Yield and soil impacts of pasture renovation methods in an australian subtropical grazing system

Pasture renovation is widely used to increase biomass production and feed quality through establishment of favourable species, while it can also contribute to improved soil health. There are a number of pasture establishment methods available, however their efficacy for establishing an annual winter feed base has not been compared in subtropical grazing systems of Australia. This study investigated pasture biomass, species composition, soil function and SOC in a subtropical pasture over two seasons where a winter pasture species mix was sown annually. The effect of a direct drill tyned seeder, under sowing (Einböck), minimal disturbance strip tillage (Soilkee Renovator) or mulch and broadcast, compared to an un-sown control. Biomass was harvested from plots in line with the grazing rotation of the paddock, and soils were sampled to 10 cm depth annually in 2021, 2022 and 2023. All establishment methods produced significantly more biomass than the control in both years, but could not be statistically separated from each other. Species composition was variable between the establishment methods with the Soilkee treatment allowing establishment of more legumes and herbs than the other methods. No significant differences were found in soil function or soil organic carbon in any sampling year. Given the limited differences of establishment methods on pasture performance, the use of the lowest cost or readily available method is recommended. In most circumstances, this will be mulch and broadcast which also minimises soil disturbance.