OPVC Project Number: Project Title: Enhanced efficiency fertilizer technologies for improved production in sweet corn (2014)

Transcription

1 OPVC CONTINUING PROJECT REPORT: 214 PROJECT YEAR: 1 OPVC Project Numer: Project Title: Enhnced efficiency fertilizer technologies for improved production in sweet corn (214) PI: Dn M. Sullivn, Dept. Crop & Soil Science Co-PI: Aron Heinrich, Dept. of Horticulture Co-PI: Ed Pechey, Dept. of Horticulture Orgniztion: Oregon Stte University Telephone: (Sullivn) Emil: Dn.Sullivn@oregonstte.edu Address: 317 Ag & Life Sciences Bldg. City/Stte/Zip: Corvllis, OR Coopertors: Joe Fitts (Wigrich Frms) Totl Project Request (ll yers): Yer 1: $28,421 Yer 2: TBA Other funding sources: Agency Nme: KOCH Agronomic Services, LLC Proposl title: Enhnced efficiency fertilizer technologies for improved production in sweet corn (214) Amt. wrded for 214: $3 ($2 for direct cost; $ for OSU indirect cost) Notes: Koch is vendor for n EEF product (SuperU)

2 2. EXECUTIVE SUMMARY Enhnced efficiency fertilizer (EEF) technologies hve the potentil to improve the crop N use efficiency (NUE) s well s minimize negtive environmentl losses compred to conventionl fertilizers. The EEF fertilizer products consist of ure plus dditives (to inhiit N loss). The mjor pthwys for N loss in our sweet corn cropping systems re 1) N leched elow the root zone s wter solule nitrte-n (NO3-N), nd 2) gseous mmoni loss (NH3-N) to the tmosphere following surfce ure ppliction. Field studies nd lortory incution study were conducted in 214 to evlute the potentil for enefit from EEF products vi reduced nitrte-n leching. Three products were evluted: ESN (polymer coted ure), SuperU (prilled ure contining oth urese nd nitrifiction inhiitor), nd Instinct (ure + nitrifiction inhiitor). Concentrtions of soil mmonium-n nd nitrte-n were mesured in the l nd in the field to ssess product efficcy in controlling nitrte-n relese vs. ure lone. In generl, out 2 to % of the ure-n pplied ws protected from conversion to nitrte-n for the first 3 to 6 weeks fter fertilizer ppliction. In field tril t the OSU Vegetle Frm, corn er yields were not different for ure lone vs. the EEF products pplied t the sme N rtes. This field tril ws mnged to mximize opportunity for nitrte leching (8.6 inches wter ws supplied vi extr irrigtions plus rinfll during the first 6 weeks fter plnting). We conclude tht EEF products hd mesurle efficcy in slowing the rte of conversion of ure-n to lechle nitrte-n. However, even under worst cse leching scenrio on medium-textured soil, the use of inhiitors ws ineffective in chieving corn er yield response. A field study ws conducted to quntify gseous mmoni loss from surfce-pplied ure (without tillge to incorporte fertilizer), nd to evlute SuperU for efficcy in reducing gseous mmoni loss. Pssive flux msts were used to cpture nd quntify mmoni lost during the first weeks fter fertilizer ppliction. Despite fvorle soil moisture nd temperture conditions for mmoni loss, the mesured mmoni loss for ure lone ws very smll (< 2% of ure-n pplied), so it ws not possile to quntify enefit from SuperU. Additionl reserch is needed to verify these results (insignificnt gseous mmoni loss) cross wider rnge of soil, crop mngement nd wether scenrios.

3 3. FULL REPORT 3. Bckground Enhnced Efficiency Fertilizers (EEF) hve the potentil to improve the crop N use efficiency (NUE) s well s minimize negtive environmentl losses compred to conventionl ure fertilizer (Guertl, 29; Shoji et l., 21). Depending on the product, they hve the potentil to reduce mmoni loss nd/or nitrte leching. Nitrte Leching The gol of EEF products tht re slow/controlled relese or contin nitrifiction inhiitor is to limit the mount of nitrte in the soil erly in the seson when N uptke is miniml nd the leching hzrd is highest due to spring rins. Once fertilizer N hs converted to nitrte, it is susceptile to leching with irrigtion or rinfll. By protecting the fertilizer N from leching nd keeping it in the root zone, there is the potentil to reduce N pplictions therey incresing the crop N use efficiency. Mny growers prefer to pply ll N fertilizer t plnting insted of splitting N into pre-plnt nd mid-seson ppliction. Although EEFs re more expensive thn conventionl fertilizers, frmers like this strtegy ecuse it elimintes pss through their fields in the middle of summer when they re usiest. Also, EEF fertilizers my directly enefit crop growth y mintining more uniform soil moisture. With EEF fertilizers, growers do not hve to suspend irrigtion in order to pply sidedress N fertilizer ppliction with trctor-mounted spreder. Despite the enefits of pplying ll N fertilizer t plnting there is potentil risk of doing so. Erly in the growing seson, crop N uptke is miniml nd rinfll is likely, resulting in high leching hzrd. Not only does this nitrte leched from the crop root zone potentilly increse groundwter nitrte concentrtions, ut less N is ville for crop growth, which could result in deficiency nd lower er yields. The timing of N relese from controlled relese fertilizers vs. crop needs is the mjor issue. Idelly, the EEF delys N relese until just prior to rpid growth of corn. The period etween seeding nd the eginning of stem elongtion (jointing) is when potentil for N loss is gretest. But, if N relese from EEF is too slow, the crop will not hve sufficient N for pek growth rte during stem elongtion growth phse. Conversely, if EEFs do nothing to lter the timing of N fertilizer conversion to nitrte-n, then it provides no enefit over untreted ure fertilizer, nd it is wsted expense. Although some EEF products hve een mrketed for mny yers, their effectiveness t incresing the NUE of corn in Western Oregon hs een vrile (Hrt et l., 2). In few yers with wet springs, yields were incresed y the ppliction of nitrifiction inhiitor to the preplnt fertilizer. But, in other experiments, EEF products hve een found to hve no enefit regrdless of wether conditions (Hrt et l., 2). Ammoni Loss When ure is rodcst, some of the pplied fertilizer N my e lost s mmoni. Although this loss cn e minimized y pplying irrigtion wter s close to the ppliction s possile (within 24 hrs), in mny cses severl dys up to week my elpse efore irrigtion is pplied. When pplied to soil, wter nd the urese enzyme hydrolyze the ure, resulting in zone of high ph round the fertilizer grnule. As result, the lnce etween mmonium nd mmoni is temporrily shifted towrds mmoni, which is voltile. Given the right environmentl conditions (soil moisture, ph, texture, temperture, wind speed, humidity, etc), surfce pplied ure cn result

