Study On The Characteristics And Defensive Technologies Of High Temperature And Drought Disasters On Tea Plants In Zhejiang Province During The Past 55 Years

In recent years, the extreme climatic events such as high temperature and drought disasters occurred frequently and with severe intensity due to the impact of global climate change and global warming, which had a serious impact on the yield and quality of tea in Zhejiang Province. This thesis clarifies the relationship between the meteorological conditions and the yield of quality and quantity of tea by corroborating resources from a large number of articles,including meteorology data in Zhejiang province and tea yielding data; provides an overview of current status of tea production and climatic resources; reveals the space-time distribution of high temperature and drought disasters in Zhejiang Province; sums up the characteristics of defensive technologies of high temperature and drought disasters on tea plants during the past 55 years; presents the problems and countermeasures in defensive technologies of the above mentioned problems affecting tea plants. The main results are as follows:The two critical requirements for tea growth are temperature and rainfall. The optimum temperature is 20?25?. All year round temperature should be greater than 10? and requires a combined total of 3000??4500? annually, with the first year of the tea growth requiring the highest cumulated temperature for the year. The most suitable annual precipitation is 1500mm. Tea yield is significantly correlated with annual average temperature, monthly average temperature, annual extreme maximum temperature, annual average relative humidity, annual average wind speed and other climatic factors. The content of amino acid in tea leaves will increase with the decrease of sunshine hours before picking, and the content of tea polyphenols will decrease. The major agricultural actives in tea production such as fertilization,irrigation, pruning and harvesting require some specific combination of meteorological conditions.The climate characteristics in Zhejiang consist of four seasons with distinct rain and heat synchronization, climate resources are abundant and meteorological disaster are numerous. Based on the June to September daily meteorological data of 43 weather stations from1958 to 2012 in Zhejiang Province, Mathematic tools and software are used to analyze the temporal and spatial variation characteristics of high temperature and drought disasters on tea plants in Zhejiang area. The results showed that high temperature and drought disasters on tea plants are mainly located in Central and Western regions of Zhejiang Province. In coastal and isle areas, disasters are relatively fewer. All levels of high temperature disasters increase from East to West; drought disasters of tea plants occurs more in North East region and less in South West region of the province. There is an obvious multi-scale and annual variation characteristics on high temperature and drought disasters after the analysis of the data collected.The defensive technologies against high temperature and drought disasters on tea plants can be divided into meteorological technology, cultivation management technology and agriculture insurance technology. The application of defensive technologies changes with various era: before 1970s the main defensive technologies included the introduction of fine breed,transformation of low-yielding orchard,fertilization and implementation planting techniques; in1970-90s, balanced fertilization, double line and multiple line planting, further fine breeding introduction,small dwarf line cultivation, mechanization of cultivated land and harvest techniques were promoted. After 1990s, there are three-dimension cultivation mode for tea plants, water retraining agent for drought resistance technologies, plastic mulch, drip and artificial rainfall technology. At the same time, the application effects of different defense techniques are discussed, and the defense techniques of high temperature and drought disasters in different regions of Zhejiang province are put forward.The features of defensive technologies of high temperature and drought disasters on tea plants are various, advanced and highly integrated. At present, the defensive technologies of high temperature and drought disasters have a few notable problems such as meteorological technologies are imperfect, information dissemination is not in wide coverage and meteorological warning technologies are not refined. Therefore, the thesis puts forward countermeasures for improving the results, including strengthening microclimate monitoring of tea garden. Improve the different types of meteorological disaster indicators, strengthen the development of tea weather service products, strengthen the breeding and biotechnology, increase drought-resistant varieties, speed up the weather index insurance and reduce the risk of meteorological disasters. The study has important significance on improving the capability of high temperature and drought disasters monitoring, warning and mitigating their impact on quality tea production.