Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/15/2003
Publication Date: 11/4/2003
Citation: Liebig, M.A., Carpenter-Boggs, L., Johnson, J.M., Wright, S.E., Barbour, N.W. 2003. Cropping system effects on soil biological characteristics in the great plains. No. S06 wright569424. IN Annual Meeting Abstracts CD-ROM, November 2-6, Denver, CO. ASA-CSSA-SSSA, Madison, WI.
Technical Abstract: Recent interest in soil quality has increased emphasis on understanding soil biological contributions to soil function. The objective of this study was to determine the effects of management and time on soil biological parameters in contrasting cropping systems in the Great Plains. The cropping systems, which were part of eight long-term experiments, differed in management intensity with respect to type or frequency of tillage, cropping intensity, and/or crop rotation diversity. Soil biological parameters were assessed at depths of 0-2.5, 0-7.5, 7.5-15, and 15-30 cm from 1999-2002 up to three times per year. Alternative systems (ALT) -characterized by continuous cropping, diverse crop sequences, and/or reduced tillage - possessed greater microbial biomass (MB) and potentially mineralizable N (PMN) than conventional systems (CONV). Alternative systems at four locations had greater water stable aggregates (WSA) than CONV systems at 0-2.5 cm. Total glomalin (TG), however, differed only at one location (Mandan), where the ALT system had 27% more TG than the CONV system. Changes in MB, PMN, WSA, and TG fluctuated with the presence/absence of fallow or legume in rotation. Location, depth, and temporal effects had a greater effect on fatty acid methyl ester profiles than cropping systems. In general, the status biological indicators reflected enhanced soil quality under ALT systems.