| The Loess Plateau is the main arid and semi-arid region in China.Yan'an City is a typical representative area,and it is also the main planting area of crops such as corn,millet and economic forest fruit in our province.The evaluation of cultivated land quality in this area is not comprehensive.In recent years,with the strengthening of agricultural fine management,it is urgent to conduct in-depth comprehensive analysis and analysis of farmland in Yan'an,in order to lay a solid foundation for more scientific and efficient use of farmland soil and sustainable agricultural development.A total of 150 typical cultivated soil samples were collected from five major agricultural production counties in Yan'an City,Shaanxi Province.The main physical and chemical properties and trace element content of the soil were determined by conventional methods.The soil quality of the tested soil was preliminarily evaluated by correlation and principal component analysis,in order to lay a foundation for the rational fertilization and quality control measures of local cultivated land.The study achieved the following main results:(1)The average content of soil organic matter in Yan'an area is 9.42 g/kg,which shows that the soil organic matter content in this area is relatively low,ranging from 5.81 to 13.18g/kg,and the coefficient of variation is 25.26%.The soil organic matter content varies greatly with the plots,etc.,and the organic matter content in Yan'an City is at a very low level;The average content of alkaline nitrogen in soil was 42.31 mg/kg,the variation range was21.64-52.44mg/kg,and the coefficient of variation was 35.09%.The difference in alkali nitrogen content among different counties is likely to be due to the difference in nutrient content between different samples due to different farming methods and fertilization management.(2)Soil available phosphorus in available nutrients is a sensitive index with a coefficient of variation of 78.21%.The difference between the samples is large.The average soil available phosphorus is 6.23 mg/kg,and the variation range is 5.02 to 8.22 mg/kg;The average available potassium in soil was 111.74 mg/kg,the variation range was90.11-124.43mg/kg,and the coefficient of variation was 32.51%.The available nutrients are also at a low level overall.(3)The effective zinc change in trace elements is sensitive,the coefficient of variation is as high as 91.98%,the variation of available iron is lower,and the coefficient of variationis 31.41%.The average values of available copper,zinc,iron and manganese in Yan'an area were 0.88,0.74,11.24 and 10.73 mg/kg,respectively,and the soil trace elements were at a medium level.(4)Soil quality system constructed by principal component analysis can characterize soil quality levels.After grading it,it was found that there were only one soil samples with good quality.The soil quality was relatively low.It can be seen that the soil fertility level in Yan'an area is generally low.It is urgent to increase the soil quality by adding organic fertilizer.The fertility information system constructed by principal component analysis can better reflect the soil quality.In summary,the overall quality of soil cultivated land in Yan'an area is low,and the nutrient content of farmland cultivated soil needs to be improved.Therefore,we should pay attention to the monitoring of cultivated land quality,pay attention to the scientific management and cultivation of soil,choose reasonable fertilization measures to improve soil fertility,and maintain the sustainable development of cultivated soil. |
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