Project Report

Transcription

1 Projet Report Projet Nme: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Priniple Investigtors: Dr. Sturt Birrell, Assoite Professor Deprtment of Agriulturl nd Biosystems Engineering Iow Stte University, 208 Dvidson Hll, Ames, IA Phone: (515) Emil: sirrell@istte.edu Dr. Dougls Krlen, Reserh Leder Soil nd Wter Qulity Reserh Unit, Ntionl Soil Tilth Lortory, 2110 University Boulevrd Ames, IA Phone: (515) Emil: doug.krlen@rs.usd.gov 2011 Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 1

2 Tle of Contents Summry... 3 Ojetives... 5 Methods nd Proedures... 5 Experimentl Plot Lyout... 5 Hrvest Equipment nd Proedures... 7 Soil Qulity Assessment... 8 Results nd Conlusions... 8 Grin Yield... 8 Stover Yield... 9 Stover Consituent nlysis Mnul Yield Smple nd Colletion Effiieny Soil Qulity Assessment nd Nutrient Removl Rtes Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 2

3 PROJECT REPORT Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Summry This projet is ollortive projet etween POET-DSM Advned Biofuels, Iow Stte University (ISU), nd the USDA-Agriulturl Reserh Servie (ARS), initited in 2008 to investigte emerging questions regrding the sustinility of stover residue hrvest. The ojetive of this work to ompre vrious orn stover hrvest strtegies to determine whih would e the most sustinle nd to evlute 1) the effet of stover hrvest nd removl on susequent rop yields, nd (2) the effet of stover hrvest nd removl on soil qulity, soil fertility, nd soil orgni mtter. The 4 yer study, inluded replited field trils (80+ totl res) with 7 different stover hrvest tretments inluding: 1) Conventionl grin hrvest (zero removl), 2) Co hrvest (0.5 ton/ removl), 3) Plnt mteril other thn grin (MOG) hrvest (0.7 ton/ removl), 4) Plnt mteril other thn grin (MOG) Diret Ble hrvest (0.9 ton/ removl), 5) High-Cut, elow er stover hrvest (1.9 ton/ removl), 6) Low-Cut, 4 inh stule hrvest (2.5 ton/ removl), 7) Multiple-pss round le hrvest (2.0 ton/ removl) The verge grin yields were 182, 162, 155, nd 151 u/ in 2008, 2009, 2010 nd 2011, respetively. The sesonl redutions in yield were prtly due to the yield penlty relted to ontinuous orn prodution, vriility in soil fertility, exessive erly seson rinfll in 2010, nd severe wind dmge in August However, grin yield ws not signifintly ffeted y stover hrvest tretments (α=0.05). Over the four yers, reltive yerly yields for the vrious tretments rnged from 92% to 117% of the onventionl grin hrvest tretment. When ll four yers re pooled, the verge reltive yerly yields for the vrious tretments rnged from 93 to 107% of the verge onventionl grin hrvest yield. Although, there were no signifint differenes in mongst the stover hrvest tretments, the highest removl tretment (Low Cut, 2.5 ton removl rte), did show on verge 10 u/ (7%) inrese in verge yield over the onventionl hrvest tretment. The reltive yield for the Low-ut stover hrvest ws 105%, 108%, 117% nd 98% of the onventionl hrvest tretment in 2008, 2009, 2010 nd 2011, respetively. The most likely use for the higher yields in the high removl rte plots (Low Cut, 2.5 ton removl rte) ws soil temperture ffets due to old spring germintion onditions, nd tht the removl of ron resulted in lower use of nitrogen y miroes. These results re onsistent with other studies onduted in Ames. However, it must e relized tht this inrese in yield my not e sustinle in the long term due to required mss lne of nutrients to mintin n equilirium within the soil. Over time depletion of orgni mtter will redue residul nitrte nd other nutrient levels. Wilhelm et l. (2007) estimted tht 2.27 ton/ of orn stover must e returned to the field to mintin soil ron. The verge yield for the low ut hrvest tretment ws 172 u/, nd ssuming HI of 0.54 the totl mss of stover produed would e 4.1 ton/. Therefore the mximum estimted sustinle removl rte would e Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 3

