| producing in China.The yield and quality of winter jujube are in the forefront of the country.But with the development of winter jujube industry,the problems of blind fertilization have arisen.In order to understand the fertilization situation and explore the soil fertility status of Dali County,this study conducted the fertilization survey and the determination of the soil fertility of jujube orchards in the winter jujube production area of Dali County,and carried out the principal component analysis on 11 soil fertility indexes of the jujube orchard.Drawing the nutrient spatial distribution map of alkali hydrolyzed nitrogen,available phosphorus,available potassium and organic matter by using Arc GIS software.The database was established based on existing soil fertility information,and the fertilization expert system was preliminarily designed.Obtained the following several main conclusions:1. By investigation,we found that the average yield of Dali winter jujube orchards reached 24571±5838 kg·hm-2,and the average fertilizing amount of nitrogen,phosphorus and potassium were 355.1±278.7 kg·hm-2,356.5±254.3 kg·hm-2,377.1±338.8 kg·hm-2,respectively,and the proportion of nutrient input was about 1:1:1.06,in which the nutrient provided by chemical fertilizer accounted for the majority.At present,the main problems of fertilizer application in Dali County are using too much chemical fertilizer and insufficient organic fertilizer application,the preference of compound fertilizer for base fertilizer results in relatively consistent input of nitrogen,phosphorus and potassium,the input of microelement fertilizer are less.2. Compared with the four planting patterns in Dali County,the yield of greenhouse,quilt shed,double-covered plastic shed,plastic shed was range from high to low.And the order of fertilization amount from high to low was the same as yield.In term of organic fertilizer input,the fertilizer input of greenhouse was much higher than double-covered plastic shed,plastic shed.3. The results of soil fertility test in Dali winter jujube orchard showed that the p H of soil was alkaline,the content of alkali hydrolyzed nitrogen was rich,the content of available phosphorus was medium,the content of available potassium was extremely rich,the content of organic matter was relatively lack.The content of available iron,available manganese,available copper and available zinc were moderate or rich.4 The spatial distribution map of soil nutrients in Dali County was drawn by Arc GIS software.The overall performance was that the content of alkali hydrolyzed nitrogen and organic matter from northwest to southeast was high,while in other areas was low,the content of available phosphorus was high in the north and low in the south,the content of available potassium was high in the northwest and low in the southeast.By principal component analysis,the results showed that organic matter,available potassium,available iron and available phosphorus were the most important factors affecting the soil quality in winter jujube production area of Dali.By calculating the comprehensive score,the average comprehensive score of each township was compared,and it was found that the soil score of each township was consistent with the spatial distribution of soil nutrients.5 Based on the existing soil fertility information,an expert system of precision fertilization in the winter jujube orchard of Dali greenhouse was established,which aims to provide guidance for farmers with simple,quick and scientific fertilization.The system based on the theory of target yield method,can make fertilization plan for farmers.To sum up,through investigation,the application of chemical fertilizer in jujube orchard was mainly composed of compound fertilizer and the application amount was too large,the application of organic fertilizer was insufficient,the nutrients input amount of nitrogen,phosphorus and potassium was relatively consistent,the input of microelement fertilizer was less.The time of ripening period was different due to different shed-type,and there was a big gap in economic benefits,which also caused the difference in fertilizer amount and yield of different shed-type jujube orchards.According to soil testing,the jujube orchard soil is relatively lacking in organic matter,rich in alkaline nitrogen,moderate to low in available phosphorus,and extremely rich in available potassium;through zoning analysis,the condition of abundance or deficiency of the nutrient in each township was discussed.By principal component analysis,the results showed that organic matter,available potassium,available iron and available phosphorus were the most important factors affecting the soil quality in jujube orchard.At present,the expert system of precise fertilization in the winter jujube orchard of Dali greenhouse was established,which aims to provide scientific fertilization guidance for farmers. |
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