/¡^S^ United States Miu) Department of Agriculture "^ Conservation Office of Governmental and Public Affairs Tillage: Agriculture SS Information Bulletin Number 461 Things to Consider Agricultural Information Bulletin No. 461 Conservation United States Department of Agriculture (USDA) Office of Information (01) Tillage: Washington, D.C. 20250 Author: Arnold D. King, Agronomist Things to Consider Soil Conservation Service, (SCS) USDA, Ft. Worth, Texas Co-author: G.B. Holcomb, 01, USDA

Credits: Contributors of individual suggestions and material Tifton, Ga.; K.L. Wells, M.J. Bitzer, and Robert L. Blevins, for use in this publication were numerous and included the University of Kentucky, Lexington; W.S. Ball and Howard following: John C. Siemens, University of Illinois, Urbana; M. Olson, North Dakota State University, Fargo; John D. W.M. Edwards of the Ohio Agricultural Research and Walker, Rexburg College, Ricks, Idaho; Charles B. Elkins, Development Center, Wooster; W.C. Moldenhauer, Agricul- ARS, USDA, at the Alabama Agricultural Experiment Sta- tural Research Service (ARS), USDA, National Soil Erosion tion, Auburn; G.R. Tupper, Auburn University, Auburn; Laboratory, Purdue University, West Lafayette, indiana; W.H. Mitchell, Delaware Agricultural Experiment Station Estel H. Hudson, University of Tennessee, Knoxville; and Cooperative Extension Service, University of Dela- Thomas C. McCutchen, Milan (Tennessee) Experiment ware, Newark; Fred W. Westbrook and Fred S. Swader, Station, University of Tennessee; Lee A. Christensen, Extension Service (ES), USDA; Charles Smith, Cooperative Economic Research Service (ERS), USDA, at the Universi- State Research Service (CSRS), USDA; Stephen Rawlins, ty of Georgia, Athens; G. Howard Turner and Robert Rice, ARS, USDA, Beltsville, Md.; John T. Alexander, Indiana American Association for Vocational Instructional Materials, farmer; Keith Kuhn, Iowa farmer; Ed Poe, Nelson Fitton, Athens, Ga.; R. Harold Brown, University of Georgia, Edna Carmichael, and Claude Gifford, 01, USDA, and Athens; Ron Hennings, Coastal Plains Experiment Station, others whose names are mentioned in the text.

Mention of a proprietary product in this publication does approval by the Department or by any agency of the U.S. not constitute a guarantee or warranty of the product by Government to the exclusion of other products that also the U.S. Department of Agriculture and does not imply its may be suitable.

COVER: Double cropping, i.e., growing two crops the same year in the same field is sometimes practiced in connection with conservation tillage. Shown planting soybeans in small grain stubble is a Maryland farmer in foreground, while a combine in background is harvesting the grain. (Photo by Tim McCabe of SCS.) Contents

Page Introduction 1 What Are the Basic Conservation-Tillage Systems 2 No-Till 2 Ridge-Plant 5 Strip-Till 6 Disk/Chisel-Plant 6 Eco-Fallow (Chemical-Fallow) 6 Sod Planting 6 How Much Does Crop Residue Affect Erosion? , 7 How Much Does It Cost To Switch to Conservation Tillage? 9 How Does Conservation Tillage Affect Crop Yields? 13 How Does Crop Residue Management Affect Soil Fertility? 15 How Does Conservation Tillage Work in Various Soils? 15 How Much Does Crop Residue Reduce Pollution from Fields? ... 16 How Does Conservation Tillage Affect Pest Control? 17 Who Is Working To Solve Problems Associated with Conservation Tillage? 18 Cost Sharing 18 Information Sharing , 18 Research Projects 18 Fertilizer 18 Subsoiling 20 Pest Controls 20 Cropping Practices , 21 Machinery 22 Other Problems 22 Should You Try Conservation Tillage on Just a Few Acres Before Switching? 23 Where Can You Get More Information About Conservation Tillage Systems? 23

February 1985 Introduction A lot of residue is involved. The major field crops har- vested in this country (from about 341 million acres) pro- In this bulletin are answers to various questions you may duce about 400 million tons of crop residue each year. have about whether you want to join the thousands of Any of that residue left on the surface shields soil from the farmers who have switched to conservation tillage. Others beating of raindrops. Residue holds soil and water and say they will change when they feel confident enough to reduces sediment and chemical runoff. borrow money for investment in conservation tillage equip- By helping keep soil in the fields, residue also helps pre- ment. Some conservation tillage advocates say that before vent crop yield reduction that occurs on eroded land, you get further into debt, you might be able to test new some researchers point out. systems before buying equipment. Another economic consequence to you as a farmer is If you're trying to save money and reduce sou erosion, the fact that switching to conservation tillage from conven- conservation tillage may be your most logical procedure. It tional tillage can cut fuel and labor costs in certain row- can help keep erosion from lowering the yield potential of crop and forage farming by 30 to 90 percent. By cutting your soil and polluting water resources. It can keep more your field operations, you might also be able to cut your soil on your farm than conventional tillage can. equipment inventory. These are factors important to all To emphasize the national need for érosion control, a sizes of farm operations—for both full- and part-time recent publication of USDA's Economic Research Service operators. (ERS),i quoted an author as stating that Phase 1 of the The wide variation in savings depends on how much Natural Resources lnventory2 conducted by US DA "shows crop residue stays on the surface and on other related a national 1977 average annual loss from sheet and rill matters discussed in this publication. erosion in excess of 4 billion tons. If it were all concen- If current trends continue, most U.S. farmers—regard- trated in one area, 4 billion tons of soil loss would mean less of crops farmed or size of operation—will be using the removal of all the topsoil (6 inches) from 4 million some types of conservation tillage techniques by the end acres. With that kind of loss each year, it would take only of the century. Almost one-fourth—about 100 million 100 years to wash away every single acre of cropland in acres—of U.S. cropland is currently being farmed by con- the United States." servation tillage, as indicated in figure 1. ses also has estimated that wind erosion in 1977 took The trend toward conservation tillage began in the early away another 4,460,000,000 tons of soil from the nation's 1970's. SCS specialists have projected acreage estimates cropland, pastureiand, forest land, and rangeland. to the year 2010, as shown in figure 1. USDA experts ex- On U.S. cropland in 1977, according to Soil Conserva- pect the past dramatic increase—by more than 300 per- tion Service (SCS) estimates, sheet and rill erosion on cent in a decade—will continue. U.S. cropland in 1977 was 1,926,000,000 tons, while the Conservation tillage is one of several soil and water sav- total such erosion by water on pastureiand was 346 ing measures emphasized in USDA's national conservation million, on forest land 435 million, and on rangeland, 1,155 program. Other measures include terracing, contour farm- million. Those figures total 3,862,000,000 tons. ing, contour stripcropping, and the building of grass water- More recently, SCS estimates that cropland (about 413 ways and headlands. million acres) erodes at the rate of about 2.8 billion tons of While deciding whether to try or adopt conservation till- soil yearly. That averages about 6.8 tons per acre. SCS age, you also need to determine whether other conserva- calculations show that 10 percent of that cropland loses tion practices should be retained or adopted for a more more than 10 tons an acre annually to sheet and rill complete conservation system for your farm. If your fields erosion—the kind that occurs before the water has cut slope only slightly, for example, you may find that a com- deep enough to form gullies. bination of conservation tillage and contour farming may USDA's Agricultural Research Service (ARS) has said be enough to retain most of your soil. that the rate of soil loss on some cropland is as much as SCS conservationists can answer your questions about 10 times greater than the natural rate of replacement. ARS evaluating the economics and effectiveness of one or more said a third of the U.S. corn acreage, 44 percent of soy- conservation practices. Using the Universal Soil Loss bean, 34 percent of cotton, and 39 percent of all sorghum Equation (USLE)—which also is described on page 7 acreage suffers from such loss. they can help you calculate probable erosion-preventing Conservation tillage systems reduce erosion and mois- effects of conservation tillage alone or in combination with ture loss by leaving crop residue on the surface until new other practices in your farm's conservation program. They crops are planted. Such systems mark a striking evolution also may have data pinpointing the economics of conser- in farming practices when compared with traditional, con- vation tillage in your county. ventional tillage. The latter refers to previously favored County SCS officials have a booklet. Assistance tillage systems using implements that buried or otherwise Available from the Soil Conservation Service, Agriculture In- mixed surface residue into the soil. formation Bulletin 345, which explains SCS help in detail. A copy is available to farmers at no charge. SCS staff members will try to help you resolve any tillage or other conservation related problem. M Comparison of Tillage Systems for Reducing Soil Erosion and Water Pollution, by Lee A. Christensen and Patricia E. Morris, ERS, USD A, USDA's Extension Service (ES), working in cooperation Agricultural Economic Report No. 499, 1983. with State Cooperative Extension Services, also has staff ^National Resources Inventory, Soil Conservation Service, USDA, Stat. members in most States available to work with farmers in Bull. 686, Dec. 1982. dealing with conservation problems. What Are the Basic Conservation-Tillage You prepare the seedbed and plant in a single trip across Systems? the field. You plant the seed into a minimally prepared seedbed and leave the preceding crop's residue virtually Common usage has not yet firmly fixed the definitions of undisturbed on the surface. You use chemicals for weed conservation-til I age systems, but for purposes of this control. publication, six are defined: no-till, ridge-plant, disk/chisel- You can use no-till farming with row crops, small grains, plant, strip-till, eco-fallow or chemical fallow, and sod or forages. The most common row crops produced by no- planting. Sometimes a system involves more tillage than till are corn and soybeans. No-till planters of row crops no-till but less tillage than conventional tillage and is called usually are equipped with smooth, rippled, or fluted limited, reduced, or minimum tillage. Eco-fatlow and sod coulters, like those shown in figure 3. The coulters slice planting are basically no-till but are singled out to clarify through the residue so the seed can be properly placed in- some differences relating to crop. to moist soil. Figure 2 shows various tillage operations possible with Since the planter tills only a very narrow strip of soil, vir- corn. Details about some implements used with row-crop tually all crop residue remains on the surface to protect planters in conservation tillage systems appear in figure 3. the soil from wind and water erosion. The amount of water A brief summary of each system follows. saved when crop residues are left is Indicated in figure 4, where no-till is matched with conventional tillage. No-Till

Sometimes called zero tillage, chemical tillage, or slot planting, no-till is the ultimate conservation-tillage system:

Figure 1.

