With climate predictions pointing towards long hot and dry springs and summers, irrigators need to put in place management strategies to maximise their water allocations. Below are some tips that improve efficiency and increase the longevity of allocations.
1. Bucket Test your irrigator – Knowing exactly how much water your irrigator is applying is essential for making good irrigation decisions. A simple bucket test can accurately assess your irrigator performance. Understanding your system capacity and return interval is also critical.
2. Minimise off target application – Look at where your irrigation is landing. Watering tracks, lane ways, and other non-productive ground wastes water. Off-target irrigation, such as watering public roads, is a prohibited in many districts. It’s also not a good look during a drought.
3. Identify your soil types and estimate water holding capacity, field capacity and irrigation trigger points – Knowing how much water your soil can hold is key to successful irrigation scheduling. Knowing the locations of your different soil types within your irrigation area is also a powerful management tool.
4. Schedule your irrigation – using soil moisture sensors or soil water budgets to understand when plants need irrigation and how much to apply is essential. For soil moisture sensors you need to measure and record all irrigation and rainfall events. For water budgets you also need to record daily plant water use (evapotranspiration).
5. Adopt deficit irrigation practices – Deficit irrigation is a scheduling practice that keeps the soil water above the irrigation trigger point but does not fully recharge the soil to field capacity. This allows any rainfall during the irrigation season to be taken advantage of, minimising drainage losses from irrigation whilst maximising both your production and water allocations.
6. Re-nozzle your irrigator – Reducing the nozzle sizes on your irrigator is an easy way to reduce application depths and tailor applications to a restricted water supply. This method will require input from your irrigation service company to avoid undermining the irrigation system.
7. Prioritise crops or paddocks to be irrigated – By targeting irrigation to areas of higher production or higher value crops maximises your profitability during drought restrictions. Lesser production areas or lower values crops will have yield losses as these areas will suffer moisture stress.
8. Reduce your irrigation area – Reducing your irrigation area increases the amount of water available per hectare, or helps to get the best from a restricted water supply. Targeting irrigation to more efficient irrigation systems or soil types increases water use efficiency. This may not be easily achieved under some irrigation system types, and may require so additional advice. More advanced irrigation system types, (e.g. VRI on pivots/linear), can target complex irrigation patterns within a single irrigation area.
Mid-season advice to help stretch out remaining water