Movement of Diuron and Hexazinone in Clay Soil and Infiltrated Pond Water

Reproduced from Journal of Environmental Quality. Published by ASA, CSSA, and SSSA. All copyrights reserved. rs,lwiflrto ae naeswt ada soils hardpan with con- areas In in 2001). rates al., infiltration et low (Troiano trast, percolation deep residues to of movement lost minimize to management suggested irrigation been coarse-tex- for have on guidelines soils, example, sandy For tured protective aquifers. are underground that of practices develop- management concomitant farm with of water ment ground to movement residues for of pathways the ap- elucidating on this relies of proach effectiveness The with protection. considerations environmental be economic balances can action of This practices course contamination. of management threat to the mitigate if is that identified water use ground continued in allow detected pesticides to approach of the regulation California, In 1989). (Hallberg, mented 7 .SgeR. aio,W 31 USA 53711 WI Madison, Rd., Segoe S. 677 © Transport Chemical and Processes doi:10.2134/jeq2004.0253 Zone Vadose Reports: Technical ulse nJ nio.Qa.34: Qual. Environ. J. in Published (tlprichard@ucdavis. 94236-0001. author CA *Corresponding Sacramento, 2005. edu). 942836, July of 1 Dep. Box California Received P.O. Guo, F. I Resources, and 1001 Water EPA, 95812-4015; California CA Regulation, Sacramento, Pesticide Street, Moni- of Environmental Dep. Marade, Way, J. Branch, Wilson and S. toring Troiano 420 J. California, 95215; of CA Univ. Stockton, Canevari, M. and Prichard T. M reduce pond. the not from did water min- mixture on of focus spray infiltration will imizing water.methods the mitigation ground to water, runoff to surfactant in the movement concentrations a that for of concluded addition source We were Since predominant water. residues the ground Herbicide was sampled pond. pond the the in near detected elevation also rise concomitant water a ground causing soil, in subsurface 20 the into at infiltrated irrigation rapidly first mea- the were 1 at residues and Herbicide water soil. runoff of in depth sured shallow results a to flow to macropore similar that limited were suggesting was soil model, LEACHM the the in distribu- from residues obtained of of pattern concentration The and irrigations. tion surface applica- border-check subsequent after two even of depth, tion soil available mm 8 was 152 the limit water above (reporting confined indicating residues mm, Herbicide lowest 953 percolation. the at for at elevated centered was application sampled after depth d 106 at irrigation before ( alfalfa and 3-yr-old Diuron a sativa to pond. of December holding infiltration in adjacent applied to were an clay hexazinone by cracking captured a water was in soil residues the where field agricultural [ diruon 6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1 of source distribution the soil determine dichlorophenyl)- comparing to by sought contamination study This of CA. Tracy, near sampled S,CS,SS ECM ecigEtmto n hmsr oe;R,reporting RL, Model; Chemistry and Estimation Leaching LEACHM, SSSA CSSA, ASA, r-mrec ebcd eiuswr eetdi oetcwells domestic in detected were residues herbicide Pre-emergence ␮ . rp ae otn fsi ae fe ao analbut rainfall major after taken soil of content Water crop. L.) oeeto irnadHxznn nCa oladIflrtdPn Water Pond Infiltrated and Soil Clay in Hexazinone and Diuron of Movement vmn fpsiieresidues pesticide of ovement plctost rudwtrhsbe eldocu- well been has water ground to applications gL Ϫ 1 o eaioe uofwtrcpue ntepond the in captured water Runoff hexazinone. for N,N dmtyue]adhxznn [3-cyclohexyl- hexazinone and -dimethylurea] er rcad*Jh rin,JeMrd,FnmoGo n ikCanevari Mick and Guo, Fengmao Marade, Joe Troiano, John Prichard,* Terry ABSTRACT ᭿ – ᭿ (2005). rmagricultural from H ,3 ␮ H gL -in]i an in )-dione] ␮ Ϫ gkg 1 o diuron for Medicago Ϫ N 1 were ) ؅ -(3,4- 1 ia s fhxznn a nafla h fetdarea affected pesti- The alfalfa. reported on was only hexazinone of the use cidal since especially applications, of rotation ( a vulgaris corn was with pattern alfalfa 1). cropping (Fig. California predominant of Valley The Central the of side western 0.098 at well 0.11 to 0.051 (6-chloro- at 0.16 wells at three in wells none town five in the detected 2.8 near was to located atrazine CA: area wells Tracy, 1554-ha seven of a in within detected were sampled Pre-emer- residues 2000). al., herbicide Cali- et gence in (Troiano detected water been ground have fornia’s residues where settings cal water. runoff in concentrations reduce to mended hne npn-ae et vrtm odetermine to time over depth the pond-water monitoring in by changes measured accompanying were and an pond water, of water-holding runoff characteristics cores, Water soil vegetation. in distribution mass measuring by their residues herbicide of hexazinone fate determine and to diuron field alfalfa an in conducted was tion herbicides of movement potential 1992). indicated al., study et Move- That (Graham 1998). of investigated area al., been another et had in California Lin soils cracking-clay 1994; in al., atrazine of et (Bouma ment Harris contamination 1981: for al., pathway et potential a as movement fied Rapid termed drying. soil, to that on through soil pathways cracks clay a surface potential was developed soil obvious predominant The any water. ground for surveyed was fpeeegnehriie notesi srecom- is soil the into incorporation herbicides improved so pre-emergence residues of of runoff in result ae,btmvmn osalwgon ae a not was water ground shallow to plow movement the below but detected layer, residues some with cracks into Sadn ta. 1979). atrazine al., and nitrate et for (Spalding contamination source water a ground be to of determined was tail-water Nebraska from in pits water recovery water of source Infiltration ground potential the contamination. another to was for of pond travel the excavation from of recharge deep, length so mm the decreased 3000 were ponds ponds and the Since 2400 mm. 4500 between around at shallow Through determined be was events. area to this water in irrigation water runoff ground or the near interviews, collected rainfall or ponds from within The generated located fields. cropped ponds the water-holding was vey confirmed. ainMngmn nomto ytm T evapotranspiration; limit. ET, System; Information Management gation Abbreviations: hs w cnro r o nlsv falgeographi- all of inclusive not are scenarios two These nrsos otedtcin erTay ninvestiga- an Tracy, near detections the to response In nte oeta aha bevddrn h sur- the during observed pathway potential Another ␮ gL ..Tersde eerltdt agricultural to related were residues The L.). N,N Ϫ 1 NV,aayi fvrac;CMS aionaIrri- California CIMIS, variance; of analysis ANOVA, irni n ela 0.06 at well one in diuron , ␮ Ј dehl135tizn-,-imn)i one in -diethyl-1,3,5-triazine-2,4-diamine) gL Ϫ e mays Zea 1 rc scnrlylctdo the on located centrally is Tracy . arpr flow macropore . n en( bean and L.) ␮ gL a enidenti- been has , Ϫ ␮ 1 n simazine and , gL Ϫ Phaseolus 1 hexazi- , Reproduced from Journal of Environmental Quality. Published by ASA, CSSA, and SSSA. All copyrights reserved. ont h 50m et otiiggaihbon ako hcswsaindfo ot onrh epciey Water respectively. north, to south from aligned was checks of dark brown, grayish spans containing horizon depth lower 1520-mm with depth the The clay 510-mm to structure. brown down the prismatic grayish to coarse dark down and strong brown spans grayish horizon containing first typically The Service, Conservation is 1992). (Soil clay horizons Capay two having suborder. cracking- has dominant described a Xerert smectitic, be the fine, to a in determined is clay and which Haploxerert clay, The Typic Capay cultivation. a thermic alfalfa was of 17 unit season approximately mapping third soil the was entering field hexazinone size, The where in ha well detected. domestic been a had near residues and CA, Tracy, near uofo eius(ugnegre l,1973). al., et (Huggenberger potential residues reducing of matrix soil runoff and between residue interaction pesticide surfac- greater the the facilitated Theoretically, have would mixture. sur- to tant spray a the was of to addition objective the factant of additional mitigation An potential determine water. asso- closely ground of elevation ciated in the changes to from related was infiltration pond Water CA. characteristics. Tracy, near infiltration site study alfalfa the of Location 1. Fig. 2 h td a odce ihna laf il located field alfalfa an within conducted was study The AEIL N METHODS AND MATERIALS ieadSuyDescription Study and Site .EVRN UL,VL 34, VOL. QUAL., ENVIRON. J. esnadtewne an r sdt noprt h herbi- the rainy incorporate the to used with are coincides rains winter application the of and season timing the in so to Mediter- ranean usually is and climate weeds The season germination. winter weed existing subsequent dormant prevent control to the January during or December are alfalfa weeds to pre-emergence when as herbicides value applied are in hexazinone and drops Diuron present. significantly and forage free 1). (Table California-Davis of DANR the University by conducted Lab, was site Analytical the from proper- collected physical soil of and ties chemical structured of from Analysis change