Effects of different application methods of polyacrylamide (PAM) on soil infiltration and erosion

Surface application of polyacrylamide (PAM) can increase infiltration and reduce soil erosion. In order to research the effects of different application methods of polyacrylamide (PAM), three forms of PAM (emulsive, solutions and dry granules) and application methods of dry granule PAM mixed were studied in this article. The results showed that surface applications of three forms of PAM increased infiltration and reduced soil erosion significantly. The final infiltration rate for emulsive, solution and dry granular PAMs increased by 1–2.5, 1.7–2.8, 0.25–1.8 times compared with their controls respectively. As for application methods of dry granule PAMs, spreading dry granular PAM on soil surface was more effective in increasing infiltration than mixing dry granular PAM with topsoil. The gypsum mixed with dry PAMs increased the efficiency of dry PAMs in increasing infiltration which increased with the amount of gypsum. The soil erosion for surface spreading dry granular PAM decreased by 80% compared with the control, which was closed to reductions of emulsive and solutions PAM treatments. However, dry granular PAM mixed with layer of topsoil decreased the efficiency of PAM in reducing soil erosion reduction. The gypsum mixed with dry granular PAM increased effectiveness of PAM in increasing infiltration, but decreased the significance of controlling soil erosion. It can be concluded by comparsion of three forms of PAMs effects on infiltration and erosion that the surface applications of dry granular PAMs can cbtain the similar results as emulsive or dissoluted PAMs in controlling infiltration and erosion and is cost effective, facilitate uses in rainfed areas.