255-3 Low Nitrous Oxide Emissions From Organic Field Beans and Wheat On a Clay Soil.



Tuesday, October 18, 2011: 1:50 PM
Henry Gonzalez Convention Center, Room 213B, Concourse Level

ABSTRACT WITHDRAWN

On the research farm “Logården” in south-west Sweden organic and integrated conventional farming systems has continued since 1991. The soil is characterized by an average clay content of 40 % and the crop rotations a 7 years sequence; where faba bean and spring wheat occurred one year each in both managements. Neither organic nor integrated beans received any nitrogen addition, but a difference was that the integrated fields had an under-sown catch crop while the organic fields were weeded by hoe where a catch-crop was not possible. At both fields of wheat, a green manure crop was under-sown while only the conventional field received 110-120 kg N-fertilizer. N2O emission rate was measured by manual chambers and gas samples were collected every second week and more frequent during freeze/thaw events and at occasions of management.

We present N2O flux data from the measurements in faba beans and spring wheat during April 2005 to Mars 2006 and April 2006 to Mars 2007. Lowest average of N2O emission was found in the organic wheat (0.2 kg N ha-1) while the integrated beans had the highest emission (2.3 kg N ha-1). The organic beans had statistically lower emission compared to the integrated. But for wheat this was found only in one year. Yield-scaled N2O emission (emitted N2O-N per harvested N) was found the lowest for both wheat production forms and the organically produced faba beans, ca 10 g N2O-N kg-1 N in harvest, but two times higher for the integrated beans.

See more from this Division: S04 Soil Fertility & Plant Nutrition
See more from this Session: Nutrient Losses