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Substantial reductions in the intensity of greenhouse gas emissions at a South Canterbury farm show environmental gains can be made hand in hand with a farm’s growth, scientists say.
Record keeping back to 1991, when Bill and Shirley Wright took on the sheep and cattle farm at Cave, has allowed scientists to study the profile of greenhouse gas emissions over time in an evolving farm system.
Analysis of the Wrights’ farm system in the last couple of years has also provided important insights into nitrate leaching (the loss of nitrogen), and what impacts on the amount of leaching and how best it can be managed.
“The present environmental and water quality issues facing the agricultural sector has highlighted some challenges that need to be addressed,” Bill Wright says.
“Farmers are conscious of their collective responsibilities to not only restore water quality and minimise their environmental footprint. But this is material we are now only learning how to manage in a way that not only protects the environment but provides opportunities to be more productive with less impact.”
Scientists from AgResearch have worked with funders the New Zealand Agricultural Greenhouse Gas Research Centre (NZAGRC) and the Ministry for Primary Industries on the study of gas emissions at the Wrights’ farm, while the Forages for Reduced Nitrate Leaching (FRNL) programme has brought together funders DairyNZ, the Foundation for Arable Research, AgResearch, Plant and Food Research, Landcare Research and the Government in funding research around the nitrate leaching.
Data shows the Wrights’ farming system increased its efficiency and reduced the amount of greenhouse gas emissions per kilogram of product (meat and wool) – also known as emissions intensity – by 18% between 1991 and 2014, and a further 17% by 2015. Emissions in 1991 were 16.9 kilograms of carbon dioxide equivalent gas* per kilogram of product, 13.8kg per kg of product in 2014, and 11.4kg per kg of product in 2015.
The farm changed from predominantly lamb and wool production in 1991 to a large proportion of beef, plus dairy support in recent years. The total amount of product leaving the farm had dramatically increased due to more forage production and use, and adoption of new technologies. The reduction in emissions intensity between 2014 and 2015 was largely due to reduced livestock numbers, in response to dry conditions in the spring of 2014 and 2015.
“What these numbers show is that with the right choices the emissions intensity can be effectively reduced while also developing a farm that is more resilient, more financially viable and still producing quality products,” says Dr Robyn Dynes, who leads AgResearch’s Farm Systems team.
“For the Wrights, as for many sheep and beef farmers, increasing the efficiency and resilience of their farming business had huge spin-off benefits for the intensity of greenhouse gas emissions. New Zealand farmers are playing a big part in lowering the emissions intensity of New Zealand’s agricultural production. Without efficiency gains, New Zealand’s agricultural emissions would now be more than 30 per cent higher than in 1990 due to increased production.”
From the research undertaken in the FRNL programme, the Wrights also gained a clear view of the nitrate leaching on their farm - 18kg per hectare in 2014 and 13kg per hectare in 2015 – and how different pastures and crops can help manage that.
FRNL programme leader Ina Pinxterhuis, a senior scientist at DairyNZ, says the inclusion of a network of monitored farms in the research programme is invaluable.
“The farmers keep the researchers focussed on delivering practical solutions that maintain the viability of the business. They also test the FRNL options on their farms, which is highly valuable for demonstration to other farmers and for determining what information is required for decision making and management support.”
Working together on programmes looking at nitrate leaching and greenhouse gas emissions is important to discover solutions that benefit both goals, says Dr Pinxterhuis.
Bill Wright says the opportunity to be monitor farmers again has allowed him and Shirley to farm with good facts helping their decision making.
“Farmers are the first to want to protect the land, water and air, but now we are developing some useful tools that will enable us to do this while protecting our incomes, communities and the opportunities for future generations to farm the land.”
“I think that although we do face a new era in the environmental awareness, farmers and our families will with new knowledge - through research, science and technology - have a sustainable future.”
*Note: Carbon dioxide equivalent (or CO2e) is a term which describes different greenhouse gases in a common unit. For any quantity and type of greenhouse gas, CO2e signifies the amount of CO2 which would have the equivalent aggregate global warming impact over the course of the next century.