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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #178333
Title: TECHNOLOGIES TO MINIMIZE WATER QUALITY IMPACTS OF IRRIGATED AGRICULTURE

Author
item Bjorneberg, David - Dave
item Sojka, Robert
item Leytem, April

Submitted to: Proceedings of the World Water and Environmental Resources Congress
Publication Type: Proceedings
Publication Acceptance Date: 2/15/2005
Publication Date: 5/16/2005
Citation: Bjorneberg, D.L., Sojka, R.E., Leytem, A.B. 2005. Technologies to minimize water quality impacts of irrigated agriculture. In: Proceedings of the World Water and Environmental Resources Congress, May 15-19, 2005, Anchorage, Alaska. 2005 CDROM.

Interpretive Summary: Irrigation is an important tool for producing reliable, high quality food and fiber. Runoff from irrigated land often contains sediment and nutrients that may degrade the quality of water in streams, rivers and lakes. Management practices have been developed to control soil erosion on irrigated land and improve the quality of water returning to streams and rivers. Applying polyacrylamide (PAM) with irrigation water can reduce erosion from furrow irrigated fields more than 90%. Using PAM in combination with other practices, such as applying straw mulch in furrows and installing small sediment ponds on fields, can virtually eliminate sediment loss from fields. Reducing sediment loss also reduces phosphorus loss. Once soil runs off a field, it can be removed from flowing water by settling in sediment ponds, although soluble nutrients remain in the water. Applying alum to irrigation return flow water can remove soluble phosphorus that will not be removed as suspended sediment settles in ponds. Using these management practices allows irrigation to continue with minimal impact on water quality.

Technical Abstract: Irrigation transformed arid land in the Pacific Northwest into productive agricultural land. However, much of this land is prone to erosion during irrigation, which can cause problems on and off of the field. Management practices have been developed to control soil erosion on irrigated land and improve the quality of water returning to streams and rivers. Applying polyacrylamide (PAM) with irrigation water can reduce erosion from furrow irrigated fields more than 90%. Using PAM in combination with other practices, such as applying straw mulch in furrows and installing small sediment ponds on fields, can virtually eliminate sediment loss from fields. Once soil runs off a field, it can be removed by settling in sediment ponds, although soluble nutrients remain in the water. Applying 20 mg/L alum to irrigation return flow water can remove about 50% of the soluble phosphorus that will not be removed as suspended sediment settles in ponds. Using these management practices allows irrigation to continue with minimal impact on water quality.