Millions of Chinese farmers have cut fertilizer use, reduced greenhouse gas emissions, and increased crop yields after adopting new region-specific management practices, according to a 10-year study published recently in the journal Nature.

Chinese farmers use about 305 kilograms of nitrogen per hectare per year, more than four times the global average, in part because the Chinese government actively promoted increased fertilizer use for many decades. Starting in 2005, researchers at the China Agricultural University in Beijing ran field trials across the country’s major agricultural regions to see how they could reduce fertilizer use while boosting yields for small-scale farmers.

In each zone, they tested optimal cultivation strategies for wheat, maize, and rice. As their findings came in, the researchers used a network of over 1,000 researchers plus thousands of additional extension agents, and agribusiness professionals to pass their advice along to millions of small-scale farmers across the country. Recommendations ranged from shifting planting density to adjusting the timing of fertilizer application. Almost 21 million Chinese farmers in 452 counties adopted the recommendations of the group—accounting for some 37.7 million hectares. While farmers implemented the new management practices in the field, campaign collaborators and extension agents collected results.

Over a 10-year period, average crop yields increased by over 10 percent, while nitrogen fertilizer use decreased by around 15-18 percent. Due to the reduction in fertilizer use, greenhouse gas emissions also decreased substantially for each of the three crops studied, as much as 13 percent for maize and wheat.

On average, these farmers saw significant increases in yields and decreases in fertilizer use. The intervention proved to be good for the farmers’ budgets, too. As a result of increased yields and decreased input, farmers collectively saved US $12.2 billion.

“The extent of the improvement in terms of yield increase and fertilizer decrease was great,” study co-author Zhengxia Dou, a professor at the University of Pennsylvania’s School of Veterinary Medicine, said in a statement. “But it was not a surprise as similar results had been attained before. It was the scale of it all, approaching it with an all-out effort and multi-tiered partnerships among scientists, extension agents, agribusinesses, and farmers, achieving a snowball effect. That, to me, is the most impressive takeaway.”

—Hannah Hauptman