A Study On Ecological Factors And Division Of Longan(Dimocarpus Longan Lour.) Production In Mindong Area

Ningde City is located in the northeastern of Fujian Province, belonging to subtropical climate. The area of Ninde City is generally thought not suit for the cultivation of subtropical fruit trees such as longan, but its offshore areas, affected by ocean and special topographical environment, have the good coastal microclimate for the development of Mindong longon. When longan fruits in Ningde area are harvested, most longan fruits have disappeared from the market, therefore'Ninde longan'has good prices and expensive market. For many years, the Ningde government has tried to Ningde introduce new varieties of late-matured longan, forming a scale and achieveing greater economic benefits, but because of its particular growth environment, varieties and regional layout are unreasonable, no economic benefit has been obtained, and many mistakes have made during the promoting work. During two big cold wave of 1991/1992 and 1999/2000, many young trees and adult longan trees suffered damage in east coastal area. In order to find out the appropriate environment to longan growth in the east coastal area of Ninde City, optimizing the layout and species regional structure of longan, limited climate factors related to longan growth and development will be surveyed and analysed in the coastal area of Ninde City in this article, primarily on the basis of relationship between the biological characteristics of longan and climates.On the basis of predecessors'study on zoning, taking the extreme mininum temperature Td as the first-class guide line of zoning,analyzing the environment of avoiding freezing in some areas synthetically,through the piled chillness value, judgement of agricultural significance,considerations about slope angle and orientation,investigation of distributing rule for chilling stress and combining the climate elements restrictive geographic information system (GIS) date and related materials,longan planted climate zoning will be comformed. At the same time, through the comparision of resourses of ecological regions, structural adjustment and improved regional distribution of longan production in east coastal ereas will be proposed. This research will provide theory basis for the arrangement of the early, middle and late longan varieties and regional supporting cultivation in Mindong coastal areas, helping to prolong the period of longan production and improve the economic, social and ecological benefits.