Effect of application rate of commercial lignite coal-derived amendments on early-stage growth of Medicago sativa and soil health, in acidic soil conditions

The occurrence of acidic soils in Australia limits agricultural productivity. It is claimed that commercially available lignite coal-derived products have the capacity to buffer soil pH. In addition, manufacturers of these products and farmer anecdotal evidence suggest promotion of plant shoot and root growth. This study investigated the effect of application rate of lignite coal-derived amendments on the early-stage growth of a pasture legume, lucerne (Medicago sativa), and soil health in a soil type common to south-eastern Australia, in a glasshouse setting. Measurements of root and shoot biomass, microbial biomass C and soil pH were taken after 6 weeks of growth. Differences were observed between the amendment application rates, particularly lucerne shoot and root growth in soil amended with 20 kg/ha of soluble K-humate granules. The results of this study will assist farmers in making decisions about the value and effectiveness of lignite coal-derived amendments on plant growth as well as their potential to improve soil health.Karen Little, Michael Rose, Antonio Patti, Timothy Cavagnaro, and Roy Jackso