Disruption of Tillage Pans By Slot Tillage.

In some areas of the central Great Plains, traditional sweep tillage for weed control has led to a root-restrictive tillage pan approximately 10 to 15 cm beneath the soil surface. Producers have shown interest in methods to disrupt this tillage pan prior to transitioning to no-till soil management. An experiment to compare no-till vs. slot tillage was conducted in a Rago silt loam at Akron, CO. The tillage operation used a one-cm wide, straight-shank chisel on 76 cm centers at a 35 cm depth. Tillage was done approximately two weeks before corn planting. Corn was planted immediately above the tillage slot. Soil strength beneath the corn row decreased from about 2 MPa in no-till plots to about 1.4 MPa in the slot-tilled plots at 10 cm depth with 30% volumetric water content. Lower soil strength from the slot tillage operation was evident 18 cm from the slot when the tillage was conducted in dry soil but was limited to the slot itself when tillage was conducted in wet soil. No effects of tillage were evident 38 cm from the slot, even when the operation was conducted on dry soil. Infiltration rate was about 30% greater in the row of the slot-tilled plots vs. either the interrow in the slot tilled plots or any position of the no-till plots. More water was extracted by plant roots in the interrow position in the slot-tilled plots compared with the no-till plots, indicating greater root exploration with the slot-till treatment. The effects of slot tillage were evident three years after tillage, indicating that the tillage operation may be useful as a one-time soil improvement method for improving soil conditions prior to transitioning to subsequent no-till management systems.