|Delate, K - IOWA STATE UNIVERSITY|
|Brummer, E - IOWA STATE UNIVERSITY|
Submitted to: ASA-CSSA-SSSA Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 14, 2002
Publication Date: November 14, 2002
Citation: DELATE, K., CAMBARDELLA, C.A., BRUMMER, E.C. LONG-TERM AGROECOLOGICAL RESEARCH (LTAR) IN IOWA: CERTIFIED ORGANIC COMPARISONS. ASA-CSSA-SSSA PROCEEDINGS. 2002. CD-ROM. MADISON, WI. Technical Abstract: In the fourth year of our examination of the agronomic and economic performance of conventional and organic systems, using certified organic production practices at the Neely-Kinyon Long-Term Agroecological Research (LTAR) site in Iowa, organic corn yields (8.1 Mg ha-1) were significantly greater than conventional (7.1 Mg ha-1). Organic soybeans following two years of alfalfa and one year of corn had significantly greater yields (3.2 Mg ha-1) versus 2.7 Mg ha-1 for conventional soybean in a C-S rotation. Oat yields averaged 3.0 Mg ha-1 while organic alfalfa yields equaled 7.6 MT ha-1. Insect pest load did not vary between systems while weed populations were equal in organic and conventional soybean systems, but greater in organic corn systems. Corn stalk nitrate concentrations at 5543 ppm in the conventional system were 55% greater than organic corn stalk concentrations. Returns for corn and soybean within the organic corn-soybean-oat and corn-soybean-oat-alfalfa rotations were significantly greater than conventional corn-soybean rotation returns.