Corn Stover Impacts on Near-Surface Soil Properties of No-Till Corn in Ohio

摘要

Corn (Zea mays L.) stover is a primary biofuel feedstock and its expanded use could help reduce reliance on fossil fuels and net CO2 emissions. Excessive stover removal may, however, negatively impact near-surface soil properties within a short periodafter removal. We assessed changes in soil crust strength, bulk density (ρsub b~(-1)), and water content over a 1-yr period following a systematic removal or addition of stover from three no-till soils under corn in Ohio. Soils from ongoing experimentsat the North Appalachian Experimental Watershed (NAEW), Western Agricultural Experiment Station (WAES), and Northwestern Agricultural Experiment Station (NWAES) of Ohio Agricultural Research and Development Center (OARDC) were studied. Six stover treatments of 0 (T0), 25 (T25), 50 (T50), 75 (T75), 100 (T100), and 200 (T200)% were imposed on 3 by 3 m plots corresponding to 0, 1.25, 2.50, 3.75, 5.00, and 10.00 Mg ha~(-1)sup~(-1) of stover, respectively. Cone index (CI), shear strength (SHEAR), ρsub b~(-1), and volumetric water content (θsub v~(-1)) were measured monthly from June through December 2004 and in May 2005. Effects of stover removal on increasing CI and SHEAR were soil-specific. Stover removal consistently increased ρsub b~(-1) and decreased θsub v~(-1) across soils (P 0.01). Compared with the normal stover treatment (T100), doubling the amount of stover (T200) did not significantly affect soil properties except θ^sub v^ where, after 1 yr, T200 increased θsub v~(-1) by 1.3 to 1.6 times compared with T100 across all sites (P 0.05). After 1 yr, complete stover removal (T0) increased CI by 1.4 times and SHEAR by 1.3 times at NAEW compared with T100 and T75, but CI increases at other sites were nonsignificant. At NWAES, T0 increased SHEAR by 26% compared with T100 (P 0.05). The T0 decreased θsub v~(-1) by two to four times except in winter months and increased ρsub b~(-1) by about 10% compared with T100 (P 0.05). In a short-term test, stover removal resulted in increased soil crust strength and reduced soil water content.