EFFECT OF WATER CHEMISTRY AND SOIL AMENDMENTS ON A SILT LOAM SOIL - PART 2 - SOIL-EROSION

This research examined the effect of rainfall and runoff water composi tion, as well as the effect of different soil surface amendments on in filtration, runoff and soil loss from a silt loam soil which was highl y susceptible to aggregate breakdown and sealing. This article describ es the soil erosion results, while infiltration and runoff findings ar e presented in a companion article. The purposes of this study were to test if soil erosion would be reduced by the presence of electrolytes in the erosive water if use of an anionic polyacrylamide (PAM) as a s urface spray or in rain water would reduce soil loss, and what the com bined effects of high electrolyte concentrations and PAM would be. The impacts of a soil surface application of 20 kg/ha of an anionic PAM a s well as 5 t/ha of a gypsiferous power-plant byproduct on soil loss w ere determined. Water type applied as rainfall or inflow was deionized , tap, or tap plus 10 ppm of PAM. The soil surface applications of the PAM were effective in controlling rill erosion, even at very high wat er inflow levels. Pill plot sediment discharge rates from deionized ra infall water applications to an initially dry soil surface were signif icantly greater than those resulting from rainfall having greater elec trolyte concentrations. However when inflow water was added to activel y eroding rills, electrolyte concentration had no significant effect o n sediment concentration or sediment discharge rate. The presence of P AM in rain water and inflow water acted to enhance soil loss when suff icient runoff was present to transport sediment from the rills.