Effects of Drainage Water Management on Nitrogen Losses to Surface Waters
Nitrogen losses from drained agricultural lands are a principal source of excess nitrogen (N) in streams and estuaries. Drainage Water Management (DWM) or Controlled Drainage (CD) can be used to significantly reduce N losses in drainage waters while conserving water and potentially increasing crop yields. Field research conducted by a number of investigators on a wide range of soils and locations has shown that CD reduced N losses by 18 to 85 percent compared to conventional drainage. Analysis of results of the various studies indicates that the difference in effectiveness of CD among soils and sites is primarily due to differences in its effect on seepage, and whether the seepage water passes through dentirified zones. This leads to the conclusion that research to determine the effectiveness of CD should be conducted on field size or larger units, such that the effect of lateral and vertical seepage will be appropriately represented. The simulation model DRAINMOD was used to predict the long-term performance of CD for a sandy loam soil in eastern North Carolina. CD reduced the 35-year average annual predicted N losses in drainage water by 37% for continuous corn and by 34% for a corn-wheat-soybean rotation. Both predicted N loads in drainage water and the reduction of those loads in response to CD varied widely from year to year. Predicted annual N loads for conventional drainage on continuous corn varied from 12.3 to 87.3 kg/ha. CD reduced the predicted annual N loads in drainage water by 18 to 58% over the 35 year period.
Controlled Drainage Water Quality DRAINMOD Nitrogen Models
R.Wayne Skaggs Mohamed A.Youssef
W.N.Reynolds Dist. Univ. Respectively North Carolina State University,Raleigh,NC27695-7625
国际会议
International Forum on Water Resources and Sustainable Development(2009水资源与可持续发展高层论坛)
武汉
英文
54-70
2009-09-22（万方平台首次上网日期，不代表论文的发表时间）