Fuzzy decision system for ecological distribution of citrus in north-cultivated-marginal area
北缘地区柑桔生态区划模糊决策系统

The fuzzy decision system for ecological distribution of citrus in north-cultivated-marginal area was established by using the data of mean extreme low temperature, accumulated active temperature (> or = 12.5 degrees C), mean temperature in coldest month, annual mean temperature integrated with annual precipitation, days with mean extreme low temperature below -9 degrees C, physiognomy, elevation, inland water body, cold air barrier, and soil nutrition and pH value. The complex reasoning model with imprecision was used in the decision system by introduction of L-R fuzzy number and recognition formula, which made the decision system have a wide range of application in practice. An example of applying the decision system was tested in Anhui province. The result showed that the development of the decision system would provide a useful tool for the decision of the ecological distribution of citrus in north-cultivated-marginal area.