Planted Cropland Where Conservation Tillage Is or Will Be Used

Acreage % of

1960 1970 1980 1990 2000 2010

1111 Percent of planted cropland reduced tillage (includes no-till)

¡III Percent of planted cropland no-tilled

Source: Soil Conservation Service, USDA. (Chart, courtesy of Monsanto Agricultural Products Go.) Figure 2: Comparison of Various Operations Involved in Different Tillage Systems with Corn

Tillage Crop Water Conservation System Residue Erosion Comments .NO^

Moldboard Plow o Least effective for erosion o O 0 O Pounds/Acre Oo/o control.

Disk Harrow May not leave sufficient surface 1500 40% residue. Buries approximately O 0 O Pounds/Acre 50% of residue per trip over the field.

Chisel Plow (twisted shank) 3000 Roughens surface, covers up to 65% 75% of residue per trip over the 0 O Pounds/Acre field.

Chisel Plow (straight shank) Roughens surface, covers about 4800 75% 20% of residue per trip over the O © O Pounds/Acre field.

Ridge-Plant

Cultivator must be used for 4800 75% O ® ® Pounds/Acre weed control and ridge forming.

No-Till High dependency on herbicides for control of weeds—special 6000 95% cultivator capable of operating ® Pounds/Acre in heavy residue may be needed.

1/ Measured in pounds per acre based on 100-bushel per acre yield. Actual residue left Legend: (^ Indicates equipment ordinarily needed. will vary with tractor speed, machinery settings, and heaviness of crop growth. 0 Optional equipment that may be used. 2/ Data are approximations. Figures will vary according to soil type, percent and length of (*) Specialized or modified equipment needed. slope, amount of rainfall, and cropping system. Source: Soil Conservation Service of Michigan. Figure 3: Soil-Engaging Tools Used in Conservation Tillage Planting

Tool Function Options

Coulter Cuts through sod or (Initial crop residue mulch penetration)

Fluted Smooth w/depth bands Ripple

Opener Opens a furrow for seed placement

Double disk Single disk Chisel

Press wheel Imbeds the seed firmly into the soil

Press wheel Rubber-tire Small-grain (rubber or metal) press wheel metal press wheel

Seed furrow Closes the closer seed furrow

Double-press Double disk wheel Knife type

Specialty tool Facilitates planting into strips void of surface mulch. (Operates in front of opener)

Serrated disks Sweep Rotary tines (trash whipper) Figure 4 Soil-Water Levels Using No-Till or Conventional Tillage Systems Inches 2.5 _ Soil Water in 0 to 7- Inch Depth

2.0 -

1.5 - Conventional-tillage corn 104 bu./acre

1.0 Dally Rainfall 2.51 inches 1.0 h Wilting = .5 , 0.6 in.

0 —r 4Í-.-U —r- M 10 20 10 20 10 20 June July August

Source; "Rainfall and soil water for corn watersheds, Coshocton, Ohio," No-Tillage Corn—Characteristics of the System, by W. M. Edwards and associates, Ohio Agricultural Research and Development Center, Wooster. Agricultural Engineering, Vol. 51, No, 3, March 1970.

Advantages spring; consequently, seed germination may be 1. More plant residue is left on the surface than with slower and more erratic than usual. (This problem other systems, thus reducing erosion and conserv- can be alleviated by use of the ridge-plant system.) ing soil moisture for crop use. 5. Special treatment of seed may be necessary 2. Less erosion means less water pollution by because of residues that may harbor rodents and chemicals attached to soil particles. pathogens that cause plant diseases. 3. Less equipment is needed than with other systems. 4. Fuel and labor expenditures are held to the Ridge-Plant minimum. 5. Unplowed soil may make harvesting easier in some Sometimes called till-plant (ridge), this system mainly en- areas where fall rains often can turn plowed soil in- tails planting the crop with little or no preliminary tillage on to mud that mires heavy equipment. ridges formed or built up during the preceding crop 6. Since residue acts as a cushion against wheels season. The ridges are 30 to 40 inches apart. Usually, a tool on the front of the planter clears a path 8 to 10 inches and hammering rain, no-till can reduce soil com- wide through the preceding crop's residues. Ridging is paction if machinery is used carefully. done during the growing season with a disk cultivator that Disadvantages also helps control weeds between rows. 1. Investment in a new planter or modification of an Some farmers have been successful in planting on the old one by means of specialized devices—such as ridges without clearing the 8- to 10-inch path. With further some of those shown in figure 3—may be neces- development, this procedure could result ¡n the combined sary in order to get adequate seed contact with the benefits of ridging and the use of crop residues from soil and uniform planting depth. These devices may earlier crops. include extra weights and coulters that cut through Advantages the residue, depth-gauge wheels to help maintain 1. Ridges, especially if contoured, can help reduce coulters at a uniform depth, and press wheels that erosion. pack the soil around the seeds. 2. Dependence on herbicides is less than with no-till. 2. Intensive management is needed to control crop 3. Fields with ridges drain and warm up in spring pests. faster than ridgeless fields, enabling earlier plant- 3. There is a strong dependence on herbicides. ing and sometimes reducing wet spots. 4. Crop residues may slow soil warmup during the 4. Only about a third of the surface area is dis- 4. The conventional planter does not always need to turbed—considerably less than with conventional be replaced. plowing but somewhat more than with no-till. 5. Soil may be warmer and drier earlier in spring than Residue on the surface between ridges conserves with no-till. moisture that would be lost if residue were incor- Disadvantages porated into the soil. 1. Tillage tends to dry the soil—but this can be an ad- Disadvantages vantage if moisture has been excessive. 1. As with no-till, better herbicide management is 2. Erosion is greater than with no-till. necessary. 3. More equipment is needed than with no-till. 2. On slopes with more than a 3 percent incline, con- tour farming may be necessary because cultivation Eco-Failow or Chemical-Faiiow for weed control and ridge maintenance may leave less residue to protect the soi! from erosion. Eco-fallow, sometimes called chem- or chemical-fallow, is 3. It can be troublesome to restrict traffic of equip- an improved method of stubble-mulch tillage, which re- ment to the same paths yearly so as to reduce soil quires equipment such as that shown in figure 5. Weeds compaction. are controlled by chemicals or a combination of chemicals 4. Ridges are easily broken unless traffic is managed and tillage. This system is commonly used on the Great with care, combine wheels are spaced well, and Plains and western regions where wheat is the primary livestock grazing is handled cautiously. crop and fallowing—leaving the ground idle a season—is a common practice. Strip-Till If you grow grain in low-rainfall areas such as the Great Plains States, you may apply persistent herbicides to stub- Strip-till is sometimes called till-plant (flat). A specialized ble to kill weeds after harvest, and then leave the land planter is used, equipped to incorporate or push aside res- fallow during winter and spring (and perhaps on through idue to form clean narrow strips for planting. Strip clearing the summer) to store scarce moisture and prevent erosion. may be done with sweeps, disk blades—sometimes called The followup crop is planted into the stubble by no-till "trash whippers"—or powered rotary tillers, the last mainly planting or some other form of reduced tillage. for truck crops that have tiny seeds. Advantages Advantages 1. Stubble, especially if it's tall, deflects wind, thus in 1. As with conventional tillage, clean strips of ground winter helping keep snow from drifting beyond the warm up faster than mulch-covered soil. field, and in summer reducing wind erosion and 2. Certain herbicides can be banded on (laid on in providing shade that reduces evaporation. bands or strips) and activated by the moist soil in 2. With increased moisture-use efficiency, wheat fields strips free of residue. may not need to be left fallow for a year; wheat 3. Dependence on herbicides may be less than with may be alternated with other crops or grown the no-till system. annually. 4. The clean strip may provide better seed-soil con- 3. Less labor and equipment is needed than with con- tact for small seeds. ventional tillage. Disadvantages Disadvantages 1. The clean strips are more erodible than mulch- 1. Use of essential herbicides may be limited by lack covered soil; contour farming may be necessary. of a dependable moisture supply when farmers are 2. Special equipment is needed to provide the clean located in a low-rainfall area. strips. 2. Special planters are needed in high-residue fields.

Disk/Chisel-Plant Sod Planting

This system differs from no-till in that you disk or chisel Sod planting is really a variety of no-till. A no-till planter in either in the fall or spring, or both in fall and spring. The a single operation either plants grass seed to renovate equipment is designed and adjusted to leave most residue pasture or plants row crops or forage in pasture or on the soil surface. You also may harrow the land to break meadow sod. up clods before planting row crops. You may use contact herbicides to kill annual weeds Conventional planters sometimes can be used, but gen- and "burn down" perennials. This practice gives new erally a coulter or sweep (see figure 3) runs in front of the seedlings a better chance to become established. planter to prevent clogging by residue and to help get the Advantages seeds properly placed in the soil. You control weeds with 1. Sod planting allows renovation of steeper slopes a cultivator or herbicides—sometimes both. with less erosion than with conventional methods. Advantages 2. Stones cause fewer problems with sod planting 1. Erosion is reduced because of more residue than than with conventional seedbed planting. with moldboard plowing. Disadvantages 2. Chemicals can be incorporated into the soil better 1. Insects may be a problem if control techniques are than with no-till. inadequate. 3. Contact herbicides may not be required at planting 2. Special planters are usually required. time. Figure 5. Chisel Plow (also see figure 3) com- due burial. Combination of roughened surface bined with air seeder drill—as shown abovQ— and protruding stubble helps reduce dust drift- sometimes is used in eco-fallow tillage system ing by winds as well as erosion from infrequent to prepare soil for seed with minimum of resi- but intense rains in the Great Plains.

