Long-term tillage and wheel traffic effects on a poorly drained mollic ochraqualf in northwest Ohio. 2. Infiltrability, surface runoff, sub-surface flow and sediment transport

Abstract

Tillage-caused alterations in water infiltration, surface runoff, subsurface flow and sediment transport in surface and subsurface flow were studied for a clayey Mollic Ochraqualf for corn-soybean rotation in northwestern Ohio. Measurements were made on field runoff plots, 0.04 ha each, established in 1975. There were 4 tillage treatments: (A) continuous no-till for 12 years; (B) no-till for 10 years followed by plow-till for 2 years; (C) plow-till for 10 years followed by no-till for 2 years; (D) continuous plow-till for 12 years. Twelve years of continuous no-till and plow-till systems resulted in differences in soil water sorptivity and transmissivity coefficients of Philip's infiltration model for the traffic zone (TZ) and the row zone (RZ) sites. Average soil-water sorptivity in plow-till treatments was 9.1 times that in no-till treatments. In no-till, sorptivity in RZ was 4.8 times that in TZ. The infiltration data was better described by the Kostiakov model than by the Philip model. Surface runoff was somewhat more in plow-till than in no-till treatments. Subsurface flow was generally more in plow-till than no-till treatments. In no-till plots, the threshold value of subsurface flow, below which there was no surface flow, was about 22% of the annual precipitation. No such relation was observed for plow-till treatment. In general, sediment load was low, but was more for plow-till than no-till treatments. The mean sediment load in surface runoff ranged from 0.09 to 0.35 t ha −1 year −1 in plow-till plots compared with 0.015–0.117 t ha −1 year −1 in the no-till treatment.