Location: Agroecosystem Management ResearchTitle: Twelve years of stover removal increases soil erosion potential without impacting yield Author
|Mitchell, Robert - Rob|
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2015
Publication Date: 7/1/2015
Citation: Jin, V.L., Schmer, M.R., Wienhold, B.J., Stewart, C.E., Varvel, G.E., Sindelar, A.J., Follett, R.F., Mitchell, R., Vogel, K.P. 2015. Twelve years of stover removal increases soil erosion potential without impacting yield. Soil Science Society of America Journal. DOI: 10.2136/SSSAJ2015.02.0053. Interpretive Summary: Continuous removal of corn stover for livestock or bioenergy purposes could decrease the productivity of agricultural soils. In this study, corn stover was removed at a rate of 55% of total non-grain aboveground biomass for 12 consecutive years in a rainfed no-till, continuous corn system. At this marginally productive site, stover removal increased the susceptibility of soils to wind and water erosion. Stover removal, however, did not affect corn grain or stover yields over time. Harvesting of corn stover, especially on more sensitive degraded croplands, will likely result in greater erosion risks even if soil organic matter improves and yields are stable. Management decisions based on yield stability and soil organic matter content should be balanced by consideration of erosion potential.
Technical Abstract: Corn (Zea mays L.) stover (non-grain aboveground biomass) in the U.S. Corn Belt is used increasingly for livestock grazing and co-feed and also is the primary feedstock for cellulosic bioenergy production. Continuous stover removal, however, could alter long-term agricultural productivity by affecting soil organic carbon (SOC) and soil physical properties, indicators of soil fertility and erosion potential. Here, we show that 12 consecutive years of stover removal (55% average annual removal) at a marginally productive rainfed site under no-tillage (NT) continuous corn did not affect mean corn grain or stover yields, regardless of N fertilizer rate. Although all soils accrued SOC in the top 30 cm of the soil profile since site establishment in 1998, stover removal tended to limit SOC gains over time compared to no removal. Near-surface soils (0- to 5-cm depth) were more sensitive to corn stover removal and showed decreased particulate organic matter (POM) stocks, smaller mean weight diameter (MWD) of dry soil aggregates, and lower abundance of water-stable soil aggregates compared to soils with no stover removal. Collectively, these changes indicated a loss of soil structure in surface soils due to lower C inputs. Increasing N fertilizer rate, however, mitigated losses in total water-stable soil aggregates in near-surface soils due to stover removal. Despite no effect on crop yields and overall SOC gains over time using conservation management practices, annually removing stover for 12 years resulted in higher risk of wind and water erosion at this no-till continuous corn site in the western Corn Belt.