How Much Does Crop Residue systems as follows: Conventional tillage, 9.0 tons an acre; Affect Erosion? "disk and plant" (termed disk-chisel plant in this publica-' tion), 4.7 tons an acre; till-plant (termed strip-till here), 2.0 Crop residue reduces both raindrop impact and velocity of tons an acre; and slot-plant (no-till), 0.8 tons an acre. runoff, and thus limits soil detachability, I.e., breakup, and University of Nebraska specialists indicated the transport. Surface residue also reduces wind erosion estimates were based on the Universal Soil Loss Equation because it absorbs wind energy. Conservation tillage also (USLE) for average conditions in the northern Corn Belt. typically leaves larger soil clods than conventional tillage, They assumed average erodibility on a 4-percent slope and reduces both wind and water erosion, according to 200 feet long and that operations were up and down the Pierre Crosson, author of a booklet on tillage^. Citing slope, with continuous corn yielding 110 bushels an acre. several studies, Crosson quoted one by R.E. Phillips and The textbook also contains a table attributed to "Ag associates" that said: "By far the most acceptable and ef- Review Northeast," June 1981, showing the amount of fective measure for control of wind and water erosion is erosion of three erosive soils in Ontario County, N.Y., the maintenance of surface residues (mulches)." under conventional tillage and no-till. With all factors iden- Crosson added, "Most studies show that conservation tical, except for tillage management, the following results tillage reduces erosion 50 to 90 percent compared with were shown: (1) Under conventional tillage, Camillus silt conventional tillage, with the percentage of surface loam lost 19.38 tons an acre, compared with 1.98 tons covered by residue the most important factor in determin- under no-till; (2) conventionally tilled Schoharie silty clay ing the amount of the reduction." loam lost 15.59 tons an acre, compared with 1.59 tons In simulated rainfall studies in Illinois and Indiana, for under no-till; and (3) conventionally tilled Palmyra fine san- example, chisel, till-plant (here called strip-till), and no-till dy loam lost 7.85 tons ah acre, compared with 0.8 of a ton systems reduced soil loss by 94, 60, and 95 percent, under no-till. The USLE also was used in this instance. respectively, compared with conventional tillage after what (The USLE is used to estimate sheet and rill erosion on was rated as a "high-intensity storm." the basis of the following five factors: R = rainfall and Similar estimates of erosion are give in Fundamentals of runoff factor, K = soil erodibility factor, LS = topographic No-Till Farming, a 148-page textbook published in 1983 by factor, D = vegetative cover and management factor and the American Association for Vocational Instructional P = support practice factor. Soil loss in tons per acre is Materials, Athens, Ga. It shows results from one study in- calculated with this equation: RxKxLSxCxP.) volving corn on Nebraska soils at the University of A third table on erosion in the textbook is from Purdue Nebraska at Lincoln. It indicates erosion under four University. It shows the "effect of crop residue on runoff, infiltration and soil loss, 5 percent slope," in part as ^Conservation Tillage and Conventional Tillage: A Comparative Assessment follows: With no crop residue, runoff is 45 percent, infiltra- published by the Soil Conservation Society of America, Ankeny, Iowa, 1981. tion is 54 percent, and soil loss is 12 tons an acre. By contrast, with 2 tons of residue per acre, runoff is 0.1 per- ""No-tillage Agriculture." Science 208: 1980, 1, 108-1, 113. cent, infiltration is 99 percent, and soil loss is zero. Table 1. Soil erosion from continuous corn on northern Illinois cropland with conventional tillage and no-till (adapted from Hayes and Kimbelin)

Soil erosion in tons per acre per year^ 3% slope 6% slope 9% slope 12% slope

Cornstalk residue on the surface (lb/acre) Tillage and planting systems 6,000 3,000 1,000 6,000 3,000 1,000 6,000 3,000 1,000 6,000 3,000 1,000

Base: Conventional tillage, fall plow; planted up and down the slope 8.2 25.4 — — 45.1 — -- 64.5 — — 1 ) Conventional tillage, spring plow; contouring with terraces^ 3.0 6.6 — 13.7 — — 19.4 — — 2) No-till; up and down the slope 0.7 2.5 6.3 2.2 9.0 19.4 3.9 13.7 34.3 5.5 19.6 49.2 3) No-till; with contouring and terraces 0.3 1.1 2.4 0.6 2.3 5.0 1.0 4.2 9.1 1.7 7.1 15.2

'Soil loss computed with Universal Soil Loss Equation, ^Terrace spacings; 3% slope, 148 ft; 6% slope, 104 ft; 9% slope, 100 ft; and 12% slope, 90 ft.

Source: "A Guide for Determining Crop Residue for Water Erosion Control," by Wifliam A. Hayes and Leon W. Kimberlin, in Crop Residue Management Systems, American Society of Agronomy Special Publication No. 31, p. 35-48, 1978.

Table 2. Estimated cost per acre (excluding land and interest) and returns of conventional versus no-till corn and soybeans In Tennessee (December 1980).*

Corn Soybeans item No-Till Conv. No-Till Conv.

Seed $12.00 $10.00 $10.35 $ 6.95 Fertilizer and Lime 47.40 47.40 23.48 23.48 Chemicals 27.99 19.14 31.82 23.49 Machinery (variable cost) 12.17 25.05 14.66 28.36 Labor 4.90 10.15 5.25 10.50 Total Variable Cost 104.46 111.74 85.56 92.78 Machinery (fixed cost) 14.77 24.54 15.84 27.18

Total Cost $119.23 $136.28 $101.40 $119.96 Calculated Gross Return $220.00 $220.00 $182.00 $182.00 Net Return (to land, labor, capital and management)** $105.67 $93.87 $85.85 $72.54

*Calcuiated on the basis of an assumed price for corn at $2.75 a bushel, with a yield of 80 bushels an acre, and for soybeans at $6.50 a bushet, with a yield of 28 bushels an acre. * *Note that labor also is listed as a variable cost.

Source: Economic Considerations of No-Tiliage Farming, by Estet H, Hudson, Professor, Agricultural Economics, University of Tennessee, and the Tennessee Agricultural Extension Service, Publication 923, 1981, with some slight revisions by its author.

SOS also has prepared material, found here in table 1, to a tolerable amount. Figure 6 shows damage that which compares results of USLE calculations of erosion on resulted from heavy rainfall on an upper Great Plains stub- cropland under different tillage systems plus additional ble field, indicating what can occur even when conserva- conservation practices described in detail. tion tillage may be involved. In this instance, the owners of Researchers and conservation experts generally agree the damaged land later found terraces and a sod water- with data, such as in table 1, indicating that with conserva- way helpful in conserving soil in the grain field. tion tillage, the greater the slope, the greater the percen- Off-the-farm erosion costs are sometimes more evident tage of reduction in soil erosion. than on-the-farm costs such as shown in figure 6. Off-the- They also agree that In many areas one kind of erosion farm costs Include those for impaired water quality, control method may not be enough to reduce loss of soil damaged aquatic life, reduced recreation values, ac- Figure 6. Conservation tillage sometimes isn't subsequently added some terraces and a sod enough, as shown by photo of damage resulting waterway to the conservation plan on his farm. from "¿Vi inches of rain falling within an hour on (SCS photo.) upper Great Plains stubble field. The farmer

celerated siltation of reservoirs and harbors, increased Most successful conservation tillage farmers apply their flood problems, and more health and esthetic damages own chemicals, but you may find it suits your needs to from dust in the air. hire custom applicators. Damage estimates for the 1960's indicated that the If you plan to experiment awhile, you may have to buy, money spent on dredging sediment from U.S. harbors and lease, or borrow some equipment to switch systems rivers totaled $250 million annually. Siltation of reservoirs among fields. In some parts of the country, you may find a and other sediment damages added another estimated disk cultivator essential as a supplement to chemicals in $250 million in yearly costs. Many engineers estimated controlling weeds. eroding cropland accounted for at least half of the Although various studies indicate how much you can calculated sedimentation. save by switching away from conventional tillage for the raising of row crops, you will need to calculate your own How Much Does It Cost To Switch to equipment needs and costs carefully. You especially need Conservation Tillage? to consider the effects of conservation tillage on your soil. Table 2 shows estimated costs and returns when no-till The cost of switching to conservation tillage depends on or conventional tillage is used for corn and soybeans whether you adapt your present equipment to your needs, under assumed crop prices and yields. For more details hire a custom operator with proper equipment, rent equip- on the affect of conservation tillage on crops, see "How ment from your conservation district or equipment dealer, Does Conservation Tillage Affect Crop Yields?"on page 13. borrow or rent from another farmer, or buy new machinery. Fuel savings also is a factor to consider in calculating In many counties across the country, USDA's Agricultur- costs of switching to conservation tillage. Table 3 com- al Stabilization and Conservation Service (ASCS) offers pares diesel fuel needs for selected tillage operations. It cost-sharing for as many as 3 years to help you establish indicates that no-till uses less than half as much fuel as a conservation tillage system. conventional tillage, only about 45 percent as much as the Your primary need is a properly equipped planter. Retail disk-plant system, and about 75 percent as much as ridge- prices vary widely among brands and sizes. No-till planters plant. (To calculate and compare gasoline use, one con- may cost anywhere from $200 to $800 more per row of version method that may be used is to multiply each diesel equipment than conventional planters. Figure 7 shows a figure by 1.4.) 16-row no-till planter—large, but not the biggest—in action in northwestern Iowa. Table 3. Estimated diesel fuel needs for selected tillage Table 4. Comparison of labor requirements for selected systems with corn tillage systems*

Tillage System and Operation Diesel Fuel Needs (gallons per acre) Tillage System and Operation Labor in Hours per Acre Conventional Conventional Chop stalks 0.55 (plow, fertilize, disk Disk 0.74 twice, plant, and Plow, moldboard 2.25 cultivate—.18 Disk 0.74 hour—once) 1.21 Harrow, spring 0.64 Plant 0.52 Disk and Plant Spray 0.23 (disk twice, fertilize, Cultivate (2 times) 0.86 plant, and cultivate Combine 1.25 once) 0.83

Total .... 7.78 Till-Plant (chop stalks, fertilize, Disk-Plant' plant, and cultivate Disk (2 times) 1.48 once) 0.72 Harrow, spring 0.64 Plant 0.52 No-Till Spray 0.23 (fertilize, spray, and Cultivate (2 times) 0.86 plant) 0.59 Combine 1.25 *Not6 that the operations here differ from those in table 2, and that harvest labor is Total ...... 4.98* not Included. Nonetheless, these comparisons indicate the differences in labor need- ed with different systems. Ridge-Plant Source: Adapted from "Eastern Nebraska Row Crop Tillage Systems," by Eibert C. Chop stalks 0.55 Dickey, Extension Agricultural Engineer (Conservation), and Allen R. Rider, Plant 0.44 formerly Extension Agricultural Engineer (Power and Machinery), University of Spray 0.23 Nebraska, in Crop Production with Conservation in the 1980's, by the American Society of Agricultural Engineers, 1980, Cultivate (2 times) 0.86 Combine 1.25

Total .... 3.33

No-Till Table 5. Estimated Costs of Machinery, Pesticides with Chop stalks 0.55 Different Systems. Plant 0.52 Dollars per Acre Spray 0.23 Combine 1.25 Machinery Tillage System Related* Pesticides Total Total .... 2.55 Fall Plow 41 14 55 Chisel ...... 39 16 55 Disk 35 18 53 *A variation of the disk-plant system entails chisel plowing, using about 1,12 galions No-Till 24 28 52 more diesel fuel per acre. This would be added to the total of 4.98.

