LIFE CYCLE ASSESSMENT OF GHG EMISSIONS ON SA PASTURE-BASED DAIRY FARMS

To sustainably increase net farm income dairy farmers must ensure resources are utilized optimally while also improving the environmental impact of the farming system. The link between economic viability and environmental awareness for intensively managed pasture-based dairy farming systems is therefore critical to consider as both play a pivotal role in securing continuous dairy production to address global and local needs. The environmental impact of intensive dairy farming systems should therefore be evaluated as such systems and the larger agriculture in general, has several negative influences on the surrounding environment, including eutrophication, declines in biodiversity, and pollution of nearby waterbodies. Dairy production in particular is characterized by the emission of greenhouse gasses (GHG) contributing toward climate change. In the study cited, the carbon footprint of South African pasture-based dairy farming systems was assessed using a farm-gate life-cycle assessment (LCA) approach.

A total of 82 pasture-based dairy farms in the Eastern Cape, Western Cape and Kwa-Zulu Natal were assessed over the period 2012 to 2022. The average carbon footprint across all farms was 1.36 ± 0.21 kg CO2eq/kg FPCM, which is slightly greater compared to commercial dairy systems in advanced dairy production countries. As expected, enteric fermentation had the largest influence on the carbon footprint. Other significant contributors included manure management, crop and pasture production, electricity and purchased feed production. Farms with high GHG emissions were characterized by greater N fertilizer usage, indicating alternative N fertilizer management strategies are required to improve pasture N uptake and utilization. Of importance is that efficient milk production was a critical factor in reducing GHG emissions from these farms.

It was concluded that in order to address all the complexities and demands within SA pasture-based dairy farming systems, an adaptable management system is required where each management practice can be tailored according to the prevailing soil and climatic conditions, farming system challenges and advantages.