4 in significnt N loss. In estern Oregon, N loss hs een mesured to e s high s % of pplied ure-n when the ure ws left on the soil surfce for 1 week (Holcom et l., 211). But, soil nd climte re different est of the Cscdes nd N loss rtes need to e vlidted for western Oregon. For exmple, soils in western Oregon tend to hve lower ph nd higher OM nd cly content, which cn uffer the soil ginst n increse in ph due to ure hydrolysis nd thus reduce mmoni loss. Studies hve shown tht y using product with urese inhiitor such s NBPT (the ctive ingredient in Agrotin nd SuperU), mmoni loss from rodcst ure cn e significntly reduced (Rwluk, 2). It works y keeping the ure from converting to mmoni/mmonium. Becuse NAPT degrdes in -14 dys, the soil should e irrigted s soon s possile fter ppliction to minimize mmoni loss even when this product is used. The gol of this prt of the project is to determine how much ure-n cn e lost when rodcst in the summer, nd how much product contining urese inhiitor cn reduce this loss. If the svings re significnt there my e n opportunity for growers to reduce their N fertilizer pplictions nd increse the nitrogen use efficiency of their crop. 3. Ojectives Nitrte leching: 1. Quntify the mount of pplied fertilizer N tht cn e protected from leching y the EEF products ESN, SuperU, nd Instinct. 2. Determine if nd y how much the EEF products tested cn increse yield/product qulity under high leching conditions (sndy soil with frequent, high intensity irrigtions) erly in the growth cycle (2- weeks). Ammoni voltiliztion: 1. Quntify mmoni voltiliztion losses under worst-cse scenrio (ure rodcst onto moist soil nd 7+ dys without irrigtion). 2. Determine if nd how much product contining urese inhiitor (SuperU) cn reduce mmoni voltiliztion, nd if the svings re enough to justify the higher cost of the EEF product tested. 3c. Significnt findings Nitrte leching: All products tested hve the ility to prevent nitrte leching under the right conditions (i.e., very sndy soils with high spring rinfll occurring within ~4 weeks fter fertilizer ppliction). In lortory soil incution, these products were effective for 6+ weeks, ut under field conditions they pper to e most effective for ~4 weeks. Despite high leching potentil in this study, we mesured no yield enefit to ny of these fertilizers. Overll the products tested re most effective within 4 weeks fter ppliction, though Instinct ppered to e effective for t lest 6 weeks. Performnce of individul products is given elow. ESN: In lortory soil incution, recovery of N from the polymer coted ure ws significntly less thn conventionl ure over the entire study period (6 weeks),

