Soil Hydraulic Properties Under Contrasting Long-Term Tillage and Cropping Systems.

Improving the capacity of soil to transmit, store, and retain water is essential for sustainable intensification of cropping systems, particularly in regions with limited precipitation. More experimental data on soil hydraulic properties are needed to better understand soil hydrology and the effects of agricultural management on soil water infiltration, runoff, leaching, drainage, and other components. The objective of this study was to characterize the soil hydraulic properties of a silty clay loam after long-term (35 years) tillage and cropping systems management in eastern Nebraska. The full experiment was established in 1981 using a randomized complete block design with six tillage treatments and four cropping systems replicated six times.  The current study evaluated only four tillage systems; no-till (NT), disk tillage (D), chisel plow (CH), moldboard plow (PT) in two cropping systems; continuous corn and corn-soybean rotation. Intact soil cores were collected at 0-7.5, 7.5-15, 15-22.5 and 22.5-30 cm depths to measure bulk density, saturated hydraulic conductivity, and water retention at different pressure heads. Water infiltration was determined using double-ring infiltrometers, while unsaturated hydraulic conductivity was measured using a tension infiltrometer in the field. Results showed that PT had about 2 times higher infiltration rate and cumulative infiltration compared with NT, D and CH treatments. Unsaturated hydraulic conductivity did not, however, differ among treatments. We expected that long-term NT management would have increased water infiltration. However, previous published studies have found that water infiltration under NT management may be lower, higher, or remain unaffected as compared with PT management. Samples for other properties are being analyzed and results will be presented and discussed at the meeting.