Research Article Crop Residue Biomass Effects on

Hindawi Publishing CorporationApplied and Environmental Soil ScienceVolume 2013 Article ID 805206 8 pageshttpdxdoiorg1011552013805206

Research ArticleCrop Residue Biomass Effects on Agricultural Runoff

Damodhara R Mailapalli1 Martin Burger2

William R Horwath2 and Wesley W Wallender2

1 Biological Systems Engineering University of Wisconsin Madison Madison WI 53706 USA2 Land Air and Water Resources Department University of California Davis Davis CA 95616 USA

Correspondence should be addressed to Damodhara R Mailapalli damiitkgpgmailcom

Received 28 March 2013 Accepted 15 July 2013

Academic Editor Davey Jones

Copyright copy 2013 Damodhara R Mailapalli et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

High residue loads associated with conservation tillage and cover cropping may impede water flow in furrow irrigation and thusdecrease the efficiency of water delivery and runoff water quality In this study the biomass residue effects on infiltration runoffand export of total suspended solids (TSS) dissolved organic carbon (DOC) sediment-associated carbon (TSS-C) and otherundesirable constituents such as phosphate (soluble P) nitrate (NO

3

minus) and ammonium (NH4

+) in runoff water from a furrow-irrigated field were studied Furrow irrigation experiments were conducted in 91 and 274m long fields in which the amount ofresidue in the furrows varied among four treatments The biomass residue in the furrows increased infiltration and this affectedtotal load of DOC TSS and TSS-C Net storage of DOC took place in the long but not in the short field because most of theapplied water ran off in the short field Increasing field length decreased TSS and TSS-C losses Total load of NO

3

minus NH4

+ andsoluble P decreased with increasing distance from the inflow due to infiltration The concentration and load of P increased withincreasing residue biomass in furrows but no particular trend was observed for NO

3

minus and NH4

+ Overall the constituents in therunoff decreased with increasing surface cover and field length

1 Introduction

The USA having more than 408 million acres of cropland and an abundant supply of food products is notedworldwide for its high productivity quality and efficiencyin delivering goods to the consumer [1] However theagricultural practices used to produce these quality productsare affecting the sustainability of crop production systemsand impacting water quality in many regions of the countryAgriculture is the third leading source of pollution in USAestuaries [2] Specifically elevated dissolved organic carbon(DOC) concentrations in runoff that finds its way to maindrinking water supplies are of significant concern becauseof serious potential health concerns During chlorinationto produce drinking water a subgroup of DOC or disin-fection byproduct precursors form disinfection byproducts(DBPs) of which trihalomethanes and haloacetic acids are

the most abundant These DBPs stringently regulated by theUSEPA are carcinogenic and mutagenic Therefore knowl-edge ofwater quality parameters such as nutrients sedimentsand bacterial concentrations of flooded fields is importantbecause the water released from these fields eventually flowsinto streams and rivers

One of the importantmethods of controlling pollution byagricultural activities is to employ bestmanagement practices(BMPs) to reduce sediment and dissolved chemicals in therunoff Conservation tillage (CT) (no-till or reduced till) andthe use of cover crops (CC) can reduce runoff by promotingincreased infiltration [3ndash8] However these practices are onlyslowly being adopted in agriculture due to the increasednumber of field operations required to maintain furrowsfor irrigation management Specifically CT and CC canleave potentially high residue loads (at least 30) on fields[9] that impair the movement of water and thus decrease

2 Applied and Environmental Soil Science

the efficiency of water delivery The residue encouragesthe decomposersmdashespecially fungimdashand increases food webcomplexity by providing food and habitat for surface feedersand surface dwellers Residue protects soil from raindropimpacts causing loss of soil surface structure and pluggingup of macropores and cycles of freezing thawing and dryingwetting [10ndash12] The presence of crop residue on the soilsurface not only substantially reduces the soil loss fromfurrows [13 14] but also may improve irrigation uniformity[14 15]

Crop residues also slow the rate of evaporation [10 11 16]by isolating the soil fromheating and elevated air temperatureand increasing resistance to water vapor flux by reducingwind speed [11] The increase in infiltration and the decreasein evaporation generally result in greater soil water storagedepending on amount and type of crop residues left on thesoil surface [16] and the duration of the dry period [3 1718] Crop residue is a convenient and valuable source oforganic matter [19 20] This improves soil aggregate stabilityduring low rainfall periods and promotes more infiltrationthrough the soil The increased aggregation might be due tosoluble carbohydrates leached from fresh residues [21] or toparticulate organicmatter [22] to the activity of fungi [23 24]or microbes

The amount of crop residues on the soil surface varieswith time [23ndash25] and directly affects soil water character-istics structural properties [26] and organic matter content[27ndash30] The most important reasons for the crop residuevariation are tillage and residue decay Tillage modifiesresidue cover nearly instantaneously and changes the per-centage of residues left on the surface versus buried accord-ing to tillage system and intensity [31] Laboratory studiesindicate that water and temperature have a greater effectduring early stages of decomposition when easily utilizablecompounds are readily available to microorganisms [32ndash34] Greater fluctuations in water and temperature alongwith reduced nutrient availability adversely affect microbescolonizing surface residue thus slowing decompositioncompared with incorporated crop residues [35ndash38] Standingbiomass seems to decompose more slowly than flat residues[39]

In addition to the biomass residue length of the fieldaffects the agricultural discharges Limited studies have beencarried out on the field length effect on runoff and DOCexport [8] in furrow- irrigated fields Increase in field lengthgenerally decreases the quantity of agricultural dischargeand elevates the concentration of pollutants However thetotal export of the pollutants decreases with increase in thefield length due to the decreased runoff [8] We proposedto consider the advantages of the residue having a beneficialinfluence on runoff water quality rather than viewing residueas deterrent to implementing furrow irrigation practicesTheobjectives of the present study are to (i) investigate the effectsof varied levels of residue cover on infiltration and runoffat different locations in fields of varying lengths (ii) charac-terize the release transport and export of DOC phosphate(soluble P) nitrate (NO

