Eric Moore1, Thomas Kaspar2, Mary Wiedenhoeft1 and Cynthia Cambardella3, (1)Iowa State University, Ames, IA (2)USDA-ARS National Laboratory for Agriculture and the Environment, Ames, IA (3)USDA-ARS-National Laboratory for Agriculture and the Environment (NLAE), Ames, IA
Farmers in the U.S. Corn Belt are showing increasing interest in winter cover crops. Known benefits of winter cover crops include reductions in nutrient leaching, erosion mitigation, and weed suppression, however little research has investigated the effects of winter cover crops on soil properties. Evidence of improvements in soil quality indicators would provide further incentive for farmers to implement winter cover crops. This experiment investigated the effects of a rye (Secale cereale L.) winter cover crop on several soil quality indicators including particulate organic matter, potential nitrogen mineralization, and total soil organic matter. The objectives of this experiment were to determine whether a rye winter cover crop improves soil quality, if rye effects on soil quality vary depending on which crop it follows in the corn silage/soybean rotation sequence, and if the effects of a rye winter cover crop differ depending on soil depth. Soil properties were measured on four treatments and at two depths, 0-5cm and 5-10cm. Treatments included no rye winter cover crop (control), rye following soybean [Glycine max (L.) Merr.], rye following corn silage (Zea mays L.), and rye following both soybean and corn silage. All three of the soil quality indicators measured in this experiment responded positively to a rye cover crop. The effects of the rye cover crop were most pronounced in the top 5 cm of soil and for treatments with rye following corn silage. Only total soil organic matter was significantly increased by a rye cover crop following corn silage in the 5-10 cm depth layer.