratio of ethylene to 34

2NH3 is 1.5. Similar data has been observed for various bacterial species, i • e. / Clostridiunt and Azobacter were

found to have of molar ratio of ethylene to 2NH3 of 1.25.

On a straight one to one basis in the reduction of N2 to NH3

the molar ratio would be three to one (three moles acetylene

reduced for every mole N2 reduced). Furthermore, one nano-

mole of is equal to 9.33 x 10~9 grams of nitrogen fixed (Rychert, 1975).

The acetylene reduction assay was derived from the

methodology of Rychert (1975). Soil, crust and core samples

were capped with injectable serum bottle stoppers and in-

jected with acetylene to 0.1 atmosphere (1.0 ml C2H2 in

serum bottles and 0.5 ml in cores). At this concentration

of acetylene, competitive inhibition by nitrogen (n 2) is

eliminated (Stewart, 1971). After the incubation period,

0.2 ml of gas was removed and analyzed on a model 1740 Vari- an gas chromatograph with a flame ionization detector.

Nitrogen (N2) was used as the carrier gas at a flow rate of

25 ml per minute, with a 0.125 inch (0.3 cm) x 6.0 ft (1.8 m) Poropack N column with 100 to 120 mesh, at 50°C. The

injection temperature was set at 55°C and the hydrogen flame detector at 90°C. The attenuation was set at 8 x 10-12 which allowed the reading of most ethylene peaks. Ethylene standards were run at the beginning of each set of assays.

Additionally, a 0.2 ml of gas was removed immediately after the samples were injected with acetylene to determine the 35

amount of ethylene contamination in the ©cstylsns.

A Varian model 20 strip chart recorder was used for

reading the ethylene and acetylene peaks. The chart speed

was eight, inches per hour. Peak height is not proportional

to sample volume injected, therefore, it is important to use

the sample volume for assay and standardization (Rychert,

1975). Purified ethylene (0.0005%, Matheson Co.) was used

for standardization and ethylene concentration was read from a standard curve.

NITROGEN FIXATION EXPERIMENT Soil Samples

All 0 to 2 inch (0-5 cm) soil samples were assayed for

their nitrogen fixation potential. One gram of sample was

weighed and placed in 10 ml serum bottles and capped with

injectable serum bottle stoppers. Distilled water was not added due to the fact that the percent moisture of the sam-

ples was near 10 percent or greater (Sorensen, 1975). Per-

cent moisture of the 0 to 2 inch (0-5 cm) soil samples are

presented in Appendix 2. Samples were allowed to acclimate

at 22°C in the dark for 30 minutes prior to assay. Nitrogen

fixation potential was determined by the acetylene reduction

technique derived from Stewart (1967). Acetylene was in-

jected to 0.1 atmospheres (1 ml C2H2).

Immediately after injection a gas sample was removed

(0.2 ml) using a gas tight syringe and analyzed for ethylene contamination; even the purest grade acetylene contains a 36

small amount of ethylene. Samples were then incubated in

the algal growth potential room at 22°C and a light inten-

sity of 240 foot-candle. After the allotted reaction period a gas sample (0.2 ml) was removed and assayed for ethylene.

Ethylene production was not observed in any of the 0 to

2 inch (0—5cm) soils after 2 hour and 24 hour assays. How- ever, some of the samples that had been assayed previously

and left on the laboratory counter for over one month at

room temperature and light intensity showed a green algal

mat growing on the soil surface. One sample was re-injected

with acetylene and reassayed for ethylene production— the

sample did produce detectable ethylene after a 24 hour incubation period.

Therefore, all 0-2 inch (0-5 cm) samples were reassayed. This time 2-3 drops of distilled water was added to each sample to create saturated conditions, and the samples were incubated for five days in the presence of light (240 foot-candle) at 22°C prior to assay. After five days the samples were innoculated with acetylene (0.1 atmospheres) and initial 0.2 ml sample withdrawn to determine ethylene contamination. The soil samples were allowed to incubate for 24 hours in the presence of acetylene. A final 0.2 ml sample was withdrawn and assayed for acetylene reduction.

Depending on the amount of acetylene reduced to ethylene, the nitrogen fixation potential based on the surface area of the soil in the serum bottle could be calculated as 37

follows:

Diameter of serum bottle = 1.5 cm

A = 1 .767 cm2 , .0001 767 m2 acres x 4046.9 = m2

acres = .0001767 m 2 = 4.37 x 10-8

4046.9

Therefore, nitrogen fixation potential is presented as grams nitrogen fixed per acre.

Crust and Soil Core Assays

Soil crusts were placed as to cover the bottom of a 10 ml serum bottle (4.37 x 10~8 acres). Soil crusts had been

frozen for 11 months prior to assay, therefore, the crusts

were moistened with two to three drops of distilled water

and allowed to incubate for 24 hours at 22°C and 240 foot-

candle fluorescent light prior to assay. After the 24 hour

acclimation period, acetylene was injected to 0.1 atmo-

spheres and an initial 0.2 ml gas sample was withdrawn to determine the amount of ethylene contamination. After the reaction period a 0.2 ml gas sample was withdrawn for ethylene analysis.

Soil cores (4.97 x 10-8 acres) were assayed using the same procedure employed in assaying the soil crusts.

Nitrogen Fixation Calculations

The surface area of the serum bottles and soil core tubes were 4.37 x 10-8 acres and 4.97 x 10-8 acres, respec- 38

tively. The following calculations were made to estimate

the amount of nitrogen (N2) fixed based on acetylene reduction :

66 * ^ N 2 ----- — ----- 2NH3

Therefore, to determine the relationship between C2Hit pro-

duced and grams nitrogen fixed, the following conversion was used. 1.0 nanomole = 1 mole N2 28.02x 10~9g N2 3 moles C2H1+ X ----SST5Ie N2--- = 9-33x10“ 9 grams N2

By multiplying the nanomoles found in a 0.2 ml sample

by 50 yields the total nanomoles in the serum bottle (10

ml). Likewise by multiplying by 25, the total nanomoles of in the cores can be determined.

Furthermore, 9.33 x 10-9g N nanomoles C2Hi+ x ------(4.37 x 10~8 acres) or (4.97 x 10-8 acres) equals nanomoles C2HLf x .214 (crust) or .188 (core) or grams nitrogen (n 2) fixed per acre.

The 0.0005 percent ethylene standard contained 22.3 nanomoles per 1.0 ml. Therefore, by running standards prior to each series of assays, a correlation between ethylene produced to peak height was determined.

Thus: (x)nanomole C^H^. standard mm(peak height of sample) x (x peak-freight standard x (50) or (25) x (.214) or (.188) = grams (n 2) fixed per acre. 39

SAMPLE PREPARATION FOR SOIL 15N ANALYSIS

The methodology used to extract the soil nitrate and

reduce it to ammonium salts used in 15n analysis was derived from Bremner (1965).

Soil samples with sufficiently high nitrate so that 10

mg of nitrogen could be collected were chosen for analysis.

An appropriate amount of soil was weighed and a 1 to 5 ex-

traction (1 part soil to 5 parts distilled water) was per-

formed on soils with nitrate concentrations greater than

1000 mg/kg. For soils with nitrate concentrations below 1000 mg/kg 1 to 2 extracts were performed.

The soil extracts were then centrifuged and a known volume of extract was decanted and adjusted to a volume of

400 ml with distilled water. The soil extracts plus dis-

tilled water were transferred to 1000 ml distillation flasks

and 3 gram MgO and 3 grams Devarda's alloy added. Samples

were distilled into 20 ml of 1 N HC1 to a final distillate

volume of 200 ml. The 200 ml distillates were evaporated on

a hot plate to final volume of approximately 10 ml. A small

portion of the 10 ml was analyzed with an ion selective

electrode using an Orion Research microprocessor ionalyzer/

901 to determine if the NHlt+-N concentrations were approximately 10 mg/ml, which is the desired concentration for running isotope ratio analysis (personal communication, Mary

Miller). Samples were placed in 20 ml glass ampules and sealed, then shipped to University of California-Davis for 40

isotope analysis. Samples were analyzed on a Micromass 602D stable isotope enrichment mass spectrometer.

BACTERIA GROWTH STUDY

Some photosynthetic bacteria are capable of fixing nitrogen (Carpenter, 1977). To determine if these bacteria

were present in the soils on and around the playas, growth

mediums were prepared to test for the purple nonsulfer bac-

teria ( Rhodospiri11aceae Athiorhodacea) and the green and purple sulfer bacteria (Chlorobiaceae Chlorobacteriaceae and Chromatatiaceae Thiorhodaceae). The mediums were prepared according to Wolfe. See Appendix 1 for the methodology of medium preparation. A one-half gram portion of soil from

the 0-2 inch (0-5 cm) soil samples was used to innoculate the growth mediums.

To test for the purple nonsulfer bacteria only medium one was used. No attempt to isolate by serial one ml dilutions in agar shakes of medium two or three was made (see Appendix 1).

No attempt was made to isolate because the experiment was conducted only to test for the presence of these bacteria in the soils. The exact species present and their population numbers were not viewed necessary, in that, the experiment was conducted as a qualitative assay for the determination of the presence or absence of bacteria capable of fixing nitrogen in the 0-2 inch (0-5 cm) soils. 41

Similarly, only a secondary enrichment was used to culture the green and purple sulfer bacteria. Appendix 1 gives the complete procedure if isolation and primary enrichments are desired. 4:2

RESULTS AND DISCUSSION

POTENTIAL SOURCES OF NITRATE IN PLAYA SOILS

Nitrate in Precipitation and Dry Fallout

Five precipitation samples from different mountains on

NTS were collected in the winter of 1982. Values are quite

variable with nitrate ranging from 0.04 ppm to 4.4 ppm,

percent N03-:TDS ranging from 2.2 to 7.9, and percent N03~: Cl- from 13.3 to 123.0 (Table 3).

Such variation, in part, could be due to the method of collection. Inverted garbage can lids with a central hole

were connected to a funnel with tygon tubing and a one way

valve that attached to a one gallon container were used to

collect the precipitation. Unfortunately, the major problem was windblown dust and pieces of vegetation which were tun- neled down into the collection containers and sometimes blocked flow in the tygon tubing.

Precipitation samples collected in the winter were collected every two months, and the samples reported in this study were frozen at the time of collection and kept frozen until analysis, reducing the possibility of changes in the water chemistry, especially nitrate values.

Samples showed great variability in the amount of sedi- ment in the precipitation sample which is partially evident by examining the TDS of the samples (Table 3). As was previously mentioned (Visser, 1964) found dust to be an Piute Traverse #3 2-9-32 110 881 .3 1.9 3.8 2.2 50.0 Piute Traverse 12 2-9-32 16.9 14‘ .3 .44 .8 3.1 55.0 Piute Traverse #1 2-9-32 1.6 1.01 .3 .04 .3 4.0 13.3 Rainier Mesa #1 2-9-32 18.3 IS1 .3 1.0 1.3 6.7 76.9 Captain Jack 2-9-32 69.4 56‘ .8 4.4 3.6 7.9 123.0 Snow from N tunnel too low to — 1-21-32 17 measure — .31 . .9 34.4 Snow from Shoshone Traverse too low to — 1 2-31 8 measure 1.7 — .09 5.30 Snow from Rainier Mesa too low to — 2-9-82 9.3 measure — .75 1.2 62.5 RUNOFF WATERS

Frenchman Flat 1-21-32 388 445 .76 12.9 15. 1 2.7 79.1 Whiterock Springs 3-6-81 104 92* .89 12.7 5.4 13.80 235 Captain Jack (upper) 104 86* .83 7.7 6.7 8.95 115 Captain Jack (lower) 103 84* .82 7.9 6. 1 9.4 129 PONDED WATERS Yucca Lake 3-6-31 213 173.5* .82 13.7 4. 1 7.9 334 Yucca Lake 1-21-82 196 131 .67 .49 2.9 .37 16.9 Frenchman Plat — — — ______3-6-81 1.95 WATER FROM N-TUNNEL

Ly3imeter water 1-21-82 245 151 .62 .09 5.0 .06 1.3 Natural leaks 41 1-21-82 183 115 .63 .30 4.8 .70 16.7 Natural leaks »2 1-21-82 194 130 .67 .71 5. 1 .55 13.9 44

important source of nitrate in rainwater and high correla-

tion between nitrate and the conductivity of rainwater.

This relationship is partially verified in the precipitation samples collected on NTS, where higher E.C. and TDS did

correspond to increased nitrate values. However, the Cap-

tain Jack sample with an E.C. of 69.4 had a higher nitrate

value (4.4 ppm) than the Pahute traverse #3 sample which had

an E.C. of 110. The nitrate value for the Pahute traverse sample was 1.9 ppm (Table 3).

In general, it could be stated that the amount of dust

in the precipitation does increase the nitrate content and

it was beneficial to confirm this variation. Precipitation

samples uncontaminated with dust would be unrepresentative of actual rainwater reaching the playa.

The three snow samples collected did not show as great

a variation in their nitrate values, with ppm nitrate vary-

ing from 0.09 to 0.75. Like the Captain Jack precipitation

sample, the snow sample also showed the highest nitrate

value and nitrate ratios (Table 3).