4 ton/, whih is less thn the tul low ut removl rte (2.5 ton/). Bsed on Wilhelm nd ollegues reommendtions, 2.5 ton/ removl level would require yield of 200 u/ or more. Over the 4 yers, the olleted iomss yield ws 2.5, 2.0, 1.9, 0.7, 0.9 nd 0.5 ton/ for the Low ut hrvest, Multiple-pss round le hrvest, High ut hrvest, MOG hrvest, MOG diret le hrvest nd Co hrvest tretments, respetively. The stover moisture ontents rnged from 9.3% (Co, MOG hrvest tretments) to 35 % (Low Cut Hrvest tretment). The stover nutrient onentrtion ws orrelted to the perentge of lower stlk in the olleted stover. The nitrogen onentrtion inresed s higher perentge of the lower portions of the plnt were olleted, from 0.45% for the o only hrvest to 0.52% for the low ut hrvest tretment, nd were signifintly different (α=0.05). Similrly, P nd K onentrtions inresed s higher pereentge of the lower portions of the plnt were olleted, lthough these differenes were not sttistilly signifint t the 5% level. The hnges in nutrient onentrtion re result of trnslotion of nutrients from the upper portions of the plnt to lower stems nd roots s plnt senesene ours. The nitrogen removl rtes per ton of iomss rnged from 9 ls-n/per ton (o only hrvest) to 12 ls-n/per ton (low ut hrvest), with n verge of 10 ls-n/per ton for ll tretments. The phosphorous removl rtes per ton of iomss rnged from 1.2 ls-p/per ton (o only hrvest) to 1.6 ls-p/per ton (low ut hrvest), with n verge of 1.4 ls-p/per ton for ll tretments. The potssium removl rtes per ton of iomss rnged from 12 ls-k/per ton to 13.6 ls-k/per ton (low ut hrvest), with n verge of 13 ls-k/per ton for ll tretments. Soil test nlyses showed sustntil field vriility ut no signifint stover hrvest tretment effets. There ws slight derese in soil orgni ron, unrelted to the stover hrvest tretments, tht is ttriuted to the intensity of tillge nd rop yields tht were lower thn expeted. In summry, oth grin yields nd soil nutrient levels were not signifintly ffeted y stover hrvest tretments. However, the sptil vriility nd sesonl effets for oth grin yield nd soil nutrient levels emphsize the importnt of strong fertility testing nd nutrient mngement progrm, efore implementing rop residue hrvesting. The sptil nd temporl vrition in soil nutrients nd overll rop mngement n hve muh greter effet on rop yields nd sustinle prodution thn the effet of different stover hrvest removl rtes. In ddition, when overll soil fertility levels nd nutrient mngement plns re mrginl the removl of rop residue ould serve s the tipping point to redue yields. The four-yer results of this projet hve shown tht with good mngement prties orn stover n e sfely nd sustinly hrvested from fields similr in nture, provided stover removl rtes re mintined elow 2 tons/ with n verge yield of ove 175 u/. If mngement prties re improved suh tht grin yields re greter thn 200 u/ there my e the possiility of inresed grin yields with higher rtes (2.5 ton/) of stover removl. However, these higher rtes of stover removl re not sustinle t lower yields nd will redue soil ron if these higher grin yields re not mintined Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 4

5 Ojetives The gol of this work is the evlution of hrvest effiieny nd pity, iomss yield nd the soil qulity impts of the different hrvest systems, inluding o only nd different stover hrvest senrios. The overll reserh ojetive is to mesure soil omposition effets resulting from vrious levels of residue removl nd evlution of the prties for sustinle feedstok prodution. The speifi ojetives of this projet inlude: 1) Evlution of the effet of orn o nd stover removl levels on yield, nutrient removl rtes, soil omposition nd soil qulity. 2) Development nd evlution of reommendtions for sustinle feedstok prodution systems. Methods nd Proedures In 2008, the field tests inluded six 32 row tretment plots (Low ut (90%), High ut (50%) removl, rke nd le removl, MOG removl, os only removl, onventionl grin only hrvest) in 3 replited loks (Figure 1). In 2009, single pss ling system ws dded to the tretments. Soil smples to determine seline soil nutrient levels nd ron sttus, nd post-hrvest soil smples for surfe nutrient nlysis were olleted. All stover hrvest tretments were imposed using the Iow Stte Biomss Hrvester single pss hrvester, with the exeption of the rke nd le tretment, nd the o only olletion in 2008, nd the single pss ling tretment. The dt olleted inluded mesurements required for hrvest pity, mteril olletion effiieny, yield nd moisture ontent for ll mterils (grin, stover, o, residue over) nd olletion of smples for nutrient ompositionl nlysis. Experimentl Plot Lyout The nturl soil produtivity levels differ etween replitions; therefore the plot lyout ws seleted to minimize nturl soil vriility within replitions. Figure 1: Lyout of replite nd field oundries (left) nd yield potentil (right) sed on soil type (Green-High potentil, Pink Low potentil). Eh replite ontined 7 tretment units onsisting of four 8-row psses (32 rows) through the field, with one 8 row uffer etween eh replite lok (Tle1). The tretment lyout is shown elow with Rep 1 eginning from the west side of the field. The gronomi dt nd field opertions for the field loted t Ltitude 43 o N; Longitude 94 o W re shown in Tle Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 5