soil. moderate a structureless from is to which lower changes massive, structure The to prismatic the clay. coarse and brown calcareous pale is and layer brown, dark brown, grayish og hc a qiaett .8h.Teha-oti end head-to-tail The ha. m 0.28 335.4 by to wide length equivalent m the 8.2 was down was which check advanced long, irrigated and to Each field applied check. the the was of of water method end The where elevated 2000. border-check, the April study was this late in irrigation in and of deficit initiated water was the irrigation for 18 up year, make past to the commence spring irrigations for rainfall, the July of in pattern of this month to response the In in yr. recorded months rainfall summer no and with spring subsequent the precipi- drops throughout rainfall tously monthly Average soil. into residues cide laf a rc setbihdo ihqaiyadweed- and quality high on established is price hay Alfalfa ᭿ – ᭿ 2005 Reproduced from Journal of Environmental Quality. Published by ASA, CSSA, and SSSA. All copyrights reserved. n tr rirgto vn.Tesratn a rpi-Frtetet ihsratn,tesratn a de ta at added was surfactant the surfactant, with treatments For proprie- a was surfactant The event. irrigation or dur- storm site off a move ing readily would that concentrations herbicide lc einwsue ihfu elct lcs(i.2.Aatrapiain ahsetwsmutdo ic fcard- of piece a on mounted was sheet Each application. cotton after foil-lined, of squares m 0.305 by 0.305 placing A by paraquat 2). tion of (Fig. efficacy blocks comparing replicate included complete four was with treatment randomized third used A was profile design IN). to soil block the Converse, designed into Products, surfactants infiltration anionic (Garrco herbicide and and water nonionic enhance of blend tary oldphSn itCa est HEC pH density Clay Silt Sand depth Soil oehneiflrto notesi,teeyrdcn ufc e.19.Apiain eemd sn .- iesprayer wide 9.2-m a using were made hexazinone were Applications and 1999. diuron Dec. of treatments Pre-emergence surface reducing thereby soil, the into infiltration to added enhance was surfactant to treatment of surfactant soil addition The mixture. an herbicide was the treatment second The tively. n ftefedt od hr,rpeetn h ed ide n alprin of portions tail and middle, head, the representing third, m 111.6 approximately third hexa- each represented of with treatment treatment thirds, herbicide into One pre-emergence measure subdivided To standard treatments. check. grower the two of tail between length the the pared down pond. advances from a it diverted as to generated dues field was water the irrigation Runoff of or end check. rainfall per either siphons from of size, check siphon number head, the hydraulic and to the determining supplied by water measured was irrigation of Amount irrigation. esnadjs lgtygetra 3 min L 833 at greater slightly just and season ioeadduo ple t05 n .8k ha kg 1.68 and 0.56 at applied diuron and zinone these but standard, grower the to application trifluralin and an providing field, field. the min the L of 795 of end of end south rate eastern the flow the supply average along in a from located ran checks 0.16 and border that the field 0.17 ditch of alfalfa head 0.20 the 17-ha into a 0.19 siphoned of was ha 3.4 encompassing design study Plot 2. Fig. 0.31 0.33 0.33 0.34 0.5 0.2 0.1 0.1 7.6 7.5 7.2 6.8 1.56 1.63 cm g 1.6 1.44 34 38 40 41 39 37 % 35 34 27 25 25 25 900–1200 600–600 300–600 0–300 site. mm test the from collected soil clay Capay for properties chemical and physical Measured 1. Table itiuino irnadhxznn eiuswscom- was residues hexazinone and diuron of Distribution Ϫ 1 o h is riaino h ooecek h odrcekirgto ehdcnaffect can method irrigation border-check The check. one to the of irrigation first the for RCADE L:MVMN FDUO HEXAZINONE & DIURON OF MOVEMENT AL.: ET PRICHARD Ϫ 1 o h second the for Ϫ 1 respec- , Bulk Ϫ 3 aeo 87 ha L 18.71 of rate or opeetdrc otc ihtesi ufc.Three surface. soil the with contact immediately direct them prevent collecting to board and surface soil the on sheets ple satn i oasm-omn laf il n23 on ha field L 309 alfalfa of semi-dormant volume a a applying to mix tank a as applied nlnt.Si n eeainsmlswr ae rmeach from check. taken the were samples vegetation and Soil length. was in check each irrigation, to due differences spatial potential itiuino eiusbcuewtrcnrdsrbt resi- redistribute can water because residues of distribution aaaentrpre.Ec elct ramn a applied was treatment replicate Each reported. not are data Ϫ ebcd Application Herbicide 1 eoiinwsmaue uigapplica- during measured was Deposition . Sm Ϫ 1 Ϫ 1 ne rsuea .5 MPa. 0.151 at pressure under Ϫ 3kPa 33 osueretention Moisture LL Ϫ 1 Ϫ 50kPa 1500 3 Reproduced from Journal of Environmental Quality. Published by ASA, CSSA, and SSSA. All copyrights reserved. eoiinrt o irnws1.69 was diuron average for The areas. rate subsampling deposition lower and middle, upper, the o7,7 o12 0 o31 1 o66 n 1 o90mm. 990 to 914 and 686, 343, to 114, 38, 610 0 at sample 381, of the of to depths center the on 305 as from reported 152, irrigation are collected Data to second were 76 first the samples 76, after the Soil to was before 2000. which June was 26 2000, between 10 which sampled June again 2000, 27 was Apr. Soil and April. 6 27–28 be- on and collected irrigation Apr. were 3 samples Decem- 23 application, tween on herbicide application After herbicide before ber. 1999, Dec. 20 and he usmlswr lcdit ls a,mxd and mixed, jar, glass a into placed were subsamples 45 three a at located fro transect sampled long simultaneously of were composite a that was boreholes sample three soil Each respectively. mm, 953 and .5.Teeapae ob isi eoiinbtenlre imtragrta a 4m ndaee a used was air-dried and diameter methanol, in then and mm cleaned water was deionized 64 with bit was quence sampling that soil smaller auger checks. The diameter sampling. the larger for of depth location length the spatial along of applica- tion even effects indicating significant, for plus not were Tests the treatments within 2). between for with- (Table deposition treatment rate surfactant the in for out average than bias greater the was treatments a where surfactant diuron, be for to treatments appeared There 0.05). eaioews0.42 was hexazinone au a oe hntetre au f05 gha kg 0.56 of value target the than lower was value ls oistre au f16 gha kg 1.68 of value target its to close et yisrigtesmlrdw ote7-mdphadisalda h oetpitisd h emdcek bat- A check. bermed the inside point lowest the at installed replicates four the samples and of the two depths, depth first deeper from 76-mm For monitored the tube. the was the from water to from Runoff soil obtained down all collecting sampler were the Samples inserting depth. by depth in mm 102 and at sampling. pond for pond the muddy the which too after in dates, was sampling collected April similarly and December were the samples Soil sealed. bit the of length the of portion central 0.15 a from obtained were of each in one check, 0.51 replicate 12 each in placed were given. is sheets level probability the otherwise effect; significant no NS, † 0.14 12 Total 1.52 12 Total 12 Total Total location and interval Sampling recovered kilograms as expressed sheets, deposition and cores soil of length entire in recovered hexazinone and diuron of Mass 2. Table 4 ierefc SNS NS NS NS† effect Linear effect Linear effect Linear effect Linear aled40.22 0.59 4 0.14 4 end Tail 1.52 4 end Tail 4 end Tail end Tail ide40.11 0.56 4 0.13 4 Middle 1.51 4 Middle 4 Middle Middle ed40.12 0.40 4 0.14 4 Head 1.53 4 Head 4 Head Head akrudsi ape eecletdbten1 Dec. 16 between collected were samples soil Background olwssmlduigabtta a 34m ndaee ftoecek ofcltt uofcleto.Wtrwscol- was Water collection. runoff facilitate to checks those of diameter in mm 33.4 was that bit a using sampled was Soil e etr.Saitclts niae o vrl ierefc flcto ncek n odce nvle rnpsdt base to transposed values on conducted and checks in location of effect linear overall for indicated logarithms. test 10 Statistical hectare. per oladVgtto Sampling Vegetation and Soil Ϯ .7k ha kg 0.07 N Њ nl ihnec pi lt The plot. split each within angle Ϫ 1 h aefrduo was diuron for rate The . Ϯ Ϫ .1k ha kg 0.41 1 iu ufcatPu ufcatMnssratn lssurfactant Plus surfactant Minus surfactant Plus surfactant Minus u h eaioeteed n h sltdsml olce noagasmason glass a into collected sample isolated the and ends the hexazinone the but Mean olatrscn riain 62 ue2000 June 26–27 irrigation, second after Soil Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ .EVRN UL,VL 34, VOL. QUAL., ENVIRON. J. olbfr is riain – p.2000 Apr. 3–6 irrigation, first before Soil Ϯ .10.24 0.67 0.11 0.10 0.16 1.68 0.05 0.35 .20.19 0.70 0.02 0.12 0.15 1.84 0.03 0.05 .50.18 0.64 0.05 0.10 0.09 2.02 0.05 0.11 .80.20 0.67 0.08 0.11 0.15 1.85 0.04 0.32 DMean SD akrudsi,1–0Dc 1999 Dec. 16–20 soil, Background eoiinset,2 e.1999 Dec. 23 sheets, Deposition Ϫ 1 Ϫ ma3m n o eto h oeb netn nvsit lt oae neither on located slots into knives inserting by core the of rest for and 1 P P ( irnHexazinone Diuron P 645, ϭ ϭ Ͻ .2NS 0.04 0.02 lge ttesraewt itr fsi n bentonite. and soil of mixture a with surface the at plugged ra htecmasdec ftesi oe.Tevegetation the The from cores. soil collected the were of each plants encompassed Alfalfa that the areas coring. and soil