5 demonstrting tht the product ws effective t slowly relesing ure. From Week 2 to 6, ESN ws protecting 2-3% of dded N from leching. By Week 6 in the l incution, ESN prills hd relesed 83% of dded ure-n. Although 6% of the prills were fully intct t Week 6 (plump with no dimpling), they were full of liquid nd much of the ure-n hd diffused out of the prill. Under field conditions ESN ws mesured to e effective up to the Week 4 smpling period, protecting etween 43 nd 37% of pplied N from leching t Week 2 nd 4, respectively. Some gronomic service compnies recommend pplying conventionl ure with ESN to prevent n erly seson crop N deficiency, sed on the ide tht ESN might reduce nitrte-n too slowly to meet crop needs.. Bsed on the 214 dt, this prctice is not wrrnted. Nitrogen uptke y sweet corn is miniml in the first month fter plnting. ESN relesed enough N to meet erly seson crop N needs. SuperU: In the l incution, the nitrifiction inhiitor in SuperU ws effective for 6 weeks t preventing the conversion of mmonium to nitrte. At Week 6, 1% of dded SuperU-N ws in the form of mmonium compred to 13% for Ure-N. From Week 3 to 6, SuperU ws protecting etween 47-3% of dded SuperU-N from leching compred to ure-n. Under field conditions SuperU ws mesured to e effective up to the Week 4 smpling period, protecting etween 3 nd 1% of pplied N from leching t Week 2 nd 4, respectively. By Week 6 there were no differences etween ure lone vs ure + SuperU. Instinct: In 214, the ure ws rodcst nd Instinct spryed over the soil surfce followed y immedite incorportion. Unlike the other products tested, Instinct performed etter in the field thn in the l incution. Possily we were unle to sufficiently replicte the field spry conditions for the l incution. In the l Instinct ws most effective round Week 2 to 3. At Week 2 nd 3, Instinct ws protecting 12 nd 27%, respectively, of dded N from leching compred to ure. After Week 3 it did not perform much etter thn ure. Under field conditions Instinct ws mesured to e effective up to 6 weeks nd possily eyond. At Week 2, 4, nd 6 n verge of 3, 1, %, respectively of totl N pplied ws potentilly protected ginst leching compred to ure. Ammoni loss Despite fvorle soil moisture nd temperture conditions for mmoni loss, the mesured mmoni loss from conventionl ure ws smll (< 2% of ure-n pplied), so it ws not possile to quntify the enefit from SuperU. Likely the high ph uffering potentil of our soil reduced the opportunity for mmoni loss. Our dt re in strk contrst to reserch done in Hermiston, OR where reserchers mesured loss of up to 6% of ure-n from surfce pplied ure. But, the lomy snd soil

6 used in the Hermiston study hd higher initil ph nd hd less ility to mintin ph elow the threshold ph for mmoni loss (pproximtely ph 7.). Our soil hd greter cly, orgnic mtter, nd CEC thn the Hermiston soil, mking it less susceptile to mmoni loss. An dditionl tril conducted t the OSU Vegetle Reserch Frm to doule check the mmoni trpping methodology lso demonstrted very low mmoni loss from lomy, cidic, Willmette Vlley soil over 1-d period. We propose to repet this study next yer on wider vriety of soil types including sndier, less well uffered soils. 3d. Methods Description of EEF fertilizers ESN (Environmentlly Smrt Nitrogen) mnufctured y Agrium Advnced Technologies, Inc. This product is polymer coted ure nd contins 44%N. The coting llows wter to move into the grnule nd dissolve the ure, which then diffuses into the soil. The rte t which the ure solution moves out through the coting is determined y soil, temperture, nd moisture. In cool soils when the crop is growing slowly nd N demnd is miniml, N relese is slow, ut s the soil wrms nd crop growth increses, the grnules relese N more rpidly. At current ure mrket prices, using ESN costs n dditionl ~$.1/l N. SuperU mnufctured y Agrotin Interntionl ( susidiry of Koch Agronomic Services). This product is grnulr ure product contining oth urese inhiitor (NBPT) nd nitrifiction inhiitor (DCD), nd contins 46%N. The comined ction of the inhiitors cn reduce mmoni voltiliztion losses nd slow the conversion of mmonium into nitrte. As result, the fertilizer-n should e less susceptile to leching in the erly prt of the seson when crop N uptke is miniml. Instinct (formultion used very similr to Instinct II) is mnufctured y Dow Agrosciences. It contins the nitrifiction inhiitor nitrpyrin in n encpsulted form. This encpsultion is designed to prevent loss from voltiliztion nd fixtion on cly prticles nd orgnic mtter. This llows it to remin on the soil surfce longer efore incorportion. This product is registered for use in sweet corn in Oregon nd hs the following replnt restrictions: Corn (field, sweet, pop), sorghum, whet, other cerels, oilseed crops (including soyens), nd lefy vegetles, my e rotted 12 dys from the lst ppliction of N-Serve 24 [ formultion of nitrpyrin]. All other crops re not to e rotted in less thn one yer fter the lst ppliction. The nitrpyrin (. l A.I. per cre) ws spryed on ure tht hd een rodcst, which ws then immeditely incorportion. Field tril: Er yield response nd product efficcy in protecting N from leching. This tril ws locted t OSU s Vegetle Reserch Frm in Corvllis. The soil (-12 inches) hd the following properties: ph 6.3, 1.8% OM (LOI), estimted CEC of 16 meq/g, Bry 1P 1 ppm, nd 22 ppm K. Using the hydrometer method for mesuring soil prticle size distriution, the soil texture from -12 inches ws sndy lom (1% cly nd 9% snd) nd from inches ws lso sndy lom (17% cly nd 7% snd). On My 7, fertilizer ws rodcst y hnd in plots x 4 ft. See Tle 1 for tretments nd rtes. Following ppliction, the fertilizer ws incorported with power hrrow to depth of ~3-4 inches. Wlking in front of the trctor tht ws incorporting the fertilizer, Instinct ws pplied t rte of. l A.I. per 3 gl per cre using oom with nozzles (8-3VS XR 2 psi) on 2 inch spcing. Time

