Influence of Surface Biosolids Application on Infiltration

Abstract

Biosolids from waste water treatment facilities applied to soils not only add plant nutrients, but also increase infiltration and decrease runoff and erosion. Wet biosolids from New York, NY, were surface applied at 0 to 90 Mg ha−1dry weight to soils near El Paso, Tex. Simulated rainfall intensities of 16.4 cm hr−1for 30 minutes applied to 0.5 m2soil plots yielded initial infiltration rates of ~16 cm hr−1for all plots. Biosolids applications extended the duration of the initially high infiltration rates. After 30 minutes, infiltration rates for bare soil were 3 cm hr−1without and 10 cm hr−1with 90 Mg biosolids ha−1. Applied biosolids, plant litter, surface gravel, and plant base contributed surface cover, which absorbed raindrop energy and reduced erosion. Biosolids increased cumulative infiltration on the vegetated, wet soils more than for the dry or bare soils. Biosolids increased cumulative infiltration from 2 to 6 cm on a bare gravelly soil and from 9.3 to 10.6 cm on a vegetated soil.