Cropland nitrogen pollution could be reduced cost-effectively, study finds
Global smart nitrogen management on croplands could generate $476 billion in societal benefits for food supply, human health, ecosystems, and climate, at a cost of only $19 billion, according to new research.
Cost and benefits of mitigation of nitrogen pollution in global croplands.
Based on a meta-analysis of 1,521 field observations over the past 20 years, the research, now published inNature, identified cost-effective measures to strongly reduce nitrogen losses from farmland across the globe, while also improving yields.
Researchers say intensified agriculture has used increasingly more nitrogen fertilisers and manure to increase food and animal feed supply. However, more than half of this nitrogen is lost to the environment, contributing to air and water pollution, soil acidification, climate change, and biodiversity loss.
An international team of researchers from Australia, China, Austria, Germany, the UK, and the Netherlands have explored nitrogen mitigation strategies, including efficiency-enhancing fertilisers, irrigation, legume rotations, and improved nutrient management by applying the right type of fertilisers at the right rate, time and place.
The researchers found that if smart abatement measures were implemented on global croplands, 22 million tons of nitrogen fertiliser could be saved, representing 21 per cent globally, and an additional 17 million tons of crop nitrogen could be harvested annually, an increase of 20 per cent.
They advocate that the costs of nitrogen reduction should be paid by society as a whole and propose an innovative agricultural nitrogen credit system that acknowledges the responsibilities and limitations of the multiple parties along the food chain, including farmers, suppliers, processors, retailers, consumers, and governments.
University of Melbourne Professor Deli Chen said a nitrogen credit system would provide economic incentives to farmers to adopt certified environmentally friendly practices to mitigate nitrogen pollution.
“The contributions to the budget should be derived from both taxing fiscal revenues of agri-food enterprises, value-added taxes for consumers, or from dedicated levies or taxes on polluting activities or products,” Professor Chen said.
“This facilitates the transfer of the cost of reducing nitrogen pollution from just farmers to those who benefit, which is all of us.”
The nitrogen credit system.
Zhejiang University Professor Baojing Gu said unfortunately smart abatement methods are seldom fully implemented by farmers due to many constraints, such as high implementation costs and variability of best practices.
“Nitrogen pollution is fast becoming the next global crisis,” Professor Gu said.
“If we truly want farmers to implement these knowledge-based nitrogen mitigation measures, which will benefit all of society, we need to find a way to help them overcome the financial barriers they face.”