6 Tle 1 Plot lyout strting from west edge of the field Rep 1 Rep 2 Rep 3 Tretment Rows Tretment Rows Tretment Rows Buffer Strip 16 Buffer Strip 8 Buffer Strip 8 Single Pss MOG 32 MOG Removl 32 High ut (50%) 32 Bler Removl Shred, Rke nd Ble 32 Single Pss MOG 32 Single Pss MOG 32 Bler Bler MOG Removl 32 Low ut (90%) 32 Low ut (90%) 32 High ut (50%) 32 Conventionl 32 MOG Removl 32 Removl Conventionl 32 High ut (50%) 32 Cos Only 32 Removl Cos Only 32 Shred, Rke nd Ble 32 Shred, Rke nd Ble 32 Low ut (90%) 32 Cos Only 32 Conventionl 32 Note: In 2008, Single Pss MOG Bler plots were treted s spre onventionl plots Buffer Strip 8 Tle 2: Summry of Tillge opertions, Fertilizer pplitions nd plnting dtes for fields Hrvest Yer, Dtes Dte Plnted Hyrid (Tillge, prior to plnting) Totl Fertilizer Applition for plots (ls./) N P2O5 K20 S Zn Plot Removl Rte /4-8 4-My DeKl 50-44VT3, Agrigold 6325VT3 nd Northrup-King NK 3616VT All Plots (Fll_DR, Spr_D, Spr_FC) My NC VT Low Removl Plots 11/5-9 (Fll_DR, Spr_D, Spr_FC) High Removl Plots Strter Fertilizer, All My NC STX Low Removl Plots 10/6-11 (Fll_DR, Spr_D, Spr_FC) High Removl Plots Strter Fertilizer, All NC STX Low Removl Plots 10/6-20 (Fll_DR, Spr_D, Spr_FC) High Removl Plots Strter Fertilizer, All Pioneer P0448XR All Plots (Fll_DR, Spr_D, Spr_FC) 40 Folir or Side-dress Notes: Fll_DR = Fll Disk-Rip, Spr_D = Spring Disk, Spr_FC = Spring Field Cultivte prior to plnting Low Removl Plots = Conventionl, Cos only, MOG, MOG Diret Ble High Removl Plots = High Cut, Low Cut, Bled 2 pss Plots 2011 Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 6

7 Hrvest Equipment nd Proedures The Low ut (90%), High ut (50%) removl, MOG removl, Co removl nd onventionl grin hrvest tretments were hrvested utilizing the single pss, dul strem iomss hrvester, sed on John Deere 9750 STS omine, with the single exeption in 2008, when the Co removl plots were hrvested with the Redkop Co Cddy. The single pss ler MOG Colletion plots were hrvested using prototype mhine lso provided y Poet. The stover mteril ws olleted in forge wgon with instrumented weigh ells. Stover smples were olleted from eh plot for moisture ontent nd onstituent nlysis s desried y Hoskinson et l., (2007). The mss of grin from eh plot nd grin moisture ws determined from weigh sle tikets for eh plot. The shred rke nd le opertion ws ontrted to lol frmer. The stnding stlks fter omining were shredded with rotry utter, windrowed nd led using lrge round ler. The mss of t lest three smple les per plot were mesured, nd smples olleted for moisture ontent nd onstituent nlysis. In 2008, the totl hrvest window ws extended over two week period, from Novemer 4-18, Although this ws not idel, the results yield results pper to e onsistent, nd removl rtes were s expeted. The only signifint devition ws tht the hrvest height for the High ut (50%). Removl ws lower thn plnned, sine high winds prior to hrvest resulted in moderte lodging. Therefore, the omine heder ws run muh lower thn norml, nd the removl rte for the High ut (50%) tretment ws higher thn norml. In 2009, the totl hrvest window ws extended over one week period, from Novemer 5-11, In 2009, the o plots were hrvested with the Deere STS mhine. However due to mehnil issues the purity of o smples ws less thn 80% y weight, s refleted in the higher olletion effiieny. In 2010, the totl hrvest window ws extended from Otoer 6-11, In 2010, due to exessive erly seson rinfll in some plots isolted low res of the field were drowned out. The totl re with zero prodution ws estimted during hrvest nd reported yields orreted for the non-produtive res. However, these lotions signifintly inresed vriility in the reported yields for single plots, nd therefore mde it less likely tht signifint sttistil differenes etween tretments would e found due to the high vrile etween reps plots. In 2011, the totl hrvest window ws extended from Otoer 6-20, On, August 23, 2011 high wind event in the re used signifint lodging in the field, this mde omining very diffiult. Prior to hrvest, the totl iomss prodution ws estimted y hnd hrvest of ove ground iomss for 2m row length for eh tretment plot. The mteril ws segregted into the following four tegories, Top 50% (ll mteril ove the o tthment lotion inluding husks), Bottom 50% (ll mteril elow o tthment lotion), Cos only, nd hnd-shelled grin mss. After 2009, in ddition to the stnding mteril, ll stover on the ground ws olleted seprtely, nd inluded in the totl mnul iomss yield Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 7