Sources: Fundamentals of No-Tifl Farming, by Robert W. Rice, pubtlshed by American * Machinery-related costs include fixed and variable machinery costs, labor at $5 per Association for Vocational Instructional Materials, Athens, Georgia, 1983, and hour, and a timeliness cost where applicable. Wead Control In Reduced Tillage Corn, by Russell Moomaw, District Extension Specialist (Crops); Alex Martin, Extension Agronomist (Weed Science), and Source: Tillage Systems for liilnols, by John C. Siemens, Professor, Agricultural Engi- David P. Shelton, District Extension Specialist {Agricultural Engineering), neering, and associates, Illinois Cooperative Extension Service, University of University of Nebraska, NebGuide G74-123, 1976. Illinois, Circular 1172, 1980.

10 Figure 7. Keith Kuhn, who farms west of An- at planting time. Mainly growing corn in the roll- thon, Iowa, decided a 16-row planter was his ing hills often hit by drought, he says he espe- best buy, despite his having to work its broad cially appreciates conservation tillage's moisture beam among terraces. He says his major un- conservation. (Photo by H.E. Alexander, Soil solved problem is proper placement of fertilizer Conservation Service, USDA.)

You also can save labor time by reducing tillage. with $19.14 on corn and $23.49 on soybeans with Nebraska engineers calculated field labor requirements for "conventional tillage" in Tennessee (table 2). selected tillage systems, with results shown in Table 4. It The difference may be accounted for partly in the defini- indicates that, with no-till, you would spend only a third as tion; that is, whether "conventional" tillage in Tennessee much of the time doing field labor as you would with con- means the same thing as "fall plowing" in Illinois. But the ventional tillage. more likely explanation, according to recent speculation by Pest management is another cost factor to consider. Illinois agronomy professor M.D. McGlamery, one of John C. Siemens, agricultural engineering specialist at the Siemens' coauthors, is that the fall-plowing Illinois farmers University of Illinois, says fuel and labor savings from con- simply used fewer pesticides at the time than did the Ten- servation tillage may be offset by higher costs for pesti- nessee conventional-till farmers. cides. He and his associates concluded, as shown in table Somewhat broader findings come from an ERS study of 5, that total cost estimates showed no clear advantage for 1,193 nonirrigated corn fields in 10 major corn producing any particular tillage system used in growing corn or States and 1,464 soybean fields in 17 major soybean pro- soybeans. ducing States.5 Cost data for Illinois farmers, in table 5 (preceding page, may be compared with cost estimates for Tennessee farmers in table 2 (page 8). In Illinois under the no-till system, for example, pesticides cost virtually the same—$28 (see table 5) —versus $27.99 an acre for chemicals on Tennessee corn and $31.82 on soybeans (table 2). However, pesticides cost just ^Returns to Corn and Soybean Tillage Practices, by Michael Duffy and Michael Hanthorn, ERS, USDA, Agricultural Economic Report No. 508 $14 an acre with the "fall plow" system (table 5), compared 1984.

11 In this study, conducted in 1980 and 1982, from 54 to The researchers found statistically insignificant dif- 59 percent of the corn farmers used what they considered ferences in soybean fertilizer use among tillage strategies a conventional tillage system, while only 1 to 4 percent in the three major regions, but they did find significant dif- practiced no-till. (The percentage of no-till Increased over ferences in pesticide uses and expenses. They summa- the two years.) The remaining farmers said they used what rized costs and returns In dollars per acre as follows: was labeled by the researchers as "reduced-till," where plant residue was only "partially disturbed." Table 7. Per-acre production costs and returns for dif- The ERS researchers found no-till producers of corn in ferent tillage practices, 1980^ 1980 spent $4.60 per acre on insecticides and $17.24 per acre on herbicides, for a total of $21.84. That compares with about $28 reported for pesticides in the two other Region, Item No-till Reduced-tiii Conventional-tiil studies noted above. Midwest: Dollars The researchers also found conventional-tillage corn Gross return 209.51 A 248.64A.B 262.49B growers spent $3.16 per acre on insecticides and $11.39 Production on herbicides, for a total of $14.55, also less than the costs- other reports. Field In this study, conventional tillers spent $7.29 per acre preparation 43.93 58.24 68.41 less than no-tillers on both types of pesticides. Fertilizers 10.83A 6.03A 6.29A According to the ERS study, 1980 yields were 99.3 Pesticides 30.60A 17.82B 17.99B Seed 9.67A 8.49A 8.56A bushels an acre for no-till corn and 95.4 bushels an acre Mechanical for conventional-till corn. The authors said these results cultivation 2.00A 5.09B 5.70B showed "no significant difference" in average yield among Total 97.03A 95.67A 106.95B the tillage systems. Regarding soybean farmers, the authors presented a Return 112.48A 152.97A,B 155.54B tabulation on per-acre costs of preparing fields using the Midsouth: three categories of tillage practices, as follows; Gross return 116.15A 143.47A 151.00A Production Table 6. Per-acre soybean field preparation costs for costs- different tillage practices, 1980 Field preparation 47.72 64.16 75.63 Fertilizers 8.22A 10.05A 11.27A Region, tillage Labor Fuei and Machinery Totai Pesticides 24.01 A 19.06A,B 16.97B practice repair ownership Seed 7.16A 6.50A 7.20A Mechanical Dollars cultivation .85A 6.33B 7.99B Midwest: Total 87.96A 196.19B 119.06C No-till 6.74 9.16 28.03 43.93 Reduced-tlll 11.65 14.56 32.03 58.24 Return 28.19A 37.37A 31.94A Conventional-till 14.04 17.97 36.40 68.41 Southeast: Midsouth: Gross return 141.99A 131.05A 127.90A No-tlll 7.51 11.74 28.47 47.72 Production Reduced-till 12.98 18.65 32.53 64.16 costs- Conventional-till 15.64 23.02 36.97 75.63 Field Southeast: preparation 43.18 58.28 68.71 No-till 7.23 10.51 25.44 43.18 Fertilizers 14.36A 19.23A 14.90A Reduced-till 12.51 16.69 29.08 58.28 Pesticides 24.78A 13.90A 18.78A Conventional-till 15.07 20.60 33.04 68.71 Seed 7.43A 8.01A 6.14A Mechanical Source: Table 12, Returns to Corn and Soybean Tillage Practices, by Michael Duffy and cultivation 0 A 4.48B 6.96B Michael Hanthorn, ERS, USDA, Agricultural Economic Report No. 508, 1984. Total 89.75A 103.89A,B 115.49B Return 52.24A 27.16A 12.41A

^Means in each row followed by different letters are significantly different from each other at the 5-percent level. Mean comparison tests were not conducted for field preparation costs because they were assumed constant for each group of farmers by tillage strategy.

Source: Table 16, Returns to Corn and Soybean Tillage Practices, by Michael Duffy and Michael Hanthorn, ERS, USDA, Agricultural Economic Report No. 508, 1984.

12 The authors summarized their findings as follows: productive than those with minimum erosion. Crops in- Average per-acre returns differ little for most U.S. vestigated by B.F. Hajek, project leader, and T.A. corn and soybean farmers using various alternative McDaniel, agronomy and soils research assistant, were strategies, according to this analysis . .. corn, soybeans, and cotton. McDaniels reported this at the Midwest conventional-till soybean farmers, however, 1983 joint annual meeting of the American Society of accrue a significantly higher average return than do Agronomy, Soil Science Society of America, and Crop Midwest no-till farmers. Most conservation-till soybean Science Society of America in Washington, D.C. He said farmers In the three major producing regions incur none of the crops differed significantly in the amount that significantly lower input costs than do conventionat-till erosion decreased their yields. soybean farmers, but also harvest lower yields except At the same agronomy meeting, similar findings were in the Southeast. Significant differences were found in reported by Maynard A. Fosberg, University of Idaho soil the use of specific corn and soybean inputs among scientist. He said Idaho researchers were studying ero- alternative tillage strategies . .. sion's yield-reducing effects on three types of soil. In 1982, We conclude that no single tillage strategy is more they found that annual wheat yields decreased by 2.2 profitable in the short run for most U.S. corn and soy- bushels per acre for each inch of Naff series topsoil lost to bean farmers. Farmers should consider their specific erosion, 1.7 bushels for Palouse series soils, and 1.2 circumstances and objectively assess the relative in- bushels for Thatuna soils. Each soil type had average put cost differences expected in choosing their tillage wheat yields in excess of 85 bushels per acre. practice. "The influence of soil erosion on crop production will de- Slightly different results reported by other researchers pend on the nature of the soils involved," he said. are shown in tables 2, 3, 4, and 5. They Indicate conven- Aside from erosion, the previously noted ERS report on tional tillage costs for labor, machinery, and fuel outweigh Returns to Corn and Soybean Tillage Practices (page 11 ) costs for those items in a no-till system by more than showed "no significant difference" in 1980 in corn yields $7.29 an acre. You will of course want to calculate your regardless of the tillage system used. They did find own costs and possible returns and other related factors conservation-till yields "slightly higher" than the average before deciding your own course of action. conventional-till yield. On loamy sands and sandy loam Although it may have little to do with whether you want soils, crops under stress from drought tended to yield bet- to switch tillage systems or not, still another cost factor to ter where conservation tillage rather than conventional consider is taxes. If you buy new equipment, how much in tillage was used. depreciation deductions will the Internal Revenue Service As to soybean yields, variations were "significantly dif- allow? Are there any tax incentives in switching "now" ferent" in the Midwest in 1980. And in this case, conven- rather than later? If you have questions about possible tax tional-till farmers harvested significantly higher yields than incentives in investment after you study 1RS Bulletin No. did no-till farmers. Average yields for all tillage strategies 225, "Farmer's Tax Guide" (1RS, 1111 Constitution were higher in the Midwest than elsewhere. Avenue, NW, Washington, D.C. 20224), your tax adviser Soil tends to dry to the depth of tillage. Residue left on may be able to help you. the surface reduces both water runoff and evaporation. A related consideration if you need credit to buy equip- Eliminating a single tillage operation may save as much as ment is whether your banker or other conventional lender an inch of soil moisture. An inch of moisture can boost a will provide funds or whether USDA's Farmers Home Ad- crop's yield several bushels an acre in some areas. But ministration (FmHA) will be able to assist you through its moisture also helps weeds. If you fail to control weeds, local county office. yields with conservation tillage can be much lower than with conventional. How Does Conservation Tillage Affect Tests made on highly erodible sllty upland soil at Crop Yields? USDA's Agricultural Research Service's Sedimentation Laboratory at Oxford, Miss., showed a slightly better yield Reducing tillage can either boost or cut crop yields- when tillage was reduced from conventional methods. With depending on factors such as kind of soil, total rainfall, conventionally tilled corn, the yield averaged 112 bushels slope, or pest management. per acre over 3 years. With no-till, the yield on equivalent Conversely, if your fields erode, you may well lose part land averaged 114 bushels, while with a reduced tillage of your crop. Preliminary results from Auburn University system somewhere between the two extremes, the yield studies at the Alabama Agricultural Experiment Station was best—124 bushels per acre. showed that eroded areas in fields were 26 percent less

