Rye cover crop effects on soil quality in no-till corn silage-soybean cropping systems

Authors: MOORE, ERIC - Iowa State University; Kaspar, Thomas; WIEDENHOEFT, MARY - Iowa State University; Cambardella, Cynthia

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2014
Publication Date: 6/10/2014
Publication URL: http://handle.nal.usda.gov/10113/6472272
Citation: Moore, E.B., Kaspar, T.C., Wiedenhoeft, M.H., Cambardella, C.A. 2014. Rye cover crop effects on soil quality in no-till corn silage-soybean cropping systems. Soil Science Society of America Journal. 78(3):968-976. DOI: 10.2136/sssaj2013.09.0401.

Interpretive Summary: Corn and soybean farmers in the upper Midwest are showing increasing interest in winter cover crops. Known benefits of winter cover crops include reductions in nutrient leaching, erosion prevention, and weed suppression; however, the effects of winter cover crops on soil quality in this region have not been investigated extensively because of the multiple years required for changes in soil properties to occur and because climate and the long corn and soybean cropping seasons limit the amount of time that cover crops can grow. Evidence of improvements in soil quality could provide further incentive for farmers to implement winter cover crops. This research found that total soil organic matter was 15% greater when a rye cover crop was grown every year in a corn silage-soybean rotation for nine years. This increase in soil organic matter should increase soil water holding capacity and may impact yields over the long term. Additionally, the incease in particulate organic matter and potential nitrogen mineralization indicate that the rye cover crop increased the soils potential to supply nitrogen and under ideal conditions this could result in an additional nine pounds of nitrogen per acre per year available to crop plants. This research will benefit scientists, soil conservationists, and farmers because it shows that cover crops can improve soil quality and this should eventually result in improved main crop yields. The impact of this research will be to increase adoption of cover crops, which will improve the sustainability of cropping systems.

Technical Abstract: Corn and soybean farmers in the upper Midwest are showing increasing interest in winter cover crops. Known benefits of winter cover crops include reductions in nutrient leaching, erosion prevention, and weed suppression; however, the effects of winter cover crops on soil quality in this region have not been investigated extensively because of the multiple years required for changes in soil properties to occur. Evidence of improvements in soil quality could provide further incentive for farmers to implement winter cover crops. The objective of this experiment was to determine the effects of a rye (Secale cereale L.) winter cover crop after nine years in a corn silage (Zea mays L.)-soybean [Glycine max (L.) Merr.] cropping system. Several soil quality indicators were measured in this experiment, including particulate organic matter, potential nitrogen mineralization, and total soil organic matter. Soil quality indicators were measured on four treatments: no rye cover crop, rye following soybean, rye following corn silage, and rye following both soybean and corn silage; and at two soil depths: 0-5cm and 5-10cm. Each soil quality indicator responded positively when rye followed both main crops as compared to the treatment with no rye cover crop. Particulate organic matter was increased by 44%, potential nitrogen mineralization rose by 38%, and total soil organic matter was 15% greater. Rye cover crop effects were most pronounced in the top 5cm of soil and when rye followed corn silage or both main crops. Data from this experiment suggests that the incorporation of a winter rye cover crop is a viable means for enhancing soil quality in corn silage-soybean cropping systems.