Effect of antecedent moisture content, rainfall intensity, aggregate stability, and plot configuration on interrill erosion processes
Abstract
Recently developed erosion models have partitioned soil erosion by water into component processes. Influence of soil properties and rainfall characteristics must be determined in order to understand the process-based concept. This study was conducted to determine the influence of antecedent water content, soil structural stability, rainfall intensity, and slope on soil detachment and transport processes occurring in interrill erosion. Soils ranged in texture from sandy loam to clay. Increase in initial moisture content increased the resistance of soil aggregates to forces of raindrop impact and flowing water. Prewetting from air-dry to $-$1.0 kPa increased Heiden clay D$\prime\sb{50}$ values (D$\sb{50}$ corrected for particle size) the most (0.49 to 1.91 mm). Prewetting prior to rainfall influenced splash detachment, soil strength, and sediment size distribution. Total splash for air-dried and prewetted Heiden clay was 770 and 169 g h$\sp{-1}$, respectively. Prewetted splash sediment was larger than air-dried splash sediment. For lab and field interrill erosion studies, prewetting influenced surface sealing, runoff characteristics, and sediment size distribution. For the interrill lab study, increase in rainfall intensity decreased infiltration, increased runoff, and increased splash and wash rates. Doubling rainfall intensity doubled total splash and increased total wash by at least 2.5 times for all soils. Doubling rainfall intensity resulted in a 6-fold increase in total splash and wash amounts for prewetted Broughton clay. For the field interrill study, antecedent moisture content, rainfall intensity, and slope influenced wash rates, runoff, near-surface strength, and sediment size distribution. Antecedent moisture content, rainfall intensity, aggregate stability, and slope influence many properties that control detachment and transport processes within interrill areas.
Degree
Ph.D.
Advisors
Bradford, Purdue University.
Subject Area
Agronomy|Soil sciences
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