8 Soil Qulity Assessment In 2008, initil soil fertility smples were olleted on June 4, to determine generl soil fertility levels fter plnting, nd in susequent yers surfe soil smples (0-15 m) were olleted eh fll fter hrvest. The surfe smples (0-15 m) were olleted from 10 ores utilizing ~32mm (1¼ inh) hnd proe, for eh tretment plot. The deeper soil smples to 1 meter depth, to doument soil C nd N distriution nd other soil properties needed to define soil qulity, were olleted in spring Deeper smples were olleted using mehnil proe with ~50 mm proe dimeter s desried in Cmrdell et l., (2004) in spring The following soil profile dt were nlyzed s desried in Krlen et l., (2006) nd Cmrdell nd Elliott, (1993); Soil ulk density (BD), soil ph nd EC, Totl orgni C nd N, Mehlih III extrtle P nd K, stndrd soil fertility testing soil mironutrient nlysis, miroil iomss C, Aggregte stility (WSA), Prtiulte orgni mtter C (POM-C) nd N (POM-N), N minerliztion potentil (PMIN-N). Results nd Conlusions Grin Yield In 2008, grin yields rnged from u/ (men 182 u/) nd s expeted there ws not signifint differene in yield etween tretments, sine no stover removl hd ourred in 2007 (Tle 3). The grin moisture ontent rnged from 15.2 to 17.5 perent. In 2009, the grin yields were lower nd rnged from u/ (men 162 u/). In 2009, plots with higher removl rtes in 2008 (low ut 2.2 ton/, high ut 2.1 ton/, nd 2-pss ling 2.3 ton/ removl rtes), hd yields 14, 12 nd 11 u/ higher thn the onventionl plots (zero removl). However, the lower removl rtes (os only 0.5 ton/, nd MOG removl 0.7 ton/) where not signifintly different thn the onventionl plots. The grin moisture ontent rnged from 15.9 to 19.7 perent. In 2010, the grin yields were lower thn previous yers due to signifint ponding in the field nd possile nutrient stress. The grin yields rnged from u/ (men 155 u/). In ddition, the ponding resulted in muh higher thn norml vriility in yields etween plots, within eh tretment rep. Similr to 2009, in 2010 the high removl rte tretment (low ut 2.5 ton/ removl rte) on verge yielded 25 u/ more thn the onventionl plots (zero removl). However, due to the high vriility etween individul plot yields the 25 u/ differene ws not sttistilly signifintly different (α=0.05). The grin moisture ontent rnged from 14.0 to 16.3 perent. In 2011, the grin yields rnged from u/ (men 151 u/). On, August 23, 2011 high wind event in the re used signifint lodging in the field. As efore, the lodging resulted in muh higher thn norml vriility in yields throughout the field, nd mde omining very diffiult. Due to the high vriility etween individul plot yields the tretment differene were not sttistilly signifintly different (α=0.05), with the exeption of the single pss ling plots. However, this is most likely due to the use of different omine for these plots whih seemed to hve higher hrvest losses in the hevily lodged field. The grin moisture ontent rnged from 13.8 to 16.1 perent. When ll yers re onsidered, the most of the tretment mens rnged from u/, with the exeption of the single pss diret le tretment plots (verge 150 u/), nd the high removl rte tretment (low ut 2.5 ton/ removl rte) whih 2011 Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 8

