Winter Annual Cover Crop Impacts on No-Till Soil Physical Properties and Organic Matter

The inclusion of winter annual cereal cover crops (WCC) in grain crop rotations is a common management practice promoted to protect soil resources and enhance water quality. However, the effects of long-term incorporation of WCC into no-till grain crop rotations on soil physical properties are not well established. We evaluated the long-term effects of WCC on soil physical properties after 13 yr of use at three locations in Maryland, USA. Continuous maize (Zea mays L) was the summer grain crop. In the control treatment, maize was followed by winter fallow and in the WCC treatment, cereal rye (Secale cereal L) was planted as a WCC in the off-season. We examined aggregate stability, total and labile organic matter, soil bulk density (BD), air permeability (AP), water infiltration rate (WIR), and hydraulic conductivity (HC), during the growing and off-season. Aggregate stability increased under the WCC treatment but there were no increases in total organic matter and labile organic matter. Only during the winter sampling season at the two Coastal Plain locations, soils under WCC displayed improved soil physical properties in comparison with the same soils under winter fallow. The heavier-textured soils at the Piedmont location exhibited no consistent differences attributable to WCC.