摘要：Intensive tillage is commonly employed in many agronomic production systems in the United States. Tillage operations may include disking the field, re-smoothing the soil, seedbed formation, reducing the seedbeds, and shallow cultivation for weed control. Tillage practices in conjunction with rainfall have been linked to soil erosion, which may adversely affect the environment. The soil erosion dynamics of two large-scale production cotton fields that utilized both modern-conventional and conservation-tillage technology were examined. Studies were conducted in the cotton-producing region of southeast Arkansas in the Bayou Bartholomew watershed. Bayou Bartholomew is currently listed by the United States Environmental Protection Agency as an impacted stream. The soils at these sites were related, coarse-textured alfisols. One field was cropped to conventionally tilled cotton and intensively tilled. The second field was cropped to cotton using modern conservation tillage technology. Both fields were furrow-flow irrigated using piped water. Intense rainfall usually occurs in the Mississippi River Delta Region, particularly in the winter and spring months. Conservation tillage proved to be immediately beneficial in controlling soil erosion and sediment loss due to field run-off water from rainfall. Sediment content of run-off water induced by rainfall from the conventionally tilled cotton field was significantly greater than the sediments found in run-off water from the conservation tilled cotton field. The amount of sediment found in rainfall run-off water decreased more rapidly with time under conservation tillage than under conventional tillage. The tillage system made little difference in sediment content of run-off water from irrigation. The water flow from furrow irrigation is typically slow and steady. There is no droplet impact on the ground from furrow-flow irrigation as there would be from rainfall. Apparently, the gentle flow of the water down the furrows was insufficient to dislodge large numbers of soil particles.
