Irrigation Evaluation and Saving Water Irrigation Efficiency or

Irrigation Evaluation and Saving Water

Irrigation Efficiency or IE Water applied is never 100% beneficially used. There is always some loss Evaporation from soil and leaf surface Spray loss from water stream Evaporation losses can range from 1% to as much as 30% Losses range from 1% to 4% Surface run off Deep percolation (water pushed past the root zone) * IE is a measure of the irrigator and the system

Distribution Uniformity or DU Distribution Uniformity is the measure of how uniformly the water is applied * DU is a measure of the irrigation system Example of a good DU Example of a poor DU

Example of a good DU Example of a poor DU The problem with a poor DU If enough water is applied to ensure every plant is given adequate water, we overwater other plants.

Planning for DU

Potential DU Permanent under tree sprinklers Linear Move Sloping Furrow Orchard Drip Border Strip of Flood Level Furrow Row Crop Drip Hand Move Sprinkler 95% 93% 90% 85% 80% 75% This is potential. Actual DU are usually lower due to poor system design, suitability, system wear, and management.

Measuring Our Current DU Sprinklers Catch can evaluation Place catch cans (minimum of 24) in an equal grid spacing Run sprinklers to gain a representative sample Measure and record amount of water collected in each catch can Multiple tests give more accurate results Near where the main line branches into laterals In the middle of the field At the ends of the laterals

Test Locations

Place all of the numbers in order from highest to lowest 122 ml 119 ml 118 ml 115 ml 110 ml 108 ml 105 ml 104 ml 100 ml 99 ml 97 ml 96 ml 92 ml 91 ml 90 ml 88 ml 87 ml Lowest ¼ of the values

Measuring Our Current DU Drip or Micro Sprinklers Emitter Uniformity Since we are not covering the entire ground surface, we only measure the water that is emitted during a certain time. Measure the water from the emitter during a given time Record amount of water collected from each emitter Calculate emitter uniformity using the same method as used with the sprinkler catch can collection

Measuring Our Current DU Drip or Micro Sprinklers Emitter Uniformity

Measuring Our Current DU Furrow or Flood Irrigation Distribution Uniformity Surface irrigation is difficult to calculate uniformity The goal is to make opportunity time consistent across the field Opportunity time = time the water is on the soil

Advance Recession Curve Time Opportunity Time Advance Curve Distance

Advance Recession Curve Slow advance times Recession Curve Opportunity Time Advance Curve Distance

Now Make Improvements Sprinklers, Drip and Micro Irrigation Check the field at every startup Look for damage and plugging Repair leaking fittings and gaskets Look for plant interference

Now Make Improvements Sprinklers, Drip and Micro Irrigation Nozzle differences Wear Over a period of time nozzles wear (replace them) Miss management Repair nozzles with correct replacements

Now Make Improvements Sprinklers, Drip and Micro Irrigation Clean and maintain filters Flush lines monthly Keep application rates less than infiltration rates Irrigate at night Less heat & less wind (also saves on pumping costs) If the field has pressure/flow problems, install pressure compensating sprinklers and emitters Irrigate longer sets less often (minimize evaporation loss)

Now Make Improvements Surface Irrigation (boarder strip and furrows) Grade and level plots Sloped furrows are more efficient than flat ones Slopes range from. 5% to 4% (depends on crop and soil type) Develop a tail water system

Now Make Improvements Surface Irrigation (boarder strip and furrows) Faster advance times (get water to run faster) Faster flow rates (fastest non erosive flow possible) Shorter runs Narrower runs Manage wheel traffic and compaction Use torpedos

Make improvements and reevaluate Efficiency in irrigation is a constant effort MJC Irrigation Technology https: //www. mjc. edu/instruction/agens/irrigationtech