Effects of Surface Treatment on Surface Sealing, Runoff, and Interrill Erosion

Surface treatment influences the nature and extent of seal/crust formation, which affects runoff and erosion.This study evaluated the effects and longevity of soil amendments, tillage, and screen cover on runoff and interrill erosionon a Cecil sandy loam (clayey, kaolinitic, thermic Typic Kanhapludult) under natural rainfall conditions. Six field plots(3.5 0.9 m) with a slope of 0.06-m m1 were used in the study. Three treatments (control, screen cover, crust-breakingshallow tillage) were studied in duplicate in the first two-month period, and another three (control, anionicpolyacrylamide (PAM), and phosphogypsum) in a subsequent five-month period. Total runoff and soil loss were 69, 61,and 47 mm and 5.3, 1.6, and 4.3 Mg ha1 for the control, screen cover, and tillage treatments, respectively. Comparedwith control, screen cover reduced soil loss significantly but not runoff, while tillage reduced runoff more than soil loss.Total runoff and soil loss for the control, gypsum, and PAM treatments were 146, 48, and 81 mm and 3.1, 2.6, and2.5 Mg ha1, respectively. Runoff was reduced by 67% and 44% for the gypsum and PAM relative to control and soil lossby 16% and 19%, showing gypsum and PAM were more effective in reducing runoff than soil loss. Runoff wassignificantly reduced in the gypsum and PAM treatments in the five months following surface application. Results showedscreen cover and tillage temporally reduced or delayed seal/crust formation, while the effects of gypsum and PAM weremore persistent. Combined with earlier findings, it appears that a combination of physical and chemical treatments is thebest practice for controlling surface sealing and reducing runoff and erosion on this soil.