13 Table 8 illustrâtes yields from three soils under different acre. Corn planted between preceding soybean rows yield- tillage systems in Kentucky. It shows a better corn yield ed 113 bushels. The following year, using the same rota- with no-till than with conventional tillage on Crider silt tion but on different soil, the yield differences declined. But loam. But yields differed little under virtually identical the 2-year average was 25 bushels an acre higher when conditions—except for the tillage method—on two some- corn was planted in the soybean rows. Mitchell says corn what heavier soils—Allegheny loam and the reddish Maury grown in the soybean rows was taller, had more leaf sur- silt loam. face, and reached the silking stage faster than that grown Research by Wells and associates showed crop rotation between rows. Corn planted In the soybean rows also took combined with conservation tillage in Allegheny loam in up more micronutrienis and m aero nutrients than the other. Kentucky boosted production on steep slopes—the angle When no-till procedures are used with doublecropping, ranging from 12 to 20 percent. Data they studied came yield is sometimes better than that when conventional from the Robinson Agricultural Experiment Station, Quick- tillage is used with singlecropping. But when conventional sand, Ky. They found that a no-till operation in a 3-year tillage is used with doublecropping, yields per acre are rotation of barley and red clover following corn should usually no better than those when this method is used enable production of enough high-energy corn silage per with singlecropping. Table 9 shows results of a number of acre to support 1.3 beef cow units a year. That's nearly 3 experiments with different no-till approaches to double- times the production needed for the usual long-range goal cropping, as compared with the same approaches to of being able to support one cow on 2 acres of silage on singlecropping. such land. One farmer's experience may illustrate some of the soil A soybean-corn rotation where corn is planted in just- and crop yield changes that occur over time when conser- harvested soybean rows may prove profitable to conserva- vation tillage is adopted. John T. Alexander, near Fountain tion tillers, according to preliminary research by W.H. Mit- City, Indiana, began switching from conventional tillage to chell and associates at the University of Delaware. They the ridge-plant system with corn on his rolling hills and found that in 1981, with a no-till operation, corn planted in bottom land in the 1960's. At first he noted little difference rows where soybeans had grown yielded 152 bushels an in his corn yield. But as the years passed, Alexander

Table 8. Average corn yields with different tiltage systems on three soils.

Soil Type, with 150 fbs. Number of Average Yield, Bushels per Acre o1 Nitrogen Added per Acre Yrs. Tested No Till Conventional

Crider Silt Loam 5 158 133 Maury Silt Loam 10 128 125 Allegheny Loam 5 175 174

Source: Economic Considerations of No-THiage Farming, op. cit., and personal communication, K,L. Wells, Extension Professor, Soils; Robert L. Bievins, Professor, Soils, and M.J. Bitzer, Associate Extension Professor, Grain Crops, University of Kentucl

Table 9. Soybean yields under various planting systems in Tennessee.

Soybean Yield, Bushels per Acre System 1976 1977 1978 1979 1980 1981 Ave. Double Cropping Conventional Seedbed Preparation(l) 27 4 33 41 23 48 29 No-Till Seeding in Wheat Stubble(2) 36 7 34 44 25 46 32 Aerial Seeding in Growing Wheat(3) 39 0 19 36 — — No-Till Seeding in Growing Wheat(4) — 6 29 46 18 18 No-Till Seeding in Wheat Harvested Somewhat Green(5) 35 41 No-Till Seeding Following Swathed Wheat(6) No-Till Seeding With Wheat Removed(7) 19 67 Single Cropping No-Till Seeding With Wheat Killed(8) 48 22 62 Conventional Seedbed Preparation 26 56 34 44 22 70 42

(1) Soybeans planted after winter wheat harvest; soil tiiied conventionally. (2) No-till seeding of soybeans after wheat was harvested conventionally. (3) Moisture and soil conditions have to be just right for aerially seeded soybeans to sprout and maicover crop until it was killed by herbicides at the time of no-till seeding of soybeans.

Source: Personal correspondence and "No-Till Soybean Production Systems," by Tom f^cCutchen, Superintendent, f^yiilan Experiment Station, University of Tennessee, published in 1981 Conference Proceedings at Memphis on 80's innovations, American Soybean Association.

14 reports he found humus buidling up in the ridges, and corn yields resulting from ridge-plant tillage were higher than yields from conventionally tilled land. in recent years, he has been getting 120 to 200 bushels per acre with ridge-plant methods, which he has adopted on all 390 tillable acres on his farm. He applies 182 pounds of anhydrous ammonia plus 200 pounds of dry formula (9-23-30) fertilizer per acre each year. That's less fertilizer than he applied before switching to conservation tillage, yet his yields have climbed. He says conservation tillage "saves fertilizer because of the humus buildup and erosion control," and that his yields are higher than those of neighbors using conventional tillage. He hasn't changed this however: He still uses his 20-year-old, 67-horsepower tractor to pull his 6-row, conservation-till planter. He said the small tractor helps him avoid soil compaction that heavier vehicles can cause. His system is not no-till; he uses a cultivator once or twice a year to help control weeds. He uses insecticides as needed with this continuous corn program. Figure 8. Even wet but relatively light textured soil works well with How Does Crop Residue Management no-till planter such as shown at work in above close-up photo. Press Affect Soil Fertility? wheels at rear are compressing wet soil after seed corn has been dropped into slot opened by coulters. Planting depth is kept fairly Various studies Indicate that tillage which keeps crop uniform by depth wheels—one of which can be seen just ahead of residues on or near the surface for 4 or 5 years causes press wheels—that move up and down over residue. Fertilizer and organic matter and total nitrogen, phosphorous, and pesticides also can be fed through the here-invisible seed channel. The press wheels usually make certain the seeds are in contact with potassium nutrients to accumulate near the surface. In germination-triggering moisture. (Photo, courtesy of John Deere.) some soils it may slow leaching of useful nutrients into areas below root zones. Phosphorous and potassium totals tend to decrease in the subsurface under no-till, according to findings reported by E.J. Deibert, North Dakota State University soil scien- 3 inches of soil, hence Immobilizing little nitrogen there. tist, at the 1983 agronomy meeting previously mentioned. By contrast, with conservation tillage, three types of He also found soil pH rates decreased—soil became residues tested produced considerable undecomposed res- more acid—in the top 3 inches of the soil. That is the area idue that tied up nitrogen in the upper 3-inch layer of soil. partially associated with continuous broadcast application Corn residue tied up 180 pounds of nitrogen per acre over of nitrogen fertilizer in conjunction with limited tillage for the test period; rye, 230 pounds; and vetch, 330 pounds. incorporation of fertilizer material, Deibert said. (Vetch, however, being a legume, also added about 100 Nitrogen fertilizer that is broadcast on the surface moves pounds a year more nitrogen to the soil than it used.) into soil with rainfall and is less of a problem under no-till The significance of such information has not been fully or reduced till than either phosphorous (P) or potassium evaluated, but Mitchell speculated that crops tilled by con- (K), he said. P and K move little in the soil; placement is servation methods need more nitrogen at first to make up more important for them. Crops tend to "mine" these for possible deficits. The amount of nitrogen need depends elements in the zone where root growth takes place. on liming practices, soil moisture, the amount and kind of To offset fertilizer problems associated with reduced residue, and the rate residue decomposes into humus. For tillage, Deibert suggested farmers sample soil at 3-inch in- your nitrogen needs, consult local information sources, crements. This will help identify areas of nutrient such as specialists with the Extension Service and SCS. depletion. More research findings about fertilizer also are found in Conservation tillage significantly reduced potassium the section on problem solving, on page 18. leaching when compared with conventional tillage on sandy soils studied by W.H. Mitchell, Cooperative Exten- How Does Conservation Tillage Work in sion Station, University of Delaware at Newark. Various Soils? He found that over an 8-year period, no-till test plots contained 60 percent more potassium in the top 3 inches As indicated previously, soil differences are an important of soil than conventionally tilled plots. In the latter plots, factor in tillage decisions. Soil differences among States, potassium leached deeper. counties, and even within fields may require changing or Mitchell and colleagues also estimated how much nitro- adjusting tillage equipment. With clay soils, for example, gen was tied up by residues associated with conservation you may need more weight on each coulter to penetrate tillage. They assumed plant residue to be 5 percent nitro- residue and soil than would be needed with lighter tex- gen. Conventional tillage leaves little residue in the upper tured soil, such as noted in figure 8.

