Location: Agroecosystem Management ResearchTitle: Wheat strip effects on nutrient loads following variable manure application Author
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2012
Publication Date: 5/21/2012
Publication URL: http://handle.nal.usda.gov/10113/54310
Citation: Thayer, C.A., Gilley, J.E., Durso, L.M., Marx, D.B. 2012. Wheat strip effects on nutrient loads following variable manure application. Transactions of the ASABE. 55(2):439-449. Interpretive Summary: Narrow grass hedges have been shown to significantly reduce nutrient loads in runoff. The effectiveness of narrow wheat strips in reducing nutrient loads was examined in this investigation. Manure from a beef cattle feedlot was applied to plots at rates required to meet 0-, 1-, 2-, or 4- year phosphorus based requirements for corn. A narrow wheat strip was located at the bottom of some of plots while other plots did not contain a wheat strip. Three 30-min simulated rainfall events, separated by 24-hour intervals, were applied to the field plots using widely adopted data collection procedures. The narrow wheat strips significantly reduced runoff loads of nitrogen but phosphorus loads were not significantly affected by the wheat strips. However, wheat strips were found to be much less effective in reducing nutrient loads in runoff than narrow grass hedges.
Technical Abstract: Narrow grass hedges have been shown to significantly reduce nutrient loads in runoff. The effectiveness of narrow wheat strips in reducing nutrient loads was examined in this investigation. The objectives of this study were to: (1) determine the effects of a narrow wheat strip, varying manure application rates, and different overland flow rates on runoff nutrient loads following manure application, and (2) evaluate the effectiveness of a narrow wheat strip in reducing runoff nutrient loads following excessive manure application. Three 30-min simulated rainfall events, separated by 24-hour intervals, were applied at an intensity of 70 mm hr-1 to 0.75 m wide by 4.0 m long plots on which manure was applied. Tests were also conducted on plots that had received excessive amounts of manure to examine the capacity of narrow wheat strips to reduce runoff nutrient loads. A 1.4 m wide strip of winter wheat was located at the bottom of selected plots. The wheat strip significantly reduced runoff loads of NO3-N, NH4-N, and total nitrogen (TN). Runoff loads of dissolved phosphorus (DP), particulate phosphorus (PP), total phosphorus (TP), NH4-N, and TN were significantly influenced by manure application rate. Runoff rate significantly affected each of the measured water quality parameters. For the plot on which excessive amounts of manure were applied, runoff loads of DP PP, TP, and NH4-N increased in a linear fashion with manure application rate. The wheat strip significantly reduced N loads in runoff but reductions were much less than those previously reported for narrow grass hedges.