While the science of calculating crop coefficients using remote sensing has been around since the 1970’s, a robust commercial product is not yet available. This is partly due to the lack of available high resolution satellite imagery.
Over the last two years many more satellites have been launched with the capability to provide high resolution data on a daily time step, however the project still found issues with the quality and frequency of high-resolution satellite data available for the 2020-21 season. This made it difficult to provide accurate irrigation scheduling decisions based purely on satellite imagery for the entirety of the growing season.
However, by interpolating the sparse satellite data, a reasonable model of crop cover was obtained, but such an approach is not commercially viable without being automated and integrated into a software platform. For example, the combination of SWAN Systems water balance model, alongside weekly high-resolution satellite data has the potential to provide farmers and growers more accurate irrigation scheduling information.
One practical output was achieved from the project – a method of calculating crop coefficients for any crop, based on crop growth stages. Water Strategies now uses this calculator to assist irrigation scheduling with two clients.
Report for the Our Land and Water Rural Professional Fund