Analysis On Water Use Demand For Irrigation And The Development Of Water-Saving Irrigation

The development modes of water-saving irrigation in different natural conditions and various crops are put forward by means of analyzing and forecasting water use demand for irrigation and water requirement structure, and evaluating the input and output of water-saving irrigation measures. This is necessary to choose the development mode and speed of regional economy suitably, to promote the development of water-saving irrigation in scientific and vigorous way, to realize the sustained utilization of water resources and to guarantee the sustained development of the economy and society. As a presider or main participator, I have finished many scientific research projects such as Sub-area and Forecast Development of Water–saving Agriculture in North-China, the Development Plan of Water–saving Agriculture in China, Technical Standard for Water-saving Irrigation, the Tenth-five Year Plan and 2010 Programming of Water–saving Irrigation in China, Water Resource demand of Agriculture and the Buildup of High Efficient Agriculture for Saving Water, Sustained Development and Water-saving Stratagem of Farming and Animal Husbandry in North-west of China, Technical Popularization of Saving-water and Increasing Yields in 300 Key Counties of China, the Development Scale of High Efficient Water Use in Agriculture and Foreground Forecast of Correlative Industry, etc. Based on above studies, from population and economy which have been regarded as main factors of increasing the demand for irrigation water, a neural network auto regressive moving average models with external nonlinear input (NNARMAX) is adopted to forecast water use demand of irrigation in a mid-long period in China. According to the nature, economy, society, water-land situation and cropping structure, the technical system, the standard index system and the effect evaluation system for water-saving irrigation have been put forward by means of following the fundamental of adjusting measures to local conditions. The development scales of water-saving irrigation in sub-areas are forecasted in 2010 and 2030 separately. The rational modes of water-saving irrigation suited to our country's situation are summarized. Main results have been achieved as follows.　The factors influencing the water use of irrigation include the inner factors such as the actuality of irrigation projects, irrigation methods and irrigation scheduling etc. and the outer factors of irrigation system, for instance, population, agricultural product requirements, natural geography condition, cropping layout, etc. During the progress of forecasting the demand of water resources, the finiteness of increasing the water demand should be considered firstly. With the development of science and technology and through increasing the ability of water management, breeding crops for high efficient water use, improving farming measures, raising water use efficiency in agriculture and updating the ideal of utilizing water, it is not true that producing more grains need more water resources. Meanwhile, the carrying capacity of water resources and the need of ecological environment should be considered next. Urbanization in rural area, the increasing of urban population and the changing of life style make a change of food supplies, which finally embodying in the requirement of water resources. Based on analyzing the advantages and disadvantages of mainly forecasting models in water resources of irrigation, such as auto-regress slide average method, regression analysis method, index analysis method, gray forecast method, artificial neural network and system dynamics method, etc., a neural network auto regressive moving average models with external nonlinear input (NNARMAX) is established, which combined the slide average model during analysis time serial, regression analysis method and artificial neural network. From mainly inner factors making the increase of water demand for irrigation, such as population and economy, the main factors affecting irrigation water use are considered. According to the statistics data from agriculture and water resources department and my correlative research results, the water demand for irrigation use has been forecasted in the mid-long term under the condition of guaranteeing the national food security. Water-saving irrigation has rich meanings and extensions which mainly including the engineering technical system, the standard index system and the effect valuation system. The technique system of water-saving irrigation consists of the exploitation techniques and the optimizing utilization of water resources, the engineering techniques of water-saving irrigation, the techniques of farming tillage and cultivation, and management techniques of water-saving irrigation. The standard index system of water-saving irrigation includes irrigation water use, the utilization efficiency of irrigation water, the technique requirement of engineering and its benefit. The effect valuation system of water-saving irrigation contains economic policies, engineering techniques, water-land resources and ecological environment. The development of water-saving irrigation has a closing relationship with various nature, society, economy conditions, the development requirement of national economy and the measures of water-saving irrigation. These conditions have regional differences and also have similar in some aspects, which contact each other and influence each other. The sub-area of water-saving irrigation is conducted to guide the development of water-saving irrigation suited to local conditions. In this paper, samples matrixes are composed of 150 third-level areas, which being pre-divided into 36 kinds. Through computation, the whole country (except Hongkong, Macao and Taiwan province) is divided into 7 water-saving irrigation areas including Huang-Huai-Hai area, Northeast of China, Inner Land area, Mid-lower Reaches of Yangtze River, Zhu-min River area, Mid-upper Reaches of Yellow River and Southwest area. The scales of developing water-saving irrigation being affected by many factors such as water and land resources, the actuality of irrigated agriculture and the demand of crop yields, etc., is a multi-objective programming problem. To reflecting the linked characteristics and development dynamic of programming, a cycle-optimize mathematical model is adopted toforecast the development scales of water-saving irrigation and the key measures of developing water-saving irrigation in seven sub-areas are put forward. A prospect of developing water-saving irrigation in former three decades of 21 centuries is made from four aspects. The deepening development of water-saving irrigation needs the new revolution of science and technology and the increase of science and technology content of saving water. Only in this way, would water-saving irrigation break through in quantity and quality, even in marketing. The changeless mode of water-saving irrigation could not be adopted because there are differences in natural conditions, economy, society situation and the objects of irrigation where water-saving irrigation is implemented. Based on the principle of adjusting measures to local conditions, various local conditions and crops, the different modes of water-saving irrigation have been established, which including Irrigation engineering techniques of saving water and increasing benefit in new establishment district, Water-saving transformation of well irrigation district in North China, Water-saving transformation of field engineering in Cannel irrigation District of north area, Engineering techniques of water-saving irrigation by conjunctive use of surface water and groundwater (Well combined with surface water in cannel) in north area, Rebuilt of water-saving in small pumping irrigated district of south area, Gathering Rain for water-saving irrigation as a way enriching local settlement, Engineering techniques of water-saving irrigation in suburb agriculture, and Irrigation engineering techniques for saving water and relieving drought. The innovation points of this research are as follows. Except the system self, the outer factors and scale effects are considered when analyzing the water use of irrigation, thus established forecast models and computation results can reflect the actual situation and have much more rationality in science. This is the first to put forward three systems (engineering technical system, standard index system and effect valuation system) forming the framework of water-saving irrigation and to analyze and recapitulate the meanings and extensions of water-saving irrigation. Based on the principle of adjusting measures to local conditions, eight kinds of engineering technical modes for water-saving irrigation suited to the different areas of China have been put forward, which creates the condition of increasing scientific rationality and reducing blindness for water-saving irrigation. Above results have been used in the national development plan of water-saving irrigation and Technical Standard for Water-Saving Irrigation and popularized in many projects, such as water-saving rebuild of large scale irrigation district in China and the key counties of saving water and increasing yield, which providing a scientific basis and a reference for macro decision-making of national water-saving irrigation. Due to the complex of demanding analysis in irrigation water use, uncertain factors affecting the development of water-saving irrigation and limited statistics data, there are many problems and disadvantages existing in the results, which need to be supplemented and perfected further.