Hydromulch and Polyacrylamide Effects on Runoff Control, Sediment Yield and N, P, K Losses in Laboratory Conditions

Soil erosion not only is threatening human being welfare, but also is intimidating his life. Considering its importance, several approaches have been made to control the soil erosion. The present research investgates the effects of slope, rainfall intensity and kind of soil cover on the run off and sediment yield generated by the erosion.Totally 24 experiment runs were carried out by employing a field rainfall simulator on a susceptible soil to erosion collected from Bonab region, north west of Iran. For each experiment, approximately 110 kg of the soil sample was passed through 4.76 mm sieve and was leveled down nearly flat on the flum of the simulator tray with 0.1 × 1 × 1 m dimensions. The experimental treatments were: two slopes %5 and %25, two rainfall intensities of 40 and 80 mm/hr and two types of soil cover/amendment including a hydromulch, polyacrylamide and the uncovered soil. The whole experiment layout was factorial design based on randomized complete blocks. In each experiment during the generated 30-min period of rainfall, the increments of runoff volume, sediment load and losses of N, P, K contents associated with both runoff and sediments were measured. Hydromulch and PAM both effectively reduced the runoff and erosion. Hydromulch practically eliminated the sediment yield and reduced the runoff volume by 45% comparing to the control. PAM application at the rate of 25 kg/ha was less effective in controlling runoff and erosion comparing to hydromulch but significantly reduced the sediment yield (30 to 62%) and the runoff (5-8%) as compared to the control. Regarding N, P, K losses, hydromulch and PAM reduced their losses significantly mainly through supressing the sediment yield and runoff volume.