By examining the N03-, C1-, and percent N03- to TDS and Cl— in the precipitation samples (Table 3) and the soil

samples (Table 4), there seems to be some relationship be-

tween the Cl— values and percent nitrate to TDS in the pre-

cipitation and the 0-2 inch (0-5 cm) soil samples. This

could lead to the conclusion that the higher N03— , Cl— , and percent N03 to TDS and Cl— in the deeper soils is merely due Table 4. Soil sample analysis for soils analyzed for chloride

Sample FF-1 (0-2") 159 -636 9.1 2.5 FF-2 (0-2") 161 1 .4 363 0 2 644 16.8 5.0 2.6 FF-3 ( - ") 63 6 336 0 2 252 16.2 .5 6.4 249 FF-5 ( - ") 111 2.0 -8 0 2 444 65.3 14.7 3265 FF ( - ") 286 1,144 FF- 1 1 0 2 86.3 4.0 7.6 2158 ( - ") 186 744 19.0 2.6 FF-1 2 (0-2" 3.5 543 0 2 ) 614 2,456 1060.0 72.5 FF- 1 3 ( - ") 216 22.1 43.3 1462 0 2 864 2.5 2.6 884 YL-1 ( - ") 1 570 628 5.1 2.0 .8 YL-2 (0-2") 255 0 2 304 1,216 6.4 1 .5 YL-3 ( - ") 278 1,112 .5 428 YL-5 0 2 7.3 2.5 .7 292 ( - ") 49 196 10.4 FF-2 (1 .5-2 .0") 1200 1 .3 5.3 832 -6 4,370 2720 179 FF (1-1 .5 3540 62.3 1519 -6 ') 13,850 8060 510 58.2 FF (1 .5-2 .0') 3560 1580 -6 14,240 6860 540 48.2 1270 FF (2-2.5 ') 3050 12,200 6110 FF-7 0 470 50.1 1300 (1 .5-2 . ') 2080 8,320 4830 340 FF- 7 (2-2.5 1710 58.0 1420 ') 6,840 3250 270 47.6 FF-7 (2.5-3 .0) 1039 2210 210 1204 4,1 55 53.3 1052 *TDS = (E.C.) x (.8) x (5)

.§■ a 46

to leaching and the evaporative concentration of rainwater

at some depth below the soil surface. However, if this were

the case, it would follow that the percent N03— to Cl— in

the precipitation 0-2 inch (0-5 cm) soils, and the deeper

soils would show similar ratios. The assumption is that

NO3— and Cl— are both anions and extremely soluble in an

aqueous environment and if they are leached to some depth

and concentrated, their ratios should remain basically the

same. The percent N03— to Cl— in precipitation ranges from

13.3 to 123 whereas in the 0-2 inch (0-5 cm) soils this II m ratio varies from 249 to 3265 and in the deeper soils (1 to

3 ft— 30 to 90 cm) from 1052 to 1580 (Table 4). This would 0 I f indicate a definite enrichment of nitrogen to the soils from 1 i I mil s some source other than precipitation.

Nitrate in Runoff Water I jj wwtfi! Another potential source of nitrate in playa soils is nitrate transported to the playa in runoff waters. The

amount of nitrate potentially reaching the playas in runoff

water would vary yearly depending upon the number of storms,

their intensity and their rainfall distribution relative to the playa.

Runoff water collected in a small sump near Frenchman

Flat (Figure 10) contained 12.0 ppm nitrate; similarly,

runoff collected near Whiterock Springs contained 12.7 ppm nitrate. Nitrate values of runoff water collected from

Captain Jack Spring were 7.7 and 7.9 ppm (Table 3). 47

Figure 10. Runoff Water Collected in a Sump near Frenchman Flat 48

Discharge from Whitscock and Captain Jack doss not actually

teach Frenchman or Yucca playas, however, the data was pre-

sented as an estimate of the potential amount of nitrate in

runoff waters. Assuming runoff water that actually reaches the playas has similar chemical properties as the runoff

collected in this study and that waters reaching the playa

and possibly concentrating at some depth are a potential source of nitrate to the playa soils, then like precip-

itation the percent N03~ to Cl— ratio should be similar in the runoff and soil profiles. As is seen in Tables 3 and 4, this does not appear to be the case. Percent N03— to Cl— ranges from 79.1 to 235 in the runoff waters, from 249 to

3265 in the 0-2 inch (0-5 cm) soils, and from 1052 to 1580 in the deeper soils (1 to 3 ft— 30 to 90 cm). Therefore, it appears that the high nitrates found in these soils is not due entirely to an evaporative-concentrating phenomenon of nitrates reaching the playa via precipitation and runoff then leached and concentrated at some depth below the surface .

Nitrate in Water Ponded on the Playa Standing water on Yucca and Frenchman Flats has two possible sources. Precipitation that falls directly on the playa and runoff water that reaches the playa. Water collected in March of 1981 from Yucca playa had much higher nitrate, percent nitrate to TDS and percent nitrate to chloride ratios than the samples collected in January of 49

1982. The values were:

March 1981 January 1982 n o 3 13.7 ppm 0.49 ppm

%N03- to TDS 7.9 37

%N03- to Cl- 334 1 6.9 Water collected in March 1981 had been ponded for a longer

period of time than in January 1982 (approximately 3 months as opposed to a month or less). If the E.C., chloride,

nitrate, and percent N03— to Cl— values are examined (TDS is

not a good indicator in that two different methods were used

to calculate it), the only real difference exists in the

nitrate and percent N03- to Cl- values. The small variation

in the E.C. and chloride values is probably due to the increased evaporation of the water as it sat for three months in the winter of 1981. Comparisons of the water chemistry of the ponded water vs. precipitation and runoff reveals similarities in the chloride concentrations of the waters ponded in 1981 and 1982 with the chloride concentrations of precipitation. In contrast, only the nitrate concentration of water ponded in the winter of 1982 resembles the nitrate levels in precipitation. The water that had been ponded for approximately 3 months in the winter of 1981 has approximately 28 times as much nitrate as does the precipitation. Additionally, the nitrate concentration of the ponded water exceeds that of the runoff waters, 13.7 ppm vs. an average of 10.0. Similarly, the percent N03— to Cl— ratio of the 50

1981 ponded water is 334 as compared to a maximum of 235 for

runoff waters and 123 for precipitation (Table 3.).

The increased nitrate concentration in the water ponded on Yucca playa in the winter of 1981 appears to be due to

the fact that water had been present on the playa for a

longer period of time, allowing the algal mat on the playa

surface more time for nitrogen fixation. This appears to be

the case, in that, the chloride concentrations of the 0-2

inch (0-5 cm) soil samples collected on the playa and the

ponded water samples are similar in both years. However,

the nitrate concentrations and percent nitrate to chloride

ratios show large variations. Soils collected in March 1981

when water had been ponded for approximately three months

had an average nitrate concentration of 6.3 mg/kg vs. 13.7

mg/kg in the ponded water from the same year. The fact that

the nitrate concentration in the ponded water is twice as

high as in the soils could be due to the fact that the ni-

trogen is fixed and oxidized on the surface of the playa where the algal mat is present, and then owing to the high solubility of nitrate it goes into solution in the water ponded on the playa surface. On the other hand, the nitrate concentrations and the percent nitrate to chloride ratios of the water ponded for approximately one month in 1982 are extremely low in comparison to the 1981 values, possibly indicating that the algal mat had had less time for nitrogen fixation. 51

Nitrate in Waters Issuing from Bedrock

Bedrock was also considered as a possible contributing source of nitrate to the playas in that ammonium could be

leached from the surrounding parent rocks oxidized and brought to the playa in runoff waters.

Lysimeter water and natural leaks water were collected from N-Tunnel. N-Tunnel is under Rainier Mesa and consists

of varying tuff beds. The purpose of collecting samples

here was that the site consists of miles of tunnels unex-

posed to years of surface weathering, therefore, the potential contribution of nitrogen by parent rock could be assessed .

Water from the tunnel lysimeter showed a much lower nitrate value than water collectd from the natural leaks liilf (0.09 ppm vs. 0.71 and 0.81 ppm), however, the chloride m

content was essentially the same, 5.0 ppm for the lysimeter

water vs. 4.8 and 5.1 for the natural leaks water (see Table

3). Possible explanations of the discrepancy in the nitrate

concentrations could be: (1) that the water collected in

the lysimeter is drained strictly through bedrock (the ly-

simeter was placed twenty feet into the tunnel wall), and

therefore, is not in contact with atmosphere or the outer

surface of the tunnel walls and does not have the potential

to be oxidized as does the natural leaks water collected

after it has flowed down the tunnel walls and collected in pipes. Hence, the nitrogen in the lysimeter water may be 52

primarily in the form of ammonium. This would follow in

that nitrogen in primary rocks is in the form of ammonium

(Stevenson, 1962); (2) Water collected at the natural leaks #2 site flowed over a wall covered by algae. This site is

also well ventilated, receiving fresh air from the exterior

of the tunnel. If there are blue—green algae on the tunnel w^ll they could be potentially fixing nitrogen which is

possibly oxidized to nitrate as the water flows from the

wall to the collecting pipes. H i

Data from the springs (Table 5) is only reported as it Is indicates the potential contribution of nitrogen from Kite groundwater flowing through bedrock and alluvium. This water never reaches Frenchman or Yucca Flats. The small ' amount of runoff from these springs rarely travels very far

(generally less than 170 ft— 50 m) before it evaporates and/ yMvwiip:] or infiltrates (personal communication, John Edkins). It is possible that subsequent runoff events could slowly move this nitrate towards the playa, however, plant uptake and denitrification over the great distance to the playas probably accounts for all the available nitrate.

SOIL NITRATE

Nitrate vs. TPS

All soil samples were analyzed for both nitrate and electroconductivity. In order to view the high nitrate values found in some of the soils, it was decided to consid- er them in relation to the total soluble salts in the soils Table 5. Water Sample Analyses (Springs)

E.C./TDS Sample TDS (mq/kg) Conversion NO,— Cl~ (Date) E.C. *TDS by 1 Factor (mg/kq) (mg/kq) % NO,-/TDS % NO,-/Cl Whiterock Springs 1-14-81 254 201* .79 7.75 12.0 3.9 64.6 Oak Springs 1-14-81 230 182* .79 1.02 8.7 .56 11.7 Cane Springs 1-14-81 440 315* .72 15.9 20.3 5. 1 78.3 Whiterock Springs 3-5-81 233 183* .79 9.3 10. 1 5. 1 92. 1 Cane Springs 3-5-81 433 311* .72 13.6 20.1 4.4 67.7 Oak Springs 3-18-81 230 184* .80 5.5 8.9 3.0 61.8 Tippipah Springs 3-18-81 209 175* .84 9.3 7.7 5.3 121.0 Topapah Springs 3-19-81 1 19 122* 1.0 5.1 3.2 4.2 222.0 Topapah Springs 5-5-81 108 1 19* 1 . 1 .31 1.6 .26 19.4 Tippipah Springs 5-5-81 208 176* .85 5.7 8.0 3.2 71.3 54

to see if nitrate and other salts were concentrated due to the evaporation of precipitation and runoff water. The

electroconductivity (E.C.) was converted to TDS by an empir-

ical factor of 0.8. In most natural water systems the rela-

tionship of E.C. to TDS generally ranges from 0.6 to 1.0

(Hem, 1970). TDS was not analytically determined due to the

sample volume, however, three duplicate samples were run for

nitrate, E.C., and TDS and the actual relationship between

E.C. and TDS ranged from .73 to 1.1. Unfortunately, error

exists in the 1.1 value, in that, when the sample was fil-

tered through a 0.45ym filter, it still remained cloudy,

hence picking up suspended solids which increased the actual

TDS value, thereby increasing the relationship of E.C. to TDS.

Percent nitrate to TDS ratios were generally lower in

the 0 to 2 inch (0-5 cm) soil interval and increased with

depth. This tends to lend evidence to the fact that water

reaching the playa is slowly leached downward. The depth to which the water is leached is probably dependent on the

nature of the playa soils (i.e., how fine grained and/or

whether a hardpan is present). The nitrate, TDS and percent

nitrate to TDS of the soil profiles are reported in Appendix

III. Soil profiles with low nitrate values generally had corresponding low TDS values and for the most part had low percent nitrate to TDS ratios. Examples are FF-2, FF-3, FF-

13, YL-1, YL-5. In these samples the percent nitrate to TDS 55

ranged from .07 to 15.6. However, in profiles where nitrate

might be being concentrated the percent nitrate to TDS is

greatly elevated. Good examples are FF-4 and FF-5. in both

profiles the percent nitrate to TDS values are low in the

first 2 feet (60 cm) and then increase at around the 2.5

foot (75 cm) interval. Percent nitrate to TDS at the depth

interval where the maximum concentration of nitrate was

found for all sample sites on and around Frenchman Flat

varied from 6.4 to 65 percent, and on Yucca Flat from 5.3 to

52 percent. Figures 11-14 graphically show the relationship between nitrate and TDS within the soil profiles. For the most part the nitrate plot closely resembles the TDS plot which would be expected in that nitrate is a constituent of

TDS, although generally not a major one in desert ecosystems. This would seem to suggest that the nitrate in the playa soils is a leaching and evaporative process of waters that reach the playa surface. Only by looking at the unusually high percent nitrate to TDS in the playa soils does it seem unlikely that these nitrate concentrations are due strictly to the evaporation of waters reaching the playa.

As previously discussed, this is further exemplified when the percent nitrate to TDS values of precipitation, water ponded on the playa, and runoff waters are examined.

Nitrate vs. Chloride

Based on the fact that the TDS values obtained might be consistently lower that the actual values due to the fact iue 11. Figure TDS TDS DEPTH 10 20 30 40 SO 60 70 80 90 10,000 11,000 12.00013,000 14,000 9000 8000 7000 6000 SOOO 4000 3000 2000 1000 0 irt adTtl isle Sld vru Dph t tto Yca ae #3 Lake Yucca Station at Depth versus Solids Dissolved Total and Nitrate DEPTH Nitrate and Total Dissolved Solids versus Depth at Station Frenchman Flat #6 iue 14. Figure irt adTtl isle Sld vru Dph t tto rnha Fa #13 Flat Frenchman Station at Depth versus Solids Dissolved Total and Nitrate TDS TDS DEPTH 10 0 30 0 00 0 70 0 80 1000 800 800 700 000 000 400 300 200 100 0 60

that the carbonates are precipitated and not soluble in a

five to one dilution at a pH between 7.0 and 9.0, it was

decided to compare percent nitrate to chloride ratios.

Similar logic was used in that if the high nitrates are

merely a function of evaporation and concentration of waters reaching the playa, then in general the average nitrate to

chloride ratios of the precipitation, ponded water, and

runoff would closely approximate the nitrate to chloride

ratios in the soil column. Due to economic constraints,

analysis for chloride was primarily run on the 0 to 2 inch

(0-5 cm) soil samples, however, seven samples at depths

corresponding to high nitrate values were also analyzed for chloride.

The percent nitrate to chloride ratios for the 0 to 2

inch (0-5 cm) soils ranged from 249 to 3265 with an average

of 922. For the 1.0 to 3.0 samples (30-90 cm) the ratios

ranged from 1052 to 1580 with an average of 1335. The great

variability in the nitrate to chloride ratios in the 0 to 2

inch (0-5 cm) soils is not completely understood. However,

no algal or algal lichen crust was observed at the site

representative of the lowest ratio (FF-3). Conversely, the

highest nitrate-chloride ratio corresponded to a site with a very active algal crust (FF-5). Percent nitrate to chloride

ratios for soil samples which were analyzed for chloride are presented in Table 4. As previously discussed, by examining the nitrate to chloride ratios in the ponded water, runoff 61

waters, precipitation and water issuing from bedrock (Tables

3 and 5) there appears to be little relationship between

these ratios and the ratios found in the soil profiles.

This would tend to support the theory that it is unlikely

that the high nitrate levels found in these playas are due

strictly to the evaporation and concentration of waters reaching the playas.

