Narrow Grass Hedge Effects on Nutrient Transport Following Compost Application

Abstract

The placement of stiff-stemmed grass hedges on the contour along a hillslope has been shown to decrease nutrient transport in runoff. This study was conducted to measure the effectiveness of a narrow grass hedge in reducing runoff nutrient transport from plots with a range of soil nutrient values. Composted beef cattle manure was applied at dry weights of 0, 68, 105, 142, and 178 Mg ha-1 to a silty clay loam soil and then incorporated by disking. Soil samples were collected 243 days later for analysis of water-soluble phosphorus (WSP), Bray and Kurtz No. 1 phosphorus (Bray-1 P), NO3-N, and NH4-N. Three 30 min simulated rainfall events, separated by 24 h intervals, were then applied. The transport of dissolved phosphorus (DP), total P (TP), NO3-N, NH4-N, total nitrogen (TN), runoff, and soil erosion were measured from 0.75 m wide 4.0 m long plots. Compost application rate significantly affected soil measurements of WSP, Bray-1 P, and NO3-N content. The transport of DP, TP, NO3-N, NH4-N, TN, runoff, and soil erosion was reduced significantly on the plots with a grass hedge. Mean runoff rates on the hedge and no-hedge treatments were 17 and 29 mm, and erosion rates were 0.12 and 1.46 Mg ha-1, respectively. Compost application rate significantly affected the transport of DP, TP, and NO3-N in runoff. The experimental results indicate that stiff-stemmed grass hedges, planted at selected downslope intervals, can significantly reduce the transport of nutrients in runoff from areas with a range of soil nutrient values.