Epsilon Open Archive

Abstract

Abstract: This field study sought to determine the all-weather surface construction providing the least contaminated runoff and drainage effluent when exposed to moderate to heavy precipitation and different manure loads in horse paddocks during wintertime. Two different combinations of non-woven and woven geotextile together with two gravel fractions of 200 mm were exposed to precipitation and horse manure/urine for two years under two manure regimes (manure removal and manure accumulation). In a simulated rainfall (SR) study, the test areas were also exposed to 50 mm precipitation for 30 min and 15 kg of horse manure under the two manure regimes. Runoff, drainage effluent and leachate flow were measured and sampled for both regimes. The geotextile-gravel construction reduced runoff and drained the test area throughout the two-year period, confirming construction stability and a dry walking surface area at a mean drain flow of 3.65 L m-2 h-1. The concentrations of total N, total phosphorus (TP), chemical oxygen demand (COD) and total solids (TS) in fluids leaving the test areas in winter were lower than in previous studies, due to lower horse density. The mean drainage concentration of TP, COD and TS was 3.4, 231, 739 mg L-1, respectively, due to manure removal in the SR study. The TP (1.9 mg L-1) concentration in drain fluids was reduced by 47% in the test area consisting of a single geotextile compared with previously reported values (3.6 mg L-1). With the paddock designs tested here, non-point pollution from paddocks could be controlled and reduced.