15 Crop response to conservation tillage is better on lighter In Minnesota, ARS Soil Scientist Ward B. Voorhees also textured, moderately well drained soils tlian on heavy and advises using controlled traffic patterns to avoid compac- poorly drained soils. On heavier, wetter soils, moldboard tion and improve ease of root growth and porosity. He plowing may help offset poor drainage. adds that If you count on conservation tillage to improve On many very poorly drained soils, for example, growing ease of root growth and porosity, you should not be continuous corn in no-till systems resulted in lower yields discouraged if you don't observe benefits the first year. than if the land had been fall plowed, according to findings He suggests this rule of thumb witfi certain soiis: Com- reported by David Van Doren, a research agronomist at paction is confined to a depth of about 8 to 10 Inches If the Ohio Agricultural Research and Development Center in the axle weight of a vehicle is not more that 5 tons. Thus, Wooster. He told the previously mentioned 1983 agronomy a heavy combine with a 6-row header may counteract meeting that he and a former coworker. Glover B. Triplett, some advantages of conservation tillage, since most such found an average reduction of 17 percent in the yield of combines bear a 10-ton load on the front axle even before corn grown in a no-till system on fine-textured, poorly grain harvested adds to the weight. drained soil in northwestern Ohio. Wide flotation tires apparently do not eliminate the com- When Van Doren and Triplett rotated tillage with con- paction problem. Laboratory tests indicate total load may tinuous corn—using no-till every other year—yields were have an important bearing on subsoil compaction. only 5 percent lower during the no-till years. When no-till Voorhees also says his research shows clay loam can be corn was rotated with another crop, corn yields were only more porous with conservation tillage than with conven- 2 percent below that of corn grown on plowed soil. Stands tional moldboard plowing—but only in places where there and weed control were kept equal. is no wheel traffic. Thus, proper management can offset the problem of poorly drained soil in some areas, Van Doren told fellow How Much Does Crop Residue Reduce researchers. Pollution From Fields? The weed control factor is important, since wetness resulting from reduced tillage can cause weed growth and Since conservation tillage limits wind and water erosion, some disease organisms that limit yields. Wetness also water runoff is less likely to carry fertilizers and pesticides sometimes prevents seed germination. away from conservation-tilled fields than from conventional- Use of the ridge-plant system of tillage can help over- ly tilled fields. This is true despite the fact that pesticides, come slow drainage. Where spring wetness is a problem, nitrogen, and phophorous usually are more concentrated the ridge-plant system may be acceptable as an alternative In water and soil runoff from fields tilled with conservation to the plow. Local conservation specialists can advise you. tillage methods, according to various research studies In some areas, a drainage system can make poorly summed up in the booklet, previously mentioned, by Pierre drained soils suitable for conservation tillage. Crosson. Without drainage, some researchers have found, seed- Other studies of chemical pollution on farms have come zone coolness from moisture maintained by residues in out of the Region V or Great Lakes District Program Office conservation tillage may require delaying planting, of the U.S. Environmental Protection Agency (EPA). (The especially in soils with as much as 55 percent clay content District Office has financed conservation tillage demonstra- in subsurface layers. tion projects by soil and water conservation districts, main- On the other hand, moisture maintenance usually is ad- ly in Ohio, in collaboration with county Cooperative Exten- vantageous, helping get the maximum advantage out of sion Service offices, Ohio State University, and SCS.) fertilizer applications. Researchers reported to EPA that good water quality When the soils are uniform in texture and well drained, should be a major benefit from reduced chemical pollution and pests are controllable with current technology, choos- facilitated by limiting erosion through conservation tillage.^ ing a successful and profitable conservation-tillage system Using the Universal Soil Loss Equation (USLE) to esti- can be relatively easy. But If your soils are poorly drained mate erosion from farms In demonstration projects, the or weeds difficult to control, conservation tillage may re- researchers found soil loss from no-tlll fields to be 35 to 94 quire more careful and Intensive management than con- percent lower than on fields plowed in the fall. (These data ventional tillage. substantiate those In the earlier section on page 7 on With any tillage system, it is Important that you analyze erosion and the USLE.) soils and apply necessary fertilizer and soil amendments Crosson also wrote, "Some commonly used pesticides such as lime. Soil pH and organic matter content play a with high toxlcity to aquatic life—trigluralln, endrln, and key role in "fine tuning" weed control. toxaphene—are so tightly bound to the soil that a reduc- The roles different soils play in compaction problems tion in erosion reduces the amounts of these materials that can cut crop yields remain under study throughout the leaving a farmer's field. This is also true of the herbicide country. Some such studies Involve ARS at the Shatter paraquat." Research Station In Kern County, Calif., and at the He cited an Iowa study comparing pesticide content in Southwest Experiment Station of the University of Min- eroded soil and runoff from land conventionally tilled as nesota near Lamberton. well as land handled under two conservation tillage Lyie Carter, leader of the Shafter Research Station, and his associates suggest that farmers try to restrict traffic paths In fields to the same locations every year and to 6"Lost Creek Demonstration Project," Defiance County, Oliio, Soil and Water Conservation District, 1981. Project Report for Grant S00553 01, crop continuously between the paths. EPA, February 1982.

16 systems: till-plant (here called strip-till) and ridge-plant. The diligence in seeking chemical mixes that can control three systenns left 3, 20, and 45 percent, respectively, of weeds. the soil surface covered with residue from the previous The ERS study of 1,193 farmers found the herbicide year's corn crop. The insecticide used was fonofos, and cost for 17 no-till farmers averaged $17.24 per acre. That the herbicides were alachlor and either atrazine or was significantly higher than either the average cost—at cyanazine.' $12.70 per acre—of herbicide for 417 farmers using re- With some exceptions, smaller amounts of the pesticides duced tillage or the cost at $11.39 per acre for 759 were lost with conservation tillage than with conventional farmers using conventional tillage. tillage. That study found no significant difference in the amount The key factor in reducing pollution by chemicals in of herbicides applied per acre among the tillage systems. runoff is how much runoff and erosion can be reduced by The average ranged from 3 pounds under a conventional- conservation tillage and complementary conservation prac- till system to 3.5 pounds under a no-till system. But the tices such as contour farming, terracing, and strip farming. herbicides used in no-till systems tended to be the more On subsurface chemical pollution from farms, Crosson expensive broad spectrum materials, the ERS researchers wrote that a number of sources in research literature found. "assert that the leaching of nitrates to ground water likely With conservation tillage, herbicides must (1) control will be greater with conservation tillage than with conven- weeds, (2) not injure the crop being planted, and (3) leave tional tillage. I found no sources that dispute this, although no chemical residue to injure later crops or pollute nearby the issue is not discussed in much of the literature." streams or water supplies. Generally, he added, the wetter the environment and the "It is important to rotate crops, herbicides, and in some coarser the soil, the greater the leaching. cases tillage methods where possible to reduce the possi- Increased leaching of nitrates results from reduced run- bility of weed escapes," advises Stephen Rawlins, ARS off and increased infiltration. The nitrate can move either tillage specialist at Beltsville, Md. "In some cases this may to ground water through percolation or to surface waters require use of a moldboard or disk plow to kill weeds." through subsurface flow. The crucial question for farmers Such perennials as johnsongrass, bermudagrass, or dai- and other water users in areas affected by conservation lisgrass are sometimes difficult to control even with a com- tillage, then, is whether their water is endangered by bination of herbicides and tillage. However, some new pollution. post-emerge grass herbicides look very promising. Phosphorus, because it is strongly adsorbed by soil, that You must learn what kinds of weeds grow in your fields, is, attached to soil particles, does not leach to ground then seek proper herbicides or other control measures. In water significantly, regardless of soil types. Likewise, with some Midwestern States, farmers are hiring migrant or pesticides, Crosson found evidence of little leaching to part-time workers to pull button weeds by hand in ground water, since most pesticides adhere strongly to soil soybeans. particles. As for insect pests, the previously cited ERS study Regarding the potential for airborne pollution and crop found insecticide use "significantly higher" for the 17 no- damage from chemicals, Crosson concluded that when till farmers than for either reduced- or conventional-till conservation tillage requires more chemicals than does farmers. Although the average insecticide material cost of conventional tillage, herbicide drift can be a potential $4.60 for the no-till farmers was $1.44 per acre higher problem. than the $3.16 average for the other 1,176 farmers, the As to the effect of herbicides on soil microorganisms, difference was "not statistically significant." Crosson said studies indicate that damages, if any, are "The additional pesticide cost incurred by the conserva- slight, and organisms recover quickly. However, he sug- tion-till farmers would be offset somewhat by a reduction gested that final judgment be withheld pending further in tillage costs. . . The substitution of pesticides for addi- research. tional tillage operations did not, however, affect the Some researchers note that soil organisms are depen- average yield harvested by farmers. . . dent on a supply of organic material at or near the soil "Although the increase in tillage costs was offset some- surface. Residues left from systems of conservation tillage what by lower herbicide costs, farmers cultivating their provide this organic material, they add, so that certain fields more than once harvested lower yields than farmers microorganisms tend to increase when tillage decreases. who cultivated less." Following the theory that residues on or near soil sur- How Does Conservation Tillage Affect faces foster overwintering of some insects, many entomo- Pest Control? logists contend conservation tillage can worsen certain in- sect problems. Many agree that slugs can thrive and cut- Weeds, insects, and other pests are a problem in any worms can damage crops planted in the sod. There is tillage system. When you reduce tillage, you must plan some disagreement on whether European corn borers in- pesticide use carefully. crease when corn residues remain on the surface several Conservation tillage doesn't lend itself readily to getting seasons. Researchers continue to study these matters. herbicides into the soil, so herbicide selection has been Insecticide treatment of seed becomes more important restricted to surface-applied material. Most reports indicate as you reduce tillage. No one insecticide Is best for all herbicides must be applied to soils under continuous con- conditions. Anticipate pest problems. Check fields fre- servation tillage at a higher rate than to soils tilled by quently for damage throughout the season. Learn to iden- other methods. This adds to costs, and it requires tify crop pests and how to control them. Consult your Ex-