7 etween Instinct ppliction nd incorportion ws less thn 3 minutes. A soil temperture proe (Hoo pendnt) ws instlled t depth of 3 inches. The tretments were rrnged in rndomized complete lock design with replictions. Seven dys fter ppliction, sweet corn vr. Cptin ws seeded nd ~4 weeks fter ppliction doules nd plnts spced closer thn 4-6 inches were removed. The finl stnd ws ~21, plnts/cre. At plnting 34 l P2O (from TSP) nd 26 l K2O (from KCl nd K-Mg) ws nded. Soil ws smpled every 2 weeks fter the fertilizer ppliction for 6 weeks from - nd -2 inches just in the tretments receiving or 7 l N/cre in 4 replictions. Smples were extrcted with 2M KCl nd nlyzed for mmonium nd nitrte y OSU Centrl Anlyticl Lortory. To increse nitrte leching, we pplied ~. inches of irrigtion wter (s mesured y plcing 6 uckets rndomly in the field) over 6 weeks. The totl mount of wter on the field from rin nd irrigtion ws 8.6 inches. At hrvest on August 2 (3 dys fter plnting), ers from forty feet of row (2 ft. from the middle two rows in ech plot) were hnd hrvested. Gross er weight, dry mtter, nd other prmeters (tip fill, length, width, unhusked wt) were mesured. Tle 1. Fertilizers nd N rtes used in EEF field tril. Tretment Fertilizer N rte l/cre 1 None 2 Ure 2 3 Ure 4 Ure 7 Ure 6 Ure 12 7 ESN 8 ESN 7 9 SuperU SuperU 7 11 Instinct 12 Instinct 7 Aeroic soil EEF fertilizer incution: The top 6 inches of soil ws collected from the field where the EEF field tril ws locted nd sieved through 2 mm mesh screen. Fertilizer (ure, ESN, nd SuperU) ws dded to 4 g of oven dry soil t rte of 4 l N/cre (ssumptions: -inch incorportion depth with ulk density of 1.33 g/cm3). After incorporting into the soil, deionized wter ws dded with spry ottle while mixing the soil until grvimetric moisture content of ~17% ws reched (ner field cpcity for this soil). For the product Instinct, field moist soil ws plced in pots nd ure ws distriuted over the soil surfce. The pots were plced rndomly in y 2 ft. re nd Instinct ws spryed over top (. l A.I. per rte of 3 gl per cre) using wnd with the sme nozzles nd spcing descried in the field tril elow.

8 After fertilizer ppliction, soil ws plced in zippered plstic gs with strw inserted into the top corner of ech g to fcilitte ir exchnge. Soil ws incuted in the drk t 71.±.4 degrees F. Additionl DI wter ws dded to the gs weekly to mke up for moisture loss. Three replictes of ech g per tretment were destructively smpled t Week 1, 2, 3, 4,, nd 6 fter ppliction. On ech smpling dte, the gs were thoroughly mixed nd -1 g soil susmple ws extrcted with 2M KCl for mmonium-n nd nitrte-n determintion t the OSU Centrl Anlyticl Lortory. Ammoni voltiliztion tril (on-frm): The mmoni voltiliztion tril ws conducted on commercil frm locted ner Independence. The experiment ws done in n 8 cre field djcent to the Willmette River nd is in the sesonl floodplin. The soil mpping units in the field were Newerg lom nd fine sndy lom, Cloquto silt lom, nd Chehlis silty cly lom. Due to the lrge field size nd soil chnges cross the field, soil smples (-1 inches) were tken t ech mmoni collection tower receiving fertilizer. See Tle 2 for soil properties. Soil prticle size nlysis ws mesured using the hydrometer method. Tle 2. Soil properties (-1 inch depth). Smples collected ner mmoni flux mesurement towers within the on-frm tril field site. Tower Tretment ph(1:2) CEC 1 OM 2 cly snd USDA texture cmol(+)/kg % 1 Ure lom 2 SuperU cly lom 4 Ure lom 6 SuperU lom 8 Ure lom 9 SuperU sndy lom Ure lom 11 SuperU lom 1- s mesured y displcement; 2- clculted s 1.7*totl C mesured y comustion (LECO) The field ws plnted to sweet corn on June 1. On June 17 the mmoni collection towers were instlled in the center of circulr plot (3 m dimeter). The corn ws t ~V2. Ech circulr plot received one of the following tretments; no fertilizer (Control), 1 l ure-n/cre (Ure), nd 1 l SuperU-N/cre (SuperU). The fertilizer ws evenly pplied y hnd in these plots. Normlly frmers fertilize their corn round V6 when N uptke egins to increse rpidly. It ws necessry for us to pply the fertilizer t V2 to e le to work round the frmer s field mngement schedule. Tretments were rrnged in rndomized complete lock design with three replictions. Ech circulr plot ws seprted y t lest 33 ft. ( m) to void contmintion of NH3 etween tretments (Vio et l., 28). The ground ws visily moist when the fertilizer ws pplied. The field ws irrigted with ig gun prior to ure fertilizer ppliction. Actul timing of irrigtion vried cross the field (1 to 3 dys prior to fertilizer ppliction) ecuse it took totl of out three dys to complete irrigtion using the ig gun system.

