China, the world’s largest grain producer and top consumer of fertilizers, should reduce its reliance on chemical fertilizers by as much as 50 per cent because excessive use has resulted in serious pollution, according to a research report.

“Not many people are aware that agriculture is the largest polluter in China, which should be a subject for serious concern,” said Wen Tiejun, head of the School of Agricultural Economics and Rural Development, Renmin University of China.

Chemical fertilizers had helped China, the world’s most populous country, to feed its population despite limited farmland, but excessive application had led to low farmland efficiency and serious pollution, according to a research report issued by the school and Greenpeace Jan. 14.

The report said farmers, particularly in northern China, used 40 per cent more fertilizers than crops needed, resulting in about 10 million tonnes of fertilizer every year being discharged into water, polluting China’s rivers and lakes.

China produced 24 per cent of the world’s total grain output, but its use of fertilizer accounted for about 35 per cent of total global consumption. China’s grain production had increased more than eightfold from the 1960s, while use of nitrogen fertilizers had surged by about 55 times, the report said.

It also urged the government to reduce subsidies to fertilizer makers and called for more support for farmers who use animal waste.