April sample the the of sample. weight soil dry the of the volume on was density sample based Bulk soil moisture. each calculated percentage of determine portion to a used analysis, was chemical of until time frozen the kept At and analysis. ice dry on placed were Samples h ape eetasotdo e c n hnsoe at stored then and ice sealed. wet lid jar on the transported and were jar glass samples 1.1-L The a into directly placed was 3.3 eildwt ocnaiae oladtesml borehole sample the and soil in noncontaminated was collected borehole with sample was The refilled field. sampling the from the removed se- and from bucket in a soil twice Excess rinsed reuse. before water, appropriate soapy next with the sample to each down between soil of borehole the clear to n ftecnrlyclbae ra olwsrmvdfrom removed was Soil area. calibrated centrally the of end a.Bfr netn h apigbtit h oeoe a borehole, the into bit sampling the inserting Before jar. eypwrdpm n la wthpae ntecollection the in placed switch was float that and bucket pump plastic 19-L tery-powered a of comprised end basin tail a the in at lected formed was berm soil A treatment. each from cm 60 at calibrated was that eeainsmlswr ae ttebcgon n at and background the at taken were samples Vegetation Њ ni analysis. until C Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ .40.04 0.13 0.04 0.00 0.10 0.38 0.04 0.26 .50.03 0.11 0.05 0.00 0.11 0.41 0.05 0.45 .50.03 0.09 0.05 0.01 0.25 0.40 0.03 0.58 .40.04 0.11 0.04 0.00 0.15 0.40 0.04 0.44 ᭿ DMean SD – ᭿ 2005 gha kg uofWtrSampling Water Runoff Ϫ 1 3 hsae a sltdfo the from isolated was area This . Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ .20.04 0.08 0.02 0.00 0.07 0.41 0.00 0.08 .10.05 0.15 0.01 0.00 0.03 0.44 0.01 0.10 .00.03 0.09 0.00 0.00 0.04 0.46 0.01 0.04 .10.04 0.11 0.01 0.00 0.05 0.44 0.01 0.07 DMean SD P ϭ 0.04 Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ 0.04 0.05 0.00 0.06 0.01 0.05 0.00 0.06 0.01 0.02 0.00 0.07 0.02 0.05 0.00 0.06 SD Reproduced from Journal of Environmental Quality. Published by ASA, CSSA, and SSSA. All copyrights reserved. rl,adwtrsmlswr rcse hog 1 P ntefrt35m oldph hsetmt a determined was estimate This depth. soil 305-mm first the in transpi- plant through water of loss for provide to included was SPE C18 a through processed were samples water mixture, acetoni- and acetone with extracted trile, and were hexane samples sediment a and vegetation with Soil extracted CA). were Sacramento, Agriculture, samples and Food of Department n hnafxdi h borehole. the in affixed then and t3.3 at agrae hnteeprmna ra o xml,te12 the a example, from for runoff area, of experimental result the the than was area pond larger the entering water the where samples Water Teflon- a with field. sealed bottle the glass amber in 1-L a sampling the in collected were for were procedures described handling as and sampling same Soil bottom pond. the at the locations of two from collected were samples soil so rce oteCne o nltclCeity(aionaSraefu est o ae naewssta 9 md mm 390 at set was intake water for density flux Surface (California Chemistry Analytical for Center the to tracted m)( (mm) ue a lcdit noe-ne,coeftigPCpipe PVC close-fitting open-ended, an into placed trans- was The transducer. ducer pressure a with measured were pond the siaepn ae ouead usqety infiltrated subsequently, [1]: to Eq. and, used to were volume according depth water water measure pond to pond in pond changes the estimate of Temporal bottom depth. the pond at additional An placed 1984). was al., et transducer (Clemmens trans- head pressure measure and to well ducer stilling (Plasti-Fab, a with flume equipped RCB OR) broad-crested Tualatin, throat measured 200-mm was Inflow a to depth. using water pond runoff in between increase of concomitant volume established the inflow cali- measured was then relating relationship by This was brated volume. relationship estimated and A depth pond pond. measurements the three-dimensional of was the pond surveying the of by volume estimated the First, measurements. depth water stopped. had inflow pond niao fteptnilft fhriie ple othe to applied when herbicides irrigation each of after collected fate were samples potential Water field. the important of an was the indicator in concentration of solely pond-water originated measure areas, that runoff treatment direct from a mass herbicide not area. of planted loss were total samples the pond-water of portion Although a were checks experimental refrigerated and ice wet on placed were Samples cap. lined at remained and facility storage a at arrival placed 3.3 until were samples ice water wet The a volume on meter. the with water for the sealed offsite by moving was indicated residue that herbicide bottle of con- centration average glass the it represented amber subsample and This cap. bucket an Teflon-lined 19-L in each stored from collected was buckets. was 19-L of subsample series 1-L a water in A volume a outflow the through which of device, 2% pumped sampling collected proportional was jar a through sample water then and initial remaining meter the the Once full, bucket. complete. was collection was same the runoff simultaneously from water withdrew until and metered operated were of pumps Both times Pumps during runoff. pump the higher sampling jar. assist battery-operated to collection utilized flow sample was lower pump 3.8-L gas-operated a capacity into larger A water runoff moved basin odn odSi n ae apigadGround and Sampling Water and Soil Pond Holding ttebgnigo h td,tehligpn a dry was pond holding the study, the of beginning the At hmclaayi o irnadhxznn eecon- were hexazinone and diuron for analysis Chemical hne ndpht rudwtri nae daetto adjacent area an in water ground to depth in Changes ehiu a eeoe odtriepn ouefrom volume pond determine to developed was technique A Њ ni analysis. until C Њ ni hmclaayi.I sipratt oethat note to important is It analysis. chemical until C y r 2 ϭ ϭ odwtrvlm (m volume water pond 0.998). ae et Measurement Depth Water y ϭ hmclAnalysis Chemical 0.0002 x 2 ϩ 3 and ) 0.12026 RCADE L:MVMN FDUO HEXAZINONE & DIURON OF MOVEMENT AL.: ET PRICHARD x ϭ x odwtrdepth water pond [1] ainadteroswr itiue ih6%apportioned 60% with distributed were roots the and growth ration Crop events. irrigation the from calculated was which nomto ytm aionaDp fWtrResources, Water of Dep. Management California Irrigation (California System; CIMIS Information a from obtained 100 eotn iisfrduo n eaioewr 8 were hexazinone and diuron form. for custody 480 limits of final chain to Reporting accompanying sampling an initial with control from result and tracked analytical 54 warning was with established sample the Each analyzed the within limits. were if fall again not spikes analyzed did were matrix spikes sets Extraction two set. extraction and each control, blank quality solvent continuing 42 For a and (RL). limits, limits control reporting and sample warning acceptable 000 established 33 ratory Water 90 solubility 90 Soil half-life Hexazinone Diuron ingredient Active and physical ingredient active pesticide for Estimates 3. Table oae prxmtl 2k ato h xeietlsite. experimental was the which of CA, east Manteca, km 22 in approximately located located station weather 2001) 1994; al., et Augustijn-Beckers publications 1994; USDA al., two et from (Vogue data 3) of (Table compilation a is which acoee l,19) ausfrsi etr n ukdensity bulk and texture soil for Values 1992). al., et Wauchope 02.Etmtsfrrfrneeaornprto (ET evapotranspiration reference for Estimates was 2002). which station, was weather data Pestcast Rainfall located Tracy 1). the (Table from data obtained measured from taken were rpriso irnadhxznn sdi h oe were model website, Extension the University in State Oregon used the from hexazinone obtained and chemical diuron and of physical for properties Data (2004) (1995). soil al. Vencill of et and Gish Tindall predictions by and model reported preferential previously to been by observed has deduce distribution dominated of to comparison was method by movement flow This which pathways. to preferential extent the could be- values indicate deviations predicted and flow, concentrations soil water observed convection– tween model model uses to LEACHM LEACHM methodology Since the dispersion 2003). using (Hutson, 4 predicted In version were her- irrigation. and residues content and water bicide of soil rainfall distributions with soil from compared expected and addition, produced cores movement soils in water within measured movement downward was of field Extent the field. pond the holding of a edge the from at infiltrated eventually that water runoff in le otesi n ocmaeadto fsratn on of surfactant resi- fate of of leaching to w downward dues respect addition for potential With compare relative field. the to herbicides, the and within distribution soil herbicide the to plied 0.25 soil, for proce- operating of standard A methods request. Specific on available WI). are Madison, analysis Decca, Corp., LCQ Electron MA) (Finnigan Thermo methodology Milford, spectrometry Corp., mass liquid Waters and with 2690, with analyzed (model eluted were chromatography was extracts that Reconstituted CA) methanol. Torrance, (Phenomenex, column uehdbe eeoe oasr eiiaino laboratory labo- the of development, method verification During