Effect of Water Chemistry and Soil Amendments on a Silt Loam Soilpart 1: Infiltration and Runof

Infiltration, runoff, and soil loss are processes that occur when rainfall and runoff water interact with thestructure and physical and chemical bonds of the soil surface. A well-aggregated soil which is strongly resistant todispersion and aggregate breakdown, and which is fairly porous, will typically have greater infiltration rates and lessrunoff and soil loss than a poorly aggregated soil that is easily dispersed and which seals and crusts. Soil surface sealformation results from: physical breakdown of soil aggregates due to raindrop impact, and/or chemical dispersion whichis dependent upon soil properties and the electrolyte concentration in the surface water solution. This study examined theeffect of electrolyte concentration in rainfall and runoff water, as well as the effect of different soil surface amendmenttreatments on infiltration, runoff, and soil loss from a typical silt loam soil susceptible to aggregate breakdown andsealing. 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 afluidized bed combustion bottom ash (a byproduct from coal-fired electric power plant emissions desulfurization) soilsurface 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 ofa small amount of an anionic polyacrylamide in tap water used as simulated rainfall greatly increased water infiltrationinto the soil, which may have potential application in sprinkler irrigation systems.