9 verged 172 u/ over the four yers. The lower verge for single pss diret le tretment plots ws result of higher omine hrvest losses in 2011 in the hevily lodged field. Therefore over the four yers, the high removl rte tretment (low ut 2.5 ton/ removl rte) on verge yielded 10 u/ more thn the onventionl plots (zero removl). However, due to the high vriility etween individul plot yields, nd sesonl vrition in yields, the 10 u/ differene ws not sttistilly signifintly different (α=0.05) from the onventionl nd the lower removl rte plots. The most likely use for the higher yields in the high removl rte plots ws soil temperture ffets due to old spring germintion wether, nd tht the removl of ron resulted in lower use of nitrogen y miroes. These results re onsistent with other studies onduted in Ames. However, it must e relized tht this inrese in yield my not e sustinle in the long term due to required mss lne of nutrients to mintin equilirium within the soil. Over time depletion of orgni mtter will redue residul nitrte levels. In summry, there were no sttistil signifint differenes in mongst the stover hrvest tretments, lthough the highest removl tretment (Low Cut), did show 10 u/ (7%) inrese in verge yield over the onventionl hrvest tretment. However, grin yield did showed signifint differene sesonl effets, ut no signifint sesonl nd tretment intertion. The sesonl effets were most likely due to the deline in yield relted to ontinuous orn prodution ( ), high sptil vriility in soil fertility, exessive erly seson rinfll in 2010, nd severe wind dmge in August Tle 3. Grin yields for seven hrvest tretments for , Emmetsurg, IA. Tretment Grin Yield (u/) Averge Conventionl Cos only MOG High ut (50%) Low ut (90%) pss ling Diret le Averge All tretments were not sttistilly different (α=0.05) Stover Yield In 2008, the olleted iomss yield ws 2.2, 2.3, 2.1, 0.7 nd 0.5 ton/ for the Low ut, 2 pss ling, high ut, MOG nd Co only removl tretments respetively (Tle 4). The moisture ontents rnged from 14.3% for os only to 24.9% for the low ut, with n verge of 19% for ll tretments. In 2009, olleted iomss yield were similr to the 2008 results, with few exeptions. In 2009, the removl rte for the High Cut (50%) ws lower thn in normlly high 2008 stover yields, when it ws neessry to run the high ut muh lower due to lodging of the orn. In ddition, the 2-pss ling opertion ws fr less ggressive in 2009 nd more moderte stover yield ws hieved. It is interesting to 2011 Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 9

10 note tht the yield for the MOG removl utilizing the Diret le (0.9 ton/) is onsistent with those for the single pss ulk MOG system (0.9 ton/), s would e expeted. The moisture ontents rnged from 10.3% for Diret le to 16.2% for the os only, with n verge of 13% for ll tretments. In 2010, olleted iomss yield were onsistent with the 2009 results. The moisture ontents rnged from 9.3% for Diret le to 35.6% for the Low ut, with n verge of 19.6% for ll tretments. In 2011, the os only olletion yields were muh lower thn expeted due to losses in olletion system resulting insuffiient trnsport from omine olletion system to the wgon. In ddition the high ut tretment yields were higher thn expeted due to signifint lodging required muh lower thn norml ut height. The moisture ontents rnged from 9.3 % for MOG removl to 35.6% for the low ut, with n verge of 19.6% for ll tretments Over the 4 yers, the olleted iomss yield ws 2.5, 2.0, 1.9, 0.7, 0.9 nd 0.5 ton/ for the Low ut, 2 pss ling, high ut, MOG, single pss diret le nd Co only removl tretments respetively (Tle 4). Tle 4. Stover yield for seven hrvest tretments for , Emmetsurg, IA. Tretment Stover Yield (dry ton/) Averge Conventionl Cos only MOG High ut (50%) Low ut (90%) pss ling Diret le Averge Stover Consituent nlysis The verge stover onsituent nlysis for the different hrvest tretments re shown in Tle 5. The nitrogen onentrtion in the olleted stover inresed s higher perentge of the lower portions of the plnt were olleted. The nitrogen onentrtion inresed from 0.45% for the o only hrvest to 0.52% for the low ut hrvest tretment, nd these two tretment were signifintly different (α=0.05). Similrly, P nd K onentrtions in the olleted stover inresed s higher pereentge of the lower portions of the plnt were olleted, lthough these differenes were not sttistilly signifint t the 5% level. The hnges in nutrient onentrtion s lrger perentge of the lower portions of the plnt re olleted re result of trnslotion of nutrients from the upper portions of the plnt to lower stems nd roots s plnt senesene ours. The nitrogen removl rtes per ton of iomss rnged from 9 ls-n/per ton (o only hrvest) to 12 ls-n/per ton (low ut hrvest), with n verge of 10 ls-n/per ton for ll tretments. The phosphorous removl rtes per ton of iomss rnged from 1.2 ls-p/per ton (o only hrvest) to 1.6 ls-n/per ton (low ut hrvest), with n verge of 2011 Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 10

