Short version: China is huge, but doesn't have much good land left for farming. And the land they *do* have is dwindling as they embrace super-dirty technologies.
6 mind-boggling facts about farms in China | Grist
Then there’s land. Here are just a few of the findings of recent investigations into the state of Chinese farms:
1. China’s farmland is shrinking. Despite the country’s immense geographical footprint, there just isn’t that much to go around. Between 1997 and 2008, China saw 6.2 percent of its farmland engulfed by factories and sprawl.
2. The United States has six times the arable land per capita as China. Today, the FAO/OECD report states, China has just 0.09 hectares of arable land per capita — less than half of the global average and a quarter of the average for OECD member countries.
3. A fifth of China’s land is polluted. The FAO/OECD report gingerly calls this problem the “declining trend in soil quality.” Fully 40 percent of China’s arable land has been degraded by some combination of erosion, salinization, or acidification — and nearly 20 percent is polluted, whether by industrial effluent, sewage, excessive farm chemicals, or mining runoff, the FAO/OECD report found.
4. China considers its soil problems “state secrets.” The Chinese government conducted a national survey of soil pollution in 2006, but it has refused to release the results. But evidence is building that soil toxicity is a major problem that’s creeping into the food supply. In May 2013, food safety officials in the southern city of Guangzhou found heightened levels of cadmium, a carcinogenic heavy metal, in 8 of 18 rice samples picked up at local restaurants, sparking a national furor. The rice came from Hunan province — where “expanding factories, smelters and mines jostle with paddy fields,” the New York Times reported. In 2011, Nanjing Agricultural University researchers came out with a report claiming they had found cadmium in 10 percent of rice samples nationwide and 60 percent of samples from southern China.
5. China’s food system is powered by coal. It’s not just industry that’s degrading the water and land China relies on for food. It’s also agriculture itself. China’s food production miracle has been driven by an ever-increasing annual cascade of synthetic nitrogen fertilizer (it now uses more than a third of global nitrogen output) — and its nitrogen industry relies on coal for 70 percent of its energy needs. To grow its food, in other words, China relies on an energy source that competes aggressively with farming for water.
6. Five of China’s largest lakes have substantial dead zones caused by fertilizer runoff. That’s what a paper by Chinese and University of California researchers found after they examined Chinese lakes in 2008. And heavy use of nitrogen fertilizer takes its toll on soil quality, too. It causes pH levels to drop, turning soil acidic and less productive — a problem rampant in China.