17 tension agent, pesticide dealers, and other experts, in- part in the ASCS Agricultural Conservation Program's cluding farmers, for advice. special project for conservation tillage in various parts of You also must protect against disease. You will want the the country. advice of the experts on possible disease controls and the most resistant crop varieties. Information Sharing When fields are covered with residue, it is easy to skip or overlap some areas when spraying pesticides. To help The National Association of Conservation Districts (NACD) solve this problem, you will find that marking methods, has established the Conservation Tillage Information such as foams or dyes, are available. Center (CTIC) as a special project operated from NACD's Because you may use more chemicals with conservation headquarters in Washington, D.C., and its Fort Wayne, tillage than with conventional tillage, it becomes even Ind., field office. Support services are provided by NACD's more important to follow details in instructions or look Service Department in League City, Tex., and five regional elsewhere for information on proper nozzles, amounts of offices around the country. water, pressure, nozzle spacing, calibration, and timing. CTIC is a computerized clearinghouse of information on Check spray nozzles regularly and replace worn ones. conservation tillage. It was organized to assist many dif- Be careful with chemicals. Keep them out of children's ferent interests—private agribusiness firms such as reach. Never convey them in containers that might by chemical and machinery companies, the 2,950 local soil chance be used for food or drink for humans or livestock. and water conservation districts, organizations such as the Iowa Natural Heritage Foundation, and Federal agencies Who is Working to Solve Problems such as USDA and EPA. CTIC began disseminating data Associated With Conservation Tillage? in 1983 on experience in demonstration projects as well as in formal research. Specialists in government agencies, nonprofit groups. Another information source involves scientists from ARS, State and Federal experiment stations, land grant univer- ERS, and SCS who are cooperating in developing a new sities, and agribusiness corporations give conservation computerized tillage analysis system. The computer model tillage research high priority. Literally hundreds of conser- is called "EPIC," which stands for Erosion-Productivity Im- vation tillage experimental projects are under way across pact Calculator. the continent. Many publications and organizations provide EPIC relates data on tillage to topics such as erosion information about conservation tillage. Major efforts and and sedimentation, hydrology, livestock grazing, nutrient activities are noted here. cycling, crop growth, soil properties, climate, weeds, in- Under Public Law 95-192—the Soil and Water Re- sects, disease, pesticides, and economics in general. sources Conservation Act of 1977—commonly abbreviated These topics indicate some of the areas covered by re- as RCA, the Secretary of Agriculture developed a program search under private, State, and Federal auspices. to ensure the sustained productivity of soil, water, and USDA officials have said that once EPIC establishes a related resources. USDA staff members consulted the relationship between erosion and productivity, it will be public widely in developing the program, described in a easier to put a dollar value on the loss of U.S. soil. 1982 report: "A National Program for Soil and Water Con- Farmers will be able to select management strategies to servation." maximize long-term crop production. Eight USDA agencies are active under the program in Still another information source is USDA's National areas of research, education, cost sharing, loans, and Agricultural Library (NAL), with its Current Research Infor- technical assistance. Named earlier in this booklet are mation System (CRIS). CRIS has information in computers ARS, ASCS, Extension, ERS, FmHA, and SCS. Others are and can provide project abstracts through various organi- the Cooperative State Research Service (CSRS) and the zations such as land-grant university libraries at cost to Forest Service (FS). farmers and others. SCS is lead agency for technical assistance in conserva- tion methods. It was established in 1935 to help the Research Projects Secretary plan and carry out programs to protect and develop the Nation's soil, water, and related resources. To Several USDA agencies are involved in conservation conduct its mission, SCS has a network of conservation tillage research. CRIS recently produced a computer print- specialists available to help the public: agronomists, out showing 143 projects that compare no-till methods with biologists, cartographers, environmental specialists, other tillage systems. As the specialist who searched out foresters, geologists, landscape architects, plant materials the projects explained, 'This is only the tip of the iceberg" specialists, range conservationists, recreation specialists, with respect to experimental tillage projects in general. resource planning specialists, soil scientists, and engi- Most of the projects cover several different factors in neers-agricultural, civil, drainage, hydraulic, and comparing no-till with other tillage systems. Some high- irrigation. lights from the comparative studies reported to CRIS, as well as others not reported, follow. Cost Sharing Fertilizer ASCS helps farmers with problems in offsetting financial Many of the studies focus at least in part on fertilizer prob- costs of switching to conservation tillage. It has provided lems involved with tillage reduction. several million dollars in cost-shares to farmers who take

18 Many of the studies are conducted by ARS researchers, A news release on his talk also said, "no-till purists are and one of significance was reported in the ARS publica- looking at equipment to place P and K where the moisture tion, Agricultural Research. It quoted ARS soil scientist is—without disturbing the surface too much. Special deep John W. Doran of the University of Nebraska at Lincoln as band fertilizer systems and other multiple-function, one- saying that somewhat deep placement of nitrogen fertilizer pass machines seem to get the job done best. could save farmers millions of dollars. Doran has done a "Deibert has found under no-till conditions that crops 4-year study of soils at seven sites ranging from West respond better and make more efficient use of deep-place Virginia to Oregon. nitrogen than surface applied nitrogen. If deep placement Doran found that no-till soils had more organic matter, Is used, fall application is better than spring since soil water content, and 35 percent more microorganisms (those disturbance creates weed problems that would be less of a active in the presence of oxygen) than plowed soils. The problem in the fall than with spring tillage." microorganisms tend to "eat the nitrate nitrogen before In connection with fall application of fertilizer, and also the crop can get it," he said. This reduces fertilizer as a way to help reduce tractor operations in areas where efficiency. land is fallowed for a year, ARS agronomist Michael R. Doran calculated that if farmers could place fertilizer 3 Barrett has been studying efficacy of mixing herbicides to 4 inches into the soil or concentrate It in a narrow zone with liquid fertilizers. at the surface, they could cut nitrogen fertilizer needs by Speaking at the 1983 joint annual agronomy meeting, 15 to 25 pounds per acre when compared with the broad- Barrett explained: cast application. "We mixed chorsulfuron with liquid nitrogen fertilizer ARS also reported^ that: and applied it in the fall after wheat harvest. It appears "Increased nitrogen-use efficiency with fertilizer place- that this herbicide is often effective for controlling ment in no-till crops has been confirmed by recent experi- broadleaf weeds well into the following summer fallow ment station trials in Indiana, Iowa, Minnesota, Kentucky, season." Georgia, and Maryland. However, at the time of his tests, which were conducted "At the Maryland locations, soil fertility scientist V. Alan with fellow ARS agronomist Randy L. Anderson at the Bändel found that no-till corn yields averaged 20 percent Central Great Plains Research Station at Akron, Ohio, the higher where nitrogen was subsurface-applied or dribbled herbicide had not yet been approved for such use and ad- in a narrow zone on the surface than where it was ditional tests were necessary. Barrett also pointed out that broadcast. the chemical does not control volunteer wheat, downy "Even with tailored fertilizer placement, conservation till- brome, foxtails, or most other grassy weeds. It can age will still require more fertilizer than conventional till- damage corn, however, so any farmer who used it would age. However, that extra cost will not be all lost. Doran be committed to follow through with plans for fallow. says. Some of the extra nitrogen will help build up organic A related study has indicated that you might need to matter in the soil." apply a high rate of phosphorous (P) only occasionally to Under the no-till system, fertilizers tend to be concentrated satisfy P needs of crops under conservation tillage, at in the top 2 inches of soil. This especially applies to such least on a loam soil in the northern Great Plains. "immobile" fertilizers as phosphates and potash, as noted by ARS soil scientist Ardell D. Halvorson reported to the findings during 8 years of research at the Southern Experiment 1983 agronomy convention on results from a single ap- Station of Waseca, Minn. Soil scientist Gyles Randall of the plication of phosphorous at the rate of 160 pounds per University of Minnesota reported these results to NAL's Current acre at the Northern Plains Soil and Water Research Research Information System (CRIS). Center at Sidney, Mont. That one application produced In four other tillage systems—moldboard plow, chisel spring wheat yields over a 15-year perod that annually ex- plow, ridge-tlll, and strip-till—the immobile fertilizer ceeded yields from an unfertilized area by 20 percent. amounts tended to be deeper, somewhat in proportion to Then, he said, by adding 40 pounds of nitrogen per year tillage depth, Randall said. per acre, yields that had received the phosphorous appli- Weeds were most abundant in the no-till plots. Average cation produced 34 percent more wheat "each crop year." corn yields under the five systems, over the period of 1975 After the 15 years, yields still were higher on the ferti- to 1982, were as follows: Moldboard plow, 154.5 bushels lized areas than on those areas that didn't get the phos- per acre; ridge-till, 149.2; strip-till, 144.9; chisel plow, phorous. Halvorson and fellow ARS soil scientist Alfred 144.4; and no-till, 129.2. Black used a spring wheat-fallow rotation for the first six Regarding crops other than corn, findings by research- crops, and then cropped wheat annually the next 4 years. ers at North Dakota State University at Fargo indicate that In Alabama, researchers found indications that potas- deep placement of fertilizer produces higher yields on no- sium is the critical fertilizer element for soybeans on the till than on broadcast wheat. Coastal Plains. George W. Martin and Joseph T. Tough- "Breaking the no-till cycle" may be a way to get deeper ton, agronomy researchers at the Alabama Agricultural Ex- placement fertilizer so it won't be too concentrated in top periment Station, Auburn University, reported to the 1983 soil for optimum efficiency, according to E.J. Deibert of joint agronomy meeting that they planned to make a firm North Dakota, mentioned above in connection with the recommendation about starter fertilizers on no-till crops in 1983 agronomy meeting. 1984 if earlier experiments were substantiated. In 1983 they used 16 different tests involving no-tlll with corn, sorghum, soybeans, cotton, and peanuts to deter- mine whether trends revealed in a three-year study would ^"Tailoring Fertilizer Placement," Agricultural Research, ARS, May 1983. hold true elsewhere. They had found out that while starter

19 Figure 9. USDA Soil Scientist Charles B. EIkins of the National Tillage through the hard "plowpan" that underlies soil in various Southeastern Machinery Laboratory, Agricultural Research Service, Auburn, Ala- States. Besides having other advantages of conservation planting, bama, checks out a 3-row planter that had chissels for subsoiling knives also require less energy than tilling with chisel-type subsoilers (cutting through earth into the subsoil) which have been replaced with that sometimes are used. (Photo by Austin Mitchell of the Laboratory) deep-slit knives. The knives show promise as a means of cutting

or "pop-up" fertilizers couldn't replace standard fertility after planting, soybean taproots reach the bottom of a slit practices on no-till soybeans, fertilizers containing potas- and then spread along it. Without the slit, roots simply do sium could Increase yields on soils having high residual not penetrate to reach moisture-bearing subsoil. The slits fertility levels. serve their function for at least 2 years, and maybe longer. They also had found that nitrogen starters, applied at All other factors considered equal, soybeans planted In planting to hasten early growth of plants, did not Increase deep slits in one study produced 27 bushels an acre soybean yields. Phosphorous Increased yields only on alongside traditionally planted soybeans that produced 15 soils lacking In residual fertility. Potassium, however, bushels. The deep-slit planting knife has been adapted to significantly Increased yields In four test situations. subsoil planters, and some Alabama farmers have built and experimented with similar planters. Subsoiling Among ARS research projects is at least one on "subsoil- Pest Controls ing," getting through the harder soil that sometimes under- Various kinds of pest controls that have a bearing on con- lies top soil. Use of no-till methods on hard "plowpan" servation tillage are being studied at research centers. For subsoil Is being studied at the Alabama Agricultural Ex- example, at the Corn Insects Research laboratory in periment Station at Auburn by ARS soil scientists such as Ankeny, Iowa, researchers have studied ways farmers can Charles B. Elkins. He and fellow researchers developed a Improve control of the European corn borer. It has been deep-slit planting knife (shown In figure 9) aimed at im- known to flourish in conservation-tillage areas. proving no-till operations on land commonly subsolled with ARS entolmologlst William B. Showers found that two chisels or various kinds of blades. applications of carbaryl Insecticide timed about 8 days The knife makes a deep vertical slit one-sixteenth of an apart on grassy areas around cornfields can greatly inch wide underneath the planted row. The slit serves as a reduce the number of borers In corn on conservation-tilled channel through which seedling taproots reach subsoil land. moisture and nutrients for growth. Within about a week

