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Nutrient losses from an irrigated watershed in southern Idaho

Bjorneberg, D.L. and Ippolito, J.A. and Koehn, A.C. (2013) Nutrient losses from an irrigated watershed in southern Idaho. pp. 1-11. In: 2013 ASABE Annual International Meeting. Kansas City, Missouri, July 21-24, 2013. 11 pp. American Society of Agricultural and Biological Engineers.

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Water, sediment and nutrients flowing into and out of the 82,000 ha Twin Falls,ID irrigation tract were measured from 2005 to 2008. Approximately 80% of the water flowing into the watershed was irrigation water diverted from the Snake River. About 40% of the watershed inflow returned to the Snake River. Much of this return flow was water from subsurface drain tiles and tunnels that drain shallow groundwater. Converting from furrow to sprinkler irrigation, improved irrigation management, and constructed sediment ponds have reduced sediment loss from 460 kg/ha in 1971 to <100 kg/ha in 2005. In 2007 and 2008, more sediment and phosphorus entered the watershed than returned to the Snake River. Diverting irrigation water into the watershed removed 6300 Mg of sediment, 21 Mg of dissolved P, and 32 Mg of total P from the Snake River on average each year. However, the watershed contributed almost 900 Mg of nitrate-N annually to the Snake River. Conservation practices have effectively reduced sediment and phosphorus losses from the watershed, emphasis now must shift to reducing nitrate loss from the watershed.

Item Type: Conference or Workshop Item (Paper)
NWISRL Publication Number: 1527
Subjects: Irrigation > Irrigation control
Irrigation > Furrow irrigation > Runoff losses
Irrigation > Furrow irrigation > Percolation water > Nutrient losses
Irrigation > Furrow irrigation > Runoff losses > Nutrients
Depositing User: Dan Stieneke
Date Deposited: 12 Dec 2014 16:25
Last Modified: 12 Dec 2014 16:25
Item ID: 1571