Strip-Till Effects On Soil Physical Properties May Improve Corn Production Over No-Till.

Averaged over six distinct growing seasons we measured an 8% corn (Zea mays L.) grain yield increase with strip-till (ST) over no-till (NT). The crop in ST consistently has greater nutrient uptake efficiency per unit of root surface area relative to NT. Our objective was to determine the effect of ST on soil physical properties that may help elucidate the differences in crop performance. Corn was planted in an ongoing study started in 2007 near Urbana, IL in 2012 and 2013 the following soil physical properties were measured: bulk density, penetration resistance, infiltration rate, and aggregate stability. Penetration resistance was measured at in-row (IR), 12, 24, and 36 cm off the planting-row to a depth of 30 cm in 2.5 cm increments and averaged over the 0-5, 5-10, and 10-30 cm depths. All other soil physical properties were measured at IR and 36 cm off the planting-row position. Bulk density was determined for the 0-5, 5-10, 10-30, and 30-50 cm increments.  Across depths, soil bulk density was higher for NTBC (1.39 g cm^-3) than for STDB (1.33 g cm^-3). Across treatments, bulk density increased with increasing depth to the 10 to 30 cm depth. Across treatments, penetration resistance was lower at IR than other row position. Across row positions, penetration resistance in the 0-5 cm depth was 0.32 MPa in ST and 34% lower than NT and in the 5-10 cm depth was 1.06 MPa in ST and 27% lower than NT. Infiltration rates and aggregate stability were not influenced by tillage type or row position. This study indicate that relative to NT, ST may provide an improved corn rooting environment for uptake of nutrients and water by reducing rooting impedance and not by enhancing rainwater infiltration into the soil profile.