Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: August 10, 1997
Publication Date: N/A
A five-year (1993-1997) study was conducted at Iowa State University's Northeast Research Center at Nashua on 40 experimental plots that were instrumented with individual sumps and subsurface drainage metering and monitoring devices for collecting water samples for nitrate-N and pesticide analysis. Treatments were established in 1993 on the forty, 0.4 ha plots consisting of two tillage systems (chisel plow and no-till), two cropping rotations (corn-soybean and continuous corn), seven nitrogen management protocols (late spring nitrogen test or LSNT; preplant application of UAN at 112 and 135 kg N/ha; fall application of swine manure at 112 and 135 kg N/ha; strip cropping system; and, an alfalfa forage cropping system). The four year average nitrate-N concentrations in the tile water from the LSNT plots were 9.8 mg/L for the no-till system and 10.9 mg/L for the chisel plow system. Tile nitrate-N concentrations for no-till and chisel plow for rthe 112 kg N/ha preplant application were 10.8 and 10.5 ng/L, respectively The LSNT resulted in higher corn yields under both tillage systems. Manured plots resulted in tile nitrate-N concentrations of 22.1 and 14.1 mg/L for continuous corn and corn-soybean, respectively. Strip cropping and the forage cropping resulted in the lowest tile nitrate-N concentrations of 6.3 and 8.2 mg/L.