PROTECTING SURFACE AND GROUND WATERS IN EMERGING FARMING SYSTEMS OF THE NORTH CENTRAL UNITED STATES
Location: Soil and Water Management Research
Title: Soil temperature regulates nitrogen loss from lysimeters following fall and winter manure application
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 27, 2012
Publication Date: July 1, 2012
Citation: Williams, M.R., Feyereisen, G.W., Beegle, D.B., Shannon, R.D. 2012. Soil temperature regulates nitrogen loss from lysimeters following fall and winter manure application. Transactions of the ASABE. 55(3):861-870.
Interpretive Summary: Land application of animal manures is challenging in northern latitudes because cool, wet spring time conditions typically prohibit manure spreading prior to planting. Thus, producers often spread manure during the period starting just after fall harvest and at times continuing throughout the winter. The purpose of this paper is to compare the amount of nitrogen lost through runoff and leaching when dairy manure is applied at soil temperatures characteristic of early fall (60°F), late fall (40°F), and winter (30°F). Manure was applied to soil cores at three different times from October through December (2009) and the cores were subjected to rainfall simulations (November – December, 2009) and natural precipitation events (January – March, 2010). The results showed that the total overall winter losses of inorganic N (ammonium-N + nitrate-N) and total-N did not vary among application dates. However, there were differences in the timing and the pathway (runoff vs. leaching) of the losses. The amount of nitrate-N remaining in the soil at the conclusion of the test was greatest for the winter application treatment. This research will benefit producers and crop consultants in nutrient management planning and practice, extension personnel in conveying recommendations about manure application, and policymakers by elucidating the fate of manurial nitrogen that is fall or winter applied.
Many producers practice fall and winter manure spreading for economic and practical reasons. In order to minimize the risk of nitrogen loss between application and crop uptake in the spring, university extension publications and industry professionals often make recommendations based on soil temperature. The objective of this research, therefore, was to determine how soil temperature affects nitrogen losses in runoff and leachate, and assess overwinter nitrogen losses based on application date and soil temperature. Phosphorus losses are discussed in a separate paper. Dairy manure was surface-applied to a channery silt loam soil contained in lysimeters at soil temperatures of 15.7, 4.8, and -1.1°C, which corresponded to early-fall, late-fall, and winter applications, respectively. Nitrogen losses were determined during a series of rainfall simulations and natural precipitation events from October 2009 through March 2010. The soil temperature at the time of manure application and first rainfall-runoff event significantly influenced nitrogen loss. As the soil temperature decreased, losses of NH4-N, organic N, and total N exponentially increased. Overwinter losses were also significantly impacted by soil temperature. The early-fall treatment had four times higher NO3-N losses compared to the manure applied during the winter. Results of this research show that incorporating quantitative tools, such as soil temperature, into manure management plans could enhance nitrogen retention and help significantly reduce the risk of overwinter nitrogen losses.