assure 1995). (Segawa, to results developed been had dure iyEtninwbie(ou ta. 1994). al., et (Vogue website Univer- Extension State sity Oregon from obtained Data properties. chemical td betvswr odtrieft fhriie ap- herbicides of fate determine to were objectives Study ␮ gkg ti h il a oprdwt oeeto residues of movement with compared was field the ithin Ͻ mfo h xeietlst Ui.o California, of (Univ. site experimental the from km 3 Ϫ 1 o eeainsamples. vegetation for ␮ gL Ϫ 1 o ae,10 water, for aaAnalysis Data dmgL ␮ gkg Ϫ 1 Ϫ o eiet and sediment, for 1 ␮ o gkg were ) Lkg K oc Ϫ Ϫ Ϫ 5 1 1 , 1 Reproduced from Journal of Environmental Quality. Published by ASA, CSSA, and SSSA. All copyrights reserved. rdcddrn h td Fg ) nte7 before d 75 the water In 3). percolated (Fig. and study runoff the during reference of produced a amount provided potential irrigation for and rainfall of amount rudsi oe a uhlwrta htmeasured back- that of than lower content much water was surface, cores period. soil soil experimental ground not the the of was near d rainfall mm 30 Except addition, 9 first only the In for 1999, recorded. measured Dec. was 15 on rainfall study of this of initiation the kg a on expressed density were bulk ha residues and Herbicide concentration depths. average the between of integrated product were the estimates depths, as sampling soil in remaining from discontinuity the for recovered between account mass To estimate segment. soil directly first soil to the two used 76-mm first was first The the depth for soil water. concentration the or so soil contiguous were of cores mass and concentration of 1988). be- Institute, logarithms (SAS 10 of analysis base homogeneity to statistical for transposed fore were Test values Levene’s vari- so of using variance heterogeneity indicated for covariate was potential a ance addition, as used In were ANOVA. data in deposition surfac- the between treatments, application tant in sheets differences measured and deposition potential the indicated linear was from data (SAS measuring Since location effects. location) contrasts spatial field quadratic end regression of split- tail orthogonal effect the and using as The middle, field 1988). the head, in Institute, (i.e., location and factor effect plot main treat- (ANOVA) the surfactant variance with as design ment of block complete analysis randomized a split-plot for and a surface using measured the from elevation in water ground concentration. changes herbicide shallow to nearby respect in with measured response bal- the water calculated and the from m the determined ance, was 1926). pond (Weaver, the soil from are of roots mm active 305 of first mature portion the a large in of a located distribution that root indicates the which of plant, depiction stylized a from (ET evapotranspiration reference cumulative of Comparison 3. Fig. 6 Ϫ oprsno uuaieET cumulative of comparison A eoee etcd aswsdtrie steproduct the as determined was mass pesticide Recovered were mass recovered on effects treatment, surfactant For right and top the on Specific indicated axes. are left irrigation depth and axes. water bottom plus and the rainfall events by cumulative rainfall indicated to as volumes and water rainfall cumulative to h otiuino eiu oeett rudwater ground to movement residue of contribution The 1 ai ofcltt oprsnt plcto rates. application to comparison facilitate to basis ae itiuinadMovement and Distribution Water aue ocnrto fhriie npn water, pond in herbicides of concentration easured RESULTS o otecumulative the to .EVRN UL,VL 34, VOL. QUAL., ENVIRON. J. o ) oae ont h oetsi et ape Fg 4B). (Fig. sampled depth soil back- lowest per- the than rainfall to down from colated greater water first that the consistently indicating before samples, at ground was was content which event, date, water irrigation coring Soil soil checks. second samples not the experimental water was the runoff rainfall significant of from amount generate pe- and to this frequency sufficient during the observed so not riod, was water runoff Rainfall ainwsgetrta anal ae a oe othe to segments. moved was soil after mm, water deepest d rainfall, 131 than 115 greater was was At ration rainfall water. of ET of total amount whereas mm total and 44.5 to the sampling of corresponded application core depth background soil added the the of an from diameter the g 239 on was based 39 core soil of entire the increase in estimated water Average of content effects. mass location water or in treatment differences to due significant no were There ET cumulative than greater in 190 water was of core mass soil estimated vs. entire A Average the Graph C). 4, and (Fig. B intervals Graphs sampling two next the for etrmie lvtda h oetsmlddepth, sampled lowest the at opportunity elevated greater remained by con- water tent caused importantly, More is infiltration. water check for time border the of 228 was cores ends—in tail 213 water to of head mass the estimated from cores average soil decrease a of was content which ( water Within cores, in effect the of 4C). linear content water significant total (Fig. on a was dy-irrigation there the border-check by checks, caused of distribution a namics of irriga- reflective border-check was two tions, after was which date, sampling con- typical of reflective second more ditions. the considered of irri- was 7.1% second the and gation from first Runoff the volumes. irrigation of applied 2.5% was occurring runoff volume water as on-flow of con- proportion moisture The soil tent. antecedent infil- by soil influenced and small rate times, tration run by volumes, caused on-flow in were differences irrigations between respectively. and irrigations, 4.3 second Differences and was first the irrigations for mm. the mm 12.4 175 for averaging depth volumes, runoff onflow Calculated and time run deficit total cumulative the ET match in to irrigations water The enough 3). (Fig. supplied irrigations contribution two the the from water illustrates accumu- of in irrigation spikes plus upward rainfall sharp lated two The ET accelerate. of to accumulation the radiation, solar creasing oain,rsetvl.Hge osuea h edend head the at moisture Higher respectively. locations, niaigta riaintetet asddrainage caused treatments irrigation that indicating n rvddaptnillahn environment. leaching potential a provided and Vegetation irnwsntdtce nbcgon ape u it but samples background in detected not was Diuron analatrDy8 a iia n wn oin- to owing and minimal was 85 Day after Rainfall h osuepoieo h olcrsa h third the at cores soil the of profile moisture The h uuaierifl muteetal became eventually amount rainfall cumulative The eaioewsntdtce nvgtto samples. vegetation in detected not was Hexazinone Ϯ oladVgtto apigwti the within Sampling Vegetation and Soil ᭿ o ohirgto vnswr iia ntrsof terms in similar were events irrigation Both . 6 n 205 and 16, – ᭿ 2005 o a 1 m lhuhevapotranspi- Although mm. 217 was Ϯ laf Field Alfalfa 2gfrha,mdl,adti end tail and middle, head, for g 12 o Ϯ taon a 0(i.3). (Fig. 60 Day around at 3g. 13 Ϯ P 5g an g, 15 ϭ o began Ϯ 0.02) 17, Reproduced from Journal of Environmental Quality. Published by ASA, CSSA, and SSSA. All copyrights reserved. eodsi emn a ny2 fthe of 2% the only in was concentration segment depth—average concentra- soil next low second segment very the soil with in first depth tions the 38-mm bulk in the The located at centered values). was residue observed diuron of see of and distribution 4, diuron The between (Table differed April. hexazinone profile 3 soil the on in sampling residues soil of ment commence- and application pesticide between rainwater aesqetrdduo tart f0006 gha kg 0.000068 would of diuron rate a of at concentration diuron average sequestered have the at which oee rmaldph niae naeaerecovery average ha kg an 0.12 indicated to re- corresponding depths mass all lower estimated from its the covered of to Summation due rate. likely es- application was were which residues undetected, Hexazinone aver- sentially were locations). depth all each only at over data aged and that mm note depth 114 please at 38-mm 4, centered (Table depth the lower next at the in centered sporadically samples all in water and soil Soil in residues of fate the samples. on focus the discussion of will following portion the (0.004%), small rate a application was total vegetation in presence Since f8% r aswudb siae t56k ha kg 576 at estimated be would content mass water dry vegetative 80%, Assuming of basis. mass fresh a o eetosa 118 at detections for ln il esrdo pi a 80k ha kg 2880 was April 3 on measured yield Plant rdbtensaillctoswti hcs(al 2). (Table checks within locations spatial between recov- mass ered in differences significant appli- no year’s were previous There the cation. from carryover 8% an imately a eetdi u f2 ape bandbfr h esrdi h is emn.I oprsn hexazi- comparison, In segment. first the in measured at were Detections 100 of April. reporting border-check the 3–6 above the of just before on or initiation obtained event before samples 24 (B) irrigation of 1999, first out Dec. 7 16–20 in taken detected was samples background (A) from: obtained cores soil in distribution Water 4. Fig. akrudSampling. Background eoeFrtIrrigation. First Before riain36Ar 00 n C fe w odrcekirgtos2–7Jn 2000. June 26–27 irrigations border-check two after (C) and 2000, Apr. 3–6 irrigation Ϯ 18 irnrsde eedetected were residues Diuron h lt eevd10m of mm 130 received plots The ␮ Ϫ gkg 1 irn hc a approx- was which diuron, ␮ RCADE L:MVMN FDUO HEXAZINONE & DIURON OF MOVEMENT AL.: ET PRICHARD Ϫ gkg 1 nadyms basis. mass dry a on Ϫ 1 ihteaverage the with concentration Ϫ 1 ,on Ϫ Ϫ 1 1 . , f16d siae aflf auswr 0ad5 for d 55 and respectively. 