Soil Health Implications Project

The project undertook a review of current literature on the impacts of piggery effluent on soil health, considering both positive and negative effects. It also undertook a survey of producers to understand current practices as well as detailed soil testing on paddocks sprayed and not sprayed with effluent to document any effects.

The project found that currently the benefits outweigh the risks of using effluent. Further research into the long-term impacts are needed and how this might change if more producers take up a waste to energy (biogas) system.

Value for producers:

• Quantifies the value of using effluent to improve soils

• Justifies that when this practice is carefully monitored and matched with conditions it can continue to be used as a valuable resource for soils

• Identifies that the use of effluent on degraded soils can help in increasing nutrients, including soil carbon

Key findings:

• Changes in carbon content between treated and non-treated paddocks were small, although some paddocks showed slight increases others showed none
• Producers reported benefits of effluent spraying included increased crop yields, savings on pest control and a reduced need for other fertilisers
• Paddocks treated with effluent can result in a lower pH and higher salinity which needs to be carefully managed
• All sites treated with effluent had greater nutrient concentrations including nitrogen, phosphorus, sulphur and potassium