Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 4, 2003
Publication Date: November 5, 2003
Citation: Green, V.S., Cavigelli, M.A., Dao, T.H., Flanagan, D.C. 2003. Cropping system effect on distribution of C, N, and P among aggregate size classes [abstract]. American Society of Agronomy Annual Meeting Abstracts [CDROM]. A08-green642204-Poster. Technical Abstract: Agricultural management systems that reduce the adverse effects of nutrient laden runoff and sediments are needed. Organic farming systems are growing in popularity in many areas of the United States as a sustainable farming alternative to conventional farming practices. However, it is not known how organic farming systems affect runoff and sediment delivery and their associated nutrient concentrations compared to synthetic conventional and no-till systems. Our objective was to determine the distribution of C, N, and P in different aggregate size classes from synthetic conventional and no-till and organic farming systems. Soil is selectively eroded from agricultural lands with the smaller particles and aggregates eroding preferentially. Our data show that no-till management has a greater proportion of stable macro-aggregates than both conventional and organic management practices (61, 41, and 41% respectively). Thus a greater proportion of smaller particles and aggregates will likely be eroded from conventional and organic systems. However, the concentration of nutrients in each of the aggregate size classes will determine the nutrient load exiting the field due to erosion. We will present the results of the distribution of C, N, and P in various aggregate size classes and discuss differences among the different farming systems and potential impacts.