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United States Department of Agriculture

Agricultural Research Service

Title: Irrigation Water Quality Alters Furrow Erosion and Infiltration

Authors
item Lentz, Rodrick
item Sojka, Robert

Submitted to: Irrigation Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 28, 1996
Publication Date: N/A

Interpretive Summary: Irrigation-induced erosion is a serious problem in the Western U.S. where irrigation water quality can vary seasonally and geographically. The salt content and proportion of sodium salts present in irrigation water affect infiltration and sediment losses from irrigated furrows. Source-water quality influences these processes via its impacts on soil stability and depositional seal formation in the furrow. Examples of water-quality effects are discussed. Four treatments included 4 combinations of low or high salt content, and low or high proportion of sodium. Soil losses increased 73% and net infiltration decreased 15% in High-sodium compared to Low-sodium treatments. Compared to Low-salt source water, high-salt waters reduced furrow soil losses by 31% and had an inconsistent effect on net furrow infiltration. Farmers who have access to several water sources can use this information to reduce irrigation-induced soil-losses. Such information is needed to accurately predict irrigation-induced erosion, and mathematical models must account for the real affects of irrigation water quality.

Technical Abstract: Irrigation-induced erosion is a serious problem in the Western U.S. where irrigation water quality can vary seasonally and geographically. Source-water electrical conductivity (EC) and sodium adsorption ratio (SAR) affect infiltration and sediment losses from irrigated furrows. Source-water quality influences these processes via its impacts on soil aggregate stability and depositional seal formation in the furrow. Examples of water-quality effects are given. Four treatments included 4 combinations of: low or high EC (0.5, 2 dS/m), and low or high SAR (0.7, 9). Average tail-water soil losses were: 1.1 T/ac from Low- EC/Low-SAR furrows, 2.0 T/ac from Low-EC/High-SAR furrows, 1.3 T/ac from High-EC/High-SAR furrows; and 0.8 T/ac from High-EC/Low-SAR furrows. Soil losses increased 73% and net infiltration decreased 15% in High-SAR compared to Low-SAR treatments. Compared to Low-EC source water, high EC waters reduced furrow soil losses by 31% and had an inconsistent effect on net furrow infiltration.

Last Modified: 9/2/2014
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