What was it all about?

This project aimed to provide vegetable growers with crop-specific information on evapotranspiration levels (the amount of water lost through plants and soil) to help guide irrigation decisions on-farm. It ran from 2016 to 2017 and completed field trials for four crops (brassicas, carrots, lettuce and spinach) to calculate their evapotranspiration rates based on their plant growth stage.

Data from the project was intended to help improve ‘The Yield’ app that allows users to see evapotranspiration, rainfall and water balance data for the day, for the past week, and estimate for the week ahead. The current iteration of the app relies on static based modelling for each crop type (based on available literature) and the project aimed to incorporate plant growth stage as a factor to improve the accuracy of estimated irrigation needs.

Two modelling approaches were undertaken, however the project found that neither drove significant improvements in accuracy when compared to the static crop coefficient curves that are already used by industry. The trials did show that variation in how water moves through soil is a stronger driver of soil moisture variation than the variable crop coefficient curves.