Ways For Growers To Maximize Irrigation Water

Growing Produce. 4 November 2014.   Dire. That is just one of many terms being used to describe the drought situation in California. As water, or the lack thereof, is a focal point in the state, managing this precious resource is critical for those producing high-value crops such as vegetables.According to The National Drought Mitigation Center, as of Sept. 28, 70% of California’s rangeland and pastures were rated to be in very poor to poor condition. It isn’t just California that is facing this issue. The report states that Oregon, Nevada, Washington, New Mexico, and Texas are also dealing with drought affected areas.

With less water available, you will need to step up your game to most efficiently manage what you have. Here are 10 pointers to get the most from the water you have available.

1. Test your water and soil for salts. The quality of your water can be as important as the quantity. Many vegetables are sensitive to salinity, so you want to be sure the water applied to your crop has a low level of salts. Also, because salts from irrigation water accumulate near the crop roots over time, one needs to test the salinity of the soil periodically to determine if leaching is needed.

The main constituents to test for in a saturated paste extract of a soil sample are pH, bulk salinity (total dissolved solids or electrical conductivity), calcium, magnesium, sodium, chloride, nitrate, bicarbonate, and boron. Test the same constituents for water but also add iron and manganese. Seek out advice from an experienced agronomist, soil scientist, or crop consultant who can help you interpret the test results.

2. Evaluate the application uniformity of your irrigation system. The more uniformly your irrigation system distributes water to your crop, the less water is needed to achieve good yields and quality. Using 30 equal-sized cups and a stop watch, you can evaluate the distribution uniformity of your sprinkler or drip system. Alternatively, consider hiring an irrigation consultant to conduct a more intensive evaluation.

3. Evaluate the design and operation of your system. Many problems with irrigation systems are caused by either a poor design or lack of maintenance, or because they are not operated correctly. An experienced irrigation consultant should be able to drill down to the main issues that limit the performance of your irrigation system and recommend the most cost-effective solutions.

4. Seek professional advice on system design. The hydraulics of an irrigation system are not very intuitive to the layman, so trying to design your irrigation system on your own can result in a poorly performing system. A professional with experience and a track record of success can help you design a cost-effective irrigation system that can apply water uniformly to your crop.

5. Monitor pressure of the irrigation system. Getting the best performance from your drip and sprinkler systems requires operating them at the right pressure. Variation in pressure will change the flow and uniformity of applied water. Use high-quality gauges to monitor pressure at different locations in the field, including at the closest and furthest points from the water source or irrigation valve.

6. Measure how much water you apply. It is difficult to save water if you do not know how much you are applying to your crops. Using a flow meter and keeping records of the amount of water applied for each crop can help you determine if the amount of water that you are applying is matching crop needs.

7. Use weather information and soil moisture to guide irrigation scheduling. The closer you can match the irrigations with the needs of your crop, the more efficient your water use will be. Irrigation scheduling is the combination of deciding when and how much water to apply. The water needs of the crop change during the season as weather conditions vary and the crop matures. Monitoring soil moisture can help you decide when to irrigate, and using evapotranspiration data from weather stations can help you estimate how much water to apply.

8. Maintain your equipment. Just like your car needs periodic servicing, an irrigation system needs regular maintenance. Leaks in drip tape, pipe, and layflat need to be patched. Drip lines and filters need to be flushed. Sprinkler heads, nozzles, and gaskets wear out and need to be replaced. Develop a schedule for irrigation system maintenance.

9. Train your irrigators. A well-trained irrigator can help solve a lot of the water management problems on your farm. An irrigator’s job goes beyond moving pipe and drip tape. They should have a basic understanding of how the irrigation system operates, be able to keep good records, and understand how to make routine measurements to assure the irrigation system is operating correctly.

They also may need training on how to operate new equipment and conduct maintenance procedures. Provide regular training opportunities so irrigators can increase their skill set. This will make them more valuable to your farming operation.

10. Infiltrate winter precipitation for salinity management. The best water for leaching salts from your vegetable fields is free, and comes from the sky. Letting storm water run off your fallow fields is a lost opportunity to remove salts. Cover crops, tillage, or adding soil amendments can increase infiltration of winter rains and will help control potential salinity problems.