EVALUATION OF STRIP-TILLAGE AND FERTILIZER PLACEMENT IN SOUTHERN IDAHO CORN PRODUCTION. D.Tarkalson and D. Bjorneberg USDA-ARS, Kimberly, ID

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1 EVALUATION OF STRIP-TILLAGE AND FERTILIZER PLACEMENT IN SOUTHERN IDAHO CORN PRODUCTION D.Trklson nd D. Bjorneberg USDA-ARS, Kimberly, ID ABSTRACT Strip tillge (ST) nd ssocited nutrient plcement cn potentilly help producers reduce fuel nd mchinery costs, increse yield, nd reduce soil erosion compred to chisel tillge (CT). This study ws initited to evlute corn production (Ze mys L.) under ST nd CT, nd vrious nitrogen (N) nd phosphorus (P) fertilizer plcements. The effects of tillge prctice nd N nd P plcement on grin nd biomss yield of field corn ws ssessed on two sites t the USDA- ARS Northwest Irrigtion & Soils Reserch Lbortory t Kimberly, ID with different levels of soil fertility nd productivity. Two sites were selected in furrow irrigted field tht hd been previously cropped to lflf. Site A ws locted in the top hlf of the field nd Site B ws locted in the bottom hlf of the field. Site A hd lower levels of soil orgnic crbon (OC) nd soil test P nd potssium (K) compred to Site B. The tretments were 1) ST with deep plcement of N nd brodcst P; 2) ST with 2 by 2 plcement of N nd brodcst P; 3) ST with deep plcement of N nd P; 4) CT with 2 by 2 plcement of N nd brodcst P; nd 5) CT with brodcst N nd P. The grin yields t Site A were greter for ST compred to CT. The deep bnd plcement of N nd P with ST hd yield (175 bu cre -1 ) dvntge of 23 nd 16 bu cre -1 over both CT tretments, respectively nd incresed yields to levels similr to the verge of Site B (178 bu cre -1 ). No differences in grin yield occurred t Site B for ll tretments. There were no differences in biomss yield of corn t the VT (tssel) growth stge nd grin hrvest time t both sites. The verge totl dry mtter biomss t grin hrvest time ws 9.1 nd 10.4 tons cre -1 verged over ll tretments, respectively. Dt from yer one of this study indictes tht ST nd deep bnd plcement of N nd P incresed corn grin yield over CT nd conventionl fertilizer plcement methods in highly eroded low fertile soils. Irrespective of the potentil yield increses, there my be n economic dvntge ssocited with less fuel due to less tillge pssges with ST compred to CT. Becuse the dt presented in this pper is from one yer, cution should be exercised in extrpolting these results from yer to yer due to the vribility in crop production ssocited with time-specific fctors. This study will be crried out over lest one to two more yers before finl conclusions nd recommendtions re issued. INTRODUCTION The use of ST nd other conservtion tillge prctices re used to conserve soil nd soil wter through residue mngement nd reduce tillge costs in mny res of the Corn Belt. However, in the Pcific Northwest these tillge prctices re less common. Reserch is needed to evlute these tillge prctices in the Pcific Northwest to determine their production nd economic fesibility. Strip tillge is prctice tht cretes residue free nd tilled zone, pproximtely 6 to 15 inches wide nd 6 to 8 inches deep. The remining portion of the field is not tilled, nd the residue from the previous crop remins on the soil surfce. Studies hve shown tht corn production under ST is comprble to or greter thn CT (Vetsch nd Rndll, 2002; Mllrino et l., 1999; Griffith et l., 1973). However, Vyn nd Rimbult (1992) showed tht ST reduced corn yields compred to moldbord plow in southern Ontrio. 1

