Yields Of Different Genotypic Crops Response To Water And Their Ecophysiological Mechanisms

Yield response to water and its ecophysiological mechanisms research of the crop are important study content of biological water saving theoretics. Field experiment was conducted in the station of the Institute of Dry Land Farming and Water-saving Agriculture, located in Hengshui, Heibei Province, from 2007 to 2008.The experiment's aim is to research and establish the relationship of yield response to water of different genotypic crops and their ecophysiological mechanisms. In this study, different water grads were taken to control the irrigation norm during different growth durations. By regularly observing some ecophysiological indices, i.e. the distribution characteristics of crops'canopy and root system, photosynthetic rate, transpiration rate, stomatal conductance, and the proportion of physical distribution, the author qualitatively analyses the source of difference in yield response to water, and quantitatively establishes the relationship of yield response to water suitable for different genotypic crops. Finally, crop yield model, namely AquaCrop model, which was based on the function of yield response to water, is simulated and validated by the experimental data. Research results are as follows:1. During whole growth period, two peak values of water requirement, water consumption and crop coefficient of winter wheat shows in tillering and jointing stage. The orders of diurnal water requirement and diurnal water consumption in each growth phase both are jointing to booting stage>flowering to filing stage>turning-green stage. Water consumption has significant difference in jointing to booting and flowering to filing stage of different genotypes. Compared different genotypic winter wheat, the diurnal water consumption of YM20 is much higher than SJZ8 in these two growth stages.2. The translocation, translocation rate and kernel contribution rate of assimilates stored by winter wheat's vegetative organ before anthesisin present the same rule: moderate deficit>light deficit>severe deficit. Bothe moderate deficit and severe deficit in different growth durations affect the nitrogen and phosphorus translocation before anthesisin, but in turning-green to jointing stage and after filling stag, moderate deficit benefits to translocation of nitrogen and phosphorus from vegetative organ to kernel.3. Differences appear in WUE and the response factors of yield to water between different genotypic winter wheat. Ky values of YM20 in turning-green, jointing and flowing stages are respectively 0.25, 0.51 and 0.30; Ky values of SJZ8 are 0.26, 0.57 and 0.36. It can be seen from these that the order of yield response to water is jointing to booting stage>flowering to filing stage> turning-green stage.4. Water deficit restrains the increase of plant height and leaf area index of maize, and the extent changes with the strong or weak of water stress and the growth period. The water deficit in jointing stage can significantly impacts the ultimate plant height and leaf area index. The influences of water treatment to the dry matter accumulation in different stages are diverse. Both the growth rate and the effect of water supply to dry matter accumulation in jointing stage are the most. 5. The research educes yield response factors of different genotypic maize. Ky values of LD981 in jointing, flowing and filing stages are respectively 0.40, 1.40 and 0.45; Ky values of SZD 958 are 0.34, 1.20 and 0.64. The order of yield response to water is flowering stage>filing stage>jointing stage.6. This research introduces AquaCrop model and expatiates on its operational mechanism. After the parameters of model are distilled and adjusted, based on the data of maize water pool experiment in 2008, the growth process and crop productivity of field maize are simulated. And the verification and validation of model's accuracy are achieved by compared simulated result with observed data.