70 hexazinone, were and interval values diuron half-life sampling estimated a d, 106 and of of dissipation first- values on exponential Based day hexazinone. order for application 74% and the diuron for from 65% decrease a sented odrcekirgtosbfr olsmln n2 June, 26 on sampling soil before irrigations border-check feto ufcatidctdgetrttlaon of amount total greater indicated surfactant of effect irnrcvrdi ramnswt de surfactant, added with treatments in recovered diuron etbtnti h lssratn ramn.Although treatment. surfactant plus the in not but ment in covariate a as used were data deposition when but edt alprino ahtetet(al ) this 2), (Table treatment the each from of application portion even tail to very head indicated evenly data depo- more Since were sition treatment. residues surfactant plus the the but in data, distributed than the lower of appeared rest end treatment the head surfactant the minus where the diuron of to similar hexa- appeared for pattern zinone the significant, not were tests statistical treat- surfactant minus minus the the for of lin- significant the was portion treatments, effect within ear lower head tested by the When plot. caused in tail surfactant be diuron to to of head of appeared recovery addition the which the between covariate, without or effect the with linear significant 2). was a (Table location for nonsignificant test was effect The the ANOVA, the asmvdblwtefrtsegment. first the below moved mass fta esrdi h is emn,wihi relation in which segment, first the in measured that of oapiainrtsrpeetdagetrprinof portion greater a represented rates application to atr ol niaeta h ufcatwseffective was surfactant the that indicate could pattern eghaeae vrbt ramnsws05 gha kg 0.59 was treatments both over averaged length field. the within residues of redistribution minimizing at o irnad01 gha kg 0.11 and diuron for oecnetaini h eodsi emn a 50% was segment soil second the in concentration none fe eodIrrigation. Second After o oa asrcvrdprcr,ats o h main the for test a core, per recovered mass total For aso eiusrcvrdfo h oa olcore soil total the from recovered residues of Mass Ϫ 1 h laf il eevdtwo received field alfalfa The o eaioe hs repre- These hexazinone. for Ϫ 7 1 Reproduced from Journal of Environmental Quality. Published by ASA, CSSA, and SSSA. All copyrights reserved. onticuersdels ntiwtr rdce eprmvmn o eaioe neffect an hexazinone, for movement deeper predicted tailwater. that in indicated lost estimates concentrations residue These between include not agreement respectively. 56 do and The hexazinone, 62 were and interval values diuron half-life sampling estimated a d, 198 and of of dissipation first- values on exponential Based day hexazinone. order for application 91% and the diuron for from 90% decrease a sented ebcd ocnrto ntesi rfl eecm infcn ifrnei irncnetainwas concentration approxi- diuron was in irrigation first difference the significant from runoff A in measured distri- soil on effect great a had whether movement determine to preferential only com- 4). made (Table were were depth comparisons sampled The profile each at soil data observed the to pared in concentration herbicide 5 0.22 0.21 953 645 5 0.26 0.26 953 645 4 0.26 0.24 343 114 0.23 0.23 343 114 aetesratn a o dqaet iiierds olsget ECMalw padmvmn of movement upward ha allows kg LEACHM 0.18 segment. was coring, soil treatments soil second both and over first the averaged between length uptake water. plant to irrigation the approxi- in redis- minimize residues modeled transpiration to of plant LEACHM this adequate tribution flow, Although not In was water water. condition. surfactant on irrigation indicate soil the effects the could case pattern with structure flows this residues soil and of water tail movement the irrigation, to head border-check the end from tail With the with 2). both compared when (Table for end were head concentrations significant the the at was lowest where checks hexazinone and of diuron location for effect n allctos(aantson.fc ol h atr a iia tteJn sampling, June the ha at kg similar 0.04 and was diuron pattern for The soil. face prefer- water where re- flow macropore the of in influence the conditions head of wetter shown). between not and residue (data segment locations of wa- 76-mm tail measured movement first and contrast, downward In similar- segment. in indicating distribu- soil locations, soil ity deepest between 4, the irriga- same first for Fig. the the in was before observed tion sampling infiltra- Although as soil water April percolation 4). greater the and received At (Table plots tion theory. the depths of segment end between head soil the evenly and two nearly segment first soil split the first residues resi- the hexazinone diuron in LEACHM where with located sampling mainly April were the dues residues to hexazinone similar and were 498 diuron of of application Distribution total water. cumulative a in Observed resulting cores soil 0.15 modeling. 24 LEACHM from for data used of values average Initial the ‡ are values Observed † 0.28 0.29 LEACHM 0.30 0.27 0.14 38 Observed L L 953 645 0.25 343 114 LEACHM 38 Observed† 38 mm depth Soil ( content water soil Observed 4. Table 8 ECMmdlpeitosfrwtrcnetand content water for predictions model LEACHM aso eiu eoee rmtettlsi oeti soil. this core soil total the from recovered residue of Mass linear overall the core, per recovered mass total For ECMmodel. LEACHM olLAH oe Predictions Model LEACHM Soil Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ olwtrcnet( content water Soil .3–0 0 – – 0.03 0.03 .302 0 0 0.25 0.26 0.03 0.03 .202 2 9 0.27 0.29 0.5 4 0.02 0.02 – – 0.02 0.01 .202 152 0 0 1 13 592 0.29 0.21 0.23 0.24 115 0.24 0.25 0.02 0.03 0.02 0.02 0.02 – 0.02 0.02 Ϫ 1 o eaioe hs er-peitdadosre olcnetain o ohpes- both for concentrations soil observed and predicted repre- These hexazinone. for Ϫ 1 T n olcnetaino irnadhxznn oprdwt rdce ausuigthe using values predicted with compared hexazinone and diuron of concentration soil and ) T irnHexazinone Diuron ) .EVRN UL,VL 34, VOL. QUAL., ENVIRON. J. fe eodirgto ue2000 June irrigation second After eoefrtirgto pi 2000 April irrigation first Before Ϯ akrud1 e.1999‡ Dec. 15 Background SD. mo uino eiusi eaint iuto hr flow where situation a to relation in residues of bution of mm o fsoil of for d Ϫ 1 Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ 73911 45 319 0.5 57 800 – 175 34 –0 2– 14 24 40 11 –0 0– 0 0– 00 00 0 00 . 0 10 0.3 113 0.3 5 8 – 9 . 0.5 0.2 0 00 0 00 3 htwsosre ntefeddata. field the in observed was that LEACHM season. the in early flow macropore of effect layers upper the to confined were residues the of bulk the iie tteArladJn apigdts(al 4). (Table dates sampling June and April the at ticides aeytietecnetaino h eodirrigation second the of concentration the twice mately concentration the where irrigations between measured ae,wihmyb as fteoeetmto for overestimation the of cause a be may which water, first the in maintained was content water mm high 155 relatively and evaporation to lost water surface of mm drier 45 a mately produce would that process another is hc a fe w ufc riain.I diinto addition In irrigations. surface two after was which subsur- wetting cracks surface through flowed reflective entially be could data observed The profile. the maining in conditions soil drier much indicated contents ter content water lower slightly predicted LEACHM tion, convection–dispersion by dominated been have would upiigygo gemn a bevdbetween observed was agreement good Surprisingly ᭿ vntog h olwtrdsrbto niae an indicated distribution water soil the though even – ᭿ 2005 uofWtrSampling Water Runoff etcd olconc. soil Pesticide ␮ gkg Ϫ 1 Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ Ϯ 354 96 13 15 0– 0– 0– 0.2 0 03 015 00 00 2– 3– 32 79 59 Reproduced from Journal of Environmental Quality. Published by ASA, CSSA, and SSSA. All copyrights reserved. vrg al odwtrvlm a acltdand calculated was volume water pond daily Average lyproae.Ec riaineetcnitdo se- a of consisted event irrigation Each eventu- percolated. that infiltration ally or evaporation to either lost was the capacity in pond than reached. maximum irrigation was when first event the irrigation in second measured runoff less unigo esfo n n ftefedt h other. the to field the of end one from sets of quencing ie nrnf ae Tbe5). (Table herbi- water of of runoff concentration Addition in the cides similar. affect not were did field. surfactant hexazinone the the leaving for mass results the The in in resulting differences irrigation, significant second no the in tripled had volume rtdwti h 4hpro.Teaon fwater of amount infil- The water m period. 