Polyacrylamide application for upland erosion control.

摘要

Guidelines for polyacrylamide (PAM) application for erosion control are not well developed. Improved guidelines are needed to conserve soil while reducing practice costs. We hypothesized that amount and frequency of PAM applications are related to soil erosion and runoff. The objective of this study was to evaluate the effectiveness of PAM applications at rates of 10-, 20-, 30- and 40-kg ha-1 combined with 5 Mg ha-1 gypsum, in a single or a split application. Mexico silt loam was repacked to a rhob of 1.3 Mg m-3 in beds and subjected to 90 mm hr-1 of simulated rainfall for 180 minutes. Runoff showed no difference among treatments from 0-180 minutes (P ∼ 0.99). A Control treatment having no PAM was characterized by an increase in erosion rate to 9.2 g m-2 min-1 at 50 minutes, decreasing to 7.5 g m-2 min-1 at 180 minutes. Erosion was reduced (P 0.001) using both single and split PAM applications. The single application 10-, 20-, 30- and 40-kg ha -1 PAM treated soils increased in erosion rates approaching that of the Control after 90-, 100-, and 160-minutes respectively. The split treatments of 30- and 40-kg ha-1 were 2.3 times more effective in reducing soil detachment than the single treatments after 180 minutes of rainfall (270 mm). No difference in soil detachment were detectable for the 10-, or 20-kg ha-1 for times >100 minutes (143 mm rain) for the split treatment. The longevity of PAM effectiveness for the split application was not different among the 20- 30- and 40-kg ha-1 treatments with the average Relative Soil Loss Ratio being 0.47 after 180 minutes (270 mm rain).