Evaluation Of Soil Quality And Fertility Of Kiwifruit Orchards In Zhouzhi County Based On GIS And MDS

Soil resources are fragile and non-renewable resources,so maintaining soil quality is the basis of sustainable utilization of agricultural soil.Zhouzhi county is the largest planting base of kiwi fruit in China,and kiwi fruit has great economic value and production benefits.Because fruit growers do not know the soil nutrient status of kiwi fruit,there is imbalance in fertilization in the production process,which affects the quality and quality of kiwi fruit.At present,the research on kiwi fruit mainly focuses on soil nutrients,but the overall quality structure of kiwi fruit soil is still lack of adequate understanding.In order to fully understand the physical and chemical properties and soil quality status of kiwi fruit in zhouzhi county,the soil status of kiwi fruit garden in zhouzhi county was studied through experimental analysis and data processing,and the soil quality was comprehensively evaluated based on GIS method.the followingconclusions were drawn:(1)Soil physical and chemical properties:The 18 physical and chemical indexes of kiwi fruit garden in Zhouzhi county were tested by K-S test,which showed normal distribution.the soil bulk density,Ph value,total potassium were weak variability,soil salinity was high variability,soil physical clay,water content,capillary porosity were medium variability.The analysis of soil physical properties shows that soil physical clay particles show an increasing trend from east to west;the soil moisture content is relatively stable,which belongs to the suitable humidity area,and the low value center of the soil moisture content is in Erqu town;the bulk density of the soil is relatively compact,and the soil near the main urban area is the most compact;the content of soil total porosity and capillary porosity showed the characteristics of higher content farther away from the urban area,while non-capillary porosity showed the trend of decreasing from east to west;the content of soil aeration is low,and the farther away from the city,the higher the value;the average Ph value of soil is 7.16,which belongs to neutral soil,and gradually decreases from Houjiacun town to others.The analysis of soil chemical properties showed that the content of total nitrogen and available nitrogen was low,the content of organic matter and total phosphorus was appropriate,the content of total potassium and available phosphorus was rich,and the content of available potassium was extremely high;the analysis of soil salt content showed that the soil in Zhouzhi county was slightly salinized,and the soil salt content in Houjiacun town was the lowest;the contents ofMg2+ ? SO42-in soil trace elements were the lowest in Shangcun town.(2)Soil quality assessment.Based on the correlation analysis of soil physical and chemical indexes,a soil quality evaluation index system based on minimum data set(MDS)was constructed,and geostatistical analysis was carried out on each index,finally,the soil quality of kiwifruit garden in Zhouzhi county was evaluated.MDS index system included in total porosity,total phosphorus,available nitrogen,Mg2+,total potassium,organic matter,water content,available phosphorus and physical clay;Pearson correlation analysis was used to verify the proposed method,and the results show that the minimum data set partition method is feasible.Geostatistical analysis of MDS index system:the best fitting model of each soil index was selected by semivariogram method,and the results showed that physical clay,organic matter and total potassium accorded with spherical model,water content,total phosphorus and available phosphorus accorded with Gaussian model,total porosity and Mg2+ accorded with linear model,and available nitrogen accorded with exponential model;in the fitting model parameters,the gold value Co of soil available phosphorus was the largest,the available nitrogen was the second,and the others were relatively small;the analysis of substrate effect shows that physical clay,water content,organic matter,total phosphorus,total potassium and Mg2+ are highly variable,while porosity,available nitrogen and available phosphorus are medium variable;the analysis of the variation range shows that there is spatial correlation among the sampling points of each index,and the variation range of organic matter is the smallest.Using the common factor variance to calculate the MDS index weight,and the membership function method to dimensionless treatment of each index,and finally the soil quality evaluation model of Zhouzhi county kiwifruit garden soil quality evaluation,obtained:the average comprehensive soil quality index of 0.53,ranging from 0.46 to 0.73,the comprehensive level of soil quality is low,including Houjiacun town soil quality is the highest,Erqu town is the lowest,soil quality index of 0.73 and 0.46,respectively,the overall performance of the characteristics of high in the west and low in the east.(3)Evaluation of soil fertility.Based on the results of soil quality evaluation,the soil fertility grade of kiwifruit garden in Zhouzhi county was classified according to the national land fertility grade classification standard,the results showed that the proportion of soil fertility grade in 93425 grid evaluation units of Zhouzhi county kiwifruit garden was in the order of grade 3>grade 4>grade2>grade5>grade 1;the main soil fertility was concentrated in grade 3 and grade 4,accounting for 94.68%.the soil quality of Zhouzhi county kiwifruit garden was generally low,and the soil fertility grade of Houjiacun town kiwifruit garden was the highest.(4)Soil improvement.By analyzing the effects of planting years on soil physical and chemical properties and global soil fertility level distribution,it was found that artificial management is very important for kiwifruit growth,fruit growers should plough the soil for a long time to maintain the basic characteristics.In order to improve kiwifruit yield,it is suggested that the precise fertilization plan of kiwifruit in Zhouzhi county should be adjusted to increase the amount of organic fertilizer and nitrogen fertilizer,adjust the amount of phosphate fertilizer and limit the amount of potash fertilizer;at the same time,the soil improvement of kiwifruit garden in Zhouzhi county should pay attention to four aspects in the future:Reducing soil Ph value properly;Regularly ploughing the soil;Increasing the input of organic fertilizer;Regulate the use of phosphate and potash fertilizers.