Cropping and Nitrogen Management Effects on Nitrate Nitrogen Leaching

摘要

Agricultural drainage wells (ADWs) are used in limited row-crop areas of Iowa as outlets for subsurface drainage systems.ADWs are potential routes of contaminant movement to underground aquifers. A study of the effects of cropping andnitrogen management on the quality of subsurface drainage from fertilized areas was performed on replicated plots todetermine the magnitude of nitrate-nitrogen transport to ADWs via subsurface drainage. Results indicate that as the nitrogenfertilizer rate used on corn is increased, concentrations increase. At economically optimum conventionally applied nitrogenrates, the nitrate-nitrogen concentration in leaching water from drainage lines exceeded the drinking water standard by 20 to40 percent The localized compaction and doming applicator had lower concentrations. Results for two cropping systems,three liquid fertilizer applicators, manure, and use of the late-spring soil nitrate test will also be discussed.