Why acid soils? 

Soil acidity affects more than 50% of intensively used agricultural land in NSW and approximately 23% in Victoria, and is especially prevalent in the higher rainfall areas in our region. Whilst some soils are naturally acidic, agricultural production exacerbates acidification by acidifying processes of the nitrogen cycle and removal of alkaline agricultural products like grain, hay, animal meat and fibre.

Recent research on soils in the NSW Southern Slopes suggests that in most cases, current rates of lime application are not addressing the current soil acidification rate. An effective liming program should aim to increase and maintain a target pH (CaCl2) of 5.8 in the top 10 cm, not 5.0 as has been the current practice. This will provide sufficient lime to raise pH in the surface soil and allow for excess lime to leach into deeper subsurface layers (5 – 20 cm) and slowly increase pH at depth.

HLN with support from NSW DPI are actively managing four replicated trial sites across the region investigating different pH targets (i.e. liming rates), incorporation methods (surface applied lime vs incorporated), and the impact these have on soil pH and crop and pasture growth. The trials were established in 2020 and 2021.

Background information and results for each of the trials can be viewed by clicking on the map icons.