Fresh thinking: Integrating greenhouse gas emissions with water use and nutrient use efficiency for dairy farming
In partnership with dairy processing company Synlait we are investigating the effects of converting traditional dryland pasture to dairy farming and the resulting environmental variables on greenhouse gas emissions and carbon storage.
Published: 24 July 2012 - by Tom Fraser
In partnership with dairy processing company Synlait we are investigating the effects of converting traditional dryland pasture to dairy farming and the resulting environmental variables on greenhouse gas emissions and carbon storage
The reason is simple; with the trend towards farm intensification and rapid expansion in converting land to dairy farming greenhouse gas (GHG) emissions are set to continue to increase. New Zealand needs to find innovative ways to reduce our GHG emissions from agriculture in ways that allows continued economic growth and prosperity.
Furthermore, the added demand for water for irrigation is an additional dimension to resource availability. Nitrous oxide emissions are also linked with nitrate leaching losses and water quality and retention of soil carbon is critical for maintaining pasture productivity. Possibilities of changing management practices to increase soil carbon storage are becoming increasingly relevant.
We are using two adjacent sites - one unirrigated, grazed dryland and the other irrigated and newly converted to dairying - on a Synlait dairy farm in Mid-Canterbury to collect data and develop models that allow fresh interpretation of the impacts of farming practices on multiple environmental benefits and consequences.
We are comparing greenhouse gas inventories for the two sites over the next five years with the aim of answering specific questions:
- What is the impact of the conversion of dryland grazing to irrigated dairy farming on net annual greenhouse gas emissions at paddock scales?
- How does conversion of dryland to irrigated dairy farming affect soil carbon storage?
- What are the environmental drivers of greenhouse gas emissions and changes in soil carbon storage and how do these vary seasonally?
- Are water use efficiency and nitrogen use efficiency decreased with irrigation and application of fertiliser?
- Is there opportunity for improved water use efficiency by modifying irrigation scheduling?
- What is the impact of irrigation and fertiliser application on nitrate leaching?