Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 10/25/2001
Publication Date: 10/25/2001
Citation: Delate, K., Cambardella, C.A. 2001. Long-term agroecological research (LTAR) in Iowa: certified organic comparisons [abstracts]. American Society of Agronomy Meetings. c03delate134846-P.pdf.
Technical Abstract: Organic farming has increased to a $8 billion industry in the U.S. and is expanding approximately 20% annually. In Iowa alone, organic acreage for all crops has increased from 13,000 in 1995 to 150,000 in 1999. The Leopold Center for Sustainable Agriculture supported the establishment of the Neely-Kinyon Long-Term Agroecological Research (LTAR) site in 1998 to document changes in the agroecology (soil dynamics, plant performance, pest status) and economic services in conventional and organic systems over time. In the two years of transition and the first year of certified organic production, there was no significant difference between organic and conventional soybean yields, with greater economic return in the organic system. Organic feed corn yields were greater in systems where a full season of alfalfa was included in the rotation; overall organic corn yields were similar to conventional yields in the third year of transition. Early improvements in soil quality during transition to organic production continued in the first year of certification. Increases in total carbon, particulate organic matter carbon, aggregate stability and potentially mineralizable nitrogen increased from 1998 to 2000. Corn stalk nitrate content was greater in the conventional system, compared with organic corn fertilized with composted manure and through crop rotational effects (alfalfa).