The objective of this study was to test through fi eld monitoring any pollutant reduction effects by the presence of silt fences and vegetative ridges. The experimental plots were established with two replications and three treatments. Each plot was designed to be 5 m in width and 22 m in length, with a 3% slope. Flumes with fl oating-type stage gauges were installed at the outlet of each plot to monitor the runoffs. For rainfall monitoring, a tipping-bucket rain gauge was installed within the experimental sites. The cultivated crops were spring daikon and autumn Chinese cabbage. The Multi-variate Analysis of Variance (MANOVA) indicated that the water quality concentrations from the three experimental plots were signifi cantly different at 5% signifi cant level. The monitoring results showed that the average pollution loads reduced by the presence of silt fences compared to the control group were SS 75.33%, TN 40.87%, TP 56.58%, BOD 52.12%, COD 36.07%, and TOC 34.99%; and by the presence of vegetative ridges compared to the control group were SS 65.27%, TN 81.80%, TP 54.26%, BOD 67.09%, COD 46.55%, and TOC 43.30%. An analysis of Spearman's rank correlation coeffi cient showed that BOD-SS and SS-Turbidity were highly related at the silt-fence and vegetated-ridge plots. In all plots, the SS-Turbidity and TP-TN relations were relatively high.
展开▼
