See more from this Session: Symposium--Organic Grain Production: Current Status and Future Opportunities/Division A12 Business Meeting
Wednesday, November 3, 2010: 8:55 AM
Long Beach Convention Center, Room 203B, Second Floor
Organic grain production continues to increase, with the majority of the 350,258 organic corn and soybean acres in the U.S. found in the Midwest. In Iowa, the Neely-Kinyon LTAR site was established in 1998 to study the long-term effects of organic production in Iowa. Treatments at the LTAR site, replicated four times in a completely randomized design, include the following rotations: conventional Corn-Soybean (C-S), organic Corn-Soybean-Oats/Alfalfa (C-S-O/A), organic Corn-Soybean-Oats/Alfalfa-Alfalfa (C-S-O/A-A), and Soybean-Wheat with a frost-seeding of Red Clover (S-W/RC). As an example, ‘Arapahoe’ winter wheat was planted on November 19, 2008, at 85 lbs/acre and ‘Cardinal’ red clover was frost-seeded into the wheat plots on March 12, 2009, at a rate of 15.5 lb/acre. On April 16, 2009, ‘Spur’ oats were underseeded with ‘B.R. Blue Jay’ alfalfa at a rate of 90 lbs/acre and 16 lb/acre, respectively. Following harvest of the organic corn plots in 2008, winter rye was no-till drilled at a rate of 75 lb/acre on November 10, 2008. Hoop-house swine compost was applied to organic corn plots at a rate of 12 tons/acre on April 20 and 4 tons/acre to oat plots on April 15. Conventional corn plots were injected with 28% UAN on May 21, providing 145 lbs/acre of nitrogen. Blue River 66H54 corn was planted at a depth of 1.75 in. as untreated seed at a rate of 32,000 seeds/acre in the organic plots and as treated seed in conventional plots, on May 20, 2009. Blue River 34A7 soybeans were planted at a depth of 2 in. in organic and conventional plots at a rate of 200,000 seeds/acre on May 21, 2009. Conventional corn plots were fertilized on April 21, 2009, with 28% nitrogen at 145 lbs N/acre. Conventional corn was also sprayed with a pre-emergence herbicide on May 28. Conventional soybeans received a pre-emergence herbicide application on May 14. All organic soybean plots were rotary hoed on May 24 before emergence, and on June 11, soybeans in the organic C-S-O/A-A rotation were also rotary hoed on May 29. All organic soybean plots were cultivated on June 17, June 23, June 30, and July 13. Organic soybean plots were “walked” on July 16 and July 29. Despite high levels of weeds and challenging weather, organic corn yields averaged 196 bu/acre in 2009. The C-S-O/A-A rotation once again produced greater yields (198 bu/acre) than the three–year organic rotation (194 bu/acre), and was equivalent to the conventional C-S rotation. Organic soybean yields averaged 60 bushels/acre, with the S-W/RC plots yielding lower at 48 bu/acre than the three– and four–year rotations (65 bu/acre). The conventional C-S soybean yields at 58 bu/acre were less than soybean yields in the organic C-S-O/A and C-S-O/A-A plots, but equivalent to the organic S-W/RC plots. Small grain yields were impacted by extended periods of wet weather in 2009; oats yielded 73 bu/acre of grain and 1.14 tons/acre of oat straw, with no significant yield differences between oat rotations. Alfalfa yielded an average of 3.9 tons/acre.