Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/22/2006
Publication Date: 1/8/2007
Citation: Blanco-Canqui, H., Lal, R., Post, W.M., Izaurralde, R.C., Shipitalo, M.J. 2007. Soil hydraulic properties influenced by corn stover removal from no-till corn in Ohio. Soil & Tillage Research. 92:144-155. Interpretive Summary: Corn crop residue consisting of stalks and cobs left in the field after the grain has been harvested can be used as an energy source and for the production of biofuels. This residue, however, is important for maintaining soil quality and its removal may have detrimental effects on how water infiltrates and moves through the soil. We looked at various rates of residue removal on three different soil types in order to determine the amount that can be safely harvested without impacting soil quality. One year of complete crop residue removal had a dramatic, negative, effect by decreasing the rate at which water moved through the soil about 10-fold. This would greatly increase the vulnerability of the soil to surface runoff and erosion. Much of this decrease in infiltration appears to be due to a decrease in earthworm populations attributable to residue removal. The removal of about 25% of the crop residue appeared to have a minimal effect on infiltration and earthworm populations. If long-term studies confirm that this rate of residue removal can be sustained without negatively affecting the soil, than this material can be used as an energy source and a source of increased farm income.
Technical Abstract: Corn (Zea mays L.) stover removal for biofuel production and other uses may alter soil hydraulic properties, but site-specific information needed to determine the threshold levels of removal for the U.S. Corn Belt region is limited. We quantified impacts of systematic removal of corn stover on soil hydraulic parameters after one year of stover management under no-till (NT) systems in three soils in Ohio including Rayne silt loam (fine-loamy, mixed, active, mesic Typic Hapludult) at Coshocton, Hoytville clay loam (fine, illitic, mesic Mollic Epiaqualfs) at Hoytville, and Celina silt loam (fine, mixed, active, mesic Aquic Hapludalfs) at South Charleston. Interrelationships among soil properties and saturated hydraulic conductivity (Ksat) predictions were also studied. Earthworm middens, Ksat, bulk density ('b), soil-water retention (SWR), pore-size distribution, and air permeability (ka) were determined for six stover treatments including 0 (T0), 25 (T25), 50 (T50), 75 (T75), 100 (T100), and 200 (T200) % of corn stover corresponding to 0, 1.25, 2.50, 3.75, 5.00, and 10.00 Mg/ha of stover, respectively. Stover removal reduced the number of middens, Ksat, SWR, and ka at all sites (P<0.01). Complete stover removal reduced earthworm middens 20-fold across sites, decreased geometric mean Ksat from 6.3 to 0.1 mm/h at Coshocton, 3.2 to 0.3 mm/h at Hoytville, and 5.8 to 0.6 mm/h at Charleston, and increased 'b in the 0- to 10-cm depth about 15% relative to double stover plots. The SWR for T0 was about 70% of that for T100 and 58% of that for T200 at 0 to -6 kPa across sites. The log ka for T200, T100, and T75 significantly exceeded that under T50, T25, and T0 at Coshocton and Charleston. Measured parameters were strongly correlated, and ka was a strong Ksat predictor. Stover harvesting induces rapid changes in soil hydraulic properties and earthworm activity, but further monitoring is needed to ascertain the threshold levels of stover removal.