235 of at estimated 24-h volume was infiltrated the the be within to trated considered was between days difference and volume area The surface precipitation. on from gain based loss evaporative for adjusted t,tepn edavlm f40m 420 of volume a capac- held pond full the At ity, surfactant. added without treatment dard htwscpue rmec ftediyirgto sets. irrigation daily the runoff of each of from surges captured the was that during occurred infiltration Thus, rmteetr il,wihrcie h rwrstan- grower the received which field, entire the from Ground Levels and Water Water Infiltrated of Measure runoff the but irrigation re- first was the herbicide from 50% diuron irriga- by of or duced treatments concentration between The detected the tions. not leaving herbicide were ( of the field trend mass irrigation, a in only first differences Significant indicated the probability at of greater level appeared also concentra- tions hexazinone Although 5). (Table event runoff ertepn n o rmteetr il Fg 5A). with irrigation (Fig. each field before entire empty the nearly from was pond not The and pond the generated runoff near winter from to originated due likely most pond which the rain, in collected small was a water indicated of amount disappearance and collection water of n t65m 615 at and h ihs aeo nitainwsetmtda 72cm 17.2 at estimated was d infiltration 5A). of (Fig. days rate few highest a The just in infiltrated was volume water frnf ae nitae ytepn sarsl of result a as pond m 850 the was by irrigations infiltrated both water runoff of riaineetDuo eaioeDuo Hexazinone event Irrigation Diuron Hexazinone Diuron Treatment event irrigation or Treatment in measured hexazinone and diuron of Concentration 5. Table Ϫ rbblt .200 .90.90 0.03 0.19 0.63 1.20 0.03 0.07 0.61 0.26 0.91 0.02 0.28 10.08 0.70 0.20 Probability 2 Irrigation 17.37 Probability surfactant Plus riain12.309 .70.03 0.77 0.03 0.95 1.06 20.53 0.42 1 Irrigation 13.27 surfactant Minus hr a opn ae-eyln ups water so pump water-recycling pond no was There h odn odcpue uofwtrgenerated water runoff captured pond holding The uofwtradrsetv asrcvrdaeae across averaged recovered irrigations. mass and respective treatments and water runoff 1 07 mh cm (0.72 3 Ϫ odn odSampling Pond Holding 1 o h eodirgto.Ttlvolume Total irrigation. second the for tapn et f95m.Iflrto odifo volumes. inflow pond Infiltration mm. 995 of depth pond a at ) ␮ oc asrecovered Mass Conc. gL 3 Ϫ h aoiyo h pond the of majority The . 1 RCADE L:MVMN FDUO HEXAZINONE & DIURON OF MOVEMENT AL.: ET PRICHARD 3 o h is irrigation first the for 3 ae.Tepattern The water. gha kg P ϭ Ϫ 1 0.07). oea 0.9 at none odadntteetr il.Smlscletdatrthe after collected Samples field. entire the not and pond nlwt h odhdcae rmtefrtirrigation first the 12.4 from at ceased diuron had the contained pond near the to conditions inflow of reflective sam- these probably generate therefore, not were field; did ples the rainfall from of runoff pattern significant the earlier, noted ␮ 50ad30 ms eiuswr uhdee nthe in deeper much were residues previous so between mm the to 3000 excavated and during was 2500 pond field the the addition, In from season. residues diuron movement of of con- indicative were soil they these low, mm Although were pond. 645 centrations the at of centered bottom the was below which sample, deepest fourth hs aibedfeecsi o paetbtmybe may for but cause apparent The not similar. is were differences water variable runoff concentra- these the the of hexazinone that in but twice tions runoff, about was treatment irrigation average first the in pond apigdate. sampling uofsmlswt irna 11.8 at irrigation diuron first the with to samples similar runoff were irrigation second the od h vrg ocnrto a lgtygetrat greater slightly was concentration average The pond. recharge to water. water pond ground levelfor nearby time water travel ground short the a in from indicated response water quick ground of The in loss pond. was the the rise to the response corresponded irrigation; elevation similar water second A the for 5B). measured surface (Fig. the from sharply the depth the the decreased that until time which indicated constant at relatively irrigation, pond first was the water near ground mea- borehole shallow depth a water in ground de-and sured depth pond water pond the tween of area wetted the creased. as decreased rates apecnee t35m eo h otmo the of bottom the deepest 69 below third mm the 345 at at located centered were first sample residues the they before Diuron and taken samples field. irrigation soil the in detected within also were measured than soil diuron soil sampling, irrigation 45 was background first at the which residues the For dry, before dates. was and sampling background pond the the at when determined was Sampling Soil ae ape olce fe anrnf ae t2.2 at water runoff rain after ␮ collected samples water Sampling Water u oacmiaino aiblt nsrydeposition spray in variability of combination a to due oue ewe eswr aibea esrdby measured as variable were Runoff sets sequentially. between applied volumes sets irrigation individual n napiaino riainwtrtruhu the throughout water irrigation of application in and niefed riaino h niefedrqie seven required field entire the of irrigation field: entire gL gL oprsno h iutnosmaueet be- measurements simultaneous the of Comparison rsneo eiusi h olpoieo h pond the of profile soil the in residues of Presence ebcd eiuswr esrdi itrdpond filtered in measured were residues Herbicide Ϯ Ϫ Ϫ 49 1 1 h ocnrtosi ape olce after collected samples in concentrations The . o irnad0.6 and diuron for ␮ gkg ␮ gL Ϫ Ϯ 1 eaioewsntdtce teither at detected not was Hexazinone . Ϫ 18 1 h ocnrto fduo nthe in diuron of concentration The . ␮ gkg ␮ Ϫ gL 1 ␮ eedtce ont the to down detected were gL Ϫ 1 Ϫ n eaioea 1.0 at hexazinone and 1 o eaioe As hexazinone. for ␮ gL Ϫ 1 n hexazi- and 9 Reproduced from Journal of Environmental Quality. Published by ASA, CSSA, and SSSA. All copyrights reserved. ac rmtepn ae;tecnetainwsnear was concentration dis- the with water; 2.5 decreasing pond water, the con- the from the tance in with diuron detected of bore- were centration mm between residues 3140 measured Herbicide to d. gradient holes. 3080 25 hydraulic from about little ranged for with water empty ground nearly to was Depth last pond the time, the this At therefore, pond. the from occurred m had transect 48 irrigation a and on 12, located 6, were 3, October at 24 on pond the near h oeoe eesmlra l apigdsacsa sipratfcosta eemn eiec ieof time residence determine that factors important as at distances sampling all at similar were boreholes in found the concentrations hexazinone The 6). (Fig. further i.6 ocnrto fduo n eaioemaue nground in measured hexazinone and diuron of Concentration 6. Fig. volume water pond holding in changes daily (A) depth: water ground in changes to relation in pond holding the in loss and gain Water 5. Fig. 10 ape fgon ae bandfo boreholes from obtained water ground of Samples ae ape bandaogatasc ticesn distances increasing at transect pond. holding a the along from obtained samples water n B hne npn ouei eaint lvto ngon ae et esrdblwtepn hr h cl sgae othat so graded is scale the where pond the below measured depth water ground in 0. elevation at to initiated relation is in measure volume deepest pond the in changes (B) and ␮ gL Ϫ 1 ertepn n odtcal t1 and m 12 at nondetectable and pond the near ebcd Concentration Herbicide and Depth Groundwater Ͼ 0dbfr hsmeasurement; this before d 40 .EVRN UL,VL 34, VOL. QUAL., ENVIRON. J. fdtcin sunclear. is detections of ie ihntefed eaioeadduo residues diuron this and at hexazinone water field, ground the en- into Within for residues site. pathway herbicide predominant the of col- as trance water pond of the in percolation lected implicated clearly results the e esrn h infcneo arpr lwhave flow macropore of significance the measuring ies eal ra htcnandcakn lysisi the in vul- identified soils of (1995) clay Bronswijk model and cracking a Oostindie Netherlands, contained in that However, areas sites. nerable those shal- to at pathway drains significant low a al., as flow et have macropore Traub-Eberhard studies shown previous 1995; these that al., acknowledge et We 1995). Brown Beck 1995; 1994; al., alleviate al., et et to (Harris systems conditions the table drainage where water shallow with soils modified clay were cracking soils other in conducted been stud- many First, restricted. indicate was movement. to movement tend residue residue evidence that of may lines all of design number detected a sampling However, adequately soil not the addition, have the In into profile. deeper moved soil The were limits depth. 8 these below soil was residues soil 152-mm in the limit below reporting detected not were 0.5 about hcns fteca ae n et ogon water ground to depth and layer clay the of thickness vntog hsivsiainwsol ri scope, in yr 1 only was investigation this though Even ᭿ – ᭿ ␮ 2005 gL Ϫ 1 h as ftedfeec npattern in difference the of cause The . DISCUSSION ␮ gkg Ϫ 1 ti osbethat possible is It . Reproduced from Journal of Environmental Quality. Published by ASA, CSSA, and SSSA. All copyrights reserved. 