Calculation Of Water Requirement For Summer Corn Under Controlled Alternative Furrow Irrigation

Controlled Alternative Irrigation (CAI) is a new control technology to save water in farmland that be put forward by Kang Shaozhong, Controlled Alternative Furrow Irrigation(AFI) is a running form of CAI. CAI has good effects of saving water in laboratory and field experiments, and has an important realistic significance for the development of water-saving agriculture in arid or semi-arid areas.It is necessary to work out an irrigation schedule before an advanced irrigation technology is applied in practice. this paper emphasizes particularly on studying the calculation problem of summer corn water requirement in AFI, and analyzing the physiological-ecological characteristic and the evapotranspiration of summer corn in farmland, which lays the foundation of formulating the irrigation schedule of summer corn with saving water and high efficiency, and also provides theoretical basis for the popularization and application of AFI technology in arid or semi-arid areas.The influence on characteristic of physiology and ecology of summer corn stem is analyzed under different lower limit of irrigation control in AFI , the saving water mechanism of AFI is explored profitably, the change regulation of soil evaporation from interim, crop transpiration and proportion between them are analyzed with different moisture disposal in crop grow period in AFI, the main environment factors of influencing soil evaporation from interim are analyzed, relation between soil evaporation from interim and soil surface evaporation, leaf area index is set up, process of soil surface evaporation of wet ditch after irrigation is analyzed, through systematic research and observation, which results indicate AFI may decrease invalid soil evaporation from interim, restrains extravagant transpiration of crop , has obvious effect of saving water , and has better reference value to guide water management. According to the results of experiment observation, the mathematics model of crop coefficient estimate of summer corn is set up, the calculation methods of each component of crop efficient are discussed , based on formula of penman-Monteith ,with single crop coefficient and double crop coefficient methods ,the water consumption of summer corn is analyzed and verified, which proves the error between crop water requirement and observed value is minimal with double crop coefficient method, the circumstance of crop water consumption is reflected truly, the gusty weakness of soil evaporation from interim after irrigation and rainfall is overcame with single coefficient method reflecting difficultly, the water consumption or requirement is calculated accurately in AFI or part irrigation.