Low irrigation efficiency has negative impacts on farm profitability and the environment. Poorly performing irrigation systems and poor scheduling are major causes of low efficiency and waste of water and energy.
Here are five things to consider when looking to improve your irrigation efficiency.
1. Irrigation Timing.
The best time to irrigate is at night when ET rates are low. Evapotranspiration (ET) is the sum of evaporation and plant transpiration from the Earth’s land and ocean surface to the atmosphere. https://en.wikipedia.org/wiki/Evapotranspiration. Irrigation scheduling involves balancing evapotranspiration and drainage (water losses) against rainfall and water application (water gains) using the soil’s available water capacity as a water storage reservoir. Accurate irrigation scheduling requires knowledge of the soil’s available water capacity and status, how fast the available water is being used up, rainfall inputs and how much water is applied by an irrigation system.
2. Irrigation Application Rates
If application rates for your irrigation exceed the soil’s infiltration rate, run-off and ponding will occur. This causes some areas to be under watered and others over watered. Any sign of ponding at the surface is an indication of efficiency loss. You should do regular checks noting surface ponding, leaks and off target application during your irrigation and puts plans in place to limit this.
3. Irrigation Distribution
Distribution uniformity describes how evenly irrigation is applied to the crop and is a critical factor in determining the potential efficiency of any irrigation system. You can check distribution uniformity by using catch cans to collect the water applied over an irrigation pass or specified time period.
4. Soil health and hummus
Compaction and levels of humus in the soil will impact the soils ability to retain moisture and use irrigation more effectively. The importance of chemically stable humus or fertility of your soil helps the soil retain by increasing microporosity, and encourages the formation of good soil structure. Humus can hold the equivalent of 80–90% of its weight in moisture, and therefore increases the soil’s capacity to withstand drought. https://en.wikipedia.org/wiki/Humus#Benefits_of_soil_organic_matter_and_humus
5. Irrigation System Maintenance
Visual checks of pumps, filters, sprinkler patterns, wear and installation should be done on a regular basis to ensure water is not lost. Testing flow and pressure at set points and monitoring power usage can also be important.
A resource consent or scheme will limit the amount and timing of water available. As a manager it is your responsibility to have strategies in place to manage the farm when water restrictions occur. Both schemes and individual consents will often have particular limits for stream flows or groundwater levels, which will result in water takes being reduced or cut-off.
Check out Reptec’s Irrigation Sprinklers