3


+) atmulti-ple locations in irrigated furrows containing varied amountsof residue and (iii) assess the effects of residue amount on

total suspended solids (TSS) and sediment-associated carbon(TSS-C) during irrigation in fields of varying lengths

2 Materials and Methods

21 Experimental Site Thefield experiments were conductedat the Campbell Tract at the University of California Davis(38∘ 321015840 0910158401015840 N 121∘ 461015840 3210158401015840 W 60 ft elevation) The alluvialsoils at the experimental site are classified as Yolo siltyloam (fine silty mixed nonacid thermic family of MollicXerofluvents) containing 24 of sand 50 of silt and 26of clay The experimental site has 02 slope Prior to theexperiments the fields had been fallow for one year and priorto the fallow period corn was grown

22 Residue Biomass Treatments The research was con-ducted on two furrowed plots of 91 and 274m length and110m width Row spacing was 15m with bed widths ofapproximately 1m and depth of furrows about 02m Fourtreatments of residue biomass (high medium low andcontrol) each comprising six beds five irrigated furrowsand one dry furrow on either side of each treatment blockreplicated three times were assigned to the two lengths ina randomized block design The plots were planted withcorn on May 20 2008 All biomass treatments includingthe control were irrigated three times at an interval of 10to 15 days To obtain low medium and high residue covercorn plants were chopped 23 32 and 39 days after plantingrespectively At the time of chopping the average corn heightwas 03 06 and 085m for low medium and high residueplots respectively The texture of the chopped corn residuewas 012 to 016m long with a diameter of 002 to 004mThe corn residue was left in the field to dry and herbicidewas sprayed to control weedsThe amount of residue biomassin a meter length of furrow was collected from five randomlocations in each replicate and dry weight was measuredResidue biomass found in furrows of control plots due towind was removed by hand raking

23 Field Experimentation The treatments of long field wereirrigated on 20th and 21st November 2008 The treatmentsof the short field were irrigated on 24th and 25th November2008 Each treatment was irrigated through gated pipes for10 hours using a constant inflow of 15 L sminus1 per furrow Toachieve a uniform inflow rate the gates were opened to equalwidth and after measuring the inflow rate at the middle andend gates of each experimental unit (5 irrigated furrows)by using a bucket and stop watch the gates were adjustedas needed The outflow from each treatment was monitoredusing ISCO6700 dataloggerswater samplers (TeledyneTech-nologies Inc Thousand Oaks CA USA) (Figure 1)

24 Data Collection From a randomly selected furrow ofeach treatment waterfront advance time was measured by asystem of clocks placed in the furrows at equal distances fromthe head end The clock (Walmart Stores Inc BentonvilleAR USA) power supply was spliced and connected by wireto metal plates attached to the jaws of a clothespin Before

Applied and Environmental Soil Science 3

Figure 1 Runoff sample collection using ISCO autosampler fromthe short field

irrigation events a soluble tablet (eg aspirin) was placedbetween the clothespin jaws to keep the circuit open andthe clock set to a predetermined time The clock circuitwas closed when the tablet was dissolved as the water frontadvanced in the furrow activating the clock and indicatingthe time it took for the water to advance in the furrow Moredetails on waterfront advance measurements using the clockmethod are given by [8]Thewater advance time of a locationis determined by the following relation

119879119886= 119879119903minus 119879119888minus 119879119894 (1)

where 119879119886is the water advance time (min) 119879

119894is the irrigation

start time (min) 119879119888is the clock time (min) and 119879

119903is the time

that the clock showed (min)The waterfront advance time patterns represent infiltra-

tion characteristics of the treatment plot that is a longerwaterfront advance time at the field end indicating greaterwater infiltration into the soil The waterfront advance mea-surements were taken from both long and short fields Fromthe treatments of the long field grab samples were collectedat 91 and 183m locations at regular time intervals and the flowrate was determined using the dye method [40] First theflow velocity at a location in the furrow was determined byplacing a drop of dye upstream of the location andmeasuringthe time to cover a 1m distance downstream Second theflow cross-section was determined by measuring the flowdepth and flow width (parabolic shape was assumed) Theflow rate at the location was determined by multiplying flowvelocity and the flow cross-section The grab samplesrsquo data atdifferent locations were used to analyze the spatial variabilityin the runoff loads The water samples were kept on iceand filtered through nominal 03120583m glass fiber filters within6 hours of collection The mass of total suspended solids(TSS) retained by the filters was measured after drying Thecarbon content in the dried sediment retained by the filterwas determined via combustion by an Elemental Carbonand Nitrogen Analyzer (Costech Analytical TechnologiesInc Valencia CA USA) The filtrate was stored at 4∘Cand within two days DOC concentration in the filtratewas measured by the UV-persulfate oxidation method [41]Furthermore phosphate (soluble P) nitrate (NO

3

minus) andammonium (NH

4

+) concentrations were measured for all

samples To assess total dissolved phosphorus a persulfatedigestion to convert dissolved P to orthophosphate (PO

4-

P) was carried out and PO4-P in the filtered subsamples

was measured colorimetrically (Shimadzu spectrophotome-ter Model UV-Mini 1240) by the ascorbic acid method[42] Ammonium (NH

4

+) was determined colorimetricallyby the phenate (indophenol blue) method [43] Nitrate in thesamples was reduced to NO

2

minus with vanadium chloride fol-lowed by analysis of NO

2

minus by diazotizing with sulfanilamidefollowed by coupling with N-(1-naphthyl)ethylenediamine-dihydrochloride and colorimetric analysis [44] Total load ofthe water constituents was calculated from their concentra-tion in the water samples and the runoff (short field) and flowrates measured at the 91 and 183m locations in the long fieldThe runoff at the end of the long field (274m) was not usedfor the analysis because after 24 hours of inflow the irrigationwater did not reach the outflow except in a few of the 60furrows The total inflow during the time considered in thisexperiment (10 hours) was 4000m3 haminus1 for the 91m longfield and 2000m3 haminus1 for the 183m location in the longerfield

25 Data Analysis Residue biomass treatment effects wereassessed by one-way analysis of variance (ANOVA) for theshort field and two-factor ANOVA with location (91 or 183mfrom the head end of the furrows) and residue biomassquantity as factors for the longer field The effects of fieldlength and biomass in the furrow on runoff TSS DOCsoluble P NO

