Seasonal trends in furrow irrigation erosion in southern Idaho

Abstract

A study was conducted to measure the seasonal irrigation furrow erosion pattern in the absence of cultivation and a growing crop. This erosion pattern was compared to those of previous measured plot experiments for different years in the presence of cultivation and a growing crop. Erosion for sugarbeets, corn and beans was low early in the season and increased to a maximum during the same 3-week period, from 24 June to 10 July over several years. Erosion decreased as the irrigation season progressed after the erosion peak. The erosion pattern from the uncultivated, non-cropped plots resembled the pattern from previous studies on cropped soil with the maximum erosion occurring about the same time of season. The pattern trends differed only after peak erosion. For the copped plots, there was a sudden erosion decline after peak erosion, followed by a continual gradual decrease. In contrast, for the uncultivated, non-cropped plots, there was a sudden erosion decline after peak erosion, followed by a gradual increase in erosion. Although the seasonal erosion pattern cannot be completely explained, it is important to report it because of the implication for erosion modeling. Sediment loss rates measured from these soils in southern Idaho in late June or early July would significantly overestimate seasonal erosion, whereas sediment loss rates measured in May or early June or after mid-July would underestimate seasonal erosion. These results show that researchers cannot rely upon a one-time measurement for model validation if attempting to predict irrigation furrow erosion over an entire irrigating season. © 1995.