Summary of the management, inherent and dynamic soil properties at Marsden and the Farming Systems Project.

<p>Variables include texture, pH and soil organic carbon(SOC), soil carbon to nitrogen ratio (C:N), particulate organic matter-carbon (POM-C) and POM-C:N ratio, occluded-POM carbon (OPOM-C), and POM-C:N ratio. Data in table are means ± standard deviation.</p>†<p>C-corn, S-soybean, rc-red clover, A-alfalfa, r-rye cover crop, W-wheat, hv-hairy vetch, W/S-wheat followed by double-cropped soybean. Conv in Maryland followed a 2 yr C-W/S rotation from 1996–1999, Long in Maryland followed a 4 yr C-r/S-W/(r+ orchard grass hay) rotation from 1996–1999.</p>‡<p>Ch-chisel plow, MB-moldboard plow, D-disk.</p>∮<p>N-urea ammonium nitrate, GM-green manure, AM-animal manures, P-triple super phosphate, K-potassium sulfate. For Iowa site, N fertilization rate was 100 kg N ha−1 with side dressing (0–100 kg N ha−1) as needed based on standard soil tests; green manure was red clover (15.7 Mg ha−1, fresh weight basis) for Med system and was second-year alfalfa for Long system; composted beef cattle manure (on average 128 kg N ha−1) was supplied to both Med and Long systems. For Maryland site, the Conv system received on average 160 kg N ha−1 each year; Med and Long systems received green manure (hairy vetch for Med system, and alfalfa for Long system) and cattle manure (on average 150 kg N ha−1) as N sources.</p><p>Values not followed by the same upper case letter differ between two sites (Iowa, Maryland), values not followed by the same lower case letter differ among cropping systems (Conv, Med, Long) within each site. Statistical significances were performed at p<0.05.</p>