Twelve Years of Stover Removal Increases Soil Erosion Potential without Impacting Yield

Virginia L Jin,Gary E Varvel,Catherine E Stewart,Ronald F Follett,Robert B Mitchell,Aaron J Sindelar,Kenneth P Vogel,Brian J Wienhold,Marty R Schmer

doi:10.2136/sssaj2015.02.0053

Abstract

Corn (Zea mays L.) stover (non-grain aboveground biomass) in the US Corn Belt is used increasingly for livestock grazing and co-feed and for cellulosic bioenergy production. Continuous stover removal, however, could alter long-term agricultural productivity by affecting soil organic C (SOC) and soil physical properties, indicators of soil fertility and erosion potential. In this study, we showed that 12 consecutive yr of 55% stover removal did not affect mean grain yields at any N fertilizer rate (4.5, 6.3, and 6.0 Mg ha−1 for 60, 120, and 180 kg N ha−1 yr−1, respectively) in a marginally productive, rainfed continuous corn system under no-till (NT). Although SOC increased in the top 30 cm of all soils since 1998 (0.54–0.79 Mg C ha−1 yr−1), stover removal tended to limit SOC gains compared with no removal. Near-surface soils (0–5-cm depth) were more sensitive to stover removal and showed a 41% decrease in particulate organic matter stocks, smaller mean weight diameter of dry soil aggregates, and lower abundance of water-stable soil aggregates compared with soils with no stover removal. Increasing N fertilizer rate mitigated losses in total water-stable aggregates in near-surface soils related to stover removal. Collectively, however, our results indicated soil structure losses in surface soils due to lower C inputs. Despite no effect on crop yields and overall SOC gains with time using NT management, annually removing stover for 12 yr resulted in a higher risk of wind and water erosion at this NT continuous corn site in the western Corn Belt.

Highlights

IntroductionContinuous stover removal, could alter long-term agricultural productivity by affecting soil organic C (SOC) and soil physical properties, indicators of soil fertility and erosion potential
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Multiple comparisons by year showed no difference in soil organic C (SOC) stocks between N fertilizer rates in the 0- to 5-cm soil depth increment

Summary

Introduction

Continuous stover removal, could alter long-term agricultural productivity by affecting soil organic C (SOC) and soil physical properties, indicators of soil fertility and erosion potential. We showed that 12 consecutive yr of 55% stover removal did not affect mean grain yields at any N fertilizer rate (4.5, 6.3, and 6.0 Mg ha−1 for 60, 120, and 180 kg N ha−1 yr−1, respectively) in a marginally productive, rainfed continuous corn system under no-till (NT). Increasing N fertilizer rate mitigated losses in total water-stable aggregates in near-surface soils related to stover removal. Despite no effect on crop yields and overall SOC gains with time using NT management, annually removing stover for 12 yr resulted in a higher risk of wind and water erosion at this NT continuous corn site in the western Corn Belt. Can have negative impacts on productivity by increasing soil erosion and decreasing SOC (Mann et al, 2002; Jarecki and Lal, 2003; Wilhelm et al, 2007; Johnson et al, 2011; Laird and Chang, 2013; Kenney et al, 2015)

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