Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/31/2019
Publication Date: 8/29/2019
Citation: Young, E.O., Sherman, J.F., Wilson, M., Vadas, P.A., Motew, M.M. 2019. Nutrient loss in snowmelt runoff following dairy manure application on snowpack. Meeting Abstract. ASA-CSSA-SSSA Annual Meeting. Nov. 10-13, 2019. San Antonio, Texas.
Technical Abstract: Manure is an important nutrient source in dairy production systems. In northern climates, much of the annual runoff occurs from spring snowmelt. The objective of our study was to determine the effect of dairy manure solids content on total solids (TS), total nitrogen (TN), ammonium-N, nitrate-N, total phosphorus (TP), and dissolved reactive P (DRP) export in snowmelt runoff following application on top of an existing snowpack. Field studies were conducted in spring 2019 at the University of Minnesota and University of Wisconsin’s Marshfield Agricultural Research Station. Steel frame plots designed to collect snowmelt runoff were installed in a grain corn field in fall 2018 in a randomized block design. After several large snowstorms in February and March 2019, fresh dairy manure was collected (15.4% total solids) and diluted to 5.5 and 8.0 % solids content and hand-applied at a rate of 26, 667 L ha-1. Results showed that variation in runoff volume appeared to be related to snowpack characteristics rather than manure treatments. While nutrient export patterns varied by event, greater manure solids content was associated with greater cumulative TN and TP export. Compared to controls, the highest manure solids content increased cumulative TN and TP export by 4.5- and 6.2-fold, respectively. Cumulative DRP and particulate/unreactive P (TP-DRP) export increased linearly with manure solids content. The relationship between ammonium- and nitrate-N export and manure solids was less clear. Results show the importance of manure management on potential runoff nutrient losses and suggest that high losses of both N and P are possible when manure is applied on top of a snowpack.