9 Voltilized NH3 mesurements were initited immeditely fter fertilizer ppliction using the modified pssive flux method (Wood et l., 2; Vio et l., 28). This consisted of rotting mst plced t the center of ech circulr plot tht ws modified with tripod to stilize the mst during high wind events. Ech mst ws equipped with pssive flux smplers t five heights (.4,.7, 1., 2.2, nd 3. m; Leuning et l., 198). Ech pssive flux smpler consisted of glss tue (.7-cm i.d. y 2 cm long) with the inside surfce coted with 3% (w/v) oxlic cid in cetone to scru the NH3 in the ir flowing through the tue. Ech tue hd n ttched nozzle with 1-mm hole to restrict incoming ir flow to prevent NH3 sturtion of the oxlic cid. Flux smplers were seled in Ziploc g fter eing coted to ensure n NH3 free environment nd were only removed when eing plced on the msts. Ammoni flux smplers were replced every dy for 8 dys following fertilizer ppliction. Immeditely fter collection of the flux smplers from the msts, they were cpped t oth ends, plced in seled Ziploc g, nd stored in refrigertor. The smples were extrcted within 3 weeks of eing collected. Flux smplers were extrcted y dding 2 ml of deionized wter nd shking for min. The extrcts were nlyzed colorimetriclly for mmonium-n. The horizontl nd verticl NH3 flux (Fx, μg N m 2 s 1 ) for ech flux smpler ws clculted using the equtions given y Schjoerring et l. (1992), Wood et l. (2), nd Vio et l. (28). A wether sttion (Onset Computer Corp model Hoo U3-NRC) ws instlled to mesure wind speed, ir nd soil temperture (t 1-inch depth), nd reltive humidity every 1 minutes. Although wind speed ws mesured every minute, the dt logger provided 1 minute verge. Ammoni voltiliztion tril (OSU Reserch Frm): An dditionl tril ws conducted t OSU s Vegetle Reserch Frm (Corvllis) to check our methods nd the sensitivity of the mesurements. This soil hd the following chrcteristics: CEC= 16 meq/g (y sum of ctions method), ph.9, OM= 1.8%, nd lom texture (18% cly nd 46% snd). This ws n unreplicted study tht only hd three tretments; 1-control (no iflow control disc), 2- Ure t 1 l N/cre (irflow control disc inserted into NH3 mesurement tues), nd 3- Ure t 1 l N/cre (no irflow control disc). Normlly the mmoni collection tues hve disc with very smll hole (. mm). By removing the disc, we wnted to see if we could increse the sensitivity of the mesurements. Tretments 2&3 were plced side-y-side in the sme circulr mesurement re. All other methods were the sme s descried ove. When clculting the flux for the tues with no disc, correction fctor of 9.9*Fx ws pplied. 3e. Results & Discussion Enhnced efficiency fertilizers (EEF). Effect on nitrte leching potentil nd er yield): L incutions: Fertilizer N ws pplied t high rte (~.26 g fertilizer per 4 g OD soil; equivlent to pproximtely 4 l N/cre). This N rte ws chosen to chieve reproducile mixing of fertilizer prills with soil. The N incorportion rte ws 2 to 4x more thn frmer would pply. The higher ure ppliction rte used in the incution could hve influenced the rte of

10 nitrifiction (conversion of mmonium-n to nitrte-n). Therefore, extrpolting the incution results to performnce under field conditions should e mde with cution. Additionlly, in the field, soil wets nd dries (moisture is not constnt). Wetting nd drying cycles could lso ffect the performnce of EEF products. Diffusion is required for N relese from ESN (polymercoted prills). Diffusion rte is incresed y greter soil moisture (present immeditely fter rin or irrigtion in the field). Rin nd irrigtion my lso dilute nitrifiction inhiitors, reducing their effectiveness. The verge incution temperture ws 71.±.4 degrees F, while the verge temperture t 3 inches in the field tril over 6 weeks ws 67±8.4 degrees F. Although the verge tempertures were similr, there ws significnt vriility in the field (rnge 1-9 degrees F). Agin, due to the differences in l nd field conditions, extrpoltion of dt should e done with cre. At Week 1 very little nitrte ws present to lech nd the mount tht these products protected ws negligile (Tle 3). By Week 2 ll fertilizer products protected 12-2% of dded fertilizer N from leching. By Week 3, ll fertilizer N from ure, SuperU, nd Instinct could e ccounted for in the soil s either nitrte or mmonium (Figure 1). However, the ppliction of either SuperU or Instinct mintined more of the N in the mmonium form, indicting tht the inhiitors were effective. ESN nd SuperU remined effective in mintining some of the N in mmonium form through Week 6, while Instinct ws mostly ineffective fter Week 3. Tle 3. Potentil reduction in nitrte leching from EEF products compred to ure 1. Lortory incution study. Trt Week 1 Week 2 Week 3 Week 4 Week Week 6 % of dded fertilizer N protected from leching compred to ure ESN SuperU Instinct * * 12 1 Clculted s the difference etween NO3-N ccumultion etween ure nd EEF products in soil t ech smpling dte. *Becuse these NO3-N vlues were not sttisticlly different vs. the conventionl ure tretment, they re shown s.