11 1.4 ls-p/per ton for ll tretments. The potssium removl rtes per ton of iomss rnged from 12 ls-k/per ton to 13.6 ls-k/per ton (low ut hrvest), with n verge of 13 ls-k/per ton for ll tretments. Tle 5. Stover onstituent nlysis y hrvest senrio for , Emmetsurg, IA. Tretment Conentrtion of Nutrients in Stover Removed from Field C N P K C Mg S N Co only MOG High ut Low ut Bled Diret le % d d d Averge Co only 21 MOG 22 High ut 28 Low ut 50 Bled Diret le 30 Al B Cu Fe Mn Zn ppm d d d Averge Levels not onneted y sme letter re signifintly different (α=0.05) Mnul Yield Smple nd Colletion Effiieny The grin yield nd dry mtter yield from the 2m hnd hrvested trnsets in shown in Tle 6. In 2008, the mnul grin yields rnged from 180 to 200 u/ with n verge yield of 189 u/ whih ws slightly higher ut onsistent with the omine grin yields (rnge 177 to188 u/; verge yield 182 u/). In 2009, the mnul grin yields rnged from 137 to 152 u/ with n verge yield of 146 u/ whih ws slightly lower thn the omine grin yields (rnge 152 to172 u/; verge yield 162 u/). In 2010, the mnul grin yields rnged from 153 to 191 u/ with n verge yield of 173 u/ whih ws higher thn the omine grin yields (rnge 140 to 178 u/; verge yield 155 u/). However, in 2010 there ws signifint ponding in the lower elevtion res in the plots, whih redued overll plot yields. These low yield res where not loted where rndom mnul plot smples were olleted. In 2011, the mnul grin yields rnged from 149 to 218 u/ with n verge yield of 194 u/ whih ws muh higher thn the omine grin yields (rnge 132 to 159 u/; verge yield 151 u/). The muh lower mhine hrvest grin yields were muh lower thn the mnul grin yields due to signifint lodging in the field due to high wind event in August. Over 50% of the field ws severely lodging whih resulted in very high hrvest losses during omining Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 11

12 Tle 6. Mnully Hrvested Grin, Cos nd Stover Yields ( ) for seven hrvest senrios. Tretment Grin nd Co Yield Stover Yields Grin, Cos, Top 50%, Bottom 50%, u/ ton/* ton/ ton/ Totl Stover, ton/ 2008 Mnul Hrvest Low ut (90%) High ut (50%) Bled Single Pss Sq. Ble MOG Removl Cos Only Conventionl Averge (2008) Mnul Hrvest Low ut (90%) High ut (50%) Bled Single Pss Sq. Ble MOG Removl Cos Only Conventionl Averge (2009) Mnul Hrvest Low ut (90%) High ut (50%) Bled Single Pss Sq. Ble MOG Removl Cos Only Conventionl Averge (2010) Mnul Hrvest Low ut (90%) High ut (50%) Bled Single Pss Sq. Ble MOG Removl Cos Only Conventionl Averge (2011) Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 12

