PPS completed a variable lime application project from 2013 – 2016
Soils in much of the Upper Wimmera and Central Victorian region are naturally acidic and are often at pH levels which restrict plant growth or allow the release of aluminium which may be at levels toxic to plant such as phalaris.
The application of lime is used to increase the soil pH and take it to levels that are not detrimental to plant growth. In most cases this is done after a soil test is done on amalgamated samples from a paddock and the standard recommendation is an application of 2.5 tonnes of lime per hectare over the whole paddock.
Soil mapping shows that soil pH usually varies within paddocks and that a blanket lime application may not be the most effective way of raising the paddock pH to the required level. Some areas of the paddock may require a higher lime application than the standard rate, while other areas may need less or even not require lime at all.
The Variable Lime Application Trial was set up to test the use of variable pH testing and the effect of variable lime applications based on the results of the testing technique. The variable lime technique involves whole paddock pH testing and the production of soil pH maps that reflect the pH variation within the paddock, the rate of lime application for each area of the paddock is then recommended. Lime is then applied at the variable rate.
PPS also used NDVI testing prior to the lime application to investigate pasture growth differences in the mapped pH ranges within the paddock. Variable P and K testing was added to the final stage of the project to assess the possibilities of the method being a tool for efficient nutrient management in pasture systems.
The project was supported by the Glenelg-Hopkins & Wimmera CMA’s