3

minus and NH4

+ export were assessed in a split-plot design with length as main effect and biomass as subploteffectThe generalized linearmodels procedurewas usedwithSAS v 92 (SAS Institute Inc Cary NC USA) The Tukeyrsquostest was used for means separation The interaction effectof field length and biomass was studied using two-factorANOVAwith SAS v 92 Using the measured data regressionanalysis was carried out to quantify the predictability ofrunoff TSS DOC sediment carbon soluble P NO

3

minus andNH4

+ export using length scale and biomass residue quantity

3 Results and Discussion

31 Residue Biomass in the Furrows In the short field (91m)the average mass of residue biomass present in the furrowswas 10 152 and 266Mg haminus1 and in the long field (274m)it was 44 123 and 19Mg haminus1 for low medium and highresidue treatments respectively The residue biomass wasnegligible in the control plots in both short and long fieldsThe residue biomass in the furrows was significantly higherin the short than in the long field (119875 lt 0001) In each fieldresidue biomass in the furrows was significantly differentamong the treatments (119875 lt 0001)

32 Waterfront Advance The waterfront advance time(Figure 2) was similar among the residue treatments both atthe end of short field (91m) and at the 91m location in thelong field However with increasing field length at the 122152 and 183m locations thewaterfront advancedmore slowlyin the furrows with high residue than that in the low residue


Waterfront advance (m)0 50 100 150 200

Tim

e (m

in)

0

50

100

150

200

250

HighMedium

LowControl

NS

Figure 2 The waterfront advance time at 30 61 and 91m fromthe inflow of the 91m long field The error bars represent thestandard error The High Medium Low and Control residuetreatments represent varying amounts of residue biomass in thefurrow NS = nonsignificant differences

and control treatments (Figure 3) These results suggest thatthe presence of residue resulted in greater water residencetime which also increased the infiltration opportunity time

33 Residue Biomass Effects on Runoff In the short field theamount of runoff did not differ among the treatments butin the longer field the high residue treatment significantlyreduced the total amount of water flow in the furrow (Tables1 and 2) Between the 91 and 183m sampling locationsthe amount of water flowing through the furrow decreasedsignificantly (Table 2) In addition to the greater infiltrationopportunity with increasing furrow length runoff was alsodecreased in the high residue treatment The runoffflowmeasurements confirmed that greater water residence timeincreased infiltration as the waterfront advance data pre-dicted The runoff measure also allowed calculation of totalload of DOC sediment and other water quality parametersfor each treatment and location within the furrow

34 Length and Residue Biomass Effects on DOC Concen-tration The mean concentration of DOC in the inflowwas 27mgCLminus1 The water source for this experiment waspredominantly Campbell tract (Davis CA USA) well waterwith a small supplement from a storage reservoir with lakeBerryessa water For all treatments the DOC concentrationat each grab sample location was initially the highest anddecreased nonlinearly to a constant value with time (Fig-ures 4 and 5) The initial maximum DOC concentrationincreased with increasing amounts of residue in the furrowsThe DOC concentration was higher at the 183m than atthe 91m location indicating increasing DOC concentrationdownstream in the furrows This suggests that the releasedcarbon is transported in convective flow down the furrow


Tim

e (m

in)

0

50

100

150

200

250

HighMedium

LowControl

b

ab

a

a

NS

Figure 3 The waterfront advance time for the 274m long fieldat varying locations from the inflow end The error bars representthe standard error The High Medium Low and Control residuetreatments represent varying amounts of residue biomass in thefurrow Means represented by symbols with same letters are notsignificantly different (119875 lt 005) NS nonsignificant differences

The interaction between location and biomass residue effectson DOC concentration was highly significant (Table 2)

In the short field DOC concentration tended to behigher with increasing amounts of residue biomass in thefurrows and in the longer field increasing amounts of residuesignificantly increased DOC concentration These resultsstrongly suggest that surface plant residue is a major sourceof DOC Doane and Horwath [44] also concluded that plantresidue enriches DOC in tailwater by reporting DOC valuesof 1mg Lminus1 from soil solution 47mg Lminus1 in irrigation canalwater and 78mg Lminus1 in runoff water

Differences in DOC export and net storage were due tofield length and residue treatment effects (Tables 1 and 2)In the short field there were no differences in DOC exportamong residue treatments and high runoff volumes relativeto inflow resulted in net losses of DOC In the longer fieldadditional infiltration of irrigation water between the 91 and183m location and thus low water flow at the 183m locationrelative to inflow resulted in net storage of DOC over the183m long furrowTheDOC storage values for this irrigationevent are similar to those reported in comparable studiesof this area [45] There were no differences in DOC exportand storage value among the residue treatments but residuebiomass in the furrows influencedDOC storage by increasinginfiltration and reducing runoff volume as evidenced by thesignificantly decreased runoff in the high residue treatment

35 Effects of Residue Treatments and Field Length on Sed-iment Export Sediment or total suspended solids (TSS)concentration in the furrow water also increased with furrowlength (Table 2) However the total amount of sedimenttransported (total load is the time integral of the product ofTSS concentration and flow rate) decreased with increasing


Table 1 Biomass effect on runoff TSS DOC and TSS-C in the short (91m long) field Shown are means (standard error) 119899 = 3

Treatment Runoff(m3 haminus1)

TSS export(kg haminus1)

DOC conc(mg Lminus1)

DOC export(kg haminus1)

DOC storage(kg haminus1)

TSS-C export(kg haminus1)

Control 3380 (30) 2298 (72)a 43 (06)e 129 (11) minus29 (11) 100 (17)Low 3520 (1010) 789 (223)b 60 (13)de 160 (26) minus60 (26) 72 (35)Medium 3370 (310) 628 (79)b 93 (18)d 186 (34) minus86 (34) 67 (16)High 2770 (390) 419 (145)b 95 (17)d 154 (18) minus54 (18) 41 (12)

NS lowastlowastlowast lowast NS NS NSNS nonsignificantly different lowast119875 lt 01 lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 for each variable values with same letters are not significantly different

