Irrigation scheduling is a key task for irrigators and getting it right can make a significant difference to your bottom line. To determine how much water to apply and when, it’s vital to know the irrigation needs of the crop alongside any forecasted rainfall.
How much yield can you lose by getting the plant water use wrong? A ryegrass seed crop will lose 0.14% of potential yield for each millimetre below the trigger point. For example, if a 2 t/ha crop experienced a 50 mm deficit over the season, the yield impact would be 2 t/ha x 50mm x 0.14% = 0.14 t/ha. At a value of $2,500/t, this is lost income of $350/ha. This is a significant amount of money, especially in the current inflationary climate.
Instead of guessing how much water each different crop or block across the farm is using based on one or two soil moisture probes, automated water balance models are now available to make decision-making easy. Does this approach work in New Zealand? Unsurprisingly yes, researchers have been successfully using them for years to predict crop growth and yields!
Primary Insight have partnered with SWAN Systems to revolutionise irrigation scheduling in NZ. SWAN is a new way of scheduling irrigation that’s rapidly taking off in both Aussie and California, particularly with crop farmers. It brings together soil information, weather data, crop growth stage, planting and harvesting dates and water meter data to automatically calculate the daily water requirements of each crop; it then predicts irrigation requirements for the next seven days. SWAN can be set up to work with any crop.
The weather forecast provided is through IBM’s global weather model and has proven to be accurate and reliable for the Canterbury Plains. Daily satellite imagery is also provided which can help identify plant health issues before they are visible on the ground, as well as pick up areas of under or overwatering.
And the best bit? You don’t need to rip out all your existing hardware to use it! SWAN is open-source software that can work with your existing water meters or weather stations, it can even talk to modern pivot panels to automatically source irrigation data.
Having an irrigation scheduling tool in place for every crop on the farm (including pasture) or every block in a horticultural operation is now an affordable reality. This of particular benefit to farms with limited water supplies; it enables irrigation to be targeted to where it is most needed to minimise any lost yield.
SWAN can also be used to automatically include irrigation water nutrient loads for fertiliser planning and can report on overall nutrient loadings against targets (or limits). We are using this feature to great effect with clients presently.
Want to know more - talk to the team at Primary Insight about SWAN and how it could be used to improve your irrigation scheduling.