RT Journal Article
SR Electronic
T1 Polyacrylamide efficacy for reducing soil erosion and runoff as influenced by slope
JF Journal of Soil and Water Conservation
FD Soil and Water Conservation Society
SP 172
OP 177
DO 10.2489/jswc.66.3.172
VO 66
IS 3
A1 S.S. Lee
A1 C.J. Gantzer
A1 A.L. Thompson
A1 S.H. Anderson
YR 2011
UL http://www.jswconline.org/content/66/3/172.abstract
AB Anionic polyacrylamide (PAM) can reduce soil erosion. Slope is an important factor determining erosion rate; however, PAM guidelines have not been well developed for different slopes. The objective of this study was to evaluate the extent which 20 kg ha−1 (18 lb ac−1) PAM (20P) and 40 kg ha−1 (36 lb ac−1) PAM (40P) increase the time to initial runoff (TRO), decrease cumulative runoff (RO), and decrease cumulative sediment loss (SL) on a Mexico silt loam soil adjusted to slopes of 10%, 20%, and 40%. Soils were packed to a bulk density of 1.3 Mg m−3 (81 lb ft−3) in test beds 0.3 × 0.3 × 0.15 m (12 × 12 × 6 in) and were subjected to a 61 mm h−1 (2.4 in hr−1) simulated rainfall with a kinetic energy of 1.5 kJ m−2 h−1 (103 ft lb ft−2 hr−1) for 1 h. Differences in TRO and SL for all slopes and PAM rates were all highly significant, as were all two-way interactions (p < 0.01). Applications of 20P and 40P significantly increased TRO compared to the untreated control (0P) at slopes 20% and greater but not at a 10% slope. No difference in TRO was found for soils at slopes up to 20% between 20P and 40P. The TRO was significantly greater at 40% slope for the 40P compared to the 20P application. Values of TRO with 20P and 40P were not increased at a 10% slope compared to 0P. Slope was not a factor in reducing RO. Applications of 40P for all slopes had significantly greater RO than either 0P or 20P. Polyacrylamide reduced SL for all slopes. A higher rate of PAM (40P) had less SL than a lower rate of PAM (20P) at slopes of 20% and 40%. With 40P, the reduction in SL was 72% greater than 0P at 40% slope. Therefore, slope is a critical factor in determining a PAM rate for reducing soil erosion and should be considered for proper application.