13 In 2008, the hnd hrvested o yields rnged from 0.66 to 0.79 ton/, with n verge of 0.71 ton/, nd the totl stover yield rnged from 3.23 to 64 ton/, with n verge of 3.40 ton/. In 2008, estimted totl stover yield did not inlude iomss lredy on ground nd therefore the totl stover yield ws underestimted nd this ws refleted in the slightly higher thn expeted HI in 2008 In 2009, the hnd hrvested o yields rnged from 0.75 to 1.04 ton/, with n verge of 0.94 ton/, nd the totl stover yield rnged from 3.89 to 5.51 ton/, with n verge of 4.16 ton/. In 2010, the hnd hrvested o yields rnged from 0.58 to 0.72 ton/, with n verge of 0.65 ton/, nd the totl stover yield rnged from 3.41 to 3.81 ton/, with n verge of 3.57 ton/. In 2011, the hnd hrvested o yields rnged from 0.46 to 0.56 ton/, with n verge of 0.51 ton/, nd the totl stover yield rnged from 3.01 to 3.97 ton/, with n verge of 3.38 ton/. Over the four yers, the hnd hrvested o yields rnged from 0.50 to 1.04 ton/, with n verge of 0.70 ton/, nd the totl stover yield rnged from 3.27 to 3.64 ton/, with n verge of 3.63 ton/. The estimted hrvest index (HI) rnged from 0.48 to 0.64, with n verge of The estimted hrvest index is slightly higher thn expeted. The o mss ws on verge 14% of the totl grin mss nd onsistent with vlues reported in literture, nd the o mss ws 19% of the totl stover iomss. In 2008, when the omine stover hrvested yields re ompred to the totl hnd hrvested stover yields, the Low ut (90%) rte olleted pproximtely 70% of the nominl ville ove ground iomss nd the High ut (50%) olletion effiieny ws out 58%. The MOG removl nd Co removl provided 20% nd 13% of the nominl ville iomss, respetively. When the omine o yield (0.46 ton/) is ompred with the hnd hrvest o yield (0.71 ton/), the estimted olletion effiieny of the o hrvest opertions is pproximtely 65%. In 2009, the Low ut (90%) rte olleted pproximtely 57% of the totl ville ove ground iomss, nd the High ut (50%) olletion effiieny ws out 41%. The MOG removl nd Co removl provided 21% nd 17% of the totl ville iomss, respetively. When the omine o yield (0.66 ton/) is ompred with the hnd hrvest o yield (0.85 ton/), the estimted olletion effiieny of the o hrvest opertions is pproximtely 78%. In 2009, the inrese in nominl o olletion effiieny inresed ove ws prtly due to lower purity o smples. The smple purity ws elow 80% y weight. In 2010, the Low ut (90%) rte olleted pproximtely 65% of the totl ville ove ground iomss, nd the High ut (50%) olletion effiieny ws out 49%. The MOG removl nd Co removl provided 17% nd 14% of the totl ville iomss, respetively. When the omine o yield (0.50 ton/) is ompred with the hnd hrvest o yield (0.64 ton/), the estimted olletion effiieny of the o hrvest opertions is pproximtely 78%. In 2011, the Low ut (90%) rte olleted pproximtely 79% of the totl ville ove ground iomss, nd the High ut (50%) olletion effiieny ws out 73%. The ltter ws higher thn norml due to the severe lodging. The MOG removl nd Co removl provided 21% nd 8% of the totl ville iomss, respetively. When the omine o yield (0.25 ton/) is ompred with the hnd hrvest o yield (0.70 ton/), the estimted olletion effiieny of the o hrvest opertions is only 50%. The os olletion yield ws muh lower thn expeted due to losses in trnsporting the os from omine to the wgon. Over, the four yers, the Low ut (90%) rte olleted pproximtely 66% of the totl ville ove ground iomss, nd the High ut (50%) olletion effiieny ws out 53%. The MOG removl nd Co removl provided 21% nd 13% of the totl 2011 Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 13

