An Evaluation of the Potential for Using Drainage Control to Reduce Nitrate Loss from Agricultural Fields to Surface Waters,

摘要

This study was an outgrowth of previous work which revealed that considerable denitrification occurred in poorly drained soils with high water tables. This resulted in less nitrate leaving fields in drainage waters than occurred in better drained soils. Two N.C. Coastal Plain sites were used:one in the poorly drained soils of the Tidewater area and the other in the moderately well drained soils of the Lower Coastal Plains. Flashboard riser type water control structures were installed in four main tile lines at each location. Each control structure was equipped with a weir and a stage recorder for computing total outflow of drainage water. A semi-proportional water sampler was installed at each weir to take samples for chemical analyses. The structures were very effective in controlling the loss of nitrate-nitrogen on the moderately well drained soils.