Studies On The Technologies Of Over-winter Facility Cultivation For Satsuma Mandarin

The thesis studies the laws of environmental factors inside the facilities for over-winter cultivation and their influences on the fruit qualities so as to provide a theoretical basis for the extension of over-winter facility cultivation technologies for citrus fruits and its researches. The project was conducted in the Daliwan Orangery, Linhai City, Zhejiang Province from 2003 to 2005. The test piece is Citrus unshiu Marc. The results of the experiments show that:1. The highest temperature inside the facilities is generally 3℃to 10℃higher than that in the open and the lowest temperature is from 1℃to 5℃higher than those in the open, furthermore, the temperature inside the facilities is mostly over 0℃during the whole winter. Under such circumstances, the collection period can be delayed and be from the next January to the next March.2. The lower the air temperature is, the bigger the differences of the temperature between the inside and the outside are. During the low temperature period, that is, from the mid-December to the next mid-February, the ground temperature inside the facilities is generally 0.5℃to 2℃higher than that in the open. The lowest temperature inside the facilities is above 8.8℃. Under such circumstances, all the roots of Satsuma Mandarin can mostly imbibe the nourishment and water during the whole winter so that the fruit quality is improved.3. From the variations of the temperature measured at right angles, if there keeps a distance from 150 cm to 200 cm between the crown of the tree and the film, the harms caused by high temperature can be effectually lightened or prevented.4. According to the variations of temperature during the whole day with the highest or the lowest air temperature, when it is hot weather in winter, attentions should be paid to the changes of the highest temperature from 10 o'clock to 12 o'clock in the morning. When the temperature is over 20℃, the film side has to be opened to keep the facilities well ventilated and keep the temperature inside under 25℃. The lowest air temperature appears from 2 o'clock to 8 o'clock, especially when it is 6 o'clock. When it is under -5℃, double films should be adopted so as to keep the inside warm and avoid cold injury.5.The index of full ripening stage under over-winter facility cultivation can be formed as the following: the rate of total soluble solid (TSS) reaches 12%, and the rate of organic acid drops to 0.8 %; The indicators of period of decline are as the following: the rate of the reducing sugar in the sugar changes from declining to rising, the peel puffing rate is near 15%, organic acid drops to 0.65%. According to the above indexes, the full ripening stage is from the mid-November or the late November to the next January, and the period of decline starts from the beginning of the next February. Therefore, the best harvest can be achieved before the Spring Festival under the over-winter cultivation mode.