0 mi e odtosaddee hn10 mi aiu oryitniymaue na2- period 24-h a in measured intensity hourly maximum in mm 1200 than around deeper was and conditions depth wet table in mm cracks—water 500 the of bottom et otewtrtbewssalw einn tterifl nest f7%o vnsws1m h mm 1 was events of 70% of the intensity between rainfall site the at occurred rainfall measured the of at beginning shallow, was modeled, table water they the conditions ground to the subsequently depth For and profile vulnerability. soil water the within water aealwdfrfrhrrsdedgaain e nitae rmtepn ihnafwdy after days the few through a apparently was within loss pond water the of from route infiltrated major fast ter residues indicated for pond conduit the direct for a collected provided data route contrast, This In proper- water. The chemical ties. and physical difference the respective because their matrix reflected soil the and residues pest- icide between interaction intimate be- of the indication interaction another to greater degradation. time to residue contributed travel further also for for have would depth allowed would time 4500-mm have the around the De- at located rates. soil, water infiltration ground the in decreases moved into limits associated detection move- deeper Vertisol in our further of below sulting rates limiting residues typical if infiltration matrix, Even in soil events ment. resi- changes the flow, temporal rain into preferential ported diffuse by intensity applications dues soil low into water flowing movement concluded the of larger (1991) after al. instead However, of that et Gish matrix effect table. 2004). water soil the minimizing pesticide the into directly thereby and into water first infiltrate allowing tended to macropores, have solute end for would inherent pathway dead properties major an to a soil winter, be These the have to during no shown season. mm not was having rainy flow 1520 as ropore above does classified table is water it it apparent of that because feature table is water important shallow clay other soil One Capay depth structureless horizon. in the a mm lower to 1520 structured the least a in at from soil changed clay it thick and a was site our otatt hs tde,bcueteCpysi at soil Capay the because studies, these provide to site Tracy contrast the a at conditions The conditions. dry ufc rcig hn itrriswudhv ildae tteopst n fti eto fln,a around at land, of the section this mimicking of end field, opposite the this at ated to the adjacent before located soil well clay that indicated the the data rainfall of promoted filled Hourly irrigations. swelling have crop have causing would would rains cracks study winter the the Then, condi- of cracking. Dry onset surface rainfall. the of at pattern tions typical the was ropores nmlu ihcnetain farzn 6clr-lctddw-rdeto h ltwr trbtdto attributed were plot the of down-gradient peaks located Seasonal site. experimental the of down-gradient using [6-chloro- water ground atrazine in herbicides of pre-emergence of N tions concentrations the high of similar noted layer (1995) anomalous Vencill shallow and flow Evaluation a Tindall contrast, Systems preferential to In soil. Management localized of ob- Nebraska irrigation were effects the in and macropores of nuances that modeled in on part indicated the depending smaller data between or results served larger in be similarity that the only water convection–dispersion, concentra- of through mechanism herbicide We was primary movement matrix. or the soil that water association suggesting the not of and close are most residues volumes the a pesticide was specific pond the indicated the the between that their distribution concluded and we an soil hexazinone water, and ground about relative diuron rapid were of the concentrations they on The soil Based observed 1977). low, wells. and Lavy, modeled domestic were LEACHM and nearby between the (Majka concurrence in water attributed adsorption of measured and was runoff soil bottom diuron diuron greater the in of to between on movement sured sediment comparison soil less a previous cyanazine, formed a and Gustafson, In collected 1987; al., 1989). et dif- (Jury for distribution so determinant soil in hexazinone, major ferences the and be diuron would both adsorption less rates soil for and Dissipation long retention relatively movement. are soil downward greater for in potential result should which rcigsi rfl n srbdtesmlrt nmv-sao niae iia ocnrto fhexazinone of in concentration differences em- their similar further phasizing adsorption, treatments. indicated pesticide have irrigation for could season surge study sources our additional from in water of system presence root off The alfalfa flow. the preferential to due bypass move- to in ment similarity the ascribed and profile and cracking-soil acid), acid] [(2,4-dichlorophenoxy)acetic 2,4-D (3,6-dichloro-2-methoxybenzoic dicamba -ethyl- eprsi oeetosre o eaioewas hexazinone for observed movement soil Deeper nte atrlseigteifuneo olmac- soil of influence the lessening factor Another N K Ј -(1-methylethyl) oc o irni rae hnfrhexazinone, for than greater is diuron for -1,3,5- K oc RCADE L:MVMN FDUO HEXAZINONE & DIURON OF MOVEMENT AL.: ET PRICHARD eut rmtedmsi elsmln htrsle in resulted that sampling well domestic the from results . triazine- 2,4- epri a in deeper diamine], provided 5 bro h 154 a . mh mm 3.3 was es o h is 2datrpsiieapiain the application, pesticide after d 62 first the For less. ebcd plcto n h pi olsmln.The sampling. soil April the and application herbicide ie ftepn eas vrtm iesi particles soil fine time over because The pond the water. of ground sides enter to water runoff in dissolved ground shallow nearby of level the elevating collection, wa- where water ground shallow to water of movement matrix. soil the and residues water herbicide of tween movement downward the in velocity creased re- re- macroporosity, (1998) decreased events al. rainfall where et soils Lin soil, movement. clay the downward swell rapid to on tended have would site this for (Ju rainfall intensity high under movement Ͼ oddwt aiu nest t76 mh mm 7.62 at intensity maximum a with corded itneo 69m otie eiuso taieand atrazine of residues contained m, 1609 of distance a situ- well Another transect. the along measured pattern hsivsiaindtce nyhxznn eiusin residues hexazinone only detected investigation this ehreta rgntdfo ice htcletdrun- collected that ditches from originated that samplers recharge in herbicides pre-emergence of and detections within, in up-gradient, located samplers multilevel concentra- monitored (2003) al. et Spalding study, Area As management. runoff subsequent and could management sites other from or years other in generated tions that noted be should It contamination. for source the likely into residues herbicide and concentrations water pond the of injection than greater magnitude of mea- order concentrations herbicide the though Even pond. ndsac rmtepn.I a esrniiybut serendipity be may It pond. the from pond. distance increase the in with from decreased outward however, radiated concentration, Diruon that transect a along 1mmh rudwtrsmldna h odltri the in later pond the near sampled water Ground ai [5-bromo-6-methyl-3-(1-methylpropyl)-2,4(1 macil Ϫ 1 fe 5Fb 00 e an eere- were rains few a 2000, Feb. 15 After . Ϫ 1 n tol i ie eeintensities were times six only at and ´ ire al., et nior Ϫ 1 Mac- . Ϫ 1 11 H or , Reproduced from Journal of Environmental Quality. Published by ASA, CSSA, and SSSA. All copyrights reserved. eiustruhu h hc.Atrtoirgto events, of irrigation two distribution After check. even the the an throughout events, residues maintain irrigation to appeared Before surfactant results. mixed produced in iaieadohrcmiain frsde had residues of combinations other and simazine tion, befriflrto n eraetettltm o infil- or for same time total the avail- the tration. water in decrease of and reuse infiltration volume for for the able pond reduce the would of field adjacent out water the Pump- ing interface. soil–herbicide manage rather the residues of to herbicide management than be contains that would water present runoff the were crops site this alfalfa at water where measure days, mitigation ground practical few most localized The a raising levels. and within recharging infiltrated directly subsequently the in Runoff and collected water. pond was ground residues to pesticide containing route water direct pond more the in a collected provided water of pond holding infiltration adjacent Mea- that an indicated may depth. in balance 152-mm that water the of residues residence surements past of undetected long to moved degradation distance in have for and resulted allowing soil have the times, would of water 8 thickness maintained (RL ground the depth were addition, soil field potential 152-mm In surface a the the flow was within above preferential field residues Although the pathway, within clay. macropores cracking predominant through the a where was area do- an soil in in located detected wells residues mestic pesticide for source dominant observed pond. rates the infiltration in water an fo- of will be management effects on not cus mitigation irri- would and Instead, crop, it combination. soil, gation this that for indicated surfactant measure mitigation consistent study the effective a this of of in modification lack the effect The and both. soil, on the surfactant of properties pesticides, and of the complex properties physicochemical are the surfactant on of depend Effects (Sanchez-Cama- 2000). lindane al., et for zano and 1972) (Koren, amide] [4-(dipropylamino)-3,5-dinitrobenzenesulfon- [2,6-dini- oryzalin trifluralin for observed tro- was soil increased into