Understanding soil pH through dual-depth grid soil mapping

Full description

This project aimed to reduce the erodibility of high risk landscapes through an increase in the area of land planted to perennial pasture species, which are both more productive and more persistent when not constrained by acidity and aluminium toxicity. To achieve this, the project aimed to increase awareness, knowledge and understanding of soil acidification and management options for topsoil and subsoil acidity.
Traditional blanket-rate lime practices do not address the issue of increasing subsoil acidity, nor target areas where acidity is most severe, and the project explored dual-depth grid soil mapping in combination with variable rate lime application for more effective and longer-term management of soil acidification.
The project aims to increase the area of land planted to perennial pasture species, as well as increase the area of soil limed to at least pH 5.2 in the topsoil (0–10cm). Grass and legume-based pastures limed using tailored rates will be more productive as a result, with pasture legumes and their rhizobia able to supply more fixed nitrogen (N) for the benefit of the mixed sward.
Based on intensive soil sampling, the project aimed to develop property soil nutrient and liming plans that identify the constraints, including soil acidity, that can influence the establishment and maintenance of perennial pasture systems. By ensuring that soil fertility and plant nutrition are understood and managed by the landholder, the focus can be on the prevention of soil erosion and the management of acidification.