Effect of Surface Cover Materials and Soil Amendments on Sediment Discharge from Upland Fields

Abstract

The effect of surface cover with rice straw mats, polyacrylamide (PAM) and gypsum on runoff and sediment discharge was investigated in a laboratory under rainfall simulation (Figure 1). Four treatments of control, straw mat covers, straw mats with a PAM cover, and straw mats with a PAM and gypsum cover were applied to small soil box plots. Rainfall simulations of 30 and 60 mm/h on 10% and 20% sloped boxes were made for 60 minutes. The runoff coefficient from the mat-covered plots decreased significantly, regardless of rainfall intensity or the slope gradient. The effect of the mat covers on the reduction of sediment discharge was greater than on runoff reduction. Under 60 mm/h rainfall intensity and 20% slope, which was the worst case, the covered plots with the mats and the soil amendments could reduce 98.8% of the sediment. It was concluded that the function of the mat was significantly improved by adding PAM and gypsum. The combined use of the mats, PAM, and gypsum could be an effective best management practice, and a series of field experiments was recommended to verify the effect of the combined use of the mats, PAM and gypsum on runoff and sediment reduction.