Effectiveness of Established Tree and Pasture Buffer Strips in Reducing Lateral Groundwater Movement and Nutrients from an Effluent Disposal Area Associated with a Beef Cattle Feedlot

Abstract

Vegetated buffer strips (VBSs) have been promoted as a method to control nonpoint sources pollution. Trees and pastures are the most common components in VBSs. The aim of this project was to determine the effectiveness of trees and improved pasture in reducing lateral groundwater movement and nutrients from an effluent irrigated disposal area associated with a beef cattle feedlot. This question is significant in the experimental site because lateral groundwater movement occurs along the A-B interface as the soil is strongly duplex with a sand loam A horizon and a heavy clay B horizon. Consequently, the soil has a significant difference in hydraulic conductivity between the A and B horizons leading to lateral movement of water above the B horizon. A field experiment was established to determine the effectiveness of tree and pasture buffer strips in reducing lateral groundwater flow and associated nutrients. The field experiment was a randomized block design with two tree species ('Eucalyptus camaldulensis' and 'Casuarina cunninghamiana'), two planting densities and three replications. Improved pasture was established as controls. A glasshouse simulation experiment was also conducted to compliment to the field experiment in measuring the ability of the trees and pasture in reducing lateral nutrient movement.