Nitrate in the Soil Profile

In general, nitrate concentration within the individual

soil profiles increased with depth, generally maximizing at

the 2.0-3.0 foot (60-90 cm) interval. Soils from the bajada

sites (FF-1, 5, YL-1, 5) were consistently lower in nitrate

than soils collected directly on the playa (FF-6, 7, 8, 11,

12 and YL-2, 3, 6). Chemical analysis for all the soil profiles is reported in Appendix IV. Soil profiles from the bajada sites showed large variations in their nitrate concentrations. However, samples collected from apparent channel beds (FF-2, 3, 13 and YL-5) where coarse alluvial soils predominated were much lower in nitrate than sample sites between beds where the soils were a mixture of the fine silts and clays of the playa and the alluvial fan material.

Nitrate variations in the bajada and playa soils at corresponding depths are presented in Appendix V. The explanation to the fact that the bajada soils are generally lower in nitrate than the playa soils appears to be two-fold. First, in the bajada soils characterized by a mixture of alluvial 62 material and the fine grained sediments, nitrate is more susceptible to downward as well a transverse leaching by precipitation and runoff. Depending on the intensity and freguency of the storm events, hence runoff velocity and volume, the bajada soils and their chemical constituents are moved downslope and ultimately transported to the playa. A playa is a depositional phenomenon with essentially no slope, therefore, the nitrate reaching the playa in runoff waters, precipitation and what is fixed by blue-green algae directly on the playa is only susceptible to potential downward leaching. A playa essentially acts as a sink for all waters and sediments reaching it. As previously mentioned, playa soils are characterized by fine silts and clays are more likely to have associated hardpans (Motts, 1970) which could concentrate the leached nitrate at some depth from the surface, in this study generally from 6 inches to 1.5 feet (15-46 cm).

Second, it is possible that the nitrogen being fixed by blue-green algae on the bajada is more susceptible to denitrification than the nitrogen fixed directly on the playa.

As previously stated, denitrifying bacteria are heterotrophic and require an organic carbon source. Noting that these playas are barren and the total organic carbon in these soils is low ranging from 7.0 to 19.0 ppm for the soils analyzed for their organic carbon content (Appendix

IX) , it is possible that the playa environment is inhospit- able to denitrifying bacteria. Based on the high nitrate

concentrations found in these playas, this appears to be an important consideration (Hunter, 1975).

On the other hand, denitrification may play more of an important role on the bajadas which have vegetation growing

on them, hence a potential source of organic carbon for the denitrifying bacteria. Additionally, plant uptake of nitrogen would also remove nitrate from the soil. However, Wal- lace (1978) proposes that the nitrogen fixation on the bajadas exceeds the need of the plant community.

Therefore, the lower nitrate values found on the bajada are probably due to erosional losses and possibly losses due to denitrification. Similarly, the high nitrate concentrations found in the playas probably represents a continual input over centuries of nitrogen fixed on the bajadas and brought to the playa in runoff waters (Wallace, 1978). Additional nitrogen fixed on the playa by blue-green algae plus nitrate contributed via precipitation and dry fallout add to the potential nitrate which accumulates in the playa soils.

Nitrate Accumulation vs. pH Nitrification is the biological process by which nitrite and nitrate are formed from ammonium in a two-step oxidation process involving two distinct species of autotro- phic nitrifying bacteria. 64

Nitrosomonas NH1++ + 3/2 02 ------N02- + 2H+ + H20 Nitrobacter N02- + 1/2 02 ------N03-

Nitrosomonas oxidizes ammonium best in soils having pH

values above 7.6 whereas maximum nitrification rates are

achieved by Nitrobacter between pH 6.2 to 7.0. However,

strains from higher pH soils have been found to have higher

pH optima (Skujins, 1978). In the oxidation of ammonium by

Nitrosomonas one nitrite ion and two hydrogen ions are pro-

duced. Depending on the amount of ammonium being oxidized,

there is a two-fold release of hydrogen ions which could

potentially lower the pH of the soil creating an environment

conducive for the oxidation of nitrite to nitrate by Nitro-

bacter .

Based on the nitrogen fixation potential of the crusts

and cores, hence ammonium addition to the soils, it was de-

cided to compare pH vs. nitrate concentration. Similar to

the percent nitrate to TDS and chloride comparisons, if the

high nitrate accumulations are due primarily to the concen-

tration of nitrate in waters reaching the playa, then it

would seem unlikely that the pH of the soil would decrease

significantly. Conversely, if the nitrate accumulations are due to bacterial oxidation of the nitrogen fixed by the

algal crusts and mats, then a decrease in soil pH would be expected. It could be argued that ammonium is present in 65

precipitation and released by the weathering of parent rock

material and available to the bacteria for oxidation which

would also lead to a pH decrease. However, based on the

extremely high nitrogen fixation potential of the crusts

(Table 6), it would seem unlikely that ammonium in precipi-

tation and parent rock would be the major source of ammonium to the system.

In order to try and delineate whether the nitrate found in the playa soils is due to nitrate reaching the playa

soils via physical inputs and concentrated or being fixed by

algae and oxidized biologically, it was decided to plot

nitrate concentration vs. depth and see if a pH decrease in

the soil is evident (Figures 15-17). The pH of the 0-2 inch

(0-5 cm) soils where nitrates were generally lower than in

the deeper soils ranged from 8.0 to 9.05. With increased

depth and an increase in nitrate concentrations, in some of

the profiles a decrease in pH is observed. The pH shift is most obvious in the 1 to 3 foot (31-91 cm) soil intervals.

As is seen in the 2-2.5 foot (61-76 cm) graph, soils low in nitrate had pH values between 9.2 to 9.6 whereas soils high

in nitrate (2000-6000 mg/kg) had associated pH values from 7.05 to 7.6. There is great variability in the graphs which in part is due to the variability of nitrate within the individual soil profiles. For example, the maximum nitrate concentration in FF-12 is in the 2-6 inch (5-15 cm) interval whereas the maximum concentration in the FF-1 soil Table 6. Grust Asa ay (I day nnd 7 day Incubation)

Incubation Assay Crams H Fixed 24 Ilr C.ll (Varna N Fixed Assay 2 Ilr (Til Crams N Fixed H i F i n r drams N Fixed Sample Date Date ProducflVn per Acrl/2 lbs Production per Acre/26 lira tiute Production per Acre/2 lira Production per Acr?/26 lira

FF-4 f l 2-16-82 2-17-82 — — 1.25 n moles 13.4 2-23-82 2.60 n moles 25.68 65.6 n moles 488.0

FF-4 12 2-16-82 2-17-82 — — 2.06 n moles 21.8 2-23-82 5.69 n moles 58.74 77.9 n moles 834.0

FF-5 #1 2-16-82 2-17-82 — — 1.36 n moles 14.6 2-23-82 9.09 n moles 97.26 171.0 n moles 1.830.0

FF-5 12 2-16-82 2-17-82 •39 n moles 4.17 1.56 n moles 16.5 2-23-82 17.8 n moles 190.89 329.0 n moles 3.520.0

FF-13 f l 2-16-82 2-17-82 .66 n moles 7.06 19.2 n moles 205.0 2-23-82 9.66 n moles 101.01 130.0 n moles 1.390.0 • FF-13 12 2-16-82 2-17-82 2.10 n moles 22.5 23.2 n moles 248.0 2-23-82 13.6 n moles 143.17 1120.0 n moles 11.900.0

YL-4 f l 2-16-82 2-17-82 .53 n moles 5.67 1.69 n moles 18.1 2-23-82 1.71 n moles 18.30 3.56 n moles 37.9

Y M 12 2-16-82 2-17-82 .26 n moles 2.78 1.61 n moles 17.2 2-23-82 1.20 n moles 12.84 6.86 n moles 52.3

FF-6 f l 3-7-82 3-8-82 — — — — 2-15-82 .28 n moles 3.00 40.9 n moles 438.0

12 — FF-6 3-7-82 3-8-82 — — — 2-15-82 6. 8 n moles 52.22 131.0 n moles 1,600.0 FF-2 f l 3-7-82 3-8-82 .65 n moles 4.82 6.61 n moles 47.2 2-15-82 20.1 n moles 214.75 3317*0 n moles 3.610.0 12 FF-2 3-7-82 3-8-82 10.3 n moles 110.0 76.6 n moles 819.0 2-15-82 267.0 n moles 2645.56 >6310.0 n moles >46,100.0

YL-3 f l 3-7-82 3-8-82 — — — — 2-15-82 — --- 23.4 250.0

12 — — Ytr-3 3-7-82 3-8-82 — --- 2-15-82 --- — — —

YL-2 f l 3-7-82 3-8-82 — — — — 3-26-83 — __ __ —

YL-2 12 — 3-7-82 3-8-82 --- — _ 2-15-82 __ ...

CT\ 67

Figure 15. Nitrate versus pH at Soil Depths of 0-2 inches 68

Figure 16. Nitrate versus pH at Soil Depths of 1.0-1.5 feet 69

to FF-

o o o o o o o o (6>|/BUI) _®0N

Figure 17. Nitrate versus pH at Soil Depths of 2.0-2.5 feet 70

profile is at the 1.5 to 2.0 foot (46-61 cm) interval.

Additionally/ the individual profiles had variable pH

values. The pH of the FF-6 soil profile dropped from 8.6 at

the surface to 7.75 at the 1-1.5 foot (31-46 cm) interval

where the maximum nitrate concentration occurred. On the

other hand, the soil profile of FF-3 shows a complete rever-

sal. In this sample nitrate was low through the entire soil

profile (from .66 to 16.2 mg/kg) with the highest value in

the 0-2 inch (0-5 cm) interval and the pH increased with

depth with values increasing from 8.93 to 9.5. Additional-

ly, there are some profiles where a definite increase in

nitrate does not correspond to a decrease in pH. The ni-

trate concentration of FF-4 maximizes at the 2.5-3.0 foot

(76-91 cm) interval. However, the pH of the soil is 9.45.

However, as is seen in Figures 15-17, there appears to be a general shift in pH as nitrate concentrations increase with pH decreases from around 9.0 to 7.0. This lends evidence to the theory that atmospheric nitrogen is being fixed and then oxidized by bacteria to nitrate.

ACETYLENE REDUCTION ASSAY

In the gas chromatography assay for ethylene and acetylene, the retention time for ethylene was 1.5 minutes and

3.0 minutes for acetylene. It was found that the ethylene standards varied daily, therefore, instead of using one ethylene standard curve to determine the peak height of the

0.5 ml sample used in the calculation of nitrogen fixation, 71

standards were run daily. Rychert (1975) reported that the

rate of acetylene reduction was essentially linear between

two and 24 hours, however, when the samples in this study

were assayed at two hours, then again at 24 hours, this was

not the case. To test this observation, one active crust

sample was assayed at 1 hour, 2 hours , 3 hours, and 24 hours, the results are as follows:

nmoles N, fixed grams N, fixed/acre

1 hour 66.0 707.0 2 hours 874.0 1300.0

3 hours 1400.0 2090.0 24 hours 2160.0 23100.0 Acetylene reduction was essentially linear for the first

three hours, however, from three to 24 hours this relationship does not hold true.

Rychert (1975) also found that a crust sample collected

in October exhibited a slight lag in acetylene reduction

when compared to a sample collected in July. He concludes

that the presence or absence of lag may depend upon such

factors as endogenous levels of ATP, concentration of ammonium, or reducing substances. These factors may be a function of the drying conditions, i.e., slower drying under lower temperatures and light intensities may have a significantly different effect than rapid drying under higher temperatures and light intensities.

Because acetylene reduction is not linear for 24 hours, 72 it is not possible to extrapolate back to get fixation for an 8-10 hour day when light is available for fixation.

Therefore, nitrogen fixation potential will be expressed for 2 hour and 24 hour assays.

Acetylene Reduction by 0-2 inch Soil Samples

Initially all 0-2 inch (0-5 cm) soils were weighed, placed in serum bottles and allowed to incubate at 22°C and

240 foot-candle for one-half hour prior to 2 hour and 24 hour assays. These soils did not reduce acetylene.

As previously stated, some serum bottles that had sat on the lab counter for over one month had a green algal mat growing on the soil surface. Therefore, the 0 to 2 inch soil samples were reassayed with 2-3 drops of distilled water added. These soils were allowed to incubate for 5 days prior to the 2 hour and 24 hour assay. Of the thirty- two samples (sixteen in duplicate), none produced detectable ethylene in the 2 hour assay and only two produced ethylene in the 24 hour assay. Of the two soil samples that did, only one of each duplicate produced ethylene. Frenchman

Flat #5 fixed 73.97 g N2/acre/day and FF #1 fixed 16.70g

N2/acre/day. Subsequent observations of serum bottles left in the lab after assay also revealed the presence of algae growing on the soil surface. It is quite possible that algae is present in the majority of the 0 to 2 inch soil samples.

However, because of the volume of soil collected, the algae 73 in the uppermost part of the soil is probably so diluted that it takes more than 5 days for the population to increase to a high enough density that acetylene reduction can be detected.

It is impossible to judge how many of the soils actually contained algae capable of fixing nitrogen in that many of the serum bottles were washed after the 5 day assay to be reused in following assays.

Additionally, whether the algal population is great enough during the winter and late summer wet seasons to fix appreciable amounts of nitrogen is also not known.

Upon microscopic examination the major algal species present in the 0 to 2 inch soils was the blue-green algae

Oscillatoria (personal communication, Sandra Cooper).

Acetylene Reduction by Crust Samples

Three types of crusts capable of fixing nitrogen were found on and around Frenchman and Yucca Flats. At bajada sample sites characterized by the fine silt and clay sediments of the older dry lake beds (when the present day playas had a much larger areal extent) that now have vegetation and some alluvial sediments associated with their sur- faces, the algal crust was a leathery organic layer that looked like a dry cracked clay surface (Figure 18). Only by picking up the crust did one find that it was very cohesive, yet spongy and bendable, like a soft piece of leather. The crust appeared the same color as the soil, however, when

water was added to the crust it turned bright green within a few hours. Frenchman Flat sites 2, 4, 5, and 6 were characteristic of this type of crust.

The second type of crust found was associated more with the alluvial sediments of the bajada. These soils were a

mixture of gravel and fine sediments with the surface typi-

cally covered with rocks and vegetation. At these sites a black algal-lichen crust was observed. At Frenchman Flat

#13 (the site was in a stream channel) this black algal-

lichen crust was the only type of crust observed; however,

at Frenchman Flat #4 and #5 the algal-lichen crust was found

in conjunction with the leathery algal crust. The third

type of algal crust found to fix nitrogen was the algae growing on the playa surface (Figure 19). In the winter of

1981 algae on the playa surface was only observed on Yucca playa due to the fact that Frenchman Flat was mostly dry at the time. Algae on Yucca was observed on the periphery

(Y.L. #3 and 4) where the soil was saturaterd. It was probably growing on all parts of the playa surface covered by water although, due to the depth and murky color of the water, visual determination of the extent of the algal cover was impossible. In January of 1982 the water on Yucca playa was not as deep or murky and examination of the west-central part of the playa revealed approximately a 90 percent algal cover where water was ponded.

