EFFECT OF WATER CHEMISTRY AND SOIL AMENDMENTS ON A SILT LOAM SOIL—PART 1: INFILTRATION AND RUNOF

摘要

Infiltration, runoff, and soil loss are processes that occur when rainfall and runoff water interact with the structure and physical and chemical bonds of the soil surface. A well-aggregated soil which is strongly resistant to dispersion and aggregate breakdown, and which is fairly porous, will typically have greater infiltration rates and less runoff and soil loss than a poorly aggregated soil that is easily dispersed and which seals and crusts. Soil surface seal formation results from: physical breakdown of soil aggregates due to raindrop impact, and/or chemical dispersion which is dependent upon soil properties and the electrolyte concentration in the surface water solution. This study examined the effect of electrolyte concentration in rainfall and runoff water, as well as the effect of different soil surface amendment treatments on infiltration, runoff, and soil loss from a typical silt loam soil susceptible to aggregate breakdown and sealing. This article presents the infiltration and runoff results, and a companion article presents the soil erosion results. Rain water electrolyte content was found to have no significant effect on final runoff or infiltration rates. The use of a fluidized bed combustion bottom ash (a byproduct from coal-fired electric power plant emissions desulfurization) soil surface amendment significantly increased infiltration on small interrill areas (41.9 mm/h vs 32.2 mm/h for the control), but was less effective on longer rill plots (20.6 mm/h vs 18.4 mm/h for the control, difference not significant). Addition of a small amount of an anionic polyacrylamide in tap water used as simulated rainfall greatly increased water infiltration into the soil, which may have potential application in sprinkler irrigation systems.