Monday, November 5, 2007
50-7

Organic Grain Cropping Systems and Soil Physical Properties.

Meaghan Mroz-Barrett1, Laura Harris1, Larry Grabau1, E. M. Pena-Yewtukhiw2, and John Grove1. (1) Plant & Soil Sciences, University of Kentucky, S126 Ag North, Lexington, KY 40546-0091, (2) Divison of Plant and Soil Sciences, 1104 Agricultural Sciences Building, West Virginia University, Morgantown, WV 26506-6108

Organic grain cropping systems (OGCS) generally involve enhanced returns of organic residues to soils (through cover crops, green manures, and forages) as well as increased tillage intensity (to incorporate such plant residues and to assist in weed control). As a result, changes in soil physical properties, both positive and negative, could be observed over time. This report will assess soil organic matter levels, dry aggregate stability, and we aggregate stability of soils after three years of three different OGCS: 1) corn (Zea mays L.) following 18 months of orchard grass (Dactylis glomerata L.)/red clover (Trifolium pratense L.) forage, 2) a two-year, two cover crop rotation involving corn following hairy vetch (Vicia villosa L.) then soybean [Glycine max (L.) Merr.] following winter rye (Secale cereale L.), and 3) corn following a winter wheat [Triticum aestivum L.]/soybean double-crop. Each of the three two-year OGCS includes an iteration of the rotation starting each year. Soil sampling will be done on a transect across both starting years and all three different OGCS. Our report will focus on the response of soil physical properties to three years of each OGCS.