Table 2 Biomass residue and field length effects on runoff TSS DOC and TSS-C in the 274m long field Shown are means (standard error)as well as analysis of variance results 119899 = 3

Location (m) Treatment Runoff(m3 haminus1)

TSS conc(mg Lminus1)






91

Control 4140 (289)b 343 (119) 712 (142)b 25 (02)c 91 (09) 09 (09) 111 (13)Low 3579 (847)b 213 (50) 508 (141)a 44 (06)bc 105 (18) minus06 (18) 85 (17)

Medium 3702 (381)b 234 (54) 469 (41)a 51 (10)b 134 (06) minus34 (07) 90 (25)High 2373 (149)a 309 (34) 447 (75)a 87 (08)a 131 (13) minus45 (21) 90 (23)

183

Control 905 (166)y 963 (242) 507 (50)x 32 (02)z 23 (02) 27 (02) 33 (10)Low 870 (146)y 191 (33) 95 (6)y 58 (11)yz 35 (01) 15 (00) 21 (2)

Medium 503 (199)y 654 (292) 155 (45)y 122 (35)y 35 (04) 15 (04) 18 (9)High 135 (45)x 507 (104) 51 (4)y 305 (36)x 27 (09) 23 (08) 5 (3)

Two-way ANOVA resultsBiomass lowast NS lowastlowast lowastlowastlowast NS NS NSLength lowastlowastlowast lowast lowastlowastlowast lowastlowastlowast lowastlowastlowast lowastlowastlowast lowastlowast

Biomass times length NS NS NS lowastlowastlowast NS NS NSFor each variable and length values designated with the same letters are not significantly different (119875 gt 005)

05

1015202530354045

0 50 100 150 200 250

DO

C co

ncen

trat

ion

(mg L

minus1)

HighMedium

LowControl

Time (min)

Figure 4 The DOC concentration at the 91m location The labelsHigh Medium Low and Control refer to the amount of residuebiomass in the furrow

length because flow rate decreased with length Biomassresidue in the furrows reduced sediment load since furrowswithout residue (control) had significantly greater sedimentconcentrations (Tables 1 and 2) The concentration of carbon(C) in the sediment was similar among the treatments andhence the load of sediment carbon carried in the furrowwater

05

1015202530354045

0 50 100 150 200 250Time (min)

HighMedium

LowControl

DO

C co

ncen

trat

ion

(mg L

minus1)

Figure 5 The DOC concentration at the 183m location The labelsHigh Medium Low and Control indicate the amount of residuebiomass in the furrow

(total sediment carbon is the time integral of the product of Cconcentration in the sediment the concentration of sedimentin water and flow rate) depended on the TSS load a notionsupported by the highly significant regression of TSS-C onTSS (119875 lt 0001 1199032 = 93)


Table 3 Biomass residue and field length effects on soluble P NO3

minus- and NH4

+- in the 274m long field Shown are means (standard error)as well as analysis of variance results 119899 = 3

Location (m) Treatment Soluble P conc(mg Lminus1)

Soluble P exp(kg haminus1)

NO3

minus conc(mg Lminus1)

NO3

minus exp(kg haminus1)

NH4

+ conc(mg Lminus1)

NH4

+ exp(kg haminus1)

91

Control 006 (001)b 014 (003) 246 (020)c 960 (136)b 011 (003)b 036 (006)Low 007 (002)b 023 (010) 327 (019)b 1007 (135)b 018 (011)b 048 (031)

Medium 009 (003)b 025 (006) 370 (038)ab 1280 (240)b 016 (009)b 041 (018)High 020 (005)a 035 (009) 332 (031)a 650 (086)a 022 (010)a 036 (015)

183

Control 008 (001)y 006 (002) 269 (021)z 220 (010)y 013 (002)y 008 (003)Low 011 (003)y 007 (002) 373 (027)y 260 (045)y 021 (010)y 009 (003)

Medium 024 (011)y 006 (001) 462 (080)xy 173 (056)y 045 (025)y 010 (002)High 074 (023)x 007 (003) 540 (034)x 057 (019)x 132 (050)x 009 (004)

Analysis of varianceBiomass lowastlowast NS lowastlowast lowast lowast NSLength lowast lowastlowastlowast lowastlowast lowastlowastlowast lowast

lowastlowast

Biomass timeslenght

lowast NS NS NS lowast NS

For each variable and length values designated with the same letter are not significantly different

The percentage of total C in the sediment ranged from4 to 22 This proportion of C in sediment is much largerthan C values in the range of 2 to 5 reported in sediment ofdistrict irrigation canal water or in sediment from runoff [45]In our experiments the analyzed sediment samples may havecontained a substantial amount of light fraction C especiallyin the grab samples The C concentration in the sediment ofthe runoff samples from the control treatment in the 91mlong field by comparison was 46 and more in range ofvalues reported elsewhere [45]Therefore these results whichindicate that a far greater amount of C is potentially lost assediment than as DOC may not be broadly generalizableHowever if well water is used for irrigation it is likely thatTSS-C loss is greater than DOC-C loss since well watercontains very little sediment and any sediment in runoffrepresents a loss of C whereas this and other studies showthat during irrigation DOC is generally contributing to anincrease in field C [46 47] In the present study sediment inthe inflow water was below our detection limit

36 Residue Treatments and Field Length Effects on NutrientConcentration and Export Soluble P concentration and loadin the runoff water followed the trend of DOC The solubleP concentration increased with increasing biomass residuein the furrows (Table 3) However the response of biomassresidue on NO

3

minus and NH4

+ concentrations in runoff did notfollow a particular trend Total load of these ions decreasedwith increasing distance from the inflow due to reducedwater flow caused by infiltration Overall concentrations ofnutrients in runoff and furrow water were low

37 Regression Analysis The observed data were fitted tothe following linear regression model with field length and

Table 4 Constants standard error and coefficients of variation ofthe regression analysis

Parameter (119911) 1199110

119886 119887Standarderror 119877

2

Runoff (m3 haminus1) 683872 minus3141 minus355 68584 082TSS (kg haminus1) 163362 minus647 minus189 40178 045DOC (kg haminus1) 2344 minus012 00015 412 063NO3

minus (kg haminus1) 1761 minus0078 minus00015 26 064Soluble P (kg haminus1) 037 minus0002 00004 01 056NH4

