Biological Systems Engineering
Date of this Version
5-2011
Citation
Transactions of the ASABE 54(3): 847-855
Abstract
The effectiveness of a narrow grass hedge in reducing runoff nutrient loads following manure application was examined in this study. Beef cattle manure was applied to 0.75 m wide by 4.0 m long plots established on an Aksarben silty clay loam located in southeast Nebraska. Manure was added at rates required to meet none or the 1, 2, or 4 year nitrogen requirements for corn. Runoff water quality was measured during three 30 min simulated rainfall events. Manure application rate significantly affected dissolved phosphorus (DP) and total phosphorus (TP) loads in runoff on the plots without a grass hedge. However, DP and TP loads were not significantly affected by manure application rate on the plots containing a hedge. The hedge reduced the mean load of DP in runoff from 0.69 to 0.08 kg ha‐1 and the load of TP from 1.05 to 0.13 kg ha‐1. When averaged across manure application rates, 0.11 kg NO3‐N ha‐1, 0.02 kg NH4‐N ha‐1, and 0.49 kg total nitrogen (TN) ha‐1 were measured from the plots with a hedge, compared to 0.39 kg NO3‐N ha‐1, 0.55 kg NH4‐N ha‐1, and 2.52 kg TN ha‐1 from the plots without a hedge. For the plots with a grass hedge, runoff loads of DP and TP where manure was applied were similar to values obtained with no manure application. Each of the runoff water quality parameters was significantly affected by runoff rate. A narrow grass hedge placed on the contour across a hillslope significantly reduced runoff nutrient loads following variable manure applications.