Farmers and advisors can now explore a new collection of resources showcasing recent research from the Department of Primary Industries and Regional Development (DPIRD) and practical liming strategies for managing soil acidity, developed by the SoilsWest team in collaboration with DPIRD soil scientists.
The first research summary outlines findings following a field trial at Kalannie considering the shallow incorporation of lime in the management of subsoil acidity (Azam and Gazey 2023). The research identified that applying lime consistently increased crop yields across a four-year period, with similar cereal performance regardless of varying lime rates, or whether it was surface‑applied or shallowly incorporated. However, surface‑applied lime alone was ineffective at treating subsoil acidity in this low‑rainfall region. In addition, combining lime with gypsum offered no extra yield, water‑use efficiency, or grain‑quality benefits. Although shallow strategic tillage raised the soil pH and lowered aluminium levels at 10–20 cm, it did not improve yields or efficiency, and in some years even reduced yields. As such, shallow strategic tillage is not recommended for low‑rainfall acidic sandy soils.
The second research summary was also based on a field trial conducted at Kalannie, presenting results around the benefits of improved crop root development in ameliorated soils (Azam et al. 2025). The field trial indicated that alleviating soil compaction, whether alone or combined with acidity management (i.e. lime application), to a depth of 45 cm greatly improved root growth, water use, and overall crop performance in compacted, acidic sandy loam. Nutrient uptake was further enhanced when lime was applied in conjunction with the soil loosening as the pH increase allowed nutrients to become more available to the crop. In this environment, compaction posed a greater limitation to wheat root development than acidity, as shallow root systems forced plants to compete for limited water and nutrients in the upper soil layers, ultimately reducing yield. Encouraging deeper root exploration substantially improves a crop’s ability to perform in water‑ and nutrient‑limited soils.
The final research summary outlines key details relevant to estimating maintenance lime rates and understanding the factors that influence these requirements. Lime requirements to ensure pH remains above target levels depend on soil type, rainfall, grain yield, and nitrogen application rates. For example, to maintain soil pH in a 325-450 mm rainfall environment, producing a 4 t/ha wheat crop and receiving 120 kilograms of nitrogen annually, the 5-year lime requirement on sandy soil is 1.9 t/ha (90% neutralising value) compared to 0.8 t/ha on loam soil. Routine soil testing to depth is important in allowing for pH trends to be monitored and addressed.
Additional resources
For more information, check out the following resources:
- iLime app – DPIRD developed tool to estimate the impact of applications of lime on soil pH, yield, and profitability of a paddock or area of soil over 20 years.
- Agricultural Lime – Soil Quality Knowledge Base
- Soil Acidity – Soil Quality Knowledge Base
References
Azam, G. and Gazey, C. (2023). Shallow incorporation of lime and gypsum has limited benefit over the sole-surface application of lime for improving grain yield and water use efficiency in the low rainfall Region of Western Australia. Sustainable Agriculture Research, 12(2), 57-72. https://doi.org/10.5539/sar.v12n2p57
Azam, G., Wickramarachchi, K., Scanlan, C., & Chen, Y. (2025). Deep and continuous root development in ameliorated soil improves water and nutrient uptakes and wheat yield in water-limited conditions. Plant and Soil, 512(1), 1405-1420. https://doi.org/10.1007/s11104-024-07153-0
Bridget Watkins is the South-West WA Regional Soil Coordinator (RSC). The RSC project provides opportunities for researchers, primary producers and community groups to collaborate and share knowledge related to soil health and management. The project is supported by the Australian Government’s Climate-Smart Agriculture Program under the Natural Heritage Trust, and in South-West WA is led by the SW WA Hub in partnership with SoilsWest at Murdoch University.
