BucksIRR WUE

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ENHANCING WATER CONSERVATION OR WATER USE EFFICIENCY IN IRRIGATED AGRICULTURE: 

USDA-ARS ENHANCING WATER CONSERVATION OR WATER USE EFFICIENCY IN IRRIGATED AGRICULTURE Dale A. Bucks, Senior National Program Leader, Water Quality and Management, Beltsville, MD Terry A. Howell, Research Leader, Soil and Water Management Research Unit , Bushland, TX

OBJECTIVES: 

OBJECTIVES To review irrigation trends in the world; To review irrigation trends in the U.S.; and To examine and review mechanisms for enhancing water conservation/WUE in irrigated agriculture Both field and basin effects

World Population: 

World Population 6 Billion on Oct. 12, 1999 80-85 million/yr 7.3 to 10.7 Billion by 2050 14 Billion by 2050 at the current rate

“New” Legal Terms: 

“New” Legal Terms Many are very qualitative Reasonable Beneficial Recoverable Unavoidable Makes you want to become a lawyer or a consultant

World Trends: 

World Trends

U.S. Trends: 

U.S. Trends

Enhancing Field Water Conservation or WUE in Irrigated Agriculture: 

Enhancing Field Water Conservation or WUE in Irrigated Agriculture

Options for Improving Irrigation Efficiency [adapted from Wallace and Batchelor (1997)]: 

Options for Improving Irrigation Efficiency [adapted from Wallace and Batchelor (1997)]

Options for Improving Irrigation Efficiency [adapted from Wallace and Batchelor (1997)]: 

Options for Improving Irrigation Efficiency [adapted from Wallace and Batchelor (1997)]

Options for Improving Irrigation Efficiency [adapted from Wallace and Batchelor (1997)]: 

Options for Improving Irrigation Efficiency [adapted from Wallace and Batchelor (1997)]

Options for Improving Irrigation Efficiency [adapted from Wallace and Batchelor (1997)]: 

Options for Improving Irrigation Efficiency [adapted from Wallace and Batchelor (1997)]

WUE in Irrigation: 

WUE in Irrigation The WUE definition becomes a little “clouded” in Irrigated Agriculture Baseline (dryland or rainfed systems) Large differences between irrigated and dryland systems Fertility, variety, pest management, sowing date, planting soil water, plant density, row spacing, etc.

Increasing Field WUE: 

Increasing Field WUE Increase Harvest Index (HI) Reduce the transpiration ratio (T/DM) Maximize Dry Matter (DM) Increase T relative to other water balance components Reduce Evaporation (E), Deep Percolation (D), Reduce Quantity (Q) Applied, and increase Soil Water Depletion (SWD)

Advanced Irrigation Techniques: 

Advanced Irrigation Techniques

Advanced Irrigation Techniques: 

Advanced Irrigation Techniques

Enhancing Basin Water Conservation or WUE in Irrigated Agriculture: 

Enhancing Basin Water Conservation or WUE in Irrigated Agriculture

Basins: 

Basins “Closed” Basin No usable water leaves the basin or project “Open” Basin Usable water does leave the basin or project

“Open” Basins : 

“Open” Basins Few problems with plentiful supplies Main problem could be capture and distribution All “open” basins approach “closed” basins when all the water is consumed and any discharge is too polluted to reuse

Example #1: 

Example #1 Texas High Plains Water source from Ogallala aquifer (essentially a closed basin) Enhanced WUE or Irrigation Efficiency may increase groundwater depletion Without restrictions on irrigated land area

Slide29: 

Winter Wheat Water Use Efficiency Bushland, Texas U.S.A. Source: Musick et al. (1994)

Example #2: 

Example #2 Eastern Idaho Water source from Snake River (open basin) Enhanced Irrigation Efficiency may decrease groundwater return flow and reduce reuse potentials Could damage downstream “junior permit” holders Could improve downstream water quality (phosphorus and sediment loadings)

Example #2: 

Example #2 Eastern Idaho Water source from Snake River Allen and Willardson (1997) Low irrigation efficiency (~40 percent) Improved river fisheries ($80 mil./yr) Increased hydropower in low flow years ($20 mil./yr) Reduced river flooding Reduced groundwater pumping depths

Summary [adopted from Seckler (1996)]: 

Summary [adopted from Seckler (1996)] Water conservation can increase output per unit evaporated water (WUE) Reduce losses of usable water to unrecoverable “sinks” Reduce water pollution Sediments, salinity, nutrients, agrochemicals Reallocate water from lower valued to higher valued uses (YOU’RE SELLING WATER)

The End: 

The End USDA-Agricultural Research Service Dale A. Bucks Senior National Program Leader Water Quality and Management dab@ars.usda.gov