Study on Water-saving Mechanism and Calculating Methods of Crop Water Requirement in Controlled Alternative Furrow Irrigation

Drought and water shortage severely restricting the sustainable socio-economic development. An irrigation of large agricultural country, the water shortage is a serious problem. However, due to the underdeveloped economy, China's farmland irrigation still traditional furrow, groove surface irrigation technology-based, more serious waste of water resources, and how the use of new theoretical research and improved surface irrigation technology to improve farmland water use efficiency and water production efficiency, has become the key issues of agricultural water-saving research. Furrow irrigation is a relatively common form of irrigation methods in the Daejeon wide row crop irrigation. However, conventional furrow irrigation process is difficult to meet the requirements of irrigation timely, appropriate. In recent years, according to the test results of indoor controlling crop root zone irrigation, soil to control moisture into the physical processes of the crop root zone, the physiological process of root water uptake, as well as the roots of the dynamic nature of the compensation function to canopy information transfer and -depth understanding of the interaction, controlled alternative furrow irrigation techniques, Daejeon wide-row crops irrigation has initially demonstrated the advantages of water conservation without cuts, proved to be an effective irrigation methods. However, research on AFI mainly crop water physiological indicators, water consumption and production in this irrigation methods, while after this irrigation soil infiltration parameter changes in Daejeon, crops need to calculate the amount of water and water consumption, as well as guidance Daejeon irrigation water to lower control indicators with actual field production is closely related to several issues, basically no in-depth study of the system, and these problems if they can not get a good solution, is bound to have a serious impact on the promotion and application of irrigation methods. In response to these problems, this paper summer maize as test material, in Daejeon and anti canopy measured pit launched a year pilot study. The paper is divided into six chapters. Chapter ground furrow irrigation improvement and development of the technology, controllability alternate furrow irrigation techniques proposed theoretical basis, the progress of the research at home and abroad, such as the analysis and elaboration of the currently pending further study and resolve major problems Chapter shed measured pit measured data; through the Daejeon irrigation test controllability AFI soil infiltration parameters, irrigation water propulsion and redistribution of moisture in the soil studies; analysis to different furrow irrigation patterns summer cornfield trees proportional relationship between soil evaporation and crop transpiration and soil soil evaporation and surface soil moisture content and the relationship of the leaf area index, irrigation the wet ditch soil surface evaporation intensity of the change process was research Finally, based on the measured yield data initially identified the summer corn alternate furrow irrigation water demand and growth stages daily average water demand strength; Chapter IV controlled alternate furrow irrigation of summer corn plant growth and development, root and shoot than filling rate, leaf water physiological indicators, yield and water use efficiency analysis to determine the controlled alternate furrow irrigation of summer corn suitable for irrigation lower limit; Chapter alternate furrow irrigation under the conditions of summer maize water requirement estimation methods, the basis of crop coefficient and soil surface evaporation coefficient of determination and and a. Study and validation; sixth chapter summarizing the main conclusions of the study, and discuss relevant issues. The main conclusions of this study can be summarized as the following: the door) differences due to the degree of surface soil drying and horizontal suction gradient, soil infiltration parameters in different the furrow ways between there are certain differences, alternate furrow irrigation soil initial infiltration rate, water flow advance rate than conventional furrow and fixed every other furrow irrigation are slow, but the infiltration rate with rapid time decay rate, the surface water in the ditch in the case of the same the single furrow irrigation water subsided lasted longer. Pattern search technology based on the establishment of the water balance equation, hill climbing, Infilt vs analysis software, the flow calculated different furrow irrigation water to promote the process and use of the measured data regression analysis to promote the process almost completely overlap, the prediction accuracy high, and therefore prove that the established model and analyze the calculation method is reasonably practicable entirely different furrow irrigation patterns can be used for soil infiltration parameters and flow advance estimates of the process. u) alternate furrow irrigation, irrigation ditch water infiltration similar GreenAmPt dry soil infiltration pump model Infiltration way of, moist frontal obvious the relatively steep upper profile at the same level horizontal lateral seepage than conventional furrow and fixed every furrow irrigation moist soil depth less than 60cm depth, completely avoids the occurrence of deep percolation. Compared with fixed every other furrow irrigation, alternating every other furrow irrigation ditch dry and wet alternating cycle will not be part of the soil of the root zone appear extremely dry long-term, and therefore more favorable to the crop root growth and absorption. Less than 50m and is playing in the end of the earth mound, different irrigation irrigation uniformity along the channel length will not have any impact on in irrigation Gougou long. (3) alternate furrow irrigation summer maize growing water demand of 310 3rum, including soil evaporation and crop transpiration were 88.43turn and 221.70mm, respectively, a decrease of 25.36% than the conventional furrow , 35 stone 2%, 20.29%, indicating that the alternate wetting and drying cycles can not only reduce the each irrigation intervals during the soil soil invalid evaporation, but also inhibits the crop of luxury transpiration, crop water requirement is significantly reduced, saving effect of very significant, furrow irrigation patterns in most scientific irrigation methods. (4) soil evaporation in summer maize mainly occurred in the period of irrigation a few days after the topsoil moist surface soil moisture and leaf area index are the two basic factors affecting soil surface evaporation. Controlled alternate furrow irrigation is shortened by reducing the wetted surface area, surface wetting time, can significantly reduce soil evaporation in summer corn growing period, and to enhance the conversion of soil water to the crop root water uptake, so that crop transpiration accounted stage the proportion of the water consumption increases. Irrigation lower limit is the same as the L Diao 0 moisture treatment, alternate furrow irrigation of summer corn, planting to emergence, emergence to jointing, jointing to tasseling, and tasseling to grouting, grouting to mature, and the whole growth period plant transpiration accounted stage the proportion of water consumption than conventional furrow increased 4.32%, 6.82%, 5.26%, 3 stone 1%, 1.89% and 4.55%, respectively. (5) summer corn