whereas mobility 1973), al., et (Huggenberger atrazine or ( observed lindane not for was mobility ef- increased variable example, indicated For fects. have surfactants Pre- with residues. studies retain to vious surfactant for potential checks, irrigation out in the supplied washed of water of end volume the tail that the indicating at greater appeared residues water. ground to from ponds water ap- of the flow water and of capture specifics subsequent and the plication and use, by pesticide dic- specific which determined tate patterns, is cropping localized that of water combination pesti- a ground six-section for to scenario original complex movement a the cide indicates within This area. wells study in detected been 3 12 H aty h diino ufcatt h pa mixture spray the to surfactant of addition the Lastly, nivsiainwscnutdt eemn h pre- the determine to conducted was investigation An prmdndoe.Ada niae nteintroduc- the in indicated as And )pyrimidinedione]. N,N dpoy--tilooehlbneaie and -dipropyl-4-(trifluoromethyl)benzenamine] ␥ 123456hxclrccoeae,diuron, -1,2,3,4,5,6-hexachlorocyclohexane), CONCLUSION .EVRN UL,VL 34, VOL. QUAL., ENVIRON. J. ␮ gkg Ϫ 1 ). i,HS,KJ cne,LP idn,adCT alak 1998. Hallmark. C.T. and Wilding, L.P. McInnes, K.J. H.S., Lin, humid the in groundwater of pollution Pesticide 1989. G.R. Hallberg, Herbicide 1992. Teso. R.R. and Neal, R.H. Ulery, A.L. R.C., Graham, C.S. Bubenzer, G. Posner, J. Perry, D.C. Kung, K.-J.S. T.J., Gish, rw,CD,RA ogisn ..Rs,JK yr,adSJ Wil- S.J. and Syers, J.K. Rose, D.A. Hodgkinson, method R.A. C.D., field Brown, A 1981. Muilwijk. C.J. and Dekker, L.W. J., Bouma, Jones. K.C. and Johnston, A.E. Howse, K.R. Harris, G.L. A.J., Beck, Wauchope. R.D. and Hornsby, A.G. P.W.M., Augustijn-Beckers, and competent their without possible assistance. project been exuberant This have and California. not of Beland University would Amy the from and Rivers Regulation, Daniel Pesticide sam- of our for thank Department also and struc- We samples. field other the pling and commercial obtain berms to a of necessary within tures construction the study with the cooperating conduct to us oe,E 92 ecigo rfuai n rzlni olwt three with soil in oryzalin and trifluralin of Leaching 1972. E. Koren, pes- of Evaluation 1987. Farmer. W.J. and Focht, D.D. W.A., Jury, Ju Model Model. Chemistry and Estimation two Leaching 2003. of J. Effect Hutson, 1973. Farmer. W.J. and Letey, J. F., Huggenberger, Mason. D.J. and Howse, K.R. Bailey, S.W. Nicholls, P.H. G.L., Harris, for method simple A score: ubiquity Groundwater 1989. D.I. Gustafson, movement Prefrential 1991. Mojasevic. M. and Helling, RBC C.S. T.J., Gish, Portable 1984. Replogle. A. and Bos, M.G. A.J., Clemmens, Irriga- California 2001. Resources. Water of Department California ´ ir ... ..Set ....Betn ...Hnrk,and Hendriks, R.F.A. Boesten, J.J.T.I. Smelt, J.H. R.P.S., nior, o esrn hr-iciigi lysis .Hdo.(Amster- Hydrol. J. soils. clay 52:347–354. in dam) short-circuiting Food Agric. measuring J. for crop. barley winter soil the a clay on of 43:1368–1376. structured season Chem. drainage in growing and isoproturon the management of over movement residue and crop persistence of Effect 1995. Environ. 137:1–82. Rev. Toxicol. compounds. Contam. Additional II. making: decision mental allowing for Pombo Ken grower the to thanks our express We ufcat.We c.20:230–232. Sci. Weed surfactants. 16: Qual. Environ. J. 422–428. biodegradation. and adsorption chemical soil 33: Qual. Environ. J. soil. clay ben- Dutch bromide, a 1473–1486. of in flow imidacloprid Preferential and 2004. tazon, Zee. der and van Physics, S.E.A.T.M. Australia. Chemistry, SA, of Adelaide, Univ., School Flinders 2005). Sciences, June Earth 20 www.scieng. verified at Dec. 2004; Available 1 (accessed [Online]. guide flinders.edu.au/cpes/people/hutson_j/leachweb.html user’s 37:215–219. and Proc. Am. description Soc. Sci. Soil soil-system. a in cides a 159:235–253. from (Amsterdam) drainage in Hydrol. pesticides J. of soil. loss cracking-clay the influencing Factors 1994. 26:299–367. Environ. Ecosyst. Agric. States. United 8:339–357. Chem. Toxicol. Environ. leachability. pesticide assessing 153:115–121. Califor- Sci. two in Soil morphology vertisols. soil nia to relation in distributions residue fluxes. mass quantifying by 33:1033–1040. rates Qual. Environ. irrigation J. varying prefer- at of Impact flow 2004. Steenhuis. ential T.S. and Kladiviko, E.J. Helling, 1699–1705. 27:1016– ASAE Trans. channels. earthen 1020. and furrows Sacra- for flumes Resources, Water of Dep. California CA. 2005). mento, June 20 veri- 2004; fied Feb. 19 www. (accessed at cimis.water.ca.gov/cimis/welcome.jsp Available [Online]. System Information Management tion 43:131–140. Sci. Pestic. soil. clay heavy oko.19.Mvmn fpsiie osraewtr rma from waters surface to pesticides of Movement 1995. cockson. environ- for database properties pesticide SCS/ARS/CES The 1994. iiegonwtrpluinptnilfo tnadidcsof indices standard from potential pollution groundwater ticide pesti- selected of mobility and adsorption on surfactants nonionic 34: ASAE Trans. conditions. field under cyanazine and atrazine of rwta osse fJfe cetefo h California the from Scheutte Jeffey of consisted that crew ᭿ – ᭿ 2005 ACKNOWLEDGMENTS REFERENCES Reproduced from Journal of Environmental Quality. Published by ASA, CSSA, and SSSA. All copyrights reserved. idl,JA,adWK ecl.19.Tasoto taie ,-,Wae,JE 96 othbt fafla hp.13. Chapt. alfalfa. of habits Root 1926. J.E. Weaver, 2,4-D, atrazine, of Transport 1995. Vencill. W.K. and J.A., Tindall, www.cdpr.ca.gov/ at Available [Online]. 1999 14, October water: preferen- of Consequences 1995. Bronswijk. J.J.B. and K., Oostindie, ru-brad . .P eshl .Kre,adW li.1995. Klein. W. and Kordel, W. Henschel, K.-P. U., Traub-Eberhard, Augustijn-Beck- P.M. Hornsby, A.G. Buttler, T.M. R.D., Wauchope, Exner, M.E. Cassada, D.A. Snow, D.D. Watts, D.G. R.F., Spalding, Chemi- 1979. Lyon. P.A. and Sullivan, J.J. Exner, County, M.E. R.F., Joaquin Spalding, San of Survey SOP Soil 1992. Service. control. Conservation Soil quality laboratory Chemistry SAS 1995. ed. 6.03 R. Release Segawa, guide. user’s SAS/STAT 1988. Institute. SAS Delgado-Pas- California R. the of and Update 2000. Sanchez-Martin, Marade. J. M.J. and Spurlock, M., F. J., Sanchez-Camazano, Troiano, degrada- and mobility, Adsorption, 1977. Lavy. T.L. and J.T., Majka, a olna etai,Msor.J yrl 6:75.0albay003fedrpot/119o.tl(cesd1 May 18 (accessed 01aglibrary/010139fieldcroproots/010139toc.html Con- Environ. Rev. making. decision environmental for database 166:37–59. Hydrol. J. Missouri. Centralia, clay- unsaturated near a soil in paths pan flow preferential through dicamba and J. Area. Evaluation 32:84–91. Qual. Systems water Environ. ground Management shallow to Nebraska’s loading benearth Herbicide 2003. Shepers. J.S. and Pest and Monitoring Environmental 00–05 EH 2005). June 20 fied shallow of contamination-risk 43:359–373. for Manage. soils Environ. clay J. cracking aquifers. in 25:401–406. Sci. flow Weed tial soils. in diuron and cyanzine of tion odCe.4:0832.mr,adD atoik 01 umr fwl ae sampling water well of Summary 2001. Bartkowiak. D. and mark, Univ., State Oregon Center, Information Pesticide National 2005). http://ace.orst.edu/ at Available [Online]. database properties cide CA. water. Davis, 8:374–383. ground adjacent Qual. to pit Environ. recovery J. water tail a from seepage cal (ac- DC. Washington, Office, www.ipm.ucdavis.edu/DISEASE/california_pestcast.html Print. Gov. at U.S. USDA-SCS. California. CA. Sacramento, Agency, Protection Environmental 2005). June California 20 verified 2004; Jan. 4 (accessed pubs/sops/qaqc001.pdf www.cdpr.ca.gov/docs/empm/ at Available [Online]. CA. QAQC001.00 Sacramento, EPA, C Inst., Agric. J. surfactants. 48:3018–3026. and Chem. amendments, Food organic influenced as properties, soils soil in linuron by of mobility and Adsorption 2000. cual. subsur- into movement pesticide on sites field different of Influence 161:2–8. in Sci. rates Soil infiltration intergrades. Vertic on and effects Vertisols moisture initial and Macroporosity r,N.suc plctos .Evrn ul 30:448–459. Qual. Environ. J. applications. source NC. ary, RCADE L:MVMN FDUO HEXAZINONE & DIURON OF MOVEMENT AL.: ET PRICHARD ou,PA,EA el,adJJ ekn.19.OUetninpesti- extension OSU 1994. Jenkins. J.J. and Kerle, E.A. P.A., Vogue, Nord- C. Pepple, M. Spurlock, F. Marade, J. Weaver, D. J., Troiano, nvriyo aiona 02 aionaPsCs Oln] Available [Online]. PestCast California 2002. California. of University osep/usearp/h05pf(cesd1 e.20;veri- 2004; Feb. 19 (accessed docs/empm/pubs/ehapreps/eh0005.pdf 05 eiid2 ue20) crwHl,NwYork. New McGraw-Hill, 2005). June 20 verified 2005; www.soilandhealth.org/ at Available [Online]. crops field of ment 123:1–155. Toxicol. tam. California Regulation, Pesticide of Dep. Branch, Management r,adJP ut 92 h C/R/E etcd properties pesticide SCS/ARS/CES The 1992. Burt. J.P. and ers, ground to pesticides of movement for analysis soil vulnerability nont/pmv.t acse 9Fb 04 eiid2 June OR. 20 Corvallis, verified 2004; Feb. 19 (accessed info/nptn/ppdmove.htm California, of Univ. 2005). June 20 verified 2004; Feb. 19 cessed nonpoint- from resulting residues pesticide detect to California in 43:121–129. Sci. Pestic. drains. face In otdevelop- Root 13