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Abstract Highly weathered soils of the Southeastern USA are poorly structured and may present special problems under continuous no‐tillage production. Soil physical properties were examined in a long‐term tillage experiment starting in its 10th year to determine if there were differences due to tillage. Fall/spring tillage treatments consisted of moldboard plow/moldboard plow (CT), moldboard plow/no‐tillage (MT), and no‐tillage/no‐tillage (NT). Cone index measurements in NT exceeded 4 MPa at a depth of 0.10 to 0.20 m, indicating the presence of a compacted zone. Bulk density was significantly higher than CT at this depth also (1.60 vs. 1.40 Mg m −3 ). Spring planting traffic compacted the top 0.15 m in all treatments. Infiltration rates, measured with a sprinkler infiltrometer, were significantly higher in NT. The straw mulch (5000 kg ha −1 ) and layer of fine organic litter at the surface of NT prevented the formation of an impermeable surface crust. Removing the mulch and litter layer from NT sharply reduced the infiltration rate. Adding a mulch to CT increased the infiltration rate. We conclude that during short‐term summer rainfall events, infiltration in conventionally tilled soil is controlled by surface crusting.
Radcliffe et al. (Sun,) studied this question.