In the attached Excel document, you will find the 'Border Check Irrigation Scheduling Tool' from Agriculture Victoria.
Instructions - It's simple!
1) Choose the closest location; a suitable "irrigation deficit"* and; a "crop coefficient."**
2) In the first column (labelled "Irrigate"), click on the date of your last surface irrigation.
3) Add your own rainfall figures (in the fourth column) - if you collect rainfall figures for your farm.***
4) View the last 2 columns and the graph for a guide of optimal timing for your next irrigation.