茶树水分胁迫建模及试验

Modeling and testing of tea tree water stress

通过观测冬季和春季塑料大棚中不同灌溉条件下茶树的冠层温度、空气温湿度、土壤热流密度、土壤湿度、太阳净辐射照度及风速等因素,利用Idso经验模式确定了冠气温差的下限方程.通过观察不同水分处理条件下茶树作物水分胁迫指数的日变化和季节变化,得出了反映茶树水分状况的关系曲线.研究分析了Jackson的理论模式与Idso的经验模式反映茶树水分胁迫的差异性,针对华南地区经常出现的冬旱及春旱,首先通过人工田间数据采集的方法,分9—12月和1—3月2个阶段测量茶树作物水分胁迫指数中所涉及的各个参数,建立了茶树冬季和春季的作物水分胁迫指数模型.研究结果发现,茶树冬季和春季作物水分胁迫指数模型相差不大,冬季经验模型中,系数A和B的值分别为1.265和-0.220,而春季经验模型中,系数A和B的值分别是1.230和-0.214,这可能与茶树属于多年生植物,冬季和春季叶面积指数等变化不大相关.

The canopy temperature, air temperature and humidity, soil heat flux, soil moisture, net solar radiation, wind speed and other factors are observed when tea trees are growing in a greenhouse under different irrigation conditions in winter and spring, then a lower limit equation of canopy tempe- rature difference is determined by using the Idso empirical model. Finally, the curves for representing tea tree moisture content status are obtained by observing the diurnal and seasonal variation curves of tea crop water stress index （CWSI） under different moisture contents. Additionally, the difference in CWSI between Jackson theoretical model and Idso empirical model are analyzed. Since drought often happens in spring and winter in South China, the field data are collected manually in September - De- cember and January - March next year. The various parameters related to CWSI are extracted, and the water stress index models for winter and spring are developed, respectively. The results reveal that there is no significant difference in tea tree water stress index models between winter and spring. In winter, the coefficients A and B in the model are 1. 265 and - 0. 220, while they are 1. 230 and - 0. 214 in spring. It may be because the tea tree is perennial crop and the leaf area index is similar in spring and winter.