20 He said the first treatment should be made when you with no-till. At a Piedmont location, trumpetcreeper con- find an average of about four adult female borers (in the tinued to increase in no-till plots treated with paraquat, but form of moths) per square yard of grassy area near the was much reduced in plots treated with glyphosate. The corn. Calculate the number of female moths by walking amount of horsenettle remained about the same with through the grass and counting the moths you flush. either herbicide, according to a report by Worsham to Those flushed are presumed to be females, since males NAL's Current Research Information System. (Tobacco instinctively affix themselves to the grass and normally quality was equal under both systems. On a 1.3 percent don't fly. The females migrate to the grass in search of slope, soil loss was 18 times greater with conventional males for mating. tillage than on no-till tobacco land.) Weed control in North Dakota studies of conservation tillage The solution to the problem of proper placement of herb- with sunflowers and sugarbeets in a four-year rotation with icides may be found by mixing herbicides with granules, small grain was best when Treflan (triffuralin) or Eptam (EPTC) according to Jim Dale, ARS agronomist at Stoneville, IVIiss. granules were applied at recommended rates in the fall. This is He sees potential promise in experiments involving the according to a report by E. J. Deibert and associates to NAL's mixing of tung oil—which dries more rapidly than oils from CRIS. Weeds were not well controlled when various pre- soybeans or cottonseeds—with herbicides and various emergence or post-emergence herbicides were applied on kinds of granules. The granules then are spread with a Fargo clay soils (fine, montmorillonitic, or frigid Vertic Hap- conservation tillage planter in a band several inches wide laquoll). The weed called kochia was the main problem, the along crop rows. Tung oil apparently slows release of cer- report said. tain herbicides. Dale said. He believes farmers should wait Using no-till, "fall-inter-till", or "fall-sweep" systems at for more data before trying to duplicate his preliminary North Dakota State University at Fargo, and while control- work. Granules, he speculated, that might be useful in- ling weeds adequately, project test yields were equal to or clude broken grain, pine needle straw, ground corn cobs, better than on conventionally plowed land. and certain clays, such as kaolin. The North Dakota researchers also noted during 2 years that deep-placed nitrogen fertilizer produced higher yields Cropping Practices on no-till soil than when fertilizer was broadcast. Also, As mentioned earlier, conservation tillage alone sometimes higher rates,of phosphorous and potassium uptake were does not control erosion adequately. Various studies are observed where nitrogen was placed deep. investigating management practices which can be linked to Also at Fargo, 1982 studies by S.D. Miller and J.D. conservation tillage. Nalewaja found that with good weed control, no-till wheat, Kentucky researchers found it more economical to add barley, flax, and corn yielded 15 to 20 percent better than the practice of strip-cropping to conservation tillage, and conventionally tilled crops. However, reducing tillage for then to combine both practices with either singlecropping soybeans and sugarbeets reduced yields 10 to 15 percent. or doublecropping. They first planted a field to wheat as a Sunflower yields were no different that year, regardless of fall and winter cover. The next spring they applied herbi- tillage system, according to a report to CRIS. The re- cide along contoured strips and planted corn in those searchers also have been evaluating various kinds of strips with a no-till planter. Wheat left growing in the alter- herbicides. nate strips was harvested in June, and soybeans were Another weed control project reported to the NAL's CRIS planted immediately with a no-till planter in the wheat stub- involves studies at Iowa State University at Ames. D. W. ble strips. Staniforth and colleagues reported that pre-emergence appli- The following year, corn was planted in the wheat strip cation of chloramben and alchlor plus metribuzin at recom- where soybeans had previously grown. This "migrating" mended rates on soybeans significantly controlled annual procedure enabled the corn to benefit from the nitrogen weeds under three tillage systems (fall plow-spring disk, fall left in the soil by the soybean nodules. This cut commer- chisel plow-spring disk, and no-till) used in a corn-soybean cial fertilizer needs. rotation. Some researchers recommend no-till planting of leg- The researchers also added glyphosate to the tank mix umes in pasture sod to help boost nitrogen availability. of pre-emergence herbicides used in no-till farming. The Researchers in several States, including North Carolina, studies began in 1965 and continued at least through Kentucky, Idaho, and Delaware, are studying use of leg- 1982. umes—hairy vetch, Austrian field peas, crimson clover—to All herbicide treatments were supplemented with be- help row crops under conservation tillage systems. tween-row cultivation a month after seeding. Weed control Some southeastern researchers have been studying a was 95 percent or more and yields of soybeans were doublecropping sequence of grain sorghum and crimson equal under all tillage systems. clover under conservation tillage. The timing of rains—which can dissipate the chemi- Clover was first established as a cover crop. After the cals—altered effectiveness of the pre-emergency her- clover seed matured, sorghum was planted in the clover bicides, the researchers noted. by the no-till method. When the sorghum was harvested in At a Coastal Plains location, A.D. Worsham of North the fall, the clover began to reestablish itself from the seed Carolina State Unversity at Raleigh found significantly in the ground. The cycle can be repeated annually. The more morning-glories in tobacco conventionally tilled than clover not only provides ground cover but also helps in no-till tobacco. But annual grasses were more numerous nourish the sorghum.

21 Figure 10. Conservation tiiiage Is catching on from 10 to 80 feet. Researchers report such among wheat producers in the upper tier of drills can cut field costs by two-thirds, whether States west of the Great Lakes and north into used with irrigated or dryland grain planted Canada; they are adopting iarge, air-seeder either in spring or fall. The planter above ad- drills such as shown above. Drill widths range justs flexibly to ridges or dips.

Machinery Other Problems Air-seeder drills are being experimented with by research- The preceding examples of current research into conserva- ers and producers of wheat and other small grains in the tion tillage problems are only a selected few. Findings upper tier of States west of the Great Lakes. The drills resulting from such research have been or will be reported were introduced some years ago as an implement for com- to the public through various private and public media bining tillage and seeding of grain in a single operation. sources from time to time. Perhaps less publicized will be The drills consist basically of a seed-holding chamber, a the results of improvements by farmers who also tradi- seed-metering device, and an air-operated seed distribu- tionally make significant contributions in the problem- tion system mounted on or attached to a chisel plow or a solving process. field cultivator. Differences among planters are mainly in An example of complex institutional comparisons of con- design. ventional and conservation tillage can be found in a study A chisel plow feeds fertilizer into the ground and cuts described to NAL's Current Research Information Service by through wheat stubble without burying much straw, while agronomy researchers J. W. Doran and T. M. IVIcCalla at the the air seeder drill, like that shown in figure 10, delivers University of Nebraska as follows: seed into the soil. Thus the small-grain farmer can till, Populations of fungi, actinomycetes, and bacteria plant, and fertilize in a single pass across the field. (including nitrifiers, denitrifiers, and anaerobes) will be Sometimes higher yields result from separate operations, measured throughout the growing season in field and one for fertilizer and another for seeding. Leaving stubble greenhouse experiments. Soil enzyme assays (pho- standing as long as possible conserves moisture that is phatase, dehydrogenase, urease, etc.) will be used to especially needed in marginal rainfall areas. evaluate the effects of tillage and residue manage- The drills operate effectively in heavy small-grain stubble ment on soil productivity. Field measurements will be and comprise one of the best tillage ideas in some time, made of soil gases which are indicators or regulators according to John D. Walker, chairman of the farm depart- of biological activity (CO2, O2, N2O, NH3, H2S, CH4, ment at Ricks College, Rexburg, Idaho. ethylene, etc.) Mechanisms regulating production of

22 soil gases will be determined in greenhouse and Where Can You Get More Information About laboratory studies. Field crops will be determined in greenhouse and laboratory studies. Field crops will be Conservation Tillage Systems? examined and rated throughout the growing season and at harvest for disease incidence and quality. As indicated previously, information can be obtained from Other studies deal with such matters related to tillage many sources, but you can begin by contacting staffs of local practices as irrigation management, animal management, offices of the Extension Service, SCS, ASCS, and FmHA. Staff plant genetics, insect control, land reclamation, and pro- members should have the latest data on conservation tillage duction of crops not previously mentioned—such as as it relates to your area. They may be able to provide names millets, potatoes, red beets, cabbage, lentils, tomatoes, of farmers who practice conservation tillage and will share sweet corn, various dry beans, lima beans, bush beans, information. snap beans, peaches, apples, cherries, bell peppers, You may also want to contact the State land-grant university muskmelons, summer squash, celery, onions, cucumbers, in your State or other States and the nearest USDA or State and many different legume-grass species. agricultural experiment station. Considerable current literature One of the studies, comparing conventional with conser- is available through USDA agencies, universities, and private vation tillage in production of dry beans, resulted in industry USDA agencies are listed under "United States Gov- development of a new dry bean variety—light red kidney ernment" in most telephone directories. line 79512—that was named "Ruddy" and released for One major data source previously mentioned, on page 18, is public use. That occurred at Cornell University, Ithaca, the Conservation Tillage Information Center, established by N.Y., during research by R.F, Standsted, W.J. Lament Jr., NACD. and A. Pabon, according to their report to NAL's Current One outstanding source of information outside government Research Information Service. As with most crops, they Is the Soil Conservation Society of America, which publishes reported, one of the most serious problems associated the Journal of Soil and Water Conservation. The journal had a with conservation tillage of beans was weed control. Part special issue on conservation tillage in 1983. of their research entails weed control trials to evaluate herbicides. Should You Try Conservation Tillage on Just a Few Acres Before Switching?

If you can rent or borrow needed equipment, you may wish to do a pilot test before switching from conventional tillage to conservation tillage. Many local soil conservation districts have conservation-tillage equipment available for rent. Some farm equipment dealers and chemical distributors may give you additional leads and ideas. You may make mistakes while learning from experience what kind of conservation tillage works best for your soils on you farm. Begin to try conservation tillage on your bet- ter land. As you (earn more, you will be able to expand conservation tillage to less favorable soils. One thing you may want to remember is that you might try conservation tillage as a rehabilitative practice even if some of your land has been so severely eroded that it has been left out of production. Darryi E. Smika, ARS soli scientist at the Central Great Plains Research Station at Akron, Colo., reported to the 1983 joint agronomy meeting that he believed conservation tillage could speed up reclamation of lands where much topsoil has been eroded. He has been studying various reclamation practices on centra! Great Plains areas since 1955. Some of his study sites had as much as 15 inches of topsoll removed before his reclamation research began.

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