Submitted to: Soil Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 9, 1995
Publication Date: N/A
Interpretive Summary: Irrigation induced erosion and subsequent sediment loss reduces the crop producing potential of the soil and causes off site water quality degredation. An understanding of the erosion processes and patterns are required to apply appropriate erosion control technology. During the past 15 years, research has found that erosion and sediment loss on Portneuf silt loam soil peaks during a three week period from late June to early July, both when cropped or when no crop was grown, and regardless of the previous irrigation pattern during the season. Following this peak, erosion and sediment loss decreases for the remainder of the irrigation season. Results show that erosion control methods can have the greatest impact when applied during this peak erosion period. Also that researchers should exercise caution in using a one-time measurement to model or estimate erosion and sediment loss for an entire irrigation season.
Technical 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 three-week period, from June 24 to July 10 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 cropped 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 over estimate seasonal erosion, whereas sediment loss rates measure 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 verification if attempting to predict irrigation furrow erosion over an entire irrigating season.