Upon microscopic examination of the algal crusts from Figure 19 Algal Mat on Playa Surface 77 the bajada the predominant species present was the blue- green algae Oscillatoria. Two other species of blue-green algae of equal dominance were also observed growing on the playa surface. These species were similar to Oscillatoria although one species had a mucilage sheath surrounding a single filament and the other had a mucilage sheath surrounding a bundle of filaments (personal communication, Sandra Cooper).

Of all the algal crusts collected only one (Y.L. #2) did not fix nitrogen after 7 days incubation under optimum conditions. Yucca Lake #2 was collected at the fan-playa interface. Crust samples collected approximately 100 yards further out onto the playa where the surface of the soil was saturated did fix nitrogen.

Great variability exists in the potential of the crusts to fix nitrogen. For the 7 day incubation and 24 hour assay grams N2 fixed per acre varied from 37.9 to greater than

46100.0 (see Table 6 for the results of the crust nitrogen fixation assay). The lowest nitrogen fixation potential was observed in the crust from Yucca Lake #4. This site was directly on the playa and an extensive algal mat was present when the crust was collected. Additionally, great variability exists between the different crusts' potential to fix nitrogen as well as between the duplicate crust sample's potential. There are a few possible explanations for the difference between the variability in the duplicate samples 78 and the orders of magnitude difference between different crusts. First, these samples were collected wet and were frozen until analysis— approximately one year. Due to freezing the algal population became dormant, hence when samples were removed from the freezer and subsamples removed to be placed into the serum bottles for assay, the distinct morphological characteristics of the algal crusts were not apparent. This problem was more crucial when choosing samples from the playas for assay. Since no distinct "crust" exists on the playa, i.e., the algae simply forms a thick mat intermixed with about the top quarter-inch of soil, it was impossible to delineate what part of the crust contained the algae. These crusts were extremely wet and sticky and upon removal from the freezer, as they began to thaw the sample essentially transformed into a "saturated paste".

The algae in the crust was not apparent, therefore, the subset of the total crust used for assay may not have contained enough of the algal mat to cultivate in a seven day incubation. This could possibly account for the low fixation by Yucca Lake #4 and likewise account for no fixation by Yucca Lake #2. This observation is further exemplified by the fact that only one of the duplicates from Yucca Lake

#3 produced detectable ethylene.

The inconsistency between duplicate crust assays collected on the fan appears to be a function of the amount and quality of the crust placed in the serum bottles. Again, 79 the morphology of the crusts after freezing for one year played a role in choosing compatible duplicate specimens to assay. However, at least it was possible to delineate the crust based on its leathery or lichenous morphology. The crusts were not weighed and only enough crust was used to cover the bottom of the serum bottle. This has inherent problems in that the volume as well as the quality (i.e., extent of development) of the crust are not necessarily comparable. Basically, this is good in that the average potential of the crust at each site can be approximated as opposed to reporting either maximum or minimum potentials.

Therefore, it is more important to use the same volume of sample when trying to determine the potential of crusts to fix nitrogen.

The fact that only about one-half of the samples produced detectable ethylene after a 24 hour incubation period and a 2 hour assay could support Rychert's (1975) finding that the crusts he collected in October displayed a lag period before acetylene reduction was observed. Further- more, the fact that these crusts were frozen for a year probably augmented the amount of time it took the crusts to become active. All but three crusts capable of fixing nitrogen reduced acetylene after a two day incubation-24 hour assay, and all crusts except YL #2 reduced acetylene after a

7 day incubation period. It is possible that after a rain the crust requires 80

several days acclimation time before nitrogen fixation be-

gins. This is probably more true of the algal mat on the

playa in that the playa is dessicated for a major portion of

the year under extreme temperatures. When winter and late summer rains come it probably takes a week or longer (as was

evident in this study) to get the algal population density

high enough to fix appreciable amounts of nitrogen.

Acetylene-Reduction by Cores

All sites with crusts capable of fixing nitrogen had

corresponding cores that fixed nitrogen except YL-3. This

is not understood in that the core had a thick algal mat

composed of Qscillatoria and two other unidentified blue-

green algae (personal communication, Sandra Cooper).

All of the cores fixed less nitrogen than the corre-

sponding crust which would be expected in that crusts were

selectively picked and placed in the serum bottles, whereas

the cores only had the limited amount of crusts that hap-

pened to be on the soil core surface.

The important finding of the assay was that five cores

were found to fix nitrogen where crusts were not visually

apparent. Additionally, when the number of cores and crusts

capable of fixing nitrogen are compared to the number of

randomly selected sample sites, it is found that potential

nitrogen fixation occurs at 79 percent of these sites. This

appears contrary to Wallace's (1978) estimation of only a 1 percent or less algal-lichen crust cover on soils in the 81 northern Mojave Desert. This would also disprove Hunter's (1976) estimation that nitrogen input to Mojave Desert soils by fixation accounts for less than 100 g N/ha/yr. (The results of the core assay are presented in Table 7.)

BACTERIA GROWTH STUDY

Growth results for the presence of sulfur and nonsulfur photosynthetic bacteria are presented in Table 8. Only three out of the sixteen soils (FF-1, FF-3, FF-7) showed morphological changes (the growth media turned milky) indicating the presence of nonsulfur nitrogen fixing baceria.

Five out of the sixteen (FF-4, FF-5, FF-7, FF-11, FF-12) showed a green growth when incubated in the sulfur bacteria growth medium. Upon microscopic examination growth in FF-4 was found to consist primarily of the blue-green algae Am- phithrix (personal communication, Sandra Cooper). Growth in

FF-11 was found to consist primarily of single celled green algae of the family Micractiniaceae (personal communication,

Sandra Cooper). Visually, the growth in FF-5, FF-7, FF-12 was similar to the growth in FF-11 (see Table 8). The fact that bacterial growth was not evident in either of the culture mediums could suggest that the organic carbon content of the soils is insufficient to support heterotrophic organisms (Hunter, 1975). Other such factors as pH and the percent moisture of the soils might also be limiting. The optimum pH for the growth of nitrogen fixing Table 1. One Aa••J lnc,j,atlon Aaur -nkc.ll-- er ..;-H _ rtaeJ-- 24ii(CJl er ... rf1•ed "-•ear z n Flaeer krll2 lira Doole Produc I ! __ per 1 Procb:t per Acr 112' lire fF-1 4-6-lll 4-J-112 lo-12-BZ 2.11 n ..lea 11.1 fF-2 1-21-112 )-24-112 J-:)()-112 4.111 II ftl)ell Zl.5 116.00 n ..1..- 546.0 ff-4 l-ZJ-112 1-24-lll 4.51 n Wllea 21.5 l-10-82 2.1,6 " ..lell 11.6 IV• n IOOie• 511.2 fF-, 1-21-lll l-21o-IZ 1-10-lll 1.04 n 1110lu 14.1 10.9 n.,lea ])1.0 ff-6 4-6-112 4-J-112 4- 12-112 1.99 n ..,.,.. 111.1 fF-11 l-21-lll )-24-112 )-J0-82 .911 n ..,,,.. 4.60 FF-11 J-21-lll l-llo-IZ l-10-112 2.22 n ...... IO.t, fF-12 1·21-IIZ 1-Zio-IIZ J-:J0-112

fF-Il 4-6-IIZ 4-J-IZ 4-12-112 ]2.6 n 1n0le• 151 560.00 n 100le• 2610

YJr] 4-6-112 4-J-112 to-12-112

IL-4 4-6-112 4-J-112 1.111n ••les 6.5 2.0 11 mole• 9.41 4-12-112 • .99 n ..,le• •to.6 6 16.1 n ..,a.,. •an llr, l-ZJ-112 1-24-IIZ J-10-112 llr6 <4-6-112 4-J-112 J-10-112 .1111 n ..,iu 4.14> Ttr6 4-6-lll 4-J-112 l-10-112 2.40 n ..,,.,. 11.1 11.6 n -.le• 1511

0 C.1a•• core c:racl

00 IV Table 8 Photosynthetic Bacterial Growth Study

Purple Nonsulfer (Athiorhodaceae) Date Placed Purple Sulfer (Thiorhodaceae) Date of Under Date Growl Site Green Sulfer (Chlorobacteriacea) Inoculation Incandescent Light Observed

19-19-81* 11-3-81 11-9-81 FF-1 purple nonsulfer — FF-1 green and purple sulfer 11-3-81 11-3-81 10-19-81* 11-3-81 — FF-2 purple nonsulfer — FF-2 green and purple sulfer 11-3-81 11-3-81 FF-3 purple nonsulfer 10-19-81* 11-3-81 12-10-81 11-3-81 11-3-81 — FF-3 green and purple sulfer — FF-4 purple sulfer 10-19-81* 11-3-81 FF-4 green and purple sulfer 11-3-81 11-3-81 1 2-2-81 FF-5 purple nonsulfer 10-19-81* 11-3-81 -- FF-5 green and purple sulfer 11-3-81 11-3-81 12-14-81 11-3-81 FF-6 purple nonsulfer 10-19-81* — FF-6 green and purple sulfer 11-3-81 11-3-81 FF-7 purple nonsulfer 10-19-81* 11-3-81 12-10-81 FF-7 green and purple sulfer 11-3-81 11-3-81 12-9-81 FF-8 purple nonsulfer 10-19-81* 11-3-81 11-3-81 FF-8 green and purple sulfer 11-3-81 — FF- 1 1 purple nonsulfer 10-19-81* 11-3-81 1 1-3-81 11-16-8 1 FF-1 1 green and purple sulfer 1 1-3-81 — FF-1 2 purple nonsulfer 10-19-81* 11-3-81 FF-1 2 green and purple sulfer 11-3-81 11-3-81 1 2-19-81 FF-1 3 purple nonsulfer 10-21-81* 11-3-81 FF-1 3 green and purple sulfer 11-3-81 11-3-81 YL-1 purple nonsulfer 10-19-81* 11-3-81 YL-1 green and purple sulfer 11-3-81 1 1-3-81 YL-2 purple nonsulfer 10-21-81* 11-3-81 YL-2 green and purple sulfer 11-3-81 11-3-81 YL—3 purple nonsulfer 10-21-81* 11-3-81 YL-3 green and purple sulfer 1 1-3-81 11-3-81 YL-5 purple nonsulfer 10-19-81 11-3-81 YL—5 green and purple sulfer 11-3-81 1 1-3-81 YL-6 purple nonsulfer 10-19-81* 11-3-81 YL-6 green and purple sulfer 11-3-81 11-3-81 Control green and purple sulfer 11-8-81 11-8-81 12-2-81 Lahonton Anaerobic Lake initially placed under flourescent lights. 0 0 * Innoculation bottles were u> 84 bacteria is 7.2 (see Appendix I), however, the pH of the soils used to inoculate the growth mediums ranged from 8.0-

9.0. Additionally, the fact that algal species were observed growing in the growth mediums could suppress bacterial growth in that the oxygen produced through photosynthesis would alter the anaerobic conditions necessary for the growth of these bacteria.

ISOTOPE ANALYSIS Samples analyzed for N 15 showed <515N ranges from +5.5 to +10.1 (Table 9). These values fall within

found in the playa soils based on known isotopic ratios of

the atmosphere, plant biomass, rocks, etc. (Fritz, 1980). However, one interesting thing was noted. The nitrate

deposits in Chilean solars have 615N values ranging from 0

to -6 as compared to +5.5 to +10.1 for the nitrate found in

the playa soils on NTS. Ericksen (1981) believes the ni-

trate deposits in Chilean solars are due primarily to spray

and evaporation from the Pacific Ocean and from volcanic

emissions from the Andes Mountains. 85

Table 9. Isotope Analysis

Sample Site N 15 o/oo

FF-1 7.0 FF-4 7.4

FF-5 5.8

FF-6 6.3

FF— 7 7.6 FF-1 1 5.5

FF-1 2 10.1

YL-2 7.7

YL-6 7.0 86

CONCLUSIONS

1 . In the acetylene reduction assay, unless purified acetylene is used, it is necessary to determine the amount of background ethylene. Additionally, it is necessary to

run ethylene standard prior to each set of assays. 2. There was a definite lag period before samples that

had been frozen or stored at 4°C began reducing acetylene.

This lag time should either be determined or samples should

be assayed a standard time after a given incubation period.

3. By comparing the nitrate ratios in precipitation and

runoff waters vs. the ratios in the soil profiles, it is unlikely that these sources are major contributors of ni-

trate to the playas. 4. The pH decrease (from about 9.0 to 7.0) in the soil

profiles where nitrate accumulates appears to indicate ni-

trogen fixed by algae and ammonium in waters reaching the

playa are oxidized by bacteria to nitrate. 5. Owing to the low organic carbon content of the

playa soils (7.0 to 19.0 mg/kg) and the unusually high ni-

trate concentrations in these soils (the maxima for all

sites averaged 4693 mg/kg), it is possible that nitrogen

losses by heterotrophic denitrifying bacteria are low. 6. Seventy-nine percent of the randomly picked sample

sites fixed large quantities of atmospheric nitrogen and an

algal mat is present on the playa when water is present. 87

Laboratory nitrogen fixation rates ranged from 4.1 to 46,100g N 2/acre/day. The average fixation by the soil cores was 359g /N2/acre/day whereas, average fixation by the algal crusts was 5527g N 2/acre/day. Based on these facts it seems likely that nitrogen fixation is largely responsible for the high nitrate concentrations found in these soils. Nitrate accumulation in the playa soils is probably due

to all of sources previously mentioned in conjunction with

the decomposition of plant and animal biomass. Large runoff

losses of nitrogen from the bajada where nitrogen fixation exceeds plant uptake, and soil nitrate was shown to accumu-

late, can occur in years when floods occur. Soil erosion

can occur which results in the loss of soil organic matter

as well as the mineral forms of nitrogen. The nitrate accumulations in the playas probably represents an input

over centuries from fixation, mineralization, and erosional

processes occurring on the bajada (Wallace, 1978). In addi-

tion, this study showed nitrogen fixation occurring on the

playa surface. REFERENCES

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, 1980. Standard Methods, 15th ed., Section 209B, Total Filtrable Residue.

