Gippsland - How Now Gippy Cow
December 2010 Edition
Planning for Summer Irrigation
In contrast to the wet spring enjoyed by most of Victoria, rainfall for the MID is nearly 100 mm (1 ML per ha) below the long term average for the July to November period.
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Luckily the rain events have trickled over the ranges to provide good inflows to Glenmaggie and provide some spill water. All good things come to an end at some point and for MID irrigators 15th December is that date. This day signals the end of the Glenmaggie spill entitlement phase and is the time when a meaningful water budget for the remainder of the irrigation season can be done.
The farm water budget needs to carefully consider how much irrigation water is needed to get through to the end of the season. The budget then needs to determine how much water you have access to. This is made up from megalitres of high security water remaining, any groundwater, and a bit of a guess as to how much low security water the district might get. If the water needed is more than is available then decisions such as buying water, drying off pasture, buying more supplements etc. need to be made.
When you are confident with your water budget and if it shows that you have more water than you need there is the option to sell it to someone that needs more. It’s dollars in your pocket and more milk for the district!
Once the water budget is done, the decision around when to irrigate can be made easier by using the evaporation information from the MID’s automatic weather stations (internet link is : http://www.agua.com.au/DPIVic/).
For farmers elsewhere in Gippsland the Bureau of Meteorology is now calculating evaporation for most observation sites (internet link is : http://www.bom.gov.au/watl/eto/). Click on the site (blue dot) closest to your farm to see the weekly summary of evaporation (E) less rainfall (R). A negative weekly E-R figure means there was more evaporation than rainfall and grass growth will be slowing if irrigation is not applied (or available).
Contact: Gavan Lamb
5147 0848 or gavan.lamb@dpi.vic.gov.au
