Effect of polyacrylamide and gypsum on surface runoff, sediment yield and nutrient losses from steep slopes

Abstract

► Crop cultivation, being done on highly sloped lands in hilly areas in Indian Himalayan regions, causes considerable sediment and nutrient losses along with runoff. ► This paper is intended to show the extent of losses without any conservation measures, and indicates the effect of soil conditioners like PAM , gypsum and their combination to be applied for reducing these losses. Hilly terrains with steep slopes and poor vegetative cover are prone to soil erosion. Crop productivity from such lands can be increased by adding correct amounts of soil conditioners such as polyacrylamide (PAM) and gypsum (G) to reduce soil erosion and to improve settling of suspended sediment. The field experiments were conducted in hilly areas with 97% land slope to evaluate the effectiveness of PAM and G when applied as single and concurrent doses of 20 and 2500 kg ha −1 , respectively to check surface runoff, sediment yield and major nutrient (N, P, and K) losses under natural rainfall conditions. The results indicate that concurrent application of PAM and G was most effective closely followed by G alone. However, considering the costs of PAM and gypsum and labor involved in their concurrent application on large scale, the application of gypsum alone is recommended in controlling the surface runoff, sediment yield and major nutrient losses from steeply sloped lands in Indian Himalayas.