Bradley, W.G., 1964. The Vegetation of the Desert Game Range with Special Reference to the Desert Bighorn: Desert Bighorn Council Trans., 1964, pp 43-67.

Bremner, J.M., 1965. Inorganic forms of nitrogen, in Meth- ods of Soil Analysis— Chemical and Micro-Biological Properties, C.A. Black, editor-in-chief, American Soci- ety of Agronomy, Inc., Madison, Wisconsin, pp. 1179— 1237. Cameron, R.E. and G.B. Blank, 1966. Soil Studies— Desert Microflora. XI. Desert Soil Algae Survival in Ex- tremely Low Temperatures. Space Programs Summary No. 37-37. 4:174-181, Jet Prop. Lab., Calif. Inst. Technol., Pasadena, California. Clements, T. , 1957. "Desert Flats," "Bedrock Fields," and "Regions Bordering Through Flowing Rivers." Articles in A Study of Desert Surface Conditions. Quarter Mas- ter Research and Development Command, Tech. Report EP- 53, U.S. Army, Natic, Massachusetts, pp. 52-72. Coulter Industrial Kem-O-Lab Operator's Reference Manual, p. C-30, 1978. Coulter Electronics, Inc., 590 West 20th St., Hialeah, FL, 33010. Eckel, E.B. (ed.), 1968. Nevada Test Site, Geologic Society of Am., Inc., Memoir 110, p. 290. EPA, 1979. Methods for Chemical Analysis of Water and Wastes. Method 350.3 . Methods for Chemical Analysis of Water and Waste. Method 352 .TI . Methods for Chemical Analysis of Water and Wastes” Method 354.1. Ericksen, G.E., 1981. Geology and Origin of Chilean Nitrate Deposits. Geol. Survey Professional Paper no. 1188.

Ericksson, E., 1952. Composition of Atmospheric Precipita- tion. I. Nitrogen Compounds. Tellis 4:2I5 222. 89

Fletcher, J.E. and W.D. Martin, 1948. Some effects of algae and molds in rain-crust of desert soils. Ecology, 29:95-100. ------

Hansen, D.S.. Tritium movement in the unsaturated zone, Nevada Test Site. Master's thesis, University of Neva- da, Reno, 1978.

Hem, J.D., 1970. Study and Interpretation of the Chemical Characteristics of Natural Water" 2nd ed., U.S. Government Printing Office, 363 p.

Houghton, J.G., 1969. Characteristics of Rainfall in the Great Basin. University of Nevada, Desert Research Institute, 205 p. (University of Nevada, Reno, NV 89507) .

Hunter, R.B., A. Wallace, E.M. Romney and P.A.T. Wieland, 1975. Nitrogen Transformations in Rock Valley and Adjacent Areas of the Mojave Desert. US/IBP, Desert Biome Res. Memo. 75-35. Utah State University, Logan. 8 p. Hunter, R.B., A. Wallace and E.M. Romney, 1976. Nitrogen Transformations in Rock Valley and Adjacent Areas of the Mojave Desert. US/IBP Desert Biome Res. Memo. 76- 28. Utah State University, Logan. 10 p.

Junge, C.E., 1958. The Distribution of Ammonia and Nitrate in Rainwater over the United States. Trans. Am. Geo- phys. Union 39:241-248. Letolle, R., 1980. Nitrogen-15 in the Natural Environment, in Handbook of Environmental Isotope Geochemistry. Vol. I, The Terrestrial Environment, P. Fritz and J. Ch. Fontes, eds., Elsevier Scientific Publishing Co., pp. 407-429. Lynn, R.I. and R.E. Cameron, 1971. Role of Algae in Crust Formation in Desert Formation in Desert Soils. US/IBP Des0^L Biome Res. Memo. 71 — 15. Utah estate University, Logan. 4p. MacGregor, A.N. and D.E. Johnson, 1971. Capacity of Desert Algal Crusts to Fix Atmospheric Nitrogen. Soil Sci. Soc. Am. Proc. 35:843-844.

Mayland, H.F., T .H._McIntosh and W.H. Fuller, 1966. Fixa- tion of Isotopic Nitrogen on a Semiarid Soil by Algal Crust Organisms. Soil Sci. Soc. Am. Proc. 30:56-60.

Meinzer, O.E., 1923. Outline of Groundwater Hydrology, with Definitions. U.S. Geol. Survey Water Supply Paper 494, 71 p. 90

Motts, W.S., 1965. Hydrologic types of playas and closed valleys and some relations of hydrology to playa geology, in Geology, Mineralogy and Hydrology of u.S. Playas, J.T. Neal, ed., Air Force Cambrige Research Lab, Report 650226, Environment Research Paper no. 96, pp. 73-104.

, 1970. Introduction to playa studies, in Geology and Hydrology of Selected Playas in Western United States, W.S. Motts, ed., Air Force Cambridge Research Lab., Report 69-0214, pp. 1-20.

O'Farrell, T.P. and L .A. Emery, 1976. Ecology of the Nevada Test Site: A Narrative Summary and Annotated Bibliog- raphy, National Technical Information Services, U.S. Department of Commerce, 5285 Port Royal Road, Spring- field, VA. 249 p. Quiring, R.F., 1965. Annual Precipitation as a Function of Elevation in Nevada South of 38 1/2 Degrees Latitude: Las Vegas, Nevada, U.S. Weather Bur. Research Station, 14 p. , 1968. Climatological Data Nevada Test Site and Nuclear Rocket Development Station, U.S. Department of Commerce Env. Science Service Adm. Report ERCTU-AKL7, NTIS, Springfield, VA, 177 p.

Rychert, R.C. and J. Skujins, 1974. Nitrogen Fixation by Blue-green Algae-lichen Crusts in the Great Basin Des- ert. Soil Sci. Soc. Am. Proc. 38:768-771.

, 1975. Nitrogen fixation in arid western soils, dissertation, Utah State University, Logan, 1975.

Skujins, J.J. and N.E. West, 1974. Nitrogen Dynamics in stands dominated by some major cool desert^ snrubs. US/IBP Desert Biome Res. Memo. 74-42. Utah State Uni- versity, Logan. 56 p. Skujins, J. and P.T. y Fulgham, 1978. Nitrification in Great Basin Desert soils, in Nitrogen m Desert Ecosys- terns, N.E. West and J.J. Skujins, eds., Dowden, Hutch- TnSon and Ross, Inc., Stroudsburg, PA, pp. 60-75 in cold desert Sorensen, D.L., In situ nitrogen fixation r soil— algal crust in northern Utah, master's thesis Utah State University, Logan, 1975. Stevenson, F.J., 1959. On the Presence of Fixed Nitrogen in Rocks. Science 130:221-222. 91

Stevenson, F.J., 1962. Chemical State of Nitrogen in Rocks, Geochim. et Cosmochim. Acta 26:797-809.

Stewart, W.D.P., G.P. Fitzgerald and R.H. Burris, 1967. In Situ Studies on N2 Fixation Using the Acetylene Reduc- tion Technique, Proc. Nat. Academy of Science 58:2071- 2078 .

Tchan, Y.T. and N.C.W. Beadle, 1955. Nitrogen Economy in Semi-arid plant communities. II. The Non-symbiotic Nitrogen-fixing Organisms. Proc. Linn. Soc. N.S.W. 80:97-104.

Thornbury, W.D., 1956. Principles of Geomorphology, John Wiley and Sons, New York, 618 p.

Urey, H.C., 1952. The Planets: Their Origin and Develop- ment, Yale University Press, New Haven, Connecticut.

Visser. S., 1964. Origin of Nitrates in Tropical Rainwater, Nature 201:35-36 . Wallace, A., E.M. Romney and R.B. Hunter, 1978. Nitrogen Cycle in the Northern Mojave Desert: Implications and predictions, in Nitrogen in Desert Ecosystems, N.E. West nd J.J. Skujins, eds., Dowden, Hutchinson and Ross, Inc., Stroudsburg, PA, pp. 207-219.

West, N.E., 1978. Physical Inputs of Nitrogen to Desert Ecosystems, in Nitrogen in Desert Ecosystems, N.E. West and J.J. Skujins, eds., Dowden, Hutchinson and Ross, Inc., Stroudsburg, PA, pp. 165-171. West, N.E. and J.J. Skujins, 1978. Nitrogen in Desert Eco- systems, Dowden, Hutchinson and Ross, Inc., Strouds- burg, PA, 307 p. Westerman, R.L. and T.C. Tucker, 1978. Denitrification in Desert Soils, in Nitrogen in Desert Ecosystems, N.E. West and J.J. Skujins, eds., Dowden, Hutchinson and Ross, Inc., Stroudsburg, PA, pp. 75-107.

Winograd, I.J. and W. Thordarson, 1975. Hydrogeologic and Hydrochemical Framework, South-central Great Basin, Nevada-California, with Reference to the Nevada Test Site. Geological Survey Professional Paper 712-C, 12b P. Wolfe, R.S. and M.J. Wolin. Laboratory Manual--Microbial Physiology. University of Illinois, Department of Microbiology. 92

Yaalon, D., 1964. The Concentration of Ammonia and Nitrate in Rain Water over Israel in Relation to Environmental Factors, Tellus 16:200-204. 9 3

APPENDIX I

GROWTH MEDIUMS FOR PHOTOSYNTHETIC BACTERIA

A. Purple nonsulfur bacteria (Athiorhodaceae)

These bacteria grow anaerobicallyin the light; many grow aerobically in the dark. The enrichment strategy se- lects organisms, from appropriate environments, which photo- metabolize organic sustrates. The organic substrates used are not usually degraded by anaerobic, dark fermentations.

1. Add about 30 ml of Medium 1 to a 60 ml glass re- agent bottle after adding the particular organic substrates chosen for enrichment from the table below:

Substrate Stock Amt./60 ml Final Cone % ml %

NH^ Acetate 5 1 .2 0.10 Na Succinate 5 1 .2 0.10 Na Caprylate 5 0.5 0.04 Na Pelargonate 5 0.5 0.04 (Caprate) 0.10 Ethanol 5 1 .2

Ethanol Inoculate with mud, soil (or other suitable inocula), and completely fill with Medium 1. Stopper with glass stopper (no air bubbles) and place the bottle about 2 feet from a 60 watt bulb at room temperature. 2. Record morphological forms of predominant organisms in the enrichment. 3. Isolate by serial 1 ml dilutions in agar shakes of Medium 2 or 3 to obtain single colonies.

a) Eyeball 1 ml amounts. (To estimate, add 9 ml H?0 to a tube, mark, add 1 ml ofH20 and mark. Use the marks as a guide for estimating the amount to be poured from one tube to the next). Carry through 8 tubes. b) Mix shakes by turning tubes upside down once with your thumb over the plug. Mix before trans- ferring 1 ml. c) Chill tubes in ice water to solidify. 94

d) Pour 1/2 to 1 inch of vaspar over each shake. After vaspar solidifies, remelt by heating by moving the burner flame around the vaspar layer. Remelt the vaspar again tomorrow. (The remelting and resolidification is necessary because contraction of the vaspar upon cooling often gives a poor anaerobic seal) .

e) Incubate as for the enrichments. Make certain that racked tubes don't block light from reaching other tubes.

f) The medium used is not selective for a partricular type of purple nonsulfur (malate is a generally used substrate) and it is a rich medium which is not selective for photosynthetic bacteria.

Medium 1

Constituent Amount

Distilled Ho 0 1 000 ml Metal Solution (SL4) 10 ml Thiamin HC1 (0.1%) 1 ml KH2P(\ 0.5 g MgSO^-7 H20 0.2 g MgCl2•6 H20 0 -2 9 CaClo•2H20 0.05g nhkCi 1-° g NaCl 1 .0 g Yeast extract 0.25 g

Adjust pH, with 2 M Na9C0q, to 6.8 for succinate enrichments and to 7.3 for the other enrichments. 95

Medium 2

Constituent Amount

Distilled H20 990 ml Metal Solution (SL4) 10 ml Thiamin HC1 (0.1%) 1 ml k h 2p o [+ 0.5 g MgSO^‘7 H20 0.2 g MgC12•6 H20 0.2 g CaCl2•2 H20 0.05 g n h 4ci 1 .0 g NaCl 1.0 g Sodium thioglycollate (Difco) 0.5 g Yeast extract 0.25 g DL Malic Acid 2.0 g Sodium acetate 1 .0 g Agar (Difco) 10.0 g Adjust pH to 7.2 with 10 N NaOH before adding the agar. Tube 9 ml per tube.

Metal Solution (SL4)

Constituent Amount 1000 Distilled H20 ml Ethylenediamine- tetraacetate-Disodium 50 0 mg 200 mg FeSO^•7 H20 10 ZnSO^•7 H20 mg MnCl2•4 H20 3 mg 3 3 30 mg H BO 20 CoCl2•6H20 mg 2 1 mg CuC1 •H20 2 NiCl2• H20 mg NaMoO^* 2H20 3 mg

pH 3-4 Medium 3 0.3% years extract 0.3% peptone 1 .0% agar 96

B. Purple (Thiorhodaceae) and Green (Chlorobacteriaceae) surfur bacteria.

1. Primary enrichments.

Collect water and black mud (with H2S odor) together with decaying leaves. If there is little mud with mainly sandy material, add black sludge from the anaerobic fermen- tation tank of the city sewage treatment plant. Fill 500 ml glass-stopped bottles. Add some CaS04*2H20 and 0-1 -0.2 ml ethanol to enhance sulfate reduction. Place bottles at a north window.

When green and purple patches develop (ca. 10-14 days), transfer from patches with a pasteur pipette to the secondary enrichment medium.

The secondary enrichment medium can also be inoculated directly with inocula sewage lagoons, H2S-containing ponds and black mud. 2. Secondary enrichments. The medium used is the same as the isolation medium except for the omission of agar and the omission of steril- ization and aseptic methods. a) Fill 4 ounce screw cap bottles (or flasks) almost completely with the complete basal medium allowing room for the addition of 5 ml of the sodium sulfide solution and inoculum. Add the sodium sulfide and inoculate with 2 ml. Fill completely with the basal medium to leave no more than a small air bubble after the bottles are capped with rubber-lined caps. b) Incubate about 2 feet from a 60 watt bulb at room temperature. c) Incubation behind infra-red filters can be used to selectively prevent the growth of green sulfur bacteria. d) The secondary enrichment cultures must be watched carefully for feeding purposes. Sulfide is the electron donor for photosynthesis. The initial addition of excess sufide, however, is toxic to the purple and green sulfur bacteria. If too little is provided, however, a good enrichment will not take place because of sulfide limita tion. It is simple, however, to note when the electron donor is exhausted by watching the cultures, and they can then be fed sulfide to allow continued growth of the bacteria. Sulfide is oxidized through elemental sulfur to 97 sulfate. The enrichment cultures go from clear to milky when elemental sulfur is formed and clear again when the sulfur is converted to sulfate. If the cultures are looked at every day, the clear to milky to clear transition can be detected. It usually takes 24 to 48 hours to go from milky to clear. Additional sulfide, 5 ml of the feeding solution, should be added after removing 5 ml of the enrichment. Keep the enrichment 5 ml around to fill to the top in case too large an air pocket remains after feeding.

