Can we maintain productivity on broad acre dairy farms during early transition from mineral to compost fertilization?

Composts are being increasingly used as an alternative to mineral fertilisers in production agriculture. However, some farmers are reluctant to utilise compost due to lack of consistent information regarding agricultural productivity and management. Here we explore the changes in soil chemistry, plant biomass production and nutrition during an 18 month transition period from mineral to compost fertiliser use. This was undertaken on plots excluding stock on two dairy farms in southeastern Australia. Biomass was not affected by compost application, demonstrating that productivity and nutrition were maintained during early stage transition. Soil chemical properties, including available nitrogen species, were influenced by compost, but changes fluctuated over the transition phase. Impacts of management practices, season and soil chemical influences on biomass production were explored using multivariate techniques. This analysis revealed that season and inherent soil chemical properties had the greatest influence on pasture biomass during early stage transition. Results are discussed in the context of a transition to compost-based nutrient management of grazed dairy pastures.