2 Although ST llows for the deep bnding of fertilizers, differences in fertilizer plcement must be compred to CT prctices in order to ssess overll differences between the systems. Mny studies hve observed mixed results when evluting fertilizer plcement in corn production. Most studies, though, hve shown tht strter fertilizer plced in bnd ner the seed cn benefit erly corn growth (Vetsch nd Rndll, 2002). However, increses in corn grin yields re less common. Low initil soil test P concentrtions re the most common conditions in which corn grin yields incresed s result of strter fertilizer pplictions. Wolkowski (2000) found tht corn yield with 2 by 2 (2 inches to the side nd 2 inched below the seed) plcement of strter fertilizer t plnting ws better thn deep plcement of fertilizer in the fll under zone tillge. The objective of this reserch ws to evlute the production of corn under ST nd CT, nd vrious N nd P fertilizer plcements. METHODS The field study ws initited in 2007 t the USDA-ARS Northwest Irrigtion & Soils Reserch Lb in Kimberly, ID, on Portneuf silt lom soil (corse-silty mixed mesic Durixerollic Clciorthid). The site ws cropped to lflf (Medicgo stiv L.) from 2004 to 2006 under furrow irrigtion. In October 2006 nd April 2007 the lflf t the field site ws spryed with LV4 t rte of 1.5 qt cre -1 nd roundup t rte of 1 qt cre -1, respectively. The field sloped from est to west nd ws divided into two study sites. Site A ws locted on the est side of the field nd hd n verge slope of 2%. Site B ws locted on the west side of the field nd hd slope of 1%. Ech site hd the sme tretments nd repliction strtegy. In 2007, prior to field opertions, twenty soil sub-smples were collected t depths of 0 to 12 nd 12 to 24 inches cross ll replictions for both Site A nd Site B. The subsmples from ech site nd depth were composited. The composited smples were ir dried, ground to pss through 2 mm sieve, nd nlyze for orgnic C (OC) by combusting 50 mg of smple in FlshEA1112 CNH nlyzer (CE Elntech, Lkewood, NJ), soil test P nd K (bicrbonte extrctble, Olsen et l., 1954), nd nitrte nitrogen (NO 3 -N) nd mmonicl nitrogen (NH 4 -N) (Keeney nd Nelsen, 1982). Tretments consisted of: 1) ST with deep plcement of N nd brodcst P; 2) ST with 2 by 2 plcement of N nd brodcst P; 3) ST with deep plcement of N nd P; 4) CT with 2 by 2 plcement of N nd brodcst P; nd 5) CT with brodcst N nd P (Tble 1). Totl N nd P rtes of 105 lbs N cre -1 nd 58 lbs P 2 O 5 cre -1 were pplied to the tretments s ure (46-0-0) nd mono-mmonium phosphte ( ). Nitrogen fertilizer ppliction rte ws bsed on University of Idho recommendtions for corn grin (Brown nd Westermnn, 1988) t yield gol of 175 bu cre -1, nd NO 3 -N nd NH 4 -N concentrtions in the 0-12 nd inch depth t Site A. A 60 lbs N cre -1 lflf credit ws pplied. All tretments were replicted 4 times in rndomized complete block design. Fertilizers were either brodcst prior to tillge (Brodcst), plced 2 inches to the side nd 2 inches below the seed t plnting (2*2), or plced 7 inches below the soil surfce directly below the seed during ST (Deep). Fertilizer ppliction rtes nd timing informtion re presented in Tble 1. 2

3 Tble 1. Rtes nd timing of N nd P pplictions for ll tretments. Tretment Tillge ST ST ST CT CT N Plcement Deep 2*2 Deep 2*2 Brodcst lbs N cre My My My My Totl P Plcement Brodcst Brodcst Deep Brodcst Brodcst lbs P 2 O 5 cre My My Totl Chisel tillge tretments consisted of chisel plow nd tndem disk (My 11) nd roller hrrow (My 16). The brodcst ppliction of ure on My 16 to Tretment 5 ws immeditely incorported with the roller hrrow. Strip tillge occurred on My 23. Corn (Pioneer 3523, GDD 50F = 2530) ws plnted to the entire study re on My 24 t rte of 31,000 seeds cre -1. All plots were irrigted t rtes to meet the crop wter requirement. On June 21, ll ST plots were spryed with Clrity herbicide t rte of 0.75 pints cre -1 to kill volunteer lflf. A 12-plnt smple ws tken from ech plot t Sites A nd B t the V12 growth stge (July 20) to determine plnt biomss (dry mtter [DM] bsis). The entire plnt smple from ech plot ws weighted s-is directly fter removl from the plots, chopped with commercil wood chipper, nd subsmple collected nd weighted. The subsmple ws dried in n oven t 140 degrees F nd re-weighted to determine the percent dry mtter of the smple. On October 9, corn grin nd plnt smples were collected from ech plot t Sites A nd B. A 6-plnt smple ws collected to determine finl plnt biomss (DM bsis). All ers from 40 ft of row, ws collected to determine grin yield (reported t 15.5% moisture). RESULTS AND DISCUSSION Soil Anlysis Soil OC, soil test P, nd soil test K in the 0 to 12 nd 12 to 24 inch depth were lower t Site A thn Site B (Tble 2). At Site A, soil test P in the surfce 12 inches ws considered low to mrginl ccording to the University of Idho fertilizer recommendtions for field corn (Brown nd Westermnn, 1988). The recommendtions suggested ppliction of 20 to 140 lbs P 2 O 5 cre - 1 depending on the soil lime content (from 5 to 15 clcium crbonte (CCO3) equivlents). The soil test K t Site A suggested no dditionl K fertilizer inputs (the criticl level is 150 ppm). At Site B, soil test P nd K were high in the surfce 12 inches nd fertilizer inputs for these nutrients would not be recommended. The difference in OC, soil test P nd K levels between the two sites ws likely due to furrow irrigted induced soil erosion from Site A (2% slope) to Site B (1% slope). Due to fertility differences, Site B would likely be more productive thn Site A. 3

