Long-term overuse of fertilisers saps China's farmlands
China's farmers use 30 per cent of world's fertiliser - twice global average
Unsustainable farming practices, such as the overuse of fertilisers, are drying out farmland in the north, posing a threat to future food and water resources, according to an international study.
Yaling Liu, a research associate at the Pacific Northwest National Laboratory in the US, which led the study, said China's excessive use of fertiliser dated back to about 1980 and was now well above the global average.
"The total amount is around 30 per cent of the world total - the average rate is more than twice the world average," Liu said.
"A lot of Chinese farmers are not well educated ... they're unwilling to risk reducing fertiliser; traditional thinking is that [using] more fertiliser leads to higher yield."
But research showed that excessive fertiliser use had a range of adverse effects on the environment, while also having little impact on crop yield, Liu said.
The team, which included researchers from Purdue University in the United States and Beijing's China Agricultural University, analysed data from farmland in northern China and found soil moisture has declined significantly over the past 30 years.
The optimal moisture level for farmland is 40 to 85 per cent of the soil's water-holding capacity, but the region's level was below that range, and getting drier, researchers said.
