| The citrus production,which more than 100 million people engage on,has increasingly become prominent industry and an important pillar of rural economy in Chongqing.In order to achieve digital precision management,promote the further development,promote soil testing and fertilizer recommendation project,and provide the optimum services for citrus production,it is necessary to investigate and understand the relative information of planting and management measurements.For the purpose of this,this research focused on massive citrus planting information including topography and geomorphology,soil nutrients,and management measure,etc.Considering different citrus production environment in different county,the current study was carried out in Jiangjin,Fengjie,Zhongxian,Wanzhou,and Yongchuan.50 representative orchards (area＞6.67 ha)were selected to collect basic information including topography,soil type,citrus age, species,and production management etc.(1)Topographical factors including elevation,slope,aspect,and curvature were extracted base on the created 1:10000 digital elevation model(DEM).Comparative analyses of distribution of citrus orchards were carried out using spatial analysis,overlay analysis,mathematical statistics.Slope was classified as 0-5°,5-8°,8-15°,15-25°,25-35°,and＞35°.Citrus orchards mainly distributed on 8-25°,the areas were 26.72%and 25.76%for 8-15°and 15-25°,respectively. However,there were still 4.38%citrus orchards occupied＞35°.For aspect,14.75%of orchards distributed in southem,only 7.93%in flat area.From southeastern to southwestern,41.91%and 29.20%occupied positive and negative aspect,respectively.In the view of curvature,the terrain was suitable for agricultural development.The studied orchards mainly distributed on negative topology area where soil and water easily accumulate.The average altitude in the study was 318 m.The orchards mainly distributed from 250 to 300 m(23.87%)and from 300 to 350 m(21.57%).However, in Fengjie,few orchards occupied below 150 m and above 550 m areas.(2)Soil nutrition contents were investigated in the study area.The results were as follows:①The investigated orchards occupied purple,paddy,limestone soil,and yellow,the distribution areas were 56.71%,28.85%,12.15%,and 2.39%,respectively.②For pH,the orchards mainly distributed in pH≤5.5 region,the percentage was 41.65%, followed by 20.17%,21.48%,and 16.70%for 5.6-6.5,6.6-7.5,and 7.6-8.5,respectively.The trend of pH decreased from east to west,which was related to the distribution of the soil types.③The soil were rich in available nitrogen and available phosphorus,the average were 95.3 mg.kg-1and 26.0 mg.kg-1,respectively.The results showed that 78.52%and 47.17%of available nitrogen and available phosphorus were higher than 60.0 mg.kg-1and 20.0 mg.kg-1,respectively.The contents of total nitrogen,total phosphorus and available potassium were moderate,and the averages were 0.177%,0.0610%,and 151 mg.kg-1,respectively.The total nitrogen,total phosphorus and available potassium concentrations were mainly distributed 0.151-0.200%(38.39%),0.041-0.060% (27.98%),and 101-150 mg.kg-1(27.55%),respectively.The content of total potassium ranged from 1.51to 2%and the average was 1.64%.④The average content of available ferrum,available manganese,available Cu,available zinc and available boron were 84.1mg.kg-1,43.4 mg.kg-1,1.57 mg.kg-1,1.92 mg.kg-1,and 0.320 mg.kg-1, respectively.The soil were rich in available ferrum,available manganese.There were 65.29%and 50.54%of available ferrum,available manganese higher than 20.0 mg.kg-1and 30.0 mg.kg-1, respectively.The contents of available copper and available zinc were in moderate level,and mainly distributed in 0.21-1.80 mg.kg-1and 1.01-3.00 mg.kg-1,respectively.The content of available boron was very low.There was 86.99%of available boron lower than the critical value(0.5 mg.kg-1).(3)The occurrences of diseases and insect pests of year 2004-2006 were investigated in the study site.The highest frequency insect pest was red spider.The occurrences were 78.00%,66.00%,and 92.00%in 2004,2005,and 2006,respectively.The least one was yellow spider.The occurrences were 32.00%,32.00%,and 38.00%,in 2004,2005,and 2006,respectively.The most serious of disease is anthracnose,the frequency of disease were 50.00%,46.00%,and 48.00%,in 2004,2005, and 2006,respectively.The least one was scab;the occurrences were 18.00%,20.00%,and 20.00%, in 2004,2005,and 2006,respectively. |
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