North Coast Local Land Services Sustainable Agriculture team has advised landholders to be aware of the potential for a wetter than average spring, building on the ongoing wet conditions since the major flood event and through the year.

The Bureau of Meteorology has forecast a 70% chance of a La Niña reforming in late 2022 which would result in higher-than-average rainfall conditions again this spring and summer. In response to these ongoing wet conditions, landholders may need to adapt their moisture management, pest and weed treatment schedules and livestock feeding approaches.

North Coast Local Land Services Senior Land Services Officer Ewan Leighton said many of the decisions landholders must make in preparation for changing seasons are based on the available soil moisture.

“In drought, a lack of soil moisture causes major challenges, but the wet conditions we are seeing here on the North Coast can provide just as many difficulties for producers to deal with,” Mr Leighton said.

While rainfall is the most obvious factor in soil moisture, there are several other things impacting soil moisture conditions:

• Soil(s) and moisture-holding capacity.
• Increasing day length and temperature, which will see an increase in plant evapo-transpiration (plant water use). As we move further into late winter and early spring, daily water use will increase significantly.
• Crops and pasture with large biomass – requiring higher water demand (and use).
• Irrigation history – particularly pre-irrigated or fully irrigated in the autumn (probably not an issue for most this season).

“Landholders should be keeping a close eye on soil moisture levels within the active rootzone of crops and pastures,” he said.

“The easiest way to do this is by pulling out some plants, digging up some soil and feeling and observing moisture levels but a more objective method is to undertake some form of soil moisture monitoring and irrigation scheduling.”

There are four methods you could consider.

1. Soil moisture monitoring – probes installed in your paddocks to measure either actual or inferred soil moisture levels.
2. Weather-based scheduling – using actual evapotranspiration values, coupled with crop factors, to determine crop use and how fast soil moisture is being deleted, and factoring in forecast data to determine when next to irrigate.
3. Remote sensing – using satellite or remote sensing information to inform decisions around plant water use and when next to irrigate.
4. Plant-based sensors – directly measuring things like sap flow, canopy temperature, and fruit and stem growth.

“There are various pros and cons of the various methods – cost, installation, ease of interpretation, calibration of results, and crop and pasture type all come into play.

“No matter what system you use, the key is to understand what the data is telling you and making valuable to you and your business, information for the sake of information is time, effort and money wasted,” Mr Leighton said.

There are a range of resources available from the Local Land Services and NSW Department of Primary Industries websites or contact the Sustainable Agriculture Team in your Local Land Services office on 1300 795 299.