+ (kg haminus1) 079 minus0004 00001 021 043TSS-C (kgC ha1) 15229 minus056 minus0154 3124 049

residue biomass as independent variables and runoff or totalload of water quality as dependent variable

119911 = 1199110+ 119886 times 119909 + 119887 times 119910 (2)

where 119911 is the output variable 119909 is the field length (m) 119910 isthe biomass (gmminus1 furrow) and 119886 119887 and 119911

0are the fitting

parametersThemodel parameters are useful in explaining the output

trend based on the variations in the inputs (Table 4)The positive sign of 119911

0and negative sign of 119887 indicate that

the output variable is the highest for the control treatment(no residue biomass)High residue cover in the furrow andorlong furrow lengths decrease the total runoff TSS and TSS-CThe positive sign of b for DOC soluble P andNH

4

+ exportindicates that increased biomass in the furrow increasesthe export of these variables The values of the parametersapply to our experimental conditions (constant inflow rateand slope) The general format of the model illustrates the


expected effects of field length and biomass residue for eachvariable

4 Conclusions

The data of this study showed that biomass residue in thefurrows increases infiltration and this affects total load ofconstituents in runoff such as dissolved organic carbon(DOC) sediment and sediment-associated C Even thoughbiomass residue releases DOC into the irrigation waterinfiltration of the irrigation water stores the solutes in thesoil profile Biomass residue increases the water residencetime in the furrow and thus the infiltration opportunity timeThis study also showed that irrigated fields are likely sinksof DOC Because even though well water contains DOC netstorage of DOC occurs during irrigation Net storage of DOCdid not occur in the short (92m) field because most of theapplied water ran off In contrast to DOC most sediment(TSS) and C associated with sediment are lost if well watercontaining little sediment is used for irrigation Thus inthe present study irrigation led to a loss of sediment andTSS-C and the presence of biomass residue in sufficientlyhigh quantity reduced these losses by increasing the waterresidence time in the furrows which presumably led todeposition of TSS within the furrow Increasing field lengthalso decreased TSS and TSS-C losses probably by increasingthe opportunity time for sediment to settle Other studiesshowed that irrigation can increase sediment and the Cbalance in the irrigated field because the irrigation watercan contain significant amounts of sediment [45] This isapparently the case when canal water is used to irrigate Itwould seem that a redistribution of sediment and C occurs assurface runoff water is recirculated at the water district level

An important conclusion from the present and otherstudies is that DOC C and sediment loss due to irrigationwill likely be a loss from agricultural fields as runoff isexported via ditches to streams and rivers However thepresence of biomass residue that affects irrigation efficiencywas only partially evaluated in this research work The factthat the waterfront in any treatment residue did not reachthe end of the long (274m) field implies that other factorssuch as low initial soil moisture played a role at this siteOur results are useful because the data demonstrate therelationships betweenmanagement and field length onDOCC and sediment storage and transport processes that are ofcritical concern in the San Francisco Bay Delta and otheragricultural regions in California

Acknowledgments

This work was fully supported by a grant from the KearneyFoundation of Soil Sciences University of California DavisThe authors thankfully acknowledge the contributions fromMike Mata of the Campbell Tract Site Brittany Smith IsraelHerrera Ryan Neimy Cynthia Kallenbach and WinstonHu of the University of California Davis SAFS (SustainableAgriculture Farming Systems) group

References

[1] N Cynthia R Ebel A Borchers and F Carriazo ldquoMajor usesof land in the United Statesmdash2007rdquo Economic InformationBulletin EIB-89 USDA 2011

[2] US Environmental Protection Agency (USEPA) National waterquality inventory 2000 report to congress EPA841-R-02-001Office of Water August 2002

[3] R J Godwin Agricultural Engineering in Development Tillagefor Crop Production in Areas of Low Rainfall FAO Rome Italy1990

[4] K N Potter H A Torbert and J E Morrison Jr ldquoTillage andresidue effects on infiltration and sediment losses on vertisolsrdquoTransactions of the American Society of Agricultural Engineersvol 38 no 5 pp 1413ndash1419 1995

[5] J E Gilley ldquoTillage effects on infiltration surface storage andoverland flowrdquo in Soil Water Conservation Society Farming fora Better Environment pp 46ndash47 Ankeny Iowa USA 1995

[6] D McGarry B J Bridge and B J Radford ldquoContrastingsoil physical properties after zero and traditional tillage ofan alluvial soil in the semi-arid subtropicsrdquo Soil and TillageResearch vol 53 no 2 pp 105ndash115 2000

[7] J Guerif G Richard C Durr J M Machet S Recous andJ Roger-Estrade ldquoA review of tillage effects on crop residuemanagement seedbed conditions and seedling establishmentrdquoSoil and Tillage Research vol 61 no 1-2 pp 13ndash32 2001

[8] D R Mailapalli W W Wallender M Burger and W RHorwath ldquoEffects of field length and management practiceson dissolved organic carbon export in furrow irrigationrdquoAgricultural Water Management vol 98 no 1 pp 29ndash37 2010

[9] CTIC (Conservation Tillage Information Center)Crop ResidueManagement Executive Summary Conservation TechnologyInformation Center West Lafayette Ind USA 1998

[10] P W Unger B A Stewart J F Parr and R P Singh ldquoCropresidue management and tillage methods for conserving soiland water in semi-arid regionsrdquo Soil and Tillage Research vol20 no 2ndash4 pp 219ndash240 1991

[11] R L Blevins andW W Frye ldquoConservation Tillage an ecolog-ical approach to soil managementrdquo Advances in Agronomy vol51 pp 33ndash78 1993

[12] S F Wright J L Starr and I C Paltineanu ldquoChanges inaggregate stability and concentration of glomalin during tillagemanagement transitionrdquo Soil Science Society of America Journalvol 63 no 6 pp 1825ndash1829 1999

[13] M J Brown ldquoEffect of grain straw and furrow irrigation streamsize on soil erosion and infiltrationrdquo Journal of Soil amp WaterConservation vol 40 no 4 pp 389ndash391 1985

