The total water resources in China are 2.8/kloc-0.00 billion m3, and the per capita water resources are about 2,200m3, which is only/kloc-0.4 of the world average. It is predicted that by 2030, the population of China will increase to 654.38+0.6 billion, and the per capita water resources will drop to about 1.76 m3, which is close to the internationally recognized warning line of 1.70 m3 severe water shortage. The proportion of total agricultural water consumption to total water consumption will continue to decline, and the shortage of water resources will become one of the most important factors restricting China's agricultural development. This paper discusses the agricultural production system in which water-saving irrigation measures such as engineering, agronomy and management are adopted in the agricultural production process to comprehensively improve the utilization rate and efficiency of natural precipitation and irrigation water, so as to achieve the purpose of saving water and improving the efficiency of agricultural water use and promote the sustainable development of agriculture. 1. China's agricultural water-saving potential China's agricultural development will face a severe challenge of the contradiction between supply and demand of water resources. Agricultural water consumption accounts for about 70% of the total water consumption in China, of which farmland irrigation water consumption accounts for 90% of agricultural water consumption. On the one hand, China's water resources are seriously inadequate, on the other hand, the phenomenon of agricultural water waste in China is very serious. (1) The utilization rate of farmland irrigation water is low, and the average utilization rate is only about 45%. (2) The utilization rate of farmland natural precipitation is low, only reaching 56%. (3) The water productivity is not high, only about 65438 0.0 kg/m3, and the water productivity of dryland farmland is 0.60~0.75 Kg/m3. In developed countries, the utilization rate of irrigation water is above 80%, and the water productivity is about 2.0 Kg/m3. Therefore, China has great potential for agricultural water saving. 2. Engineering water-saving measures Water-saving irrigation measures can be divided into three categories: engineering measures, agronomic water-saving measures and management measures, among which engineering measures can be further divided into three categories: water-saving measures for canal system water delivery, water-saving measures for field irrigation and water-saving measures for combining canals and wells. Water-saving measures of canal system are usually divided into canal seepage control measures and pipeline water delivery measures. Water-saving measures for field irrigation can usually be divided into improving surface irrigation technology, popularizing sprinkler irrigation technology and micro-irrigation technology. The water-saving measures of the project can be specifically broken down as follows: (1) Construction of seepage-proof canal area, hardening of irrigation canals with various materials, such as concrete slope protection boards for branch canals and bucket canals, and concrete U-shaped grooves for agricultural and wool canals; (2) Construction of sprinkler irrigation areas such as low-pressure pipe irrigation, drip irrigation, infiltration irrigation, sprinkler irrigation and micro-spraying. , play the role of demonstration area, mainly used for efficient agriculture; (3) Construction and renovation of electromechanical irrigation station, expansion of surface water storage projects and various hydraulic structures such as bridges, culverts, gates, aqueducts, falling water and inverted siphons. 3. Agronomic water-saving measures Agronomic water-saving measures include field runoff interception, land consolidation and farmland cultivation techniques. 3. 1 field runoff interception. The runoff interception project of water-saving agriculture is limited to all natural precipitation in farmland and some water from marginal slopes. Generally speaking, it is a soil and water conservation engineering system including civil and biological measures, which is composed of slope management, slope water diversion and storage, and a small number of branches and ponds on sloping farmland in mountainous and hilly areas. 3. 1. 1 slope treatment project. It is mainly to change the slope of the ground, intercept surface runoff, increase soil infiltration, improve soil structure and improve soil water storage capacity. 3. 1.2 Slope water project. It is mainly used to intercept, divert and adjust the surface runoff that the soil can't fully accept, including local rainfall and external water. 3. 1.3 regulation project of tangba and waterway. The scale of the project is larger than that of ordinary field pits, with larger water collection area and greater water collection capacity. The project construction should make full use of the local topography and water resources, focusing on small scattered areas, avoiding repairing the big and abandoning the small, abandoning the old and building the new, and focusing on transforming the old pond, turning shallow into deep, turning small into big, and turning dead into life. 3. 1.4 Vegetation and ecological construction. Vegetation and ecological construction in water-saving agricultural system are the parts of planting trees and grass. By planting trees and grass, soil and water can be maintained, the water storage capacity of natural vegetation can be increased, and the ecological environment of farmland can be improved, so as to achieve the purpose of saving water, increasing income, increasing efficiency and sustainable development. The construction contents include farmland forest network, surrounding shelterbelt system, professional forest base and pasture planting. 3.2 Land consolidation. Land consolidation project is the field engineering part of water-saving agriculture, and it is the combination of engineering measures and agricultural measures. On the basis of water-saving irrigation project or soil and water conservation project, the farmland operation field is introduced and transformed to give full play to the water-saving benefits of the project and improve the utilization rate of field water. It can be simply divided into two parts: land leveling and site planning adjustment. 