11 Figure 1. Nitrte nd mmonium s percentge recovered of totl fertilizer N dded to soil during 6 week eroic incution. Error rs represent the SE (n=3). For ech dte, different letters represent sttisticl difference (Fisher LSD P<.) mong tretments. c c c c c c c c c c d c d

12 Mesurements of soil N in the EEF field tril: Soil minerl N Soil ws smpled for 6 weeks fter fertilizer ppliction). During this period, the field received totl of 8.6 inches of wter from irrigtion (7.3 inches) nd rinfll (1.3 inches; Figure 2). These irrigtions were used to simulte worst cse nitrte leching scenrio; wet spring with hevy rinfll. Bsed on reference evpotrnspirtion (ET) from the Hyslop Agronomy Frm wether sttion nd estimted crop ET coefficients for corn, we estimte tht the evpotrnspirtion over 6 weeks ws pproximtely 2 inches. Cumultive wter pplied ws 2.1 inches for Weeks -2, 4.6 inches for Weeks 2-4, nd 1.9 inches for Weeks 4-6. Wter pplied ws greter thn the 3 yer historicl verge for Corvllis (verge = 2.3 inches in My, 1. inches in June). Irrigtion intensity (~.7 inches per hour) ws likely greter thn precipittion. However, even though the field received excessive irrigtion, nitrte leching ppers to hve een miniml. Soil nitrte + mmonium-n were higher in the - inch depth thn in the -2 inch depth for ll tretments t ll smpling dtes. Soil minerl N concentrtions for ESN, SuperU, nd Instinct re given in Figures 3, 4 nd, respectively. This study ws not designed to quntify nitrte-n leched. Percent recovery of pplied N (-2 inch depth) ws vrile nd sometimes exceeded % due to vriility inherent in soil smpling. Percent of fertilizer N tht ws protected from leching ws clculted s: (Ure NO3-N - EEF fertilizer NO3-N)/(totl fertilizer N pplied) x Where: Ure NO3-N = nitrte-n mesured for conventionl ure fertilizer tretment (control), ppm ESN NO3-N = nitrte-n mesured for EEF fertilizer tretment, ppm Totl N fertilizer pplied, ppm Nitrte-N tht leched elow smpling depth (-2 inches) ws not ccounted for y this clcultion method. At 6 weeks fter fertilizer ppliction, mmonium + nitrte-n (-2 inch depth) ws the sme for conventionl ure nd ll of the EEF fertilizer tretments. ESN Soil minerl N concentrtions for ESN re given in Figure 3. In the first 4 weeks fter ppliction, nitrte concentrtions were sttisticlly lower thn the ure (P.2), ut t Week 6, there were no sttisticl differences. At Week 2 nd 4, n verge of 43 nd 37%, respectively of totl N pplied ws potentilly protected ginst leching. This is equivlent to protecting 18 l/cre when l N /cre of N fertilizer ws pplied, or 3 l N/cre when 7 l N/cre ws pplied. After Week 4, there ws little or no enefit. Soil nitrte concentrtions t -2 inch depth hd lower nitrte-n for ESN thn for ure, nother qulittive indictor of ESN efficcy. However, some or ll of the nitrte-n leched elow the 2-inch depth ws likely ville for uptke y corn during the growing seson.

13 SuperU Soil minerl N concentrtions for SuperU re given in Figure 4. Like ESN, in the first 4 weeks nitrte concentrtions were sttisticlly lower thn the ure (P.2), ut t 6 weeks, there were no sttisticl differences. At Week 2 nd 4, n verge of 3 nd 1%, respectively of totl N pplied ws potentilly protected ginst leching. However, t Week 6 there ws no enefit, which is in contrst with the l incution (Tle 2). Possily rin nd irrigtions my hve diluted the nitrifiction inhiitor or field conditions roke it down fster. Instinct Soil minerl N concentrtions for Instinct re given in Figure. In the first 4 weeks fter ppliction, nitrte concentrtions were sttisticlly lower thn the ure (P.2), ut t 6 weeks fter ppliction, there were no sttisticl differences. At Week 2, 4, nd 6 n verge of 3, 1, %, respectively of totl N pplied ws potentilly protected ginst leching compred to ure. Instinct performed much etter in the field thn it did in the lortory incution. Cumultive wter (in) Cumultive Dily 2.1" 4.6" 1.9" Dily wter (in) Week fter fertilizer ppliction Figure 2. Cumultive nd dily wter pplied during the first 6 weeks fter fertilizer ppliction (My 7 to June 18). The totl rinfll for ech 2 week soil smpling intervl is given etween the dshed lines. For comprison, the 3 yr verge of rinfll in Corvllis for My nd June is 2.3 nd 1. inches, respectively..

14 Nitrte N (ppm) Nitrte -" Nitrte N (ppm) Nitrte -2" Zero N Ure N Ure 7N ESN N ESN 7N 3 2 Ammonium -" 3 2 Ammonium -2" Ammonium N (ppm) 2 1 Ammonium N (ppm) Nitrte+mmonium N (ppm) Totl -" Nitrte+mmonium N (ppm) Totl -2" Week Figure 3. ESN- Soil minerl N from - nd -2 inches. Ech point is n verge of 4 vlues. Error rs were excluded for ese of viewing. Week

15 3 3 2 Nitrte -" 2 Nitrte -2" Nitrte N (ppm) 2 1 Nitrte N (ppm) Ammonium -" 3 2 Ammonium -2" Ammonium N (ppm) 2 1 Zero N Ure N Ure 7N SuperU N SuperU 7N Ammonium N (ppm) 2 1 Nitrte+mmonium N (ppm) Totl -" Nitrte+mmonium N (ppm) Totl -2" Week Figure 4. SuperU- Soil minerl N from - nd -2 inches. Ech point is n verge of 4 vlues. Error rs were excluded for ese of viewing. Week

