Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: February 27, 2004
Publication Date: March 27, 2004
Citation: Green, V.S., Cavigelli, M.A., Meisinger, J.J. 2004. Nitrogen balance in organic and conventional cropping systems in the mid-Atlantic region [abstract]. Mid-Atlantic Ecology Conference. Paper No. 82.
One of the goals of sustainable agriculture is to maximize nutrient retention and minimize off-farm environmental costs. As part of an assessment of system sustainability, we compared nitrogen inputs and outputs during a 5-year period for six cropping systems at the USDA-ARS Farming Systems Project in Beltsville, MD. The systems, which included corn (C), soybean (S) and wheat (W) crops, were designed to mimic systems used by area farmers and/or to reduce inputs. Two cropping systems were managed according to National Organic Program standards: one was a 2-year C-S rotation; the other was a 3-year C-S-W rotation. Both rely on rye and legume cover crops and the 3-year rotation also includes poultry litter (PL) inputs. The other four systems were 2-year C-W-S rotations managed using conventional fertilizers and herbicides. One system is managed using no-till (NT) methods; the other three use conventional tillage methods and mineral fertilizers only (CT-MF), MF and PL (CT-PL), or MF and composted PL (CT-CPL). Nitrogen inputs were greater than N outputs for the C phase of all rotations and for the S phase of the 3-year rotation. Nitrogen inputs were less than N outputs during the W-S phase of the 2-year rotations. After 5 years, the CT-PL and the 3-year organic systems retained N (N inputs > N outputs), the no-till system had a net loss of N, and the other three systems showed no significant net N losses or gains. These results suggest that systems that include PL may retain more N than similar systems that do not use PL.