Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 9, 2005
Publication Date: September 27, 2005
Citation: Alberts, E.E., Kitchen, N.R., Lerch, R.N., Sadler, E.J. 2005. Dissolved nitrogen and phosphorus losses in surface runoff from the corn phase of three cropping rotations [abstract] [CDROM]. ASA-CSSA-SSSA Annual Meeting Abstracts. Technical Abstract: Nonpoint source pollution associated with runoff from agricultural fields continues to be a problem in many areas of the Midwest U.S. due to excessive fertilizer application, runoff prone soils, and climatic conditions that produce large thunderstorms during and after spring planting and fertilizer application. The primary objective of our research was to evaluate the influence of three cropping rotations and tillage systems on dissolved nitrogen and phosphorus concentrations and losses in surface runoff. The study was initiated in 1996 on 0.34-ha plots located in north-central Missouri. Soils are Vertic Epiaqualfs and are poorly drained because of a naturally occurring claypan soil horizon located 150 to 450 mm below the soil surface. The cropping systems evaluated included a conservation tillage corn-soybean rotation (CS1), a no-till corn-soybean rotation (CS2), and a no-till corn-soybean-wheat rotation (CS5). Only plots associated with the corn phase of each rotation were instrumented to measure surface runoff and collect samples for water quality analysis. Measurements were obtained from fertilizer application to grain harvest for six years (1997-2002). Mean growing season runoff losses for five years with common runoff events were 61, 70, and 72 mm for CS1, CS2, and CS5, respectively. Mean growing season NO3-N and PO4–P concentrations exceeded 10 and 0.2 mg/L for all cropping systems. The knife banding of P fertilizer 150 mm to the side of the corn row and 150 mm deep in CS5 did not reduce PO4–P concentrations as much as expected because runoff tended to concentrate in the knife slits. No-till did not decrease surface runoff relative to conservation tillage. Concentrations of dissolved nutrients generally exceeded water quality standards associated with drinking water and eutrophication.