3. Isolation

Serially dilute 1 ml amounts through 9 tubes of the isolation medium. Cool in ice water to solidify. Seal with melted vaspar. The technique is the same as for the nonsulfur purple bacteria.

Isolation Medium

The preparation of the medium is a bit more complicated than the preparation of most of the "soups" used to grow bacteria. This is mainly caused by the necessity for providing the appropriate amounts of C02 and sulfide and anaerobic conditions and the proper pH. Nature easily provides an environment for the growth of these organisms. Media preparation facilities for microbiology courses are not designed to easily reproduce all of the natural environments where bacteria are found. Once prepared, however, the medium is stable if stored as indicated below.

Solution A (autoclaved)

0.04% CaCl2•2H20 Solution B (Filter Sterilized with Solution C)

Constituents Amount

Distilled water 40 ml 60 ml Heavy metal solution (SL^) 6 Vitamin B12 Solution (2mg/100 ml) ml 2 2 2 g KH P0 2 KC1 g 2 g NH^Cl 2 MgCl2•6H 2 0 g 9

Solution C (Filter sterilized with Solution B)

Constituent Amount

Distilled water 900 ml NaHC03 9 g Solution D (Autoclave)

Constituent Amount

Distilled water 400 ml Na2S-9H20 6 g

FEEDING SOLUTION - To 50 ml of solution D of 2 M H2S04 . Store in completely filled screw cap test tubes.

Solution E (autoclaved)

2 M H2SOl+

Instructions

1. The medium is to be stored after constitution in 4 ounce crew cap flasks which have rubber cap liners to provide anaerobic seals. Each bottle or flask holds about 132-135 mg. a) Start by dispensing 105 ml of Solution A in each flask and autoclave with caps loose. b) Autoclave some extra Solution A to be used as a final filling solution. About 5 ml of filling solution is needed for each 4 ounce flask of medium prepared. c) Allow the medium to cool to room temperature and set the screw cap flasks aside for the moment. 2. Flush (bubble) solution C with 100% C02 for at least 30 minutes while stirring vigorously on a magnetic stirrer.

a) Then mix in solution B. b) Filter sterilize the combined solutions through a positive pressure filter set-up (Millipore, Seitz) with 15 lbs. per sq. inch C02 pressure. c) Bubble C02 into the sterilized filtrate using a sterile, cotton plugged pipette. 99

d) Use a sterile, automatic syringe to dispense 2 ml amounts into the flasks containing sterile solution A.

3. Take 1 Jtiask containing combined solutions A, B and C. Add 4 ml of solution D. Check the pH with a pH meter. If the pH is below 7.2 add small amounts (0.5 ml) to bring to 7.2. Record how much you add. (It is easier to do this without worrying about maintaining the sterility of the flask contents. Once the appropriate additions for pH adjustment have been determined for this test flask, the recorded values are used for the remaining flasks). If the pH goes about 7.2 or is above 7.2 at the start, solution E can be used for adjustment. A range of 7.15-7.25 is satis- factory.

a) After the appropriate amounts of Solution D and/or Solution E are noted, make the additions aseptically to all of the flasks to combined A, B and C solutions.

4. Fill the flasks to the top with sterile solution A and cap leaving no more than a small air bubble in the flasks. The medium can now be stored for long time periods.

5. To prepare agar shakes. a) Melt sterile agar in test tubes. Cool to 55-60 C.

b) Warm flasks of the medium up to 38°C.

c) Add 6 ml of the warmed medium to the agar, mix by inverting and keep at 38°C for preparation of the dilution series.

Spectrum Determination - Phytosynthetic Bacteria

Recommendations by Dr. N. Pfennig.

1. Whole cultures To 3.5 ml of culture, add 5 grams of fine, granulated sugar. If the cell density is very heavy, add 1.5 ml H20 to 2.0 ml of culture before adding sucrose. For a blank, add 5 grams of sugar to 3.5 ml of distilled H20. Allow 1/2 hour for the sugar to dissolve. Read the spectrum of the culture between 350 nm and 950 nm if possible, or at least between 600-950 nm. 100

2. Extraction of pigments

Centrifuge 10 ml of culture. Resuspend cells in 1 ml of H20. Add 9 ml of CH3oH. Suspend and shake occasionally for 5 to 10 min. Centrifuge. Chlorophyll is in the supernatant. To remove carotenoids, extract the pellet with 5 ml of acetone and centrifuge. APPENDIX II

Percent Moisture of 0-2 inch (0-5 cm) and 2-6 inch (5-15 cm) Soil Samples 102

PERCENT MOISTURE FRENCHMAN FLAT

Site Depth Collection Data Analysis Date % Moisture

FF-1 0-2" 3-5-81 5-27-81 24.68 2-6" 3-5-81 5-19-81 6.13

FF-2 0-2" 3-5-81 5-19-81 18.67 2-6" 3-5-81 5-20-81 4.63

FF-3 0-2" 3-5-81 5-19-81 9.15 2-6" 3-5-81 5-19-81 6.15

FF-4 0-2" 3-5-81 5-19-81 8.58 2-6" 3-5-81 5-19-81 6.43 0 2 5-19-81 10.98 FF-5 - " 3-5-81 2.01 2-6" 3-5-81 5-20-81

FF-6 0-2" 3-5-81 5-19-81 43.17 2-6" 3-5-81 5-20-81 6.25

FF-7 0-2" 3-5-81 5-19-81 18.02 2-6" 3-5-81 5-20-81 7.05 -8 0 2 5-19-81 19.23 FF - " 3-6-81 6.10 2-6" 3-6-81 5-20-81

FF-1 1 0-2" 3-6-81 5-20-81 16.67 2-6" 3-6-81 5-27-81 6.35

FF-1 2 0-2" 3-6-81 5-19-81 18.69 2-6" 3-6-81 5-20-81 9.70 16.30 FF-1 3 0-2" 3-6-81 5-19-81 2-6" 3-6-81 5-20-81 2.48 2 6 stored at 4°C All 0- 2" and - " samples were collected and until analysis. All samples were dried at 104 C for 5 days 103

PERCENT MOISTURE YUCCA LAKE

Site Depth Collection Data Analysis Date % Moisture

YL-1 0-6" 3-5-81 5-19-81 13.29 YL-2 0-1 " 3-5-81 5-19-81 16.25 1-6" 3-5-81 5-27-81 9.80 YL-3 0- 1" 3-5-81 5-20-81 19.73 1-6" 3-5-81 5-27-81 10.31 YL-5 0-2" 3-6-81 5-27-81 10.06 2-6" 3-6-81 5-19-81 11.44 YL-6 0-2" 3-6-81 5-20-81 20.70 2-6" 3-6-81 5-19-81 13.37

All 0-2" and 2-6" were collected and stored at 4°C until analysis All samples were dried at 104°C for 5 days APPENDIX III

Percent Nitrate to TDS in Soil Profiles 105

FRENCHMAN FLAT #1

NO 3 TDS Depth (mg/Kg) (mg/Kg (NO3/TDS)

(0-5 cm) 9.08 636 1 .43 0-2"

(5-15 cm) 131 514 25.4 2-6"

(15-31 cm) 1,570 3,058 51.4 6"-1 .0'

(31-46 cm) 2,210 4,180 53.0 1 .0-1.5'

(46-61 cm) 2,7 201 4,3701 62.31 19,3002 64.22 1 .5-2.0' 2,880 4,426 65.0

(61-76 cm) 2,880 4,406 65.3 2.0-2.5')

(76-91 cm) 2,430 4,211 57.8 2.5-3.O'

Total 12,000 21,431 56.5

1 - duplicate sample 2 - indicates values obtained from using a saturated paste extract 106

FRENCHMAN FLAT #2

NO 3 TDS Depth (rag/Kg) (mg/Kg (NO3/TDS)

0-2" 16.8 644 2.61

2-6" 13.7 356 3.85

6"-1 .0' 1 1 .7 1 441 2.66 1 1.0-1.5' 9 . 7 430 2.27 N C o ID 1 ■ • 26.6 565 4.70

2.0-2.5' 68.6 666 10.3

2.5-3.O' 115.1 830 13.9

Total 262.3 3,932 6.7

1 - N03 by Brucine Method 107

FRENCHMAN FLAT #3

NO 3 TDS Depth (rag/Kg) (mg/Kg (NO3/TDS) FRENCHMAN FLAT #3

0-2" 45.41 4 20 1 1 0.8 1 16.2 252 6.41 390.02 9882 39.52

2-6" 10.6 278 3.82

6"-1 .0' 2.2 269 .82

1.0'-1.5' 2.9 309 .93

1 .5'—2.0' . 66 390 .17 2.0-2.5' 3.3 450 .74

2-5-3.O' 6.0 602 .99

Total 41 .8 2,550 1 .64

1 - duplicate 2 - indicated values obtained from using saturated paste extract 108

FRENCHMAN FLAT #4

N°3 TDS Depth (mg/Kg) (mg/Kg (NO3/TDS)

0-2" 59.8 455 13.1

2-6" 16.8 367 4.58

6 " -1 .0 ' 2.88 484 .60

1 .0-1.5' 8.85 681 1 .30

1.5-2.0' 21 .0 799 2.63

2.0-2.5' 124.0 1,008 12.3

2.5-3.O' 531 .0 1 ,654 32.1

Total 765.0 5,448 " 14.0 109

FRENCHMAN FLAT #5

TDS Depth (mg/Kg)N ° 3 (mg/Kg (NO3/TDS)

0-2" 65.3 444 14.7

2-6" 11.1 324 3.42

6"-1.0' 5.76 1 290 1 .99 1 Ul • • O 9.52 318 3.00

1.5-2.0' 46.5 403 11.5

2.0-2.5' 443.0 942 47.0 m o CM n i l • • 686.0 1 ,410 48.7

Total 1 ,267.0 4,131 30.7

1 N03 determined by Brucine Method 9$sm

110

FRENCHMAN FLAT #6

NO a TDS Depth (mg/Kg) (mg/Kg (NO3/TDS)

0-2" 24.4 525 4.64

2-6" 1 ,310.0 2,759 47.3

6"-1 .0' 6,640.0 11 ,445 58.0 1.0-1.5' 20,1 00.0 1 30,000 1 67.01 7,750.0 14,038 55.2 8,060.02 1 3,8 5 0 2 58.22

1.5-2.0' 6,860.0 14,240 48.2

2.0-2.5' 6,110.0 12,200 50.1

2-5-3.O' 5,530.0 10,384 53.3

3.0-3.5' 3,980.0 8,566 46.5

Total 38,200.0 7,415.0 51 .5

1 - values obtained from using saturated paste extract 2 - duplicate sample Ill

FRENCHMAN FLAT #7

b TDS Depth (mg/Kg)N ° (mg/Kg (NO3/TDS) CM O 1 26.1 511 5.11

2-6" 2,210.01 4,150 58.7 2,430.0

6"-1 .0' 5,310.0 9,565 55.5

1.0-1 .5' 5,090.0 9,590 53.1 CM O LD 1 • • 4,830.0 8,320 58.0

2.0-2.5' 3,250.0 6,840 47.6

2.5-3.O' 2,210.0 4,155 53.3

3.0-4.O' 147.0 5,000 2.93

Total 21 ,100.0 48,131 43.82

1 - duplicate sample FRENCHMAN FLAT #8

N°3 TDS Depth (mg/Kg) (mg/Kg (NO3/TDS)

0-2" 86.3 1,144 7.55

2-6" 64.2 504 12.7

6"-1.0' 509.0 1 ,061 48.0

1.0-1.5' 1 ,590.0 2,547 62.6 1.5-2.0' 2,660.0 3,801 69.9

2.0-2.5' 2,790.0 7,376 37.8

2.5-3.O' 3,100.0 7,172 43.2

Total 10,700.0 23,605 45.5 113

FRENCHMAN FLAT #11

N°3 TDS Depth (mg/Kg) (mg/Kg (NO3/TDS)

0-2" 19.0 744 2.56

2-6" 487.0 516 94.4

6"-1 .0' 465.0 1 ,437 32.4

1.0-1.5' 930.0 2,323 40.0 1.5-2.0' 1 ,020.0 2,074 49.1 .6 2.0-2.5' 863.0 1 ,672 51

2.5-3.O' 753.0 1 ,353 55.6

Total 4,530.0 10,119 44.8 114

FRENCHMAN FLAT #12

N°3 TDS Depth (mg/Kg) (mg/Kg (NO3/TDS)

0-2" 1 ,060.0 2,456 43.3

2-6" 11,100.0 16,956 65.3

6"-1 .0' 7,750.0 12,911 60.0

1 .0-1.5' 7,080.0 16,238 43.6

1.5-2.0' 5,310.0 9,245 57.5

2.0-2.5' 3,100.0 5,942 52.2

2.5-3.0 2,660.0 4,618 57.5

Total 38,000.0 68,366 55.6 115

FRENCHMAN FLAT #13

N°3 TDS Depth (mg/Kg) (mg/Kg (NO3/TDS)

22.1 0-2" 864 2.56

2-6" 17.5 268 6.52

6"-1 .0' 35.4 362 9.78 20.1 1 .0-1.5' 362 5.56 1 .5-2.0' 1 1 .1 1 426 2.60

2.0-2.5' 31.0 491 6.31 8.22 2.5-3.O' 53.1 646

3.0-4.O' 151 .0 966 15.6

7.77 Total 341 .0 4,385

!n 0 3 - by Brucine method .116

YUCCA LAKE #1

N° 3 TDS Depth (mg/Kg) (mg/Kg (NO3/TDS)

Depth NO,/mg/Kg) TDS/mg/Ka) % NO,/TDS

0-6" 5.09 628 .81

6"-1 .0' 5.98 1 ,049.2 .57

1.0-1.5' 21 .0 817.2 2.57 1 tv ) • o • cn 22.1 828.0 2.67

2.0-2.5' 310.0 3,767.2 8.23

Total 364.0 7,089.6 5.14 117

YUCCA LAKE #2

N° 3 TDS Depth (mg/Kg) (mg/Kg (NO3/TDS)

