Growers across the state received above-average rainfall in April, with the SFS Probe Trax network showing that the soil moisture “bucket” in the south-west’s high rainfall zone (HRZ) is already near capacity.
Moisture probes indicate paddocks around Teesdale, Westmere and Glenthompson are 90, 88 and 92 per cent saturated respectively. All three sites reached a 100 per cent plant available water (PAW) rating in late April.
These percentages are to be expected, considering Hamilton and Westmere recorded about 95mm in April. Inverleigh recorded 123mm. The long-term April average for these sites is 35mm.
These large falls follow above-average rainfall last year, meaning soils had little room to move with water holding capacity this season.
The question on everyone’s lips is: what does so much early moisture mean for the rest of the year?
Current models show there is a higher than normal chance of the season becoming drier over the coming months. While this may not be good for growers north of the divide, the HRZ tends to have consistent winter rainfall which may work in its favour considering plants will not root as deeply early in the season due to PAW levels. Shallower roots mean plants will not be able to access water as readily as the PAW decreases.
If there is normal winter rain on top of a full profile in the HRZ, waterlogging could be a real concern.
Proper drainage management early in the season is crucial to minimising waterlogging. Should the winter remain wet, management of in-season fertiliser, fungicide and herbicide could be exceedingly difficult due to paddocks being too wet to traffic. The key message is to be prepared and act early, rather than delaying applications until the last minute.
If the paddock is dry enough to traffic and the crop is ready for application, do it before things become too wet. If you already know you will struggle to do this, have a backup strategy that may include aerial applications. For more details, or to join the Probe Trax network, visit probetrax.sfs.org.au
