Assessing the use of polyacrylamide synthetic polymer to control runoff and soil losses in arid and semi-arid regions:

Abstract

Use of anionic polyacrylamide (PAM) as soil conditioner was found to be effective in reducing rainfall runoff and soil loss, while increasing infiltration rate. In this study, the effective granular PAM rate that best reduces runoff and soil loss was determined in the laboratory under simulated rainfall condition. Minitab17 software was used to design the experiments whose treatments were control, and then granular PAM mixed uniformly into soil at rates of 14.6g, 100.0g, 50.0g, and 85.4g under the impact of 5414.2ml, 4000.0ml, 6000.0ml,2000.0ml, and 2585.8ml of rainfall per hour. Although all PAM rates reduced runoff and soil loss, the RRE and SLRE show that 50.0g of PAM (77.9% RRE) with 2000ml/hr. of rainfall and 14.6g of PAM (93%SLRE) with 2585.8l ml/hr. of rainfall are the most effective in controlling runoff and soil loss respectively. However, the effectiveness of PAM in reducing soil loss increased with increasing PAM rate but diminished with time over the entire duration of the simulation. Furthermore, the application of PAM leads to a better reduction in soil loss compared to runoff, as shown by the fitted line plot from the Minitab17software), with the value of R-sq. being 81.1%. Basing on the results of the software, the amount of runoff and soil loss in the study area can be seen as evident in large proportions, and it was from the model that rainfall-runoff and sediment load of Longiro river was shown to be evident.