[14] M J Brown and W D Kemper ldquoUsing straw in steep furrowsto reduce soil erosion and increase dry bean yieldsrdquo Journal ofSoil and Water Conservation vol 42 no 3 pp 187ndash191 1987

[15] R D Berg ldquoStraw residue to control furrow erosion on slopingirrigated croplandrdquo Journal of Soil amp Water Conservation vol39 no 1 pp 58ndash60 1984

[16] D E Smika and P W Unger ldquoEffect of surface residues on soilwater storagerdquo Advances in Soil Science vol 5 pp 111ndash138 1986

[17] T M McCalla and T J Army ldquoStubble mulch farmingrdquoAdvances in Agronomy vol 13 pp 125ndash196 1961

[18] J J Bond and W O Willis ldquoSoil water evaporation long-term drying as influenced by surface residue and evaporationpotentialrdquo Soil Science Society America Journal vol 35 pp 984ndash987 1971


[19] S D Logsdon and T C Kaspar ldquoTillage influences as measuredby ponded and tension infiltrationrdquo Journal of Soil and WaterConservation vol 50 no 5 pp 571ndash575 1995

[20] M A Arshad A J Franzluebbers and R H Azooz ldquoCompo-nents of surface soil structure under conventional and no-tillagein northwestern Canadardquo Soil and Tillage Research vol 53 no1 pp 41ndash47 1999

[21] B C Ball M V Cheshire E A G Robertson and E AHunter ldquoCarbohydrate composition in relation to structuralstability compactibility and plasticity of two soils in a long-termexperimentrdquo Soil and Tillage Research vol 39 no 3-4 pp 143ndash160 1996

[22] W J Gale C A Cambardella and T B Bailey ldquoRoot-derivedcarbon and the formation and stabilization of aggregatesrdquo SoilScience Society of America Journal vol 64 no 1 pp 201ndash2072000

[23] H Bossuyt K Denef J Six S D Frey R Merckx andK Paustian ldquoInfluence of microbial populations and residuequality on aggregate stabilityrdquo Applied Soil Ecology vol 16 no3 pp 195ndash208 2001

[24] F Ghidey and E E Alberts ldquoResidue type and placementeffects on decomposition field study and model evaluationrdquoTransactions of the American Society of Agricultural Engineersvol 36 no 6 pp 1611ndash1617 1993

[25] B Singh D S Chanasyk W B McGill and M P K NyborgldquoResidue and tillage management effects on soil properties ofa typic cryoboroll under continuous barleyrdquo Soil and TillageResearch vol 32 no 2-3 pp 117ndash133 1994

[26] A J Franzluebbers ldquoWater infiltration and soil structure relatedto organic matter and its stratification with depthrdquo Soil andTillage Research vol 66 no 2 pp 197ndash205 2002

[27] C A Campbell V O Biederbeck G Wen R P ZentnerJ Schoenau and D Hahn ldquoSeasonal trends in selected soilbiochemical attributes effects of crop rotation in the semiaridprairierdquo Canadian Journal of Soil Science vol 79 no 1 pp 73ndash84 1999

[28] C A Campbell G P Lafond V O Biederbeck G Wen JSchoenau and D Hahn ldquoSeasonal trends in soil biochemicalattributes effects of crop management on a Black ChernozemrdquoCanadian Journal of Soil Science vol 79 no 1 pp 85ndash97 1999

[29] J C Franchini F J Gonzalez-Vila F Cabrera M MiyazawaandM A Pavan ldquoRapid transformations of plant water-solubleorganic compounds in relation to cationmobilization in an acidOxisolrdquo Plant and Soil vol 231 no 1 pp 55ndash63 2001

[30] C S Dominy and R J Haynes ldquoInfluence of agricultural landmanagement on organic matter content microbial activity andaggregate stability in the profiles of two oxisolsrdquo Biology andFertility of Soils vol 36 pp 298ndash305 2002

[31] H Kok and J Thien ldquoCrop residue conservation and tillagemanagement softwarerdquo Journal of Soil Water Conservation vol49 pp 551ndash553 1994

[32] D E Stott L F Elliott R I Papendick and G S CampbellldquoLow temperature or low water effects on microbial decompo-sition of wheat residuerdquo Soil Biology and Biochemistry vol 18no 6 pp 577ndash582 1986

[33] M M Roper ldquoStraw decomposition and nitrogenase activity(C2H2reduction) effects of soil moisture and temperaturerdquo Soil

Biology and Biochemistry vol 17 no 1 pp 65ndash71 1985[34] HH Schomberg J L Steiner andPWUnger ldquoDecomposition

and nitrogen dynamics of crop residues residue quality andwater effectsrdquo Soil Science Society of America Journal vol 58no 2 pp 372ndash381 1994

[35] P L Brown and D D Dickey ldquoLosses of wheat straw residueunder simulated field conditionsrdquo Soil Science Society AmericaJournal vol 34 no 1 pp 118ndash121 1970

[36] C L Douglas R R Allmaras Jr P E Rasmussen R E Ramigand N C Roager Jr ldquoWheat straw composition and placementeffects on decomposition in dryland agriculture of the PacificNorthwestrdquo Soil Science Society America Journal vol 44 no 4pp 833ndash837 1980

[37] V Gaillard C Chenu and S Recous ldquoCarbon mineralisationin soil adjacent to plant residues of contrasting biochemicalqualityrdquo Soil Biology and Biochemistry vol 35 no 1 pp 93ndash992003

[38] C Poll J Ingwersen M Stemmer M H Gerzabek andE Kandeler ldquoMechanisms of solute transport affect small-scale abundance and function of soil microorganisms in thedetritusphererdquo European Journal of Soil Science vol 57 no 4pp 583ndash595 2006

[39] J L Steinera H H Schomberga P W Ungerb and J CresapbldquoCrop residue decomposition in no-tillage small-grain fieldsrdquoSoil Science Society of America Journal vol 63 no 6 pp 1817ndash1824 1999