16 3 3 Nitrte N (ppm) Nitrte -" Nitrte N (ppm) Nitrte -2" Zero N Ure N Ure 7N Instinct N Instinct 7N 3 Ammonium -" 3 Ammonium -2" 2 2 Ammonium N (ppm) 2 1 Ammonium N (ppm) 2 1 Nitrte+mmonium N (ppm) Totl -" Nitrte+mmonium N (ppm) Totl -2" Week Figure. Instinct- Soil minerl N from - nd -2 inches. Ech point is n verge of 4 vlues. Error rs were excluded for ese of viewing. Er Yield No differences were mesured in gross er yield (Figure 6) or er chrcteristics (dt not shown) etween ure nd EEF products for given N rte. At the nd 7 l N/cre fertilizer rte the plnts were N deficient, which is wht we wnted. Becuse corn plnts were growing within the N deficiency rnge, the potentil of mesuring yield response incresed. For exmple, if the EEF fertilizers reduced nitrte leching (i.e., kept N in the root zone), then we would likely see yield increse for those products. However, we sw no differences for given fertilizer rte, which is wht we would expect sed on soil N concentrtions t Week 6 in which there were smll or no difference etween Ure nd the EEF products. Although the soil smpling suggested tht there ws more leching elow 2, possily the corn plnts were le to ccess nitrte elow this level. Week

17 Gross er yield (ton/cre) l N/A l N/A 7 l N/A l N/A 12 l N/A Ure ESN SuperU Instinct Figure 6. Gross er yield from ure vs. EEF products for different N rtes. Error rs represent SE of the men (n=). Ammoni voltiliztion on-frm field tril: Environmentl conditions Environmentl conditions were fvorle for mmoni loss (Figure 7). Totl precipittion t the study site ws.2 inch which occurred etween 6/2 nd 6/28 (8 to 11 dys fter ppliction). Reltive humidity fluctuted from 26 to 98%, with n verge of 71%. The ir temperture vried etween 44 to 84 F, with n verge of 64 F. The soil temperture t 1 inch vried from to 1 F, with n verge of 74 F. Wind speeds vried from to 13. mph, with n verge of 4 mph. Averges were derived from mesurements tken every 1 min. The 8-cre field site ws surrounded y other crops (hzelnuts, grss seed, nd snp ens) s well s ordered y riprin uffer djcent to the Willmette River. No fertilizers pplied to ny of these djcent res during the tril. Bckground mmoni loss (NH3-N cptured from the tmosphere in the sence of N fertilizer ppliction) ws pproximtely 2 l N/cre. The field hd een irrigted over the 3 dys prior to ure ppliction (it took them 3 dys to move cross the field using ig guns). As result, there ws visile moisture on the soil surfce. Within the first dy ~% of the fertilizer hd dissolved nd y 3 dys fter ppliction, ll prills hd disppered. Once the prills hve dissolved, there usully is 2-3 dy lg period efore mmoni loss increses drmticlly. Holcom et l. (211) oserved tht 7% of totl mmoni loss occurred etween dy 2 nd 8 dys fter irrigtion. Becuse there ws sufficient moisture (from soil nd ir) to dissolve the prills in our experiment, ut no rin to wsh it into the soil or dilute it, conditions should hve een idel to mesure gseous mmoni loss. However, we mesured no differences etween control nd fertilizer tretments (Figure 8). We mesured cumultive mmoni-n loss of 23 l/cre for ll tretments over the entire 7-dy period. Soil chrcteristics my explin some of the differences etween our dt nd tht of Holcom et l. (211). Tle 3 shows the relevnt soil chrcteristics for our field site nd the field site used y Holcom et l. (211). As the ure hydrolyzes, it rises the ph round the prill. The ph

18 present round the prill is depends on the cpcity of the soil to dmpen or uffer rise in ph. In poorly uffered soil, the ph round prills will e higher, nd more mmoni will e lost. Apprently, our soil hd sufficient uffering cpcity to prevent ph rise ove the threshold for mmoni loss (ph 7.). Our soil ws well uffered compred to the soil from Holcom s field site. Our soil hd CEC tht ws three times greter, OM tht ws 2X greter, nd cly content tht ws 4X greter thn the soil from Holcom s field site. The urese inhiitor NBPT (ctive ingredient in SuperU) hs een shown to e effective in reducing mmoni loss (Engel nd Wllnder, 212). Our results suggest tht mmoni loss my e miniml when ure is pplied to well uffered, cidic Willmette Vlley lomy soil. Tle 3. Soil chrcteristics from the Holcom et l. study vs. those from our field sites. Property Holcom field On frm field OSU Reserch Frm field ph CEC (meq/g) OM (%) < cly (%) snd (%) USDA texture sndy lom lom lom For the Holcom et l. (211) field site, only soil ph ws reported. Other soil chrcteristics listed here re sed on NRCS soil mp dt. Soil test vlues for mst loctions within the on-frm field site re given in Tle 2. Ammoni voltiliztion OSU Reserch frm field tril: The soil t the reserch frm ws less uffered thn the soil present t the on-frm tril, ut it hd much greter ph uffering cpcity thn the soil used y Holcom et l. (211). At one dy fter ppliction, out 8% of the prills dissolved due to hevy morning dew. At 4 dys fter ppliction, out 2% of prills remined, decresing to % remining t dys fter ppliction (following light rin of.2 inches). At 12 dys fter ppliction, prills were not visile on the soil surfce. Ammoni loss is shown in Figure 9. Despite removing the disc from the mmoni collection tues, there ws little difference in mesured mmoni flux compred to the tues with the disc. This suggests tht the method we used in the on-frm tril should hve een sensitive enough to mesure tretment differences (i.e., removing the disc in the on frm tril would likely not hve improved the results). Compred to the control, the ure tretments only lost out 2 l N/cre over 1 dys, which is only out 1.3% of totl N pplied. Although 8% of the prills rpidly dissolved in the first dy fter ppliction, the soil ws dry, likely slowing the rte of which my hve slowed ure hydrolysis. Although this tril ws unreplicted, it suggests tht with modertely to well uffered soils, mmoni loss my e smll even when conditions should e idel for loss (i.e., enough moisture to dissolve prills, ut not enough to move ure deeper into the soil.

