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 phosphorus loss from lysimeters following fall and winter-applied manure application
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 2, 2012
Publication Date: July 1, 2012
Citation: Williams, M.R., Feyereisen, G.W., Beegle, D.B., Shannon, R.D. 2012. Soil temperature regulates phosphorus loss from lysimeters following fall and winter-applied manure application. Transactions of the ASABE. 55(3):871-880.
Interpretive Summary: Land application of animal manures is challenging in northern latitudes because cool, wet spring time conditions typically inhibit 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 phosphorus (P) 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 (channery silt loam) 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 P losses were significantly influenced by the soil temperature and freeze/thaw condition at the time of manure application and first rainfall-runoff event. As the soil temperature decreased, losses of dissolved reactive P (DRP or ortho P), total dissolved P (TDP), and total P increased. Over winter losses were also impacted by soil temperature and freeze/thaw condition, with the winter treatment having twice the total P loss compared to the early fall 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 P that is fall or winter applied.
Applying manure in the fall and winter increases the potential that some portion of the nutrients will be lost prior to crop uptake in the spring. In order to minimize the risk of nutrient loss, recommendations are often based on soil temperature, since biological activity has been shown to decrease substantially at temperatures less than 10°C. These recommendations are often targeted toward reducing nitrogen losses; thus, little information is available on the fate of phosphorus from fall- and winter-applied manure. The objective of this research was to determine how soil temperature affects phosphorus loss in runoff and leachate, and assess overwinter phosphorus losses based on application date and soil temperature. Nitrogen 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 represented early-fall, late-fall, and winter applications, respectively. Phosphorus losses were determined during a series of rainfall simulations and natural precipitation events from October 2009 through March 2010. Phosphorus losses were significantly influenced by the soil temperature at the time of manure application and first rainfall-runoff event. As the soil temperature decreased, losses of DRP, TDP, and total P increased. Overwinter losses were also significantly impacted by soil temperature. The winter treatment had two times higher total P losses compared to the manure applied during the early-fall. Results of this research show that soil temperature is not only important for determining nitrogen losses, but also phosphorus, and that incorporating quantitative tools, such as soil temperature, into manure management plans could enhance phosphorus retention and help reduce the risk of overwinter phosphorus losses.