[40] D R Mailapalli N S Raghuwanshi R Singh G H Schmitzand F Lennartz ldquoSpatial and temporal variation of manningrsquosroughness coefficient in furrow irrigationrdquo Journal of Irrigationand Drainage Engineering vol 134 no 2 pp 185ndash192 2008

[41] APHA (American Public Health Association) ldquoMethod 5310-Crdquo in Standard Methods For the Examination of Water andwasteWater 20th edition 1998

[42] J Murphy and J P Riley ldquoA modified single solution methodfor the determination of phosphate in natural watersrdquoAnalyticaChimica Acta vol 27 pp 31ndash36 1962

[43] J C Forster ldquoSoil nitrogenrdquo in Methods in Applied Soil Micro-biology and Biochemistry K Alef and P Nannipieri Eds pp79ndash87 Academic Press San Diego Calif USA 1995

[44] T A Doane andW R Horwath ldquoSpectrophotometric determi-nation of nitrate with a single reagentrdquo Analytical Letters vol36 no 12 pp 2713ndash2722 2003

[45] R M Poch J W Hopmans J W Six D E Rolston and J LMcIntyre ldquoConsiderations of a field-scale soil carbon budgetfor furrow irrigationrdquoAgriculture Ecosystems and Environmentvol 113 no 1ndash4 pp 391ndash398 2006

[46] A P King K J Evatt J Six R M Poch D E Rolston and J WHopmans ldquoAnnual carbon and nitrogen loadings for a furrow-irrigated fieldrdquo Agricultural Water Management vol 96 no 6pp 925ndash930 2009

[47] D R Mailapalli W R Horwath W W Wallender and MBurger ldquoInfiltration runoff and export of dissolved organiccarbon from furrow-irrigated forage fields under cover crop andno-till management in the arid climate of californiardquo Journal ofIrrigation and Drainage Engineering vol 138 no 1 pp 35ndash422011

Submit your manuscripts athttpwwwhindawicom

Forestry ResearchInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Environmental and Public Health

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Applied ampEnvironmentalSoil Science

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ClimatologyJournal of


the efficiency of water delivery The residue encouragesthe decomposersmdashespecially fungimdashand increases food webcomplexity by providing food and habitat for surface feedersand surface dwellers Residue protects soil from raindropimpacts causing loss of soil surface structure and pluggingup of macropores and cycles of freezing thawing and dryingwetting [10ndash12] The presence of crop residue on the soilsurface not only substantially reduces the soil loss fromfurrows [13 14] but also may improve irrigation uniformity[14 15]

Crop residues also slow the rate of evaporation [10 11 16]by isolating the soil fromheating and elevated air temperatureand increasing resistance to water vapor flux by reducingwind speed [11] The increase in infiltration and the decreasein evaporation generally result in greater soil water storagedepending on amount and type of crop residues left on thesoil surface [16] and the duration of the dry period [3 1718] Crop residue is a convenient and valuable source oforganic matter [19 20] This improves soil aggregate stabilityduring low rainfall periods and promotes more infiltrationthrough the soil The increased aggregation might be due tosoluble carbohydrates leached from fresh residues [21] or toparticulate organicmatter [22] to the activity of fungi [23 24]or microbes

The amount of crop residues on the soil surface varieswith time [23ndash25] and directly affects soil water character-istics structural properties [26] and organic matter content[27ndash30] The most important reasons for the crop residuevariation are tillage and residue decay Tillage modifiesresidue cover nearly instantaneously and changes the per-centage of residues left on the surface versus buried accord-ing to tillage system and intensity [31] Laboratory studiesindicate that water and temperature have a greater effectduring early stages of decomposition when easily utilizablecompounds are readily available to microorganisms [32ndash34] Greater fluctuations in water and temperature alongwith reduced nutrient availability adversely affect microbescolonizing surface residue thus slowing decompositioncompared with incorporated crop residues [35ndash38] Standingbiomass seems to decompose more slowly than flat residues[39]

In addition to the biomass residue length of the fieldaffects the agricultural discharges Limited studies have beencarried out on the field length effect on runoff and DOCexport [8] in furrow- irrigated fields Increase in field lengthgenerally decreases the quantity of agricultural dischargeand elevates the concentration of pollutants However thetotal export of the pollutants decreases with increase in thefield length due to the decreased runoff [8] We proposedto consider the advantages of the residue having a beneficialinfluence on runoff water quality rather than viewing residueas deterrent to implementing furrow irrigation practicesTheobjectives of the present study are to (i) investigate the effectsof varied levels of residue cover on infiltration and runoffat different locations in fields of varying lengths (ii) charac-terize the release transport and export of DOC phosphate(soluble P) nitrate (NO

3


+) atmulti-ple locations in irrigated furrows containing varied amountsof residue and (iii) assess the effects of residue amount on

total suspended solids (TSS) and sediment-associated carbon(TSS-C) during irrigation in fields of varying lengths

2 Materials and Methods

21 Experimental Site Thefield experiments were conductedat the Campbell Tract at the University of California Davis(38∘ 321015840 0910158401015840 N 121∘ 461015840 3210158401015840 W 60 ft elevation) The alluvialsoils at the experimental site are classified as Yolo siltyloam (fine silty mixed nonacid thermic family of MollicXerofluvents) containing 24 of sand 50 of silt and 26of clay The experimental site has 02 slope Prior to theexperiments the fields had been fallow for one year and priorto the fallow period corn was grown

22 Residue Biomass Treatments The research was con-ducted on two furrowed plots of 91 and 274m length and110m width Row spacing was 15m with bed widths ofapproximately 1m and depth of furrows about 02m Fourtreatments of residue biomass (high medium low andcontrol) each comprising six beds five irrigated furrowsand one dry furrow on either side of each treatment blockreplicated three times were assigned to the two lengths ina randomized block design The plots were planted withcorn on May 20 2008 All biomass treatments includingthe control were irrigated three times at an interval of 10to 15 days To obtain low medium and high residue covercorn plants were chopped 23 32 and 39 days after plantingrespectively At the time of chopping the average corn heightwas 03 06 and 085m for low medium and high residueplots respectively The texture of the chopped corn residuewas 012 to 016m long with a diameter of 002 to 004mThe corn residue was left in the field to dry and herbicidewas sprayed to control weedsThe amount of residue biomassin a meter length of furrow was collected from five randomlocations in each replicate and dry weight was measuredResidue biomass found in furrows of control plots due towind was removed by hand raking

