| Fruit industry is not only one of main rural economics in shaanxi province, but also important constitutes of rural economics in arid and semi-arid area and entire country, and is an approach of increasing farmer's earning to pull impoverish off. With China's entry into WTO, plenty of foreign fruit will swarm into, which impacts fruit market, and fruit growers will sell fruit one disaster after another. This requires our enhancing fruit quality to strengthen market competition ability. Water supply for fruit trees at proper time and quantity can guarantee high quality and high yield. Nowadays water resource tends to strain and water environment deteriorates increasingly, which impacts fruity yield and quality and restricts sustainable development of fruit industry. Improving orchard irrigation and management technology, can heighten WUE (water use efficiency and increase fruit yield and meliorate fruit quality, which settle this contradiction down. Applying CRAI (controlled root-divided alternate irrigation) into orchard irrigation, not only reduces water use quantity for irrigation or increases fruit yield (saving water can be irrigated in more flooding area), but also improve fruit quality. If we want to do it, we must settle down fruit tree water requirement calculation and dynamic prediction under CARL Therefore, studying on fruit tree transpiration variety law and setting up a model for fruit transpiration prediction, have important theory meaning and practical value.In this study, advanced heat pulse technology, tube-TDR system and automatic weather station are employed to determine the peach sap flow under CRAI, soil moisture and weather parameters. The law of heat pulse response to peach rootstock sap flow and measure precision of sap flow sensor are investigated. The feasibility of diagnosis of peach water status by heat pulse technology and the implement of it in automatic irrigation system are also analyzed. Study on changes of peach rootstock sap flow and soil water dynamics is exerted. At the same time three types model of peach transpiration are built on the base of theory analysis, and validated by experimentation result. Results as following,Heat pulse responds well to peach rootstock sap flow variety. The diurnal variant waves of sap flow is same and synchronous between the stem and root, and shows parabolic type trend. Velocities of rootstock sap flow at different depths below the cambium have not same value, but the same temporal changes. Under unremitting water stress, there are some fluctuations of stem sap flow, the value ofwhich is smaller than full irrigation. Heat pulse technology underestimates actual transpiration. The coefficient is 0.7667 (r2=0.8367) under full irrigation and 0.6714 (r2=0.7654) under water stress.Peach transpiration change trend is same as potential transpiration, solar-radiation and vapor pressure difference. Peach water deficit index correlates negatively linearly with soil moisture, which reflects fruit tree water status. It is feasible to apply heat pulse technology and WDI into orchard automatic irrigation system.Under the condition of three type of irrigation fashion, there are different laws among peaches rootstock sap flow change. BPI sap flux is greatest among them, and API's takes second place and FPI's is the least. Root sap flow at both sides of BPI is same, and root sap flow of wet side is more percent 80 than dry side in the API treatment, and root sap flow of wet side is more percent 90 than dry side in the FPI treatment Root sap flow of wet side in the API and FPI treatment is greater than both sides root sap flow in the BPI treatment, such as percent 60 and 50. Root sap flow of wet side in the API treatment is greater than FPI, because soil moisture of wet side in the FPI treatment is higher than API, and root system growth has compensate effect. Resuming irrigation of two sides in the three treatments, stem sap flow in the API treatment is the greatest among them, BPI's takes second place and FPI's is the least. Root sap flow of tw...
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