Farmers in both are fighting a losing battle to save the soil that produces our food. By contrast, there's not enough water in the vast Yangtze basin, which produces a third of China's crops. Soil erosion could lead to a 10% loss in global crop production by 2050, according to the UN's Food and Agriculture Organization (FAO). Similarly, other measures such as digging thousands of new wells and encouraging farmers to switch crops to boost yields have limited impact. Options include not tilling soil to reduce erosion, and planting off-season cover crops to prevent erosion and nutrient loss.

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