摘要：Soil moisture and water storage pit depth are important indicators of orchard irrigation under water storage pit irrigation. The reasonable selection of these indicators is essential for the photosynthetic characteristics of young apple trees. Field experiments were conducted to study the effects of different soil moistures (50%-80%, 60%-90%, and 70%- 100% field capacities) and pit depths (20, 40, and 60 cm) on tree photosynthesis and to determine the optimum soil moisture and storage pit depth combination through principal component analysis. Results showed that the most suitable irrigation conditions of stomatal conductance, intercellular carbon dioxide concentration, transpiration rate, and photosynthetic rate were H60W2, H60W2, H60W1, and H40W2, and the most unfavorable irrigation condition was H20W1. The highest leaf water use efficiency was found at H20W1, whereas the lowest was detected at H60W3. At different stages, the effects of water storage depth, soil moisture, and their interaction on the photosynthetic characteristics of young fruit trees were different and their influencing power quantification sorting also varied. A two-factor interaction could remarkably affect stomatal conductance, transpiration rate, and photosynthetic rate in some parts of the growth period but could not considerably influence intercellular carbon dioxide concentration and leaf water use efficiency. The most suitable combination of water storage pit irrigation in terms of photosynthetic characteristics was as follows: soil moisture at 60%-90% field capacity and pit depth of 60 cm.