4 Tble 2. Selected soil chemicl properties from Site A nd Site B t depths of 0-12 nd inches. Soil Smple Anlyte Site A Site B Depth (in) OC (%) P (mg/kg) K (mg/kg) NO 3 -N (mg/kg) NH 4 -N (mg/kg) OC (%) P (mg/kg) K (mg/kg) NO 3 -N (mg/kg) NH 4 -N (mg/kg) Grin Yield There were significnt differences in grin yields between tretments t Site A (Figure 1). Tretment 3 (ST-deep N-deep P) t Site A hd greter grin yields thn both the CT tretments. Tretment 3 grin yields were 23 nd 16 bu cre -1 greter thn Tretment 4 (CT-2*2-brodcst P) nd Tretment 5 (CT-brodcst N-brodcst P), respectively. A direct comprison of tillge effects on grin yield could be mde between Tretments 2 (ST 2*2 N nd brodcst P) nd 4 (CT 2*2 N nd brodcst P) due to the two tretments hving the sme fertilizer plcements. Strip tillge hd greter grin yield compred to CT (+14 bu cre -1 ). There ws no significnt difference in grin yield between the ST tretments (Tretments 1, 2, nd 3), but trend for incresed yield with the deep N nd P plcement ws evident (Tretment 3). Averged over ll tretments, the grin yield t Sites A nd B were 164 bu cre -1 nd 178 bu cre -1, respectively. Unlike site A, there were no grin yield differences between tretments t Site B. The response of grin yield to tillge nd nutrient plcement t Site A ws likely result of the overll lower fertility sttus ssocited with furrow irrigted induced soil, OC, nd nutrient trnsport. The impct of tillge nd nutrient plcement ws negligible t Site B due to n overll greter level of fertility, result of soil, OC, nd nutrient deposition from Site A. These results indicte tht corn grown in res of fields with shllower soil depths, low in OC, nd nutrients due to erosion nd other fctors my hve greter yield response to ST nd deep plcement of N nd P compred to CT nd conventionl fertilizer plcements. Biomss Yield There were no significnt differences in the biomss yield between tretments t the V12 growth stge (dt not shown) or finl hrvest t both sites (Figure 2). Site A biomss yield trends were similr to Site A grin yield trends. 4

5 Site A 10.0 Site A b b 9.5 Corn Grin Yield (bu cre -1 ) c bc Site B Totl Dry Mtter (tons cre -1 ) Site B ST - Deep N - Brodcst P ST - 2*2 N - Brodcst P ST - Deep N - Deep P CT - 2*2 N - Brodcst P CT - Brodcst N - Brodcst P Figure 1. Corn grin yield for tillge nd fertilizer plcement tretments t Site A nd Site B loctions in Error brs re the stndrd errors of the tretment mens. Tretments with the sme letter re not significntly different t the 0.05 level. ST - Deep N - Brodcst P ST - 2*2 N - Brodcst P ST - Deep N - Deep P CT - 2*2 N - Brodcst P CT - Brodcst N - Brodcst P Figure 2. Corn biomss yield t grin hrvest time for tillge nd fertilizer plcement tretments t Site A nd Site B loctions in Error brs re the stndrd errors of the tretment mens. Tretments with the sme letter re not significntly different t the 0.05 level. 5

6 CONCLUSIONS Results from one yer of reserch indicted tht ST provided corn grin production dvntge over CT ssocited with tillge s well s fertilizer plcement on highly eroded, low fertile soils. On the more fertile site, there were no differences in corn grin yield between ST nd CT or fertilizer plcement strtegies. Although no economic nlysis hs been conducted to dte, there my be n economic dvntge for ST over CT due to potentil fuel svings ssocited with less tillge psses t both reserch sites. Remember, due to the vribility in crop production ssocited with time-specific fctors, cution should be exercised in extrpolting these results from yer to yer. This study will be crried out over lest one to two more yers before finl conclusions nd recommendtions re issued. These dt should be viewed s only preliminry. REFERENCES Brown, B.D., nd D.T. Westermnn Idho Fertilizer Guide: Irrigted field corn for silge or grin. Current Informtion Series No University of Idho Extension, Moscow, ID. Griffith, D.R., J.V. Mnnering, H.M. Gllowy, S.D. Prsons, nd C.B. Richey Effects of eight-plnting systems on soil temperture, percent stnd, plnt growth, nd yield of corn on five Indin soils. Agron. J. 65: Keeney, D.R., nd D.W. Nelson Nitrogen: Inorgnic forms. In Methods of soil nlysis, Prt 2, Chemicl nd microbiologicl properties, nd ed. A.L. Pge (ed). Americn Society of Agronomy nd Soil Science Society of Americ. Mdison, WI. Mllrino, A.P., J.M. Bordoli, nd R. Borges Phosphorus nd potssium plcement effects on erly growth nd nutrient uptke of no-till corn nd reltionships with grin yield. Agron. J. 91: Olsen, S.R., C.V. Cole, F.S. Wtnbe, nd L.A. Den Estimtion of vilble phosphorus in soils by extrction with sodium bicrbonte. USDA. Circ 939. U.S. Government Printing Office, Wshington, DC. Vetsch, J.A., nd G.W. Rndll Corn production s ffected by tillge system nd strter fertilizer. Agron. J. 94: Vyn, T.J., nd B.A. Rimbult Evlution of strip tillge systems for corn production in Ontrio. Agron. J. 93: Wolkowski, R.P Row-plced fertilizer for mize grown with n in-row crop residue mngement system in southern Wisconsin. Soil Tillge Res. 54: