Ground Water Depletion by Agricultural Intensification In China's Hhh Plains.

Sustainable use of groundwater is critical to China’s present and future food security. Natural resources of Huang-Huai-Hai plains, which produces 60-80% of China’s wheat and 35-40% of its maize, are being jeopardized. In this article we show that the groundwater is being depleted quickly. The severity of groundwater depletion is attributed to agricultural intensification, because precipitation and runoff have been constant, and water requirements by urban and industrial use have only moderately increased. China’s present and the future food security may depend more on the availability of water than that of the arable land (40), and more so on that of the groundwater. The environment foot print of agricultural intensification must be drastically reduced. Thus, effective measures must be adopted to curb groundwater depletion. First, the HHH must adopt a cropping system which is compatible with the available groundwater resources. Second, conversion to alternative rotations or intercropping may improve water and nutrient-use efficiency. Site-specific intensification at landscape-scale may reduce agricultural water use. Trees and shrubs as buffer strips among cultivated fields may decrease transpiration, and improve water and nutrient use efficiency. Third, farmers and land managers may be incentivized for adopting micro-irrigation(drip), improving soil quality by enhancing soil organic carbon concentration by mulching,conservation agriculture, manuring and integrated nutrients management, and balanced application of plant nutrients. Producing “more crops per drop of water” by improving water use efficiency is the most critical strategy.