Distribution Of Soil Organic Matter,Nitrogen,Phosphorus And Potassium Nutrition In Cultivated Land Of Xi'an City

Soil nutrients not only provide a dispensable nutrient for crop