Long term effects of annual additions of animal manure on soil chemical, physical, and biological properties in the Great Plains

Authors: Spiehs, Mindy; Woodbury, Bryan; Tarkalson, David; Wienhold, Brian; Eigenberg, Roger

Submitted to: International Symposium on Air Quality and Waste Management for Agriculture
Publication Type: Proceedings
Publication Acceptance Date: 8/10/2010
Publication Date: 9/13/2010
Citation: Spiehs, M.J., Woodbury, B.L., Tarkalson, D.D., Wienhold, B.J., Eigenberg, R.A. 2010. Long term effects of annual additions of animal manure on soil chemical, physical, and biological properties in the Great Plains. 2010. In: Proceedings of the American Society of Agricultural and Biological Engineers. International Symposium on Air Quality and Manure Management for Agriculture, September 13-16, 2010, Dallas, Texas. 2010 CDROM.

Interpretive Summary: Manure can be a valuable input in crop production systems when used as a fertilizer. Manure application to soil can increase crop productivity and improve soil properties, with some effects lasting for several years after manure application. Cover crops increase organic matter in soil and improve water infiltration into the soil. This study was conducted to determine the effects of long-term annual application of beef manure and wheat and rye cover crops on chemical, physical, and biological properties of a typical Midwest U.S. soil under corn silage production. Treatments included manure application/cover crop, manure application/no cover crop, no manure/cover crop, and no manure/no cover crop. Annual additions of beef manure applied to meet nitrogen needs of corn silage increased carbon, nitrogen, and phosphorus in the upper 15 cm of the soil. This increase in nutrients may promote a more diverse microbial population and sustain crop productivity. However, high concentrations of water soluble phosphorus in the soil indicate increased risk to surface waters that receive runoff from the fields. This risk may be reduced when a winter cover crop is planted. Use of winter cover crops retain nutrients near the soil surface and have been shown to reduce soil erosion.

Technical Abstract: The objective of this study was to determine the effects of long-term annual beef manure amendments and wheat and rye cover crops on selected chemical, physical and biological properties of a typical Midwest U.S. soil under corn silage production. The treatments included: manure application/cover crop, manure application/no cover crop, no manure/cover crop, and no manure/no cover crop each sampled at three depths (0 to 7.5, 7.5 to 15, and 15 to 30 cm). Using beef manure significantly increased the total, organic, and microbial biomass carbon by over 60%, 40%, and 125%, respectively, when compared with commercial fertilizer. Planting a cover crop also significantly increased soil concentrations of total, organic, and biomass carbon; however the level of increase was not as dramatic as the fertilizer treatment. Using beef manure as a fertilizer significantly increased total, organic, and microbial biomass nitrogen and nitrate-nitrogen in the upper 30 cm profile by 78%, 75%, 130% and 130%, respectively. Annual applications of beef manure applied to meet the entire nitrogen needs of a corn silage crop resulted in excessively high Bray-phosphorus concentrations for the surface horizons particularly for the 0-7.5 cm depth. High water soluble P concentrations were measured in the upper 0-15 cm depth of the treatment receiving annual beef manure applications. Use of a cover crop on the beef manure treatments increased the surface concentration of plant nutrients such as Bray-phosphorus and High water soluble P. This indicates the importance of a cover crop for retaining mobile plant nutrients near the surface.