Drying soil threatens China’s future crops

Chinese private equity firms have previously sounded the alarm on China’s agriculture industry, noting its lack of economies of scale, low-tech farming techniques and broken value chains challenge the ability to generate returns.

But there may be even more fundamental problems starting to appear: the soil of northern China is drying out and by 2090 may no longer be able to support crops, warns a new study, which says intensive farming practices may be to blame.

Researchers at Purdue University and China Agricultural University looked at 30 years’ worth of data and found that soil moisture levels in northern China have decreased by 6 percent since 1983. The optimal soil moisture level for farmland is typically 40 percent to 85 percent of the water holding capacity, but the region’s soil has a less than 40 percent capacity and is getting drier, according to the study. The results showed the reduction of soil moisture correlated with increased fertiliser usage and the widespread planting of crops with high water demands, such as maize.

The region is home to 40 percent of the country’s population and 65 percent of its cropland, making the long-term impacts of continued drying a cause for concern.

“A 10 percent decline in soil moisture over the course of a century would have major implications for agriculture and the fresh water supply in this heavily populated area,” Qianlai Zhuang, leader of the research group, said in a statement. “The soil moisture declined by 1.5 to 2.5 percent every decade of the study and this water depletion appears to be largely driven by human activities.”

Other agricultural practices may also be contributing to drying the land, such as newly developed water-intensive crop varieties, while increased irrigation may be leading to the extraction of more ground and freshwater. If this trend continues, the soil may not be able to support crops by as early as 2090, the study said.

“Fertiliser has been over-used in China,” said Yaling Liu, lead author of the study, who told Agri Investor that sustainable agricultural practices need to be developed. “Integrated soil-crop system management, water-saving technologies such as mulching and drip irrigation, and data analytics are critical for sustainable agriculture in northern China.”

Liu also says that “aside from how you grow, another lesson is what you grow also matters for food security and sustainability,” and points to the drought in California as a lesson for China. “Forage and alfalfa grown for animal feed, and nuts such as almonds, consume large amount of water and are being blamed for the drought in California. A daily diet toward nuts and meat will inevitably cause more water consumption.”

Like California, China has implemented water saving targets, with a goal of limiting total water use to 670 billion cubic meters by 2020. “Water use keeps increasing,” says Liu. “Limiting it to 670 billion cubic meters by 2020 will be challenging.”