3.2. 1 Land leveling. Land leveling is the most conventional water-saving agricultural measure, including dry land leveling, irrigated land leveling and paddy field leveling, but it is mainly used to irrigate irrigated land and paddy field. According to the factors such as ground slope, field height difference and soil layer thickness, scientific design is carried out to ensure that irrigation water and precipitation fully infiltrate into the field, reduce water loss and deep leakage, improve irrigation uniformity, shorten irrigation time, and then reduce ineffective transpiration and irrigation quota in the field. 3.2.2 Site planning adjustment. Land planning adjustment is also an important aspect of water-saving land consolidation. For example, turn sloping farmland into terraces and change large beds into small beds. 3.3 Farming and cultivation techniques. Farming and cultivation links in water-saving agriculture, that is, narrow sense of agricultural water saving, or agricultural water saving. Mainly through field cultivation and cultivation management measures, reduce the field water consumption during crop growth (including partial ground evaporation loss during water transportation). It is to reduce the loss of ineffective water in the field, that is, to reduce the net water consumption in the field and improve the utilization rate and productivity of natural precipitation and irrigation water while giving consideration to agricultural output and benefit. This part of water saving is the real resource saving and benefit saving, and it is the core part of the whole water-saving agriculture. 3.3. 1 soil water storage project. Water from any source provides water for crop growth through soil, a special carrier, so soil is actually a huge reservoir without free water surface and has great water storage capacity. According to rough calculation, the water storage capacity of soil with the depth of 1 m can be equivalent to the annual precipitation under semi-humid climate conditions, and its water storage potential is very huge, so people regard it as the third largest water storage means after surface reservoirs and underground reservoirs. 3.3.2 Farming and mulching for soil moisture conservation. This is the most widely used agricultural water-saving measure in traditional dry farming. Drought-resistant and moisture-saving technologies, namely, cutting off soil capillary action, reducing ground evaporation, controlling weeds and field humidity, especially reducing inter-plant evaporation, are the ineffective transpiration part to be reduced by agricultural water-saving goals, so it is an important technical link to reduce field water consumption. Through tillage and mulching, soil moisture can be effectively maintained, and water use efficiency and water productivity of natural precipitation and irrigation water can be improved. 3.3.3 Water-saving planting system and planting structure. This is also a very important link in the current water-saving agricultural measures. Based on the principle of high-quality and efficient market benefit and the goal of sustainable development of resources and environment, we choose and design high-quality and efficient water-saving planting system and crop structure. In areas lacking in resources, it is necessary to appropriately compress and control the irrigation area, restore some dry crops, and reduce some crops with high water consumption and low efficiency. Each region can choose the most ideal mode according to the conditions of its own region. 3.3.4 Water-saving cultivation techniques. The so-called water-saving cultivation techniques have a wide range of contents, and most of them are comprehensive agronomic measures related to the biological characteristics of crops. Such as variety characteristics, growth period, population traits, plant nutrition, etc. These aspects are also interactive and interrelated. 3.3.5 Application of drought-resistant and water-retaining chemicals. Since fulvic acid was successfully separated from humic acid in China, the application of chemical drought-resistant water-retaining agent has developed rapidly. It has been widely used in field crops, melons and vegetables and fruit trees, and achieved certain results. Each region can choose according to the local climate, soil conditions and crop cultivation. 3.3.6 Water saving irrigation system. Among all agricultural water-saving measures, scientifically designed water-saving irrigation system can be said to be a comprehensive destination. It is not only the embodiment of the comprehensive effect of agricultural water-saving measures, but also the combination of engineering water-saving, agronomic water-saving and management water-saving. Water-saving irrigation system is designed according to the natural precipitation in a region or a growing season, the dynamic change of soil moisture and the demand of crops for irrigation. By adjusting soil moisture, adjusting crop growth and development, and fully tapping water-saving potential, the best economic yield and water production efficiency can be obtained. The demand for water in different growth stages of various crops varies greatly, and not all growth stages need sufficient water supply and soil wetting. The contents of scientific water-saving irrigation system design include: the date of each irrigation, irrigation times in the whole growth period, irrigation cycle (interval), irrigation quota, irrigation quota, upper and lower limits of soil water content before and after each irrigation, and soil wetting depth in different growth periods. The water-saving effect of all water-saving measures will eventually be implemented on the above irrigation indicators, which is reflected in the comparison between the new irrigation system and the old irrigation system.
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