ARS | Publication request: Soil Organic Matter in Agricultural Systems

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 15, 2008
Publication Date: January 13, 2009
Citation: Mikha, M.M. 2009. Soil Organic Matter in Agricultural Systems. Meeting Abstract. Presented at the 2009 Farmers Agriculture, Conservation and Technology Conference. Liberal, KS. Jan. 13, 2009.

Technical Abstract: In agricultural systems, soil organic matter (SOM) has been recognized as an important source of nutrients and maintains favorable soil structure. Organic matter is considered a major binding agent that stabilizes soil aggregates. Soil aggregates especially, water stable aggregates, are important in reducing soil erosion and improving soil structure. Soil organic matter was evaluated (i) in five long-term study sites across the state of Kansas and (ii) in long-term cropping systems at seven locations in the Great Plains Region (USA and Canada, as part of regional project). At the Kansas sites, we investigated the changes in soil organic C (SOC) as affected by tillage practices, N sources, N rate, and crop rotation. At the USA and Canada sites, we investigated the effect of alternative cropping systems on SOC and particulate organic matter (POM) in relation to the traditional cropping systems. The results from the Kansas sites indicated that the mass of SOC (0-2 inches depth) declined as tillage intensified. Soil organic carbon accumulation was also impacted by crop rotation, nitrogen source (commercial fertilizer and organic amendment), and nitrogen rate. The results from the regional project indicated that no-tillage (NT) and/or elimination of fallow treatment with alternative cropping systems improved OC (0-3 inches depth) in 5 out of 7 study sites. The same pattern was almost observed with POM (0-3 inches depth), where it was greater at 4 out of 7 study sites. In conclusion, improvement in SOM was observed with NT, manure addition, and reducing fallow frequency indicating the advantage of NT and alternative cropping systems in Great Plains region