North China super-mining area: starting the battle of agricultural water-saving and fighting against difficulties

In recent years, the situation of groundwater overexploitation in water funnel area of North China is becoming more and more serious. We should make good use of rainwater, pay attention to water conservation, make an issue of planting structure, drought-resistant varieties and water-saving technologies, and realize the transformation of agriculture from confrontational agriculture to adaptive agriculture, and from passive drought resistance to active disaster avoidance.

The Agriculture Department of Hebei Province recently announced that Hebei will appropriately reduce the planting area of winter wheat relying on groundwater irrigation in the severely overexploited groundwater area, change the winter wheat and summer corn two-crop system to one-crop system, realize "one season fallow, one season rain cultivation", and tap the potential of increasing production at the same time of autumn grain rain and heat. Hebei also stipulates that farmers who reduce wheat planting in the project area shall be subsidized according to the subsidy standard of 500 yuan per mu.

At the beginning of September, Beijing City also issued a plan to designate the serious groundwater overexploitation area as a key control area, gradually withdraw from the planting of high-water-consuming crops in an orderly manner, and restore the water conservation function by adopting the mode of forest suitable for forest, grass suitable for grass, fruit suitable for fruit, and fallow for fallow cultivation; develop dry farming or plant ecological crops that cannot be withdrawn temporarily. In accordance with the principle of "determining business by water", the water consumption structure will be adjusted and reduced.

Why did the two provinces and cities launch similar initiatives? Gao Xiangzhao, director of the Water Conservation Division of the National Agricultural Technology Extension Center, said that China uses 580 billion cubic meters of water every year, of which agricultural water accounts for 62 percent. The annual agricultural water shortage exceeds 30 billion cubic meters, and the average water consumption for producing 1 kilogram of grain is as high as 800 kilograms, while the world advanced level water consumption is only 500 kilograms. On the one hand, there is no water, on the other hand, there is flood irrigation. In this case, it is an inevitable choice to adjust planting structure and promote efficient water-saving irrigation in different regions.

"Groundwater overexploitation areas must establish a long-term mechanism for sustainable agricultural development, allowing land to recuperate and reducing agricultural groundwater irrigation. This reflects the new national strategy for food security, which places greater emphasis on agricultural environmental governance and sustainable development while focusing on food quantity." Cheng Guoqiang, a researcher at the Development Research Center of the State Council, said in an interview with reporters from Economic Daily that the planning of Hebei and other places is a good measure. This year, the No.1 Document of the Central Committee proposed for the first time to carry out pilot projects for the recuperation of agricultural resources, among which the comprehensive management of groundwater overexploitation funnel areas in North China was included, and proposed that comprehensive measures such as financial awards and structural adjustment should be adopted to ensure that the overall income level of farmers in the restoration areas will not be reduced.

Wheat is a large water user for agricultural irrigation in the north, and it is also the focus of the adjustment of planting structure in the two provinces and cities. According to the comprehensive water demand and natural precipitation of wheat, the basic supply and demand balance in Jianghuai region; the water shortage in the north of Huaihe River is more than 100 mm, and the precipitation in the north of Yellow River can only meet one third of the water demand of wheat, so the gap needs irrigation supplement; the arid area in northwest China mainly depends on irrigation.

Will crop restructuring affect food security in the project area? Before the introduction of the plan, Hebei has carried out relevant pilot research. Wang Huijun, president of Hebei Province Academy of Agricultural and Forestry Sciences, introduced that from this year's 5000 mu wheat field of micro-irrigation water and fertilizer integration technology in Wuqiang County, under the premise of stable yield and yield increase, each mu can save 70 tons to 80 tons of water. If it is popularized in the whole province, even if 50 tons of water is saved per mu, the water saving amount of 35 million mu of wheat in the whole province will be equivalent to the water consumption given to Hebei by the South Water Transfer Plan.

Beijing City, on the basis of defining the annual water consumption standard of 200 cubic meters per mu of field, also uses measures such as facilities and agronomy to tap the potential of water-saving agriculture and ensure the stable supply of "vegetable basket" products. Beijing will build high-efficiency water-saving irrigation facilities, and different facilities will be used for different planting structures. In grain fields, advanced water-saving equipment such as mobile sprinkler irrigation and pointer sprinkler irrigation and water-fertilizer integration technology shall be popularized; in vegetable fields, film-covered irrigation and water-fertilizer integration shall be taken as the core water-saving technologies.

In recent years, the occurrence scope and degree of drought in China are increasing, and the situation of groundwater overexploitation in the water funnel area of North China is becoming more and more serious. Experts believe that in order to comply with the weather and crop growth laws, not blindly increase irrigation, but strive to reduce water and crop water demand period synchronization. This requires making good use of rainwater, paying attention to water conservation, making an issue of planting structure, drought-resistant varieties and water-saving technologies, so as to realize the transformation of agriculture from antagonistic agriculture to adaptive agriculture and from passive drought resistance to active disaster avoidance. In addition, good technical measures such as deep ploughing, rational fertilization and intertillage management can effectively increase soil water storage capacity and improve water use efficiency.