14 ville iomss, respetively. When the omine o yield is ompred with the hnd hrvest o yield, the estimted verge olletion effiieny of the o hrvest opertions is only 67%, lthough this is slightly inflted due to husk ontmintion Soil Qulity Assessment nd Nutrient Removl Rtes The mro-nutrient nd mironutrient nlysis results for the 0-15m soil fertility smples olleted on y yer nd tretment re shown in Tle 7. The verge soil fertility levels ross ll tretments re shown in Tle 8. The different stover removl tretments resulted in no signifint differenes (α=0.05) for ll soil nutrients, soil OM, nd soil ph. However, there ws signifint differene etween repetitions for ll for soil nutrients (exept Mg, Zn, S, nd N), soil OM nd ph, refleting the sptil vriility in soil type nd nturl fertility levels ross the field. In ddition, when the soil nutrients (exept Fe), soil OM nd ph for ll tretments were pooled nd ompred ross the yers, signifint differene etween ws found (α=0.05). In 2008 nd 2009, the residul nitrte levels in the soil fter hrvest were lower thn those in 2010 nd This is most likely due to the inresed rtes of nitrogen pplied in the spring of 2010 nd 2011, resulting inresed residul nitrogen in fll. The Nitrogen fertilizer rtes were inresed in 2010 nd 2011 s result of N er lef nutrient levels testing elow ritil vlues. In ddition, soil P deresed from 2008 to 2010 from 35.1 to 19.0 ppm, lthough verge P er lef nutrient levels remined ove ritil vlues. In 2011, post hrvest soil P levels inresed k to 28.3 ppm. Soil K deresed from 2008 to 2010 from 1971 to 147 ppm, lthough verge P er lef nutrient levels remined ove ritil vlues. Prior to 2011 plnting, K fertiliztion rtes were inresed (Tle 2), nd whih resulted in verge post hrvest soil K levels inresing to 183 ppm. In ddition, over the four yers of the study there ws slight derese in soil orgni mtter from 4.5 to 4.0 %, lthough this ws unrelted to hrvest tretment effets. These hnges in orgni mtter re ttriuted to the intensity of tillge nd lower thn expeted rop yields due to wether nd other ftors. Stover removl my provide n opportunity to redue tillge intensity levels. Both grin yields nd soil nutrient levels, were not signifintly ffeted y stover hrvest tretments. However, the signifnt differene etween repetitons nd sesonl effets for oth grin yield nd soil nutrient levels, emphsize the importnt of strong fertility testing nd nutrient mngement progrm, efore implementing rop residue hrvesting. The sptil nd temporl vrition in soil nutrients nd overll rop mngement n hve muh greter effet on rop yields nd sustinle prodution thn the effet of different stover hrvest removl rtes. In ddition, when overll soil fertility levels nd nutrient mngement plns re mrginl the removl of rop residue ould serve s the tipping point to redue overll prodution Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 14

15 Tle 7. Ner-surfe soil test vlues fter hrvest, y yer nd hrvest tretments Ner-surfe soil test vlues fter 2008 Hrvest Tretment ph OM N03-N P K C Mg N S B Cu Fe Mn Zn % ppm Conventionl Cos only MOG High ut Low ut Bled 2 pss Diret Ble Men ll tretments Ner-surfe soil test vlues fter 2009 Hrvest Tretment ph OM N03-N P K C Mg N S B Cu Fe Mn Zn % ppm Conventionl Cos only MOG High ut Low ut Bled 2 pss Diret Ble Men ll tretments Ner-surfe soil test vlues fter 2010 Hrvest Tretment ph OM N03-N P K C Mg N S B Cu Fe Mn Zn % ppm Conventionl #### Cos only #### MOG #### High ut #### Low ut #### Bled 2 pss #### Diret Ble #### Men ll tretments #### Ner-surfe soil test vlues fter 2011 Hrvest Tretment ph OM N03-N P K C Mg N S B Cu Fe Mn Zn % ppm Conventionl Cos only MOG High ut Low ut Bled 2 pss Diret Ble Men ll tretments Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 15

16 Tle 7. Ner-surfe soil test vlues Hrvest, Men for ll Tretments y Yer Ner-surfe soil test vlues Hrvest, Men for ll Tretments y Yer Tretment ph OM N03-N P K C Mg N S B Fe Mn Zn % ppm Men ll tretments, Men ll tretments, Men ll tretments, Men ll tretments, Levels not onneted y sme letter re signifntly different (α=0.05) Referenes ASAE S358.2 FEB03 Moisture Mesurement Forges. Mdison, WI: ASABE; 2003 ASAE S352.2 APR1988 (R2008) Moisture Mesurement Unground Grin nd Seeds. Mdison, WI: ASABE; 2008 Cmrdell C.A., Moormn T.B., Andrews S.S., Krlen D.L. A Wtershed-sle ssessment of soil qulity in the loess hills of southwest Iow. Soil & Tillge Reserh 78 (2004) Krlen D.L., Hurley E.G., Andrews S.S., Cmrdell C.A., Meek D.W., Duffy M.D., Mllrino A.P. Crop Rottion Effets on Soil Qulity t Three Northern Corn/Soyen Belt Lotions. Agron. J. 98: (2006). Logsdon S.D., Krlen D.L. Bulk density s soil qulity inditor during onversion to no-tillge. Soil & Tillge Reserh 78 (2004) Wilhelm, W.W., J.M.-F. Johnson, D.L. Krlen, nd D.T. Lightle Corn stover to sustin soil orgni ron further onstrins iomss supply. Agronomy Journl, 99: Report: Emmetsurg Soil Study: Evlution of orn o nd stover removl levels on rop prodution, soil qulity nd nutrient levels. Iow Stte University. 16