Variable Rate lime does reduce the variability of soil pH

Variable rate (VR) lime aims to reduce the variability in soil pH across the paddock by liming to a uniform pH target. Measuring the efficacy of VR lime is often challenging in a commercial environment due to infrequent sampling (5 or more years) and changes in sample design and methods between sampling events. This paper presents the results of grid soil mapping conducted in 13 paddocks (830 ha) in Victoria in 2016/17 and 2 years later after VR lime addition in 2018/19. Grid soil mapping and variable rate lime applications were effective in increasing the average pH and reducing the variation in pH within the paddocks. More specifically, the results showed a greater change in soil pH at the lower pH values, meaning the VR lime applications successfully ameliorated the most acidic areas of the paddock, where soil pH is most likely to negatively impact crop and pasture production.