Title: Runoff nutrient transport as affected by land application method, swine growth stage, and runoff rate
Authors: Gilley JE, Bartelt-Hunt SL, Lamb SJ, Li X, Marx DB, Snow DD, Parker DB, Woodbury BL
Journal: T ASABE
Accepted date: 2013 Nov 11
Interpretive summary: This study was conducted to measure the effects of slurry application method, swine growth stage, and flow rate on runoff nutrient transport. Swine slurry was obtained from production units containing grower pigs, finisher pigs, or sows and gilts. The swine slurry was applied using broadcast, disc, or injection methods at a rate required to meet annual nitrogen requirements for corn. Three 30 minute simulated rainfall events, separated by 24 hour intervals, were applied to the experimental plots. Inflow was applied at the top of each plot in four successive increments after the third rainfall simulation run to simulate greater plot lengths. The dissolved phosphorus (DP) load obtained on the broadcast treatment was significantly greater than that measured on the disc and injected treatments. The DP runoff load measured for the sows and gilts treatment was significantly greater than that obtained for the finisher treatment. In contrast, the NH4-N load obtained on the finisher treatment was significantly greater than the load measured on the grower and sow treatments. Runoff rate was found to be an important variable significantly influencing each of the measured water quality parameters. Land application method, swine growth stage, and runoff rate should each be considered when estimating runoff nutrient transport.