Submitted to: American Society of Agronomy
Publication Type: Abstract Only
Publication Acceptance Date: November 3, 2004
Publication Date: November 3, 2004
Citation: Cavigelli, M.A., Green, V.S., Meisinger, J.J. 2004. Nitrogen balance in organic and conventional cropping systems [abstract]. American Society of Agronomy Annual Meeting Abstracts [CDROM]. No. 4703.
A fundamental goal of sustainable agriculture is to develop productive cropping systems that minimize nutrient losses. We compared nitrogen inputs and outputs (measured and estimated) during a 5-year period for organic and conventional cropping systems at the USDA-ARS Farming Systems Project in Beltsville, MD. Two cropping systems were managed according to National Organic Program standards: a 2-year corn-soybean (C-S) rotation and a 3-year C-S-wheat (W) rotation. Both rely on rye and legume cover crops; 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 (MF) only, MF and PL (CT-PL), or MF and composted PL. 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 greater than 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.