23 Field Experimentation The treatments of long field wereirrigated on 20th and 21st November 2008 The treatmentsof the short field were irrigated on 24th and 25th November2008 Each treatment was irrigated through gated pipes for10 hours using a constant inflow of 15 L sminus1 per furrow Toachieve a uniform inflow rate the gates were opened to equalwidth and after measuring the inflow rate at the middle andend gates of each experimental unit (5 irrigated furrows)by using a bucket and stop watch the gates were adjustedas needed The outflow from each treatment was monitoredusing ISCO6700 dataloggerswater samplers (TeledyneTech-nologies Inc Thousand Oaks CA USA) (Figure 1)

24 Data Collection From a randomly selected furrow ofeach treatment waterfront advance time was measured by asystem of clocks placed in the furrows at equal distances fromthe head end The clock (Walmart Stores Inc BentonvilleAR USA) power supply was spliced and connected by wireto metal plates attached to the jaws of a clothespin Before




119879119886= 119879119903minus 119879119888minus 119879119894 (1)




119903is the time



3


4



4-



4


2


2



3

minus and NH4


3

minus andNH4







Tim

e (m

in)

0

50

100

150

200

250

HighMedium

LowControl

NS






Tim

e (m

in)

0

50

100

150

200

250

HighMedium

LowControl

b

ab

a

a

NS
























91



183





05

1015202530354045

0 50 100 150 200 250

DO

C co

ncen

trat

ion

(mg L

minus1)

HighMedium

LowControl

Time (min)



05

1015202530354045

0 50 100 150 200 250Time (min)

HighMedium

LowControl

DO

C co

ncen

trat

ion

(mg L

minus1)





minus- and NH4




NO3


NO3


NH4

+ conc(mg Lminus1)

NH4

+ exp(kg haminus1)

91



183




lowastlowast

Biomass timeslenght





3

minus and NH4




Parameter (119911) 1199110

119886 119887Standarderror 119877

2





119911 = 1199110+ 119886 times 119909 + 119887 times 119910 (2)


0are the fitting





4




4 Conclusions



Acknowledgments


References






















































Journal of












Volume 2014

Advances in









Geophysics

















119879119886= 119879119903minus 119879119888minus 119879119894 (1)




119903is the time



3


4



4-



4


2


2



3

minus and NH4


3

minus andNH4







Tim

e (m

in)

0

50

100

150

200

250

HighMedium

LowControl

NS






Tim

e (m

in)

0

50

100

150

200

250

HighMedium

LowControl

b

ab

a

a

NS
























91



183





05

1015202530354045

0 50 100 150 200 250

DO

C co

ncen

trat

ion

(mg L

minus1)

HighMedium

LowControl

Time (min)



05

1015202530354045

0 50 100 150 200 250Time (min)

HighMedium

LowControl

DO

C co

ncen

trat

ion

(mg L

minus1)





minus- and NH4




NO3


NO3


NH4

+ conc(mg Lminus1)

NH4

+ exp(kg haminus1)

91



183




lowastlowast

Biomass timeslenght





3

minus and NH4




Parameter (119911) 1199110

119886 119887Standarderror 119877

2





119911 = 1199110+ 119886 times 119909 + 119887 times 119910 (2)


0are the fitting





4




4 Conclusions



Acknowledgments


References






















































Journal of












Volume 2014

Advances in









Geophysics
















Tim

e (m

in)

0

50

100

150

200

250

HighMedium

LowControl

NS






Tim

e (m

in)

0

50

100

150

200

250

HighMedium

LowControl

b

ab

a

a

NS
























91



183





05

1015202530354045

0 50 100 150 200 250

DO

C co

ncen

trat

ion

(mg L

minus1)

HighMedium

LowControl

Time (min)



05

1015202530354045

0 50 100 150 200 250Time (min)

HighMedium

LowControl

DO

C co

ncen

trat

ion

(mg L

minus1)





minus- and NH4




NO3


NO3


NH4

+ conc(mg Lminus1)

NH4

+ exp(kg haminus1)

91



183




lowastlowast

Biomass timeslenght





3

minus and NH4




Parameter (119911) 1199110

119886 119887Standarderror 119877

2





119911 = 1199110+ 119886 times 119909 + 119887 times 119910 (2)


0are the fitting





4




4 Conclusions



Acknowledgments


References






















































Journal of












Volume 2014

Advances in









Geophysics
































91



183





05

1015202530354045

0 50 100 150 200 250

DO

C co

ncen

trat

ion

(mg L

minus1)

HighMedium

LowControl

Time (min)



05

1015202530354045

0 50 100 150 200 250Time (min)

HighMedium

LowControl

DO

C co

ncen

trat

ion

(mg L

minus1)





minus- and NH4




NO3


NO3


NH4

+ conc(mg Lminus1)

NH4

+ exp(kg haminus1)

91



183




lowastlowast

Biomass timeslenght





3

minus and NH4




Parameter (119911) 1199110

119886 119887Standarderror 119877

2





119911 = 1199110+ 119886 times 119909 + 119887 times 119910 (2)


0are the fitting





4




4 Conclusions



Acknowledgments


References






















































Journal of












Volume 2014

Advances in









Geophysics
















minus- and NH4




NO3


NO3


NH4

+ conc(mg Lminus1)

NH4

+ exp(kg haminus1)

91



183




lowastlowast

Biomass timeslenght





3

minus and NH4




Parameter (119911) 1199110

119886 119887Standarderror 119877

2





119911 = 1199110+ 119886 times 119909 + 119887 times 119910 (2)


0are the fitting





4




4 Conclusions



Acknowledgments


References






















































Journal of












Volume 2014

Advances in









Geophysics
















4 Conclusions



Acknowledgments


References






















































Journal of












Volume 2014

Advances in









Geophysics

















































Journal of












Volume 2014

Advances in









Geophysics


















Journal of












Volume 2014

Advances in









Geophysics














Documents

Research Article Crop Residue Biomass Effects on