19 Soil temp (F) Air temp (F) Wind speed (mph) Reltive humidity (%) /17 6/19 6/21 6/23 6/2 6/27 6/29 7/ /17 6/19 6/21 6/23 6/2 6/27 6/29 7/ /17 6/19 6/21 6/23 6/2 6/27 6/29 7/ /17 6/19 6/21 6/23 6/2 6/27 6/29 7/1 Figure 7. Environmentl conditions t the on-frm field site. On-frm mmoni loss experiment. Fertilizer ws pplied on 6/17. By 6/18 ~% of prills hd dissolved nd y 6/2 ll the prills hd dissolved (3 dys fter ppliction). Between 6/2 to 6/28,.2 inches of rin ws recorded.

20 NH3-N loss (l N/cre) Ammoni N loss (l N/cre) Control Ure SuperU Dy fter fertilizer ppliction Figure 8. Cumultive mmoni loss following fertilizer ddition. On-frm tril. Ammoni loss mesurement vi pssive flux tower equipped with irflow control discs within the mmoni mesurement tues. Error rs represent SE of the men (n=4). 14 Cumultive mmoni loss 12 8 Control Ure nodisk Ure disk Dys fter ppliction Figure 9. Cumultive mmoni-n loss t the OSU Vegetle Reserch Frm. This study ws designed to test the sensitivity of mmoni trpping to mesurement technique (pssive flux mst equipped with or without irflow control discs).

21 References Engel, R., E. Willims nd R. Wllnder NBPT degrdtion nd mitigtion of mmoni loss from surfce-pplied ure in n cidic nd lkline soil. Gret Plins Soil Fertility Conference Proceedings. 14: Mrch 6-7, 212, Denver, Colordo. Guertl, E.A. Slow-relese Nitrogen Fertilizers in Vegetle Production: A Review. 29. HortTech, 19: Hrt, J., D.M. Sullivn, J.R. Myers, nd R.E. Pechey. 2. Nutrient Mngement Guide for Sweet Corn (Western Oregon). Oregon Stte University Extension Puliction EM 9-E Holcom, J.C., D.M. Sullivn, D.A. Horneck, nd G.H. Clough Effect of Irrigtion Rte on Ammoni Voltiliztion. Soil Sci. Soc. of Am. Journl. 7: Leuning, R., J.R. Freney, O.T. Denmed, nd J.R. Simpson A smpler for mesuring tmospheric mmoni flux. Atmos. Environ. 19: Rwluk, C.D.L. 2. Effect of soil texture, temperture nd irrigtion on the performnce of ure fertilizers mended with the urese inhiitor N-(N-utyl) thiophosphoric trimide. Thesis. University of Mnito, Cnd. Schjoerring, J.K., S.G. Sommer, nd M. Ferm A simple pssive smpler for mesuring mmoni emission in the field. Wter Air Soil Pollut. 62:13 24 Shoji, S., J. Delgdo, A. Mosier nd Y. Miur. 21. Use of Controlled Relese Fertilizers nd Nitrifiction Inhiitors to Increse Nitrogen Use Efficiency nd to Conserve Air nd Wter Qulity. Com. in Soil Sci. nd Plnt Anl., 32:1-7 Vio, N., M.L. Crer, D.E. Kissel, J.A. Rem, J.F. Newsome, nd V.H. Clvert III. 28. Ammoni voltiliztion from ure-sed fertilizers pplied to tll fescue pstures in Georgi, USA. Soil Sci. Soc. Am. J. 72: Wood, C.W., S.B. Mrshll, nd M.L. Crer. 2. Improved method for field-scle mesurement of mmoni voltiliztion. Commun. Soil Sci. Plnt Anl. 31:81 9.

22 4. BUDGET DETAILS Ctegory 214 Budget Items 214 (Yer 1) Slry & Benefits Wges & Benefits Slry, Heinrich OPE, Heinrich (67%) 67 Wges (Summer lor) 22 Benefits, summer lor, 8% 176 Equipment Equipment Supplies Supplies (field nd l) Trvel Trvel 6 Plot Fees Plot Fees (lnd rentl) 138 Other Other (nutrient nlyses, mmoni trpping, plnt, soil) 636 Totl Totl 28421