The Study On Agricultural Climate Regionalization Of Citrus In Chongqing Province Based On GIS

As the largest fruit tree in the world,citrus has fresh and delicious taste and rich nutrition.It can be processed and eaten directly.It's a very healthy food all over the world.China is the first country to plant citrus,at the same time it's one of the largest producing countries in the world.In addition,Chongqing is the main province of citrus planting and management.In this study,we analyzed the meteorological conditions affecting the growth and development of sweet orange and tangerine in Chongqing,and also set up the regionalization indexes.Based on the 30 years observation data of temperature,relative humidity,duration of day,solar radiation and other meteorological elements,combined with digital elevation models with high resolution in the region,each meteorological element is spatially expanded,which is based on the results of spatial expansion.According to the regionalization index the climatic regionalization of two citrus crops in Chongqing was carried out.In addition,analyzed the distribution and characteristics of low temperature disasters affecting citrus' growth and development.The research results are:(1)The main climatic resources in Chongqing.Based on the observation data of34 meteorological stations in Chongqing,the distribution climate elements is made according to the different spatial expansion methods.In this study we analyzed the temperature,sunshine,solar radiation and relative humidity.The spatial distribution of sunshine duration is the longest in the northeast,the second in the west and middle,and the shortest in the southeast.The annual solar radiation in Chongqing is high in the northeast and low in high altitude mountainous area.The annual average temperature is high in the west and low in the east.The annual relative humidity of Chongqing is high in the Midwest and low in the northeast and east.(2)The regionalization of Sweet orange in Chongqing was completed by using the function of spatial analysis of ArcGIS,based on the climate elements and index of regionalization..It is divided into 9 areas: the most suitable cultivation area for fresh navel with abundant light and heat resources,the suitable cultivation area for fresh navel orange with abundant heat and light,the most suitable cultivation area for freshsweet orange with rich heat and light,and fresh taste with rich light and light and the sub-suitable cultivation area and the unsuitable cultivation area of sweet orange.The ratio of these areas are 0.3%,0.5%,0.6%,2.6%,3.04%,13.2%,15.8%,20.5%,43.1%.(3)Tangerine was divided into 6 suitable regions: the most suitable area for citrus with light and heat,the suitable area for light and light enrichment,the suitable area for light rich citrus,the suitable area for citrus with rich light and heat,and the heat quantity for light and heat abundance,the sub-suitable cultivation area of broad-skinned citrus and the unsuitable cultivation area.The ratio of these areas are5.7%,30%,3.4%,12.1%,18.7% and 31.1%.(4)The main meteorological disasters affecting citrus cultivation and growth in Chongqing are cold damage and low temperature.According to the low temperature index calculate the spatial distribution of low temperature frequency in Chongqing.The results are as follows: the spans of low temperature frequency in spring are larger than that in autumn,and the frequency of low temperature in spring increases rapidly between 10% to 90% in spring.The low temperature in autumn in Chongqing is more serious than that in spring.The high altitude area is in the northeast and the frequency of low temperature reaches more than 90% in most parts of the Yangtze River which can reach to 100%.In addition,the overall trend of change is consistent,but the frequency in the corresponding region is different.