Best practice liming project to help address sub-soil acidity

We are looking for a farmer from north-east Victoria to host a trial site as part of this project. If you think you have a subsoil acidity constraint (ideally less than pH 5 in the 5-20cm zone) and would like to be involved in a trial looking at best practice liming and lime quality issues, please email Riverine Plains Project Officer, Jane McInnes at jane@riverineplains.org.au .

Riverine Plains is pleased to be leading a new GRDC investment, Best practice liming to address sub-soil acidity in NE Victoria, which aims to increase awareness of acidity and pH stratification in local soils, as well as the management tools available to farmers.

While many grain growers are working towards maintaining surface soil pH values above pH 5 through regular soil testing and targeted lime applications, highly acidic layers in the 5-20cm sub-soil can affect production and economic returns, especially when sensitive crops such as pulses are grown.

Because surface-applied lime only moves very slowly down the soil profile, applied lime may only be acting in the surface zone, failing to reach acidic layers further down the profile. Moreover, because soil testing has traditionally been done by bulking surface and subsoil layers together, many farmers may be unaware they have an acid soil layer that is limiting production.

As part of this new project, Riverine Plains will establish a replicated trial to look at how the incorporation of lime can improve the distribution of lime down the soil profile and lessen the impacts of soil acidity on subsequent crops. Some of the techniques which are being considered for the trial include spading, discing, ripping and prickle-chaining.

The lime treatment trial will be established during February 2022 and will compare crop performance of subsequent crops across the different treatments. These results will then be used to inform an economic analysis of the treatment options, while intensive soil sampling will also help to understand differences in nutrient availability, pH and soil organic carbon between treatments.

Lime quality can be quite variable so Riverine Plains will also be establishing a demonstration trial at the same site looking at the quality effect of lime.

For further information about the project, or to learn how to become involved, please contact Riverine Plains Project Officer, Jane McInnes on 03 5744 1713 or email jane@riverineplains.org.au.