1 0-1 " 6.42 ,216.0 .53 1-6" 1 ,730.0 3 ,991 .6 43.3

6"-1 .0' 3,320.0 7,127.6 46.6 6 1.0-1.5' 2,880.0 ,702.4 42.9

1.5-2.0' 2,430.0 5,592.4 43.5

2.0-2.5' 86.3 4,418.4 1 .95

Total 10,500.0 29,048.4 36.0 118

YUCCA LAKE #3

N° 3 TDS Depth (mg/Xg) (mg/Kg (NO3/TDS)

1,112 .66 0-1 " 7.31

1-6" 6,860.0 13,517.6 50.8

6"-1 .0' 6,640.0 12,718.8 52.2

1.0-1.5' 5,760.0 10,223.6 56.3 8 1.5-2.0' 4,870.0 ,003.6 60.8

2.0-2.5' 3,540.0 7,004.0 50.6

Total 27,700.0 52,579.6 52.6 119

YUCCA LAKE #5

N° 3 TDS Depth (mg/Kg) (mg/Kg (NO3/TDS)

0-2" 10.4 196 5.31

2-6" 2.66 1 84 1 .44

6"-1 .0' 6.42 444 1 .45

1.0-1.5' 3.76 446.4 .84 1 .5-2.0' 1.11 276.4 .40

2.0-2.5' .22 321 .2 .07

1 868.0 Total 24.6 , 1 .32 120

YUCCA LAKE #6

NO 3 TDS Depth (mg/Kg) (mg/Kg (NO3/TDS)

0-2" 84.1 780 10.8

2-6" 27.0 4,880 .55

6: — 1 .0' 2,990.0 8,160 36.6 1.0-1.5' 2,660.0 6,298.4 42.2

1.5-2.0' 2,430.0 5,01 1 .2 48.60 CM D I CM O 1 • • 2,210.0 4,960 44.6

2.5-3.0 2,200.0 5,440 40.4

3.0-3.5 18,600.0 4,577.6 40.60

3.5-4.O' 1 ,330.0 3,408 39.0 121

APPENDIX IV

Chemical Data for Soil Profiles SO IL EXTRACT ANALYSIS (mgAg-PP") FRENCHMAN FLAT #1 7°C

Collection E.C. Ortho Total Organic Date Time Depth pH (Wtihos) TDS1 n o 2-n n o 3- Phosphate Na Cl % Moisture Carbon

3-5-81 1030 0-2" 8.20 159 6361 .1 9.08 .7 53.0 2.5 24.68 9.0

3-5-81 1030 2-6” 8.80 128.5 5141 .1 131.00 - - - 6.13 -

3-5-81 1030 6"-1.0' 7.95 764.5 3,058' < .05 1,570.00 - - - - “

3-5-81 1030 1.0-1.5' 7.96 1,044.9 4,180* < .05 2,210.00 - - - - 3-5-81 1030 1.5-2.O' 7.50 1,200.02 4 ,37021 < .05 2,720.002 179 .02 1,106.5 4,426* 2,880.00 19,330.03 19,300*' 12,400.003 '

3-5-81 1030 2.0-2.5' 7.55 1,101.6 4,406 .15 2,880.00 - - - - -

3-5-81 1030 2.5-3.O' 7.40 1 ,052.8 4,211 * < .025 2,430.00 3-5-81 1030 3.0-3.5' ------3-5-81 1030 3.0-4.O' ------

1 - IDS = 0.8 (E.C.) x 5 (where 0.8 = conversion factor, 5 = dilution of 5 parts water to 1 part soil) 2 - duplicate -2' TDS value is the actual value obtained from laboratory analysis 3 - Saturated paste extract - 31 TDS = E.C. x 1.0 (conversion factor) 122 SOIL EXTRACT ANALYSIS (mg/kg-ppn) FRENCHMAN FLAT #2 8°C

Total Organic Collection E.C. Ortho n o Phosphate Na Cl % Moisture Carbon Date Time Depth pH (umhos) IDS* n o 2-n 3-

16.5 5.0 18.67 18.5 3-5-81 1230 0-2" 8.31 161.0 6441 .15 16.8 .8 - - 4.63 “ 3-5-81 1230 2-6" 8.91 89.1 3561 <.05 13.7 - - - 3-5-81 1230 6"-1.0' 9.20 110.3 4411 - 11.7 - - 3-5-81 1230 1.0-1.5’ 9.25 107.5 4301 - 9.7 - - - - 3-5-81 1230 1.5-2.0' 9.35 141.3 5651 <.05 26.6 - “ 3-5-81 1230 2.0-2.5' 9.45 166.4 6661 .035 68.6 - - - ~ 3-5-81 1230 2.5-3.O' 9.40 207.6 8301 <.05 115.1 - — 3-5-81 1230 3.0-3.5' - - - - - 3-5-81 1230 3.0-4.O' - - - " 1 part soil) 1 - TDS = 0.8 (E.C .) x 5 (where 0.8 = conversion factor, 5 = dilution of 5 parts water to 123 SOIL EXTRACT ANALYSIS (mgAg-PPm) FRENCHMAN FLAT #3 9°C

Ortho Tbtal Organic Collection E.C. n o n n o 3- Phosphate Na Cl % Moisture Carbon Date Time Depth pH (mhos) TDS1 2-

45.502 .40 10.15 18.52 9.15 3-5-81 1315 0-2" 8.93 762 4202' < .025 9883 9883' 16.20 6.5 63 2521 390.463 - - - 6.19 “ 3-5-81 1315 2-6” 8.8 69.5 2781 < .05 10.6 2.2 - - — 3-5-81 1315 6"-1.0' 8.7 67.3 2691 < .05 2.9 - ~ 3-5-81 1315 1.0*1.5' 8.85 77.2 3091 < .025 .66 - “ 3-5-81 1315 1.5-2.0* 9.25 97.4 3901 .05 3.3 - - 3-5-81 1315 2.0-2.5* 9.2 112.5 4501 < .05 6.0 - - 3-5-81 1315 2.5-3.O' 9.5 150.6 6021 < .025 - 3-5-81 1315 3.0-3.5* - - - - " — — 3.0-4.O' 1315 3.0-4.0* - -

1 - IDS = 0.8 (E.C.) x 5 where (0.8 = conversion factor, 5 = dilution of 5 parts water to 1 part soil) 2 - duplicate -21 TDS value is the actual value obtained from laboratory analysis 3 _ saturated paste extract - 31 TDS - E.C. x 1.0 (conversion factor) 124 SOIL EXTRACT ANALYSIS (mg/kg-ppm) FRENCHMAN FLAT #4 8°C

Tbtal Organic Collection E.C. Ortho % Moisture Carbon Date Time Depth pH (umhos) TDS1 n o 2-n n o 3- Phosphate Na Cl

8.53 - 3-5-81 1400 0-2" 8.7 113.7 4551 .5 59.8 - - -

3-5-81 1400 2-6" 8.9 91.7 3671 < .05 16.8 - - - 6.43 - - 3-5-81 1400 6"-1.0' 9.2 121.1 4841 .05 2.88 - - - - - 3-5-81 1400 1.0-1.5' 9.7 170.3 6811 .15 8.85 - - - 3-5-81 1400 1.5-2.O' 9.75 199.7 7991 .30 21.0 - - - — 3-5-81 1400 2.0-2.5' 9.6 252.1 1,008‘ 2.3 124.0 - - - 3-5-81 1400 2.5-3.O' 9.45 413.5 1,6541 .10 531.0 - - - - — 3-5-81 1400 3.0-3.5' ------3-5-81 1400 3.0-4.O' - - - - ' - ~ — 1 - TDS = 0.8 (E.C.) x 5 (where 0.8 = conversion factor, 5 = dilution of 5 parts water to 1 part soil) 125 SOIL EXTRACT ANALYSIS (mgAg-PPn) FRENCHMAN FLAT #5 9°C

Ortho Total Organic Collection E.C. % Moisture Carbon TDS1 N02-tt n o 3- phosphate Na Cl Date Time Depth pH (tunhos) 10.98 4441 .1 65.3 1.5 3.4 2.0 3-5-81 1500 0-2" 8.6 111 <.05 11.1 2.01 3-5-81 1500 2-6" 8.8 81.0 3241 — 5.76 3-5-81 1500 6"-1.0' 8.72 72.5 2901 <.05 9.52 3-5-81 1500 1.0-1.5* 8.8 79.5 3181 <.05 46.5 3-5-81 1500 1.5-2.O' 8.7 100.7 4031 9421 .1 443.0 3-5-81 1500 2.0-2.5' 8.6 235.5 352.6 14101 <.05 686.0 3-5-81 1500 2.5-3.O' 8.65 ______— —

IDS = 0.8 (E.C.) x 5 (where 0.8 = conversion factor, 5 = dilution of 5 parts water------to 1 ------part soil) 126 SO IL EXTRACT ANALYSIS (rng/kg-ppm) FRENCHMAN FLAT #6 10°C

Tbtal Organic Collection E.C. Ortho n o Phosphate Na Cl % Moisture Carbon Date Time Depth PH (umbos) TDS1 n o 2-n 3-

— 24.4 43.17 3-5-81 1500 0-2" 8.6 131.2 5251 — 6.25 3-5-81 1500 2-6" 8.72 689.7 2,75s1 1,310.0 6,640.0 3-5-81 1500 6"-1.0' 7.8 2,861.2 11,445* — 3-5-81 1500 1.0-1.5' 7.75 3,5402 13,8502' 8,060.2 3,509.4 30,0003* 7,750.0 30,0003 14,0381 20,1003 5102 — 1380 540 3-5-81 1500 1.5-2.O' 7.89 3,560 14,240* <.025 6,860.0 .1 1375 470 3-5-81 1500 2.0-2.5' 7.48 3,050 12,200* <.025 6,110.0 — 5,530.0 3-5-81 1500 2.5-3.O' 7.85 2,596.1 10,384* 2,141.5 8,566* — 3,980.0 3-5-81 1500 3.0-3.5 7.75 —

1 _ i d s = 0.8 (E.C.) x 5 (where 0.8 = conversion factor, 5 = dilution of 5 parts water to 1 part soil) 2 - duplicate 2| TDS value is the actual value obtained from laboratory analysis 3 - Saturated paste extract - 3' TDS - E.C. x 1.0 (conversion factor) 127 SOIL EXTRACT ANALYSIS (mgAg-ppn) FRENCHMAN FLAT #7 7°C

Collection E.C. Ortho Tbtal Organic Date Time Depth pH (l>mhos) IDS1 n o 2-n N03- Phosphate Na Cl % Moisture Carbon

3-5-81 1540 0-2" 8.5 127.8 5111 26.1 18.02 3-5-81 1540 2-6" 8.45 1037.6 41501 2210.02 7.05 2430.0

3-5-81 1540 6"-1.0' 7.7 2391 .3 95651 5310.0 3-5-81 1540 1.0-1.5' 7.3 2397.4 95901 5090.0 3-5-81 1540 1.5-2.0' 8.0 2080 83201 <•025 4830.0 340 3-5-81 1540 2.0-2.5' 7.25 1710 68401 <•025 3250.0 270 3-5-81 1540 2.5-3.O' 7.8 1038.8 41551 2210.0 210 3-5-81 1540 3.0-4.O' 7.59 1250 50001 <.025 147.0

1 - TDS = 0.8 (E.C.) x 5 (where 0.8 = conversion factor, 5 = dilution of 5 parts water to 1 part soil) 2 - duplicate sanple 128 SOIL EXTRACT ANALYSIS (mg/kg-pfm) FRENCHMAN FLAT #8 6 ° C ______- ______. ------O r t h o Tbtal Organic C o l l e c t i o n E.C. % M o i s t u r e C a r b o n 2- n NO,- P h o s p h a t e N a C l D a t e T i m e D e p t h p H ( M m h o s ) T D S 1 n o 7 . 0 . 0 5 8 6 . 3 . 9 5 5 2 . 5 4 . 0 1 9 . 2 3 3 - 6 - 8 1 0 8 3 0 0- 2 ” 8 . 0 4 2 8 6 1 1 4 4 1 6 4 . 2 6.10 3 - 6 - 8 1 0 8 3 0 2- 6 " 9 . 0 5 1 2 6 5 0 4 1 5 0 9 . 0 3 - 6 - 8 1 0 8 3 0 6"-1 - 0 ‘ 8 . 5 5 2 6 5 . 3 1 0 6 1 1 1 5 9 0 . 0 3 - 6 - 8 1 0 8 3 0 1 . 0 - 1 . 5 ' 7 . 4 0 6 3 6 . 7 2 5 4 7 1 2 6 6 0 . 0 3 - 6 - 8 1 0 8 3 0 1 . 5 - 2 . 0 ' 7 . 2 5 9 5 0 . 3 3 8 0 1 1 2 7 9 0 . 0 3 - 6 - 8 1 0 8 3 0 2 . 0 - 2 . 5 ' 7 . 0 5 1 8 4 4 7 3 7 6 3 1 0 0 . 0 3 - 6 - 8 1 0 8 3 0 2 . 5 - 3 . O' 7 . 1 5 1 7 9 3 . 1 7 1 7 2 1

IDS - 0.8 (E.C.) x 5 (where 0.8 - conversion factor, 5 = dilution of 5 parts water to 1 part soil) 9 2 1 SO IL EXTRACT ANALYSIS (mg/kg-ppm) FRENCHMAN FLAT #11 6.5°C

Ortho Tbtal Organic Collection E.C. Carbon n o n n o 3- Phosphate Na Cl % Maisture Date Time Depth pH (imihos) TDS1 2-

19.0 63.5 3.5 16.6 12.5 3-6-81 0925 0-2" 8.32 186 7441 .05 .6 — 487.0 6.35 3-6-81 0925 2-6" 9.12 129 5161 465.0 3-6-81 0925 6"-1.0' 8.60 359.3 14371 — — 930.0 3-6-81 0925 1.0-1.5' 8.30 589.8 23231

— 3-6-81 0925 1.5-2.O' 8.30 518.4 20741 1020.0 — 863.0 3-6-81 0925 2.0-2.5' 8.35 417.9 16721 — 753.0 3-6-81 0925 2.5-3.O' 8.40 338.2 13531

1 - TDS = 0.8 (E.C.) x 5 (where 0.8 = conversion factor, 5 = dilution of 5 parts water to 1 part soil) 130 SOIL EXTRACT ANALYSIS (mg/kg-ppm) FRENCHMAN FLAT #12 9°C

Total Organic E.C. Ortho Collection N03- Phosphate Na Cl % Moisture Carbon Date Time Depth PH (Mmhos) TDS1 n o 2-n

— ,060.0 .25 72.5 18.69 3-6-81 1030 0-2" 8.09 614 2.4561 .15 1 222 ,100.0 9.7 3-6-81 1030 2-6” 7.55 4239.1 16,956! — 11 — 7,750.0 3-6-81 1030 6“-1.0' 7.80 3227.7 12,9111 7,080.0 3-6-81 1030 1.0-1.5' 7.30 4059.5 16,23s1 — 5,310.0 3-6-81 1030 1.5-2.O' 7.60 2311.2 9,24s1 — — 3,100.0 3-6-81 1030 2.0-2.5 7.60 1485.6 5,942! — 2,660.0 3-6-81 1030 2.5-3.0 8.15 1154.6 4,618

1 - IDS = 0.8 (E.C.) x 5 (where 0.8 = conversion factor, 5 = dilution of 5 parts water to 1 part soil) 131 SOIL EXTRACT ANALYSIS (mg/kg-ppm) FRENCHMAN FIAT #13

Ortho Total Organic Collection E.C. % Moisture Carbon n o 2-n n o 3- phosphate Na Cl Date Time Depth pH (wnhos) TDS1

1.35 20 2.5 16.30 17.5 3-5-81 0-2" 8.16 216 8641 .1 22.1 2.48 — 17.5 3-5-81 2-6" 9.10 67.0 2681 — 35.4 3-5-81 6"-1.0' 9.20 90.5 3621 — 3-5-81 1.0-1.5' 9.05 90.6 3621 20.1 — 3-5-81 1.5-2.O' 9.30 106.6 4261 11.1 — 31.0 3-5-81 2.0-2.5 9.45 122.7 4911 — 53.1 3-5-81 2.5-3.O' 9.40 161.4 6461 — 151.0 3-5-81 3.0-3.5' 9.45 241.5 9661

■IDS = 0.8 (E.C.) x 5 (where 0.8 = conversion factor, 5 = dilution of 5 parts water to 1 part soil) 132 SOIL EXTRACT ANALYSIS (mg/kg-ppm) YUCCA FLAT # 1 8°C

Ortho Tbtal Organic E.C. Carbon Collection n o 3- Phosphate Na Cl % Moisture Date Time Depth pH (mnhos) IDS1 N02-N 13.29 13.5 628.01 <-05 5.09 1.55 38.65 2.0 3-5-81 0-6” 8.30 157.0 1049.21 5.98 3-5-81 6"-1.0' 8.65 262.3 T m o 817.2* 21 .0 3-5-81 9.45 204.3 828.0* 22.1 3-5-81 1.5-2.0‘ 9.95 207.0 3767.2* 310.0 3-5-81 2.0-2.5' 8.10 941.8

■IDS = 0.8 (E.C.) x 5 (where 0.8 = inversion factor, 5 = dilution of 5 parts water to 1 part soil) 133 SOIL EXTRACT ANALYSIS (mg/kg-pprn) YUCCA FLAT #2 8 “C

Ortho Total Organic Collection E.C. n o 3- Phosphate Na Cl % Moisture Carbon Date Time Depth pH (mnhos) IDS1 N02-N

6.42 .3 156.5 1.5 16.25 11.5 3-5-81 0-1" 8.13 304.0 1216.0 1 <.05 1730.0 9.80 3-5-81 1-6" 8.15 997.9 3991.6* 3320.0 3-5-81 6"-1.0' 7.55 1781.9 7127.61 T in o 2880.0 3-5-81 7.25 1675.6 6702.41 2430.0 3-5-81 1.5-2.O' 7.65 1398.1 5592.41 86.3 3-5-81 2.0-2.5 7.75 1104.6 4418.41

■IDS = 0.8 (E.C.) x 5 (where 0.8 = conversion factor, 5 = dilution of 5 parts water to 1 part soil) 134 SO I L EXTRACT ANALYSIS (rng/kg-pprn) YUCCA FLAT #3 8°C

Ortho Total Organic Collection E.C. Carbon n o 3- Phosphate Na Cl % Moisture Date Time Depth P« (ymhos) IDS1 N02-N

7.31 .5 148.5 2.5 19.73 14.0 3-5-81 0-2" 8.25 278 1,112* .05 6860.0 10.31 3-5-81 2-6" 7.55 3379.4 13,517.61 Co 7 O 6640.0 3-5-81 7.35 3179.7 12,718.8* 5760.0 3-5-81 1.0-1.5’ 7.30 2555.9 10,223.6* 4870.0 3-5-81 1.5-2.O’ 7.25 2000.9 8,003.6* 7.25 1751.0 7,004.0* 3540.0 3-5-81 2.0-2.5* —

1 = IDS = 0.8 (E.C.) x 5 (where 0.8 = conversion factor, 5 = dilution of 5 parts water to 1 part soil) 135 i

SOIL EXTRACT ANALYSIS (rng/ky-ppm) YUCCA FLAT #5 11°C

Ortho Total Organic E.C. % Moisture Carbon Collection ms n o 2-n n o 3- phosphate Na Cl Date Time Depth PH (Mmhos) 1 10.06 <.025 10.4 .55 1.85 1.25 3-6-81 1015 0-2" 9.06 49 1961 11.44 1841 2.66 3-6-81 1015 2-6" 9.04 46 4441 6.42 3-6-81 1015 6"-1.0' 9.24 111 446.41 3.76 3-6-81 1015 1.0-1.5' 8.65 111.6 276.41 3-6-81 1015 1.5-2.O' 8.85 69.1 1.11 321.21 .22 3-6-81 1015 2.0-2.5’ 9.15 80.3

■ms = 0.8 (E.C.) x 5 (where 0.8 = conversion factor, 5 = dilution of 5 parts water to 1 part soil) 136 SOIL EXTRACT ANALYSIS (mgAg-PPn) YUCCA FLAT #6

Tbtal Organic Collection E.C. Ortho % ftoisture Carbon Date Time Depth pH (wnhos) TDS1 N02-N n o 3- Phosphate Na Cl

19.0 3-6-81 1200 0-2" 8.36 195 7801 .05 84.1 .45 103 . 4.5 20.70 CO o CO 3-6-81 1200 2-6" 7.75 1220 27.0 13.37 3-6-81 1200 6"-1.0' 7.38 2040 81601 2990.0 3-6-81 1200 1.0-1.5' 7.55 1574.6 6298.41 2660.0 3-6-81 1200 1.5-2.0’ 7.40 1252.8 5011.21 2430.0 3-6-81 1200 2.0-2.5’ 7.44 1240 49601 2210.0 3-6-81 1200 2.5-3.0’ 7.45 1360 54401 2200.0 3-6-81 1200 3.0-3.5 7.7 1144.4 4577.61 1860.0 3-6-81 1200 3.0-4.O' 7.71 852 34081 1330.0

1 _ i d s = 0.8 (E.C.) x 5 (where 0.8 = conversion factor, 5 = dilution of 5 parts water to 1 part soil) APPENDIX V

Variation of Nitrate with Depth at Different Sample Sites FRENCHMAN FLAT 0-2" (0-5.0cm)

3 Site NO3(mg/Kg) TD3(mg/Kg) % NO /TDS

FF-1 9.08 636 1 .43

FF-2 16.8 644 2.61

FF-3 16.2 252 6.41 FF-4 59.8 455 13.1 66.0 FF-5 444 1 4.9 4.69 FF-6 24.6 525 5.11 FF-7 26.1 511 7.55 FF-8 86.3 1 ,144 2.56 FF-1 1 19.0 744 1 43.3 FF-1 2 ,060.0 2,456 22.1 2.56 FF-1 3 864 140

FRENCHMAN FLAT 2-6" (5.0-15 cm)

3 Site NO3(mg/Kg) TD3(mg/Kg) % NO /TDS

FF-1 131.0 514 25.4

FF-2 13.7 356 3.85

FF-3 1 0.6 278 3.82

FF-4 16.8 367 4.58 11.2 FF-5 324 3.45

FF-6 1 ,320.0 2,759 47.8

FF-7 2,430.0 4,150 58.7

FF-8 64.2 504 12.7 94.4 FF-1 1 487.0 516 11 100.0 65.3 FF-1 2 , 16,956 6.52 FF-1 3 17.0 268 141

FRENCHMAN FLAT 2-6" (5.0-15cm)

Site N03(mg/Kg) TDS(mg/Kg) % NOg/TDS

FF-1 131.0 514 25.4

FF-2 1 3.7 356 3 .85

FF-3 1 0.6 278 3.82

FF-4 16.8 367 4.58 11 .2 FF-5 324 3.45

FF-6 1 ,320.0 2,759 47.8

FF-7 2 ,430.0 4,150 58.7 12.7 FF-8 64.2 504 94.4 FF-1 1 487.0 516 11 100.0 65.3 FF-1 2 , 16,956 1 6 .82 FF-1 3 7.0 268 142

FRENCHMAN FLAT 6"-1.0’ (15-31 cm)

3 Site NO 3(mg/Kg) TD3(mg/Kg) T NO /TDS

FF-1 1 ,570.0 3,058 51 .4 1 2.66 FF-2 1 1 .7 441 2.21 FF-3 269 .82 2.88 FF-4 484 .60 1 2.0 FF-5 5.81 290 58.6 FF-6 6,710.0 1 1 ,445 55.5 FF-7 5,310.0 9,565 1 48.0 FF-8 5,090.0 ,061 32.4 FF-1 1 465.0 1 ,437 60.0 FF-1 2 7,750.0 12,911 9 .78 FF-1 3 35.4 362

1 - N03 by Brucine Method 143

FRENCHMAN FLAT 1.0-1.5' (31-46 cm)

3 3 Site NO (mg/Kg) TD3(mg/Ka) T NO /TDS

2 210.00 FF-1 , 4,180 53.0 1 FF-2 9.74 430 2.27

FF-3 2.28 309 .93 1 FF-4 8.85 681 .30 3.03 FF-5 9.62 318 55.8 FF-6 7 ,830.00 14,038 53.1 FF-7 5 ,900.00 9 ,590 69.9 FF-8 1 ,590.00 2,547 40.0 FF-1 1 930.00 2 ,323 43.6 FF-1 2 7,080.00 1 6,238 20.1 5.56 FF-1 3 362

l _ n q 3 by Burcine Method 144

FRENCHMAN FLAT 1.5-2. O' (46-61 cm)

3 % N O 3/TDS Site NO (mg/Kg) TDS(mg/Ka)

2 65.0 FF-1 ,880.0 4 ,426

4 .70 FF-2 26.6 565

.66 .17 FF-3 390

21 .0 799 2.63 FF-4 1 1 403 .70 FF-5 47.0

14,240 47.1 FF-6 6,710.0

8,320 * 58.0 FF-7 4,830.0

3,801 69.9 FF-8 2,660.0

1 020.0 2,074 49.1 FF-1 1 ,

9 ,245 57.5 FF-1 2 5,310.0

1 1 .1 1 426 2.60 FF-1 3

l _ n 03 - by Brucine Method 145

FRENCHMAN FLAT 2.0-2.5" (61-76 cm)

3 3 Site NO (mg/Kg) TD3(mg/Kg) % NO /TDS

2 65.3 FF-1 ------,880.0 - 4,406 68.6 666 10.3 FF-2 .74 FF-3 3.32 450 1 1 12.3 FF-4 24.0 ,008 47.5 FF-5 447.0 942 12,220 50.6 FF-6 6,170.0 6 47.6 FF-7 3,250.0 ,840 37.8 FF-8 2,790.0 7,376 51 .6 FF-1 1 863.0 1 ,672 100.0 5,942 52.2 FF-1 2 3, FRENCHMAN FLAT 2.5-3.O' (76-91 cm)

3 Site NO3(mg/Kg) TD3(mg/Kg) % NO /TDS

FF-1 2 ,430.0 4,211 57.8

FF-2 115.0 830 1 3.9

FF-3 5.98 602 .99

FF-4 531 .0 1 ,654 32.1 49.2 FF-5 693.0 1 ,410 53.8 FF-6 5,590.0 10,384 2 210.0 53.3 FF-7 , 4,155 43.2 FF-8 3,100.0 7,172 55.6 F-1 1 753.0 1 ,353 57.5 FF-1 2 2,660.0 4,618 8.22 FF-1 3 53.1 646 147

YUCCA LAKE 0-2" (0.5 cm)

3 Site NO3(mg/Kg) TDS(mg/Ka) % NO /TDS

YL-1 ( o - 6 " [. 5.09 628 .81 1 YL-2 (0- 1") 6.42 ,216 .53 1,112 .66 YL-3 (0- 1") 7.31

YL-5 10.4 196 5.31 10.8 YL-6 84.1 780 148

YUCCA LAKE 2-6" (5-15 cm)

3 Site NO3(mg/Kg) TD3(mg/Kg) % NO /TDS

YL-1 (0-6") 5.09 628.0 .81 .6 YL-2 (1-6") 1 ,730.0 3 ,991 43.3

YL-3 (1-6") 6,860.0 13,517.6 50.8

YL-5 2.66 184.0 1 .44

YL-6 27.0 4,880.0 .55 YUCCA LAKE 6'-1.0' (15-31 cm)

3 Site NO3(mg/Kg) TDS(mg/Kg) % NO /TDS

YL-1 5.98 1 ,049.2 .57 YL-2 3,320.0 7,127.6 46.6

YL-3 6,640.0 1 2,718.8 52.2

YL-5 6.42 444.0 1 .45

YL-6 2 ,990.0 8.160.0 36.6 150

YUCCA LAKE 1.0-1.5' (31-46 cm)

3 Site NO3(mg/Kg) TDS(mg/Kg) % NO /TDS

YL-1 21 .0 817.2 2.57 6 YL-2 2,880.0 ,702.4 42.9

YL-3 5,760.1 10,223.6 5 6.3

YL-5 3.76 446.4 .84

YL-6 2,660.0 6,298.4 42.2 151

YUCCA LAKE 1.5-2.O' (46-61 cm)

3 Site NO3(mg/Kg) TDS(mg/Kg) % NO /TDS

YL-1 22.1 828.0 2.67

YL-2 2,430.0 5,592.4 43.5

YL-3 4,870.0 8,003.6 60.8

YL-5 1.11 276.4 .40

YL-6 2,430.0 5,01 1 .2 48.6 15

YUCCA LAKE 2-2.5' (61-76 cm)

Site NO3(mg/Kg) TDS(mg/Kg) % NO3/TDS

YL-1 310.0 3 ,767.2 8.23

YL-2 86.3 4 ,418.4 1 .95

YL-3 3,541.0 7 ,004.0 50.6

YL-5 .22 321 .2 .07

YL-6 2,210.0 4 ,960.0 44.6