Study On Early Warning Model Of Low Temperature And Defensive Measure On Fruit Tree In South Of Fujian Province

This paper studied the affecting degree of eight low temperature factors on the yield reduction rate of fruit in Zhangzhou city where is the representative zone in south of Fujian province, Huaan county and Pinghe county. Then analyzed the data about ten days average value of minimum temperature per day ((?)) and extreme minimum temperature in each ten days (T_XD) in winter during 1961-2006 ,and January , February in 1961. The rule of low temperature in that zone is revealed and the early-warning model about low temperature on fruit is established. And the map of spatial distribution about extreme minimum temperature was represented by Geographic Information System (GIS), some measures preventing damage by low temperature were put forward. Results were as following.The result about the most relation degree to the yield reduction rate is the days of minimum temperature being below 5.0℃every day in every sliding five days was analyzed by using the grey system theory; it was also the most important factor which results in the low temperature injury.The rule of low temperature in winter in south of Fujian province was found and the eighteen early-warning model about (?) and T_XD of Change tendency were established by using the data of (?) and T_XD in winter during 1961-2006 ,and January ,February in 1961 to do mathematical simulation by harmonic analysis method. Then verified the result of simulation with the data about (?) and T_XD in winter in. 2007,it showed that the result of forecast conform to actual conditions. The trend of low temperature in winter in 2008 in southof Fujian province were analyzed, the value of (?) and T_XD, are 3.0℃above, and the main fruit will prevent from damage by low temperature.By using the data of geography that provided by digital Fujian project and established model which calculated the value of extreme minimum temperature in year, then we represented the map of spatial distribution about extreme minimum temperature intuitively by GIS. According to the map, Zhangzhou city was divided to four Fruit Crop areas, such as suitable area, sub-suitable area, possible area and unsuitable area.The study on measures preventing damage form low temperature of fruit showed that: the defence should concentrate on the earlier stage. According to the map of spatial distribution about extreme minimum temperature, select a reasonable planting areas and variety of cold hardiness, use the cultivation of the high-access, base on enhancing the resistibility of tree by improving it's vegetative storage, make greater efforts to improve the external environment conditions etc. The short-term defense measure in pre-disaster stage is very important, such as smoking method (smoke screen test in four synoptic type,the result showed that the temperature of orchard which in smoke screen condition is higher than control orchard under different synoptic type,that indicated smoke screen have good effect on heat preservation for sure) , spray irrigation method, spraying growth regulator method, and method of bagging. In order to reduce the damage, the orchard which was damaged by low temperature should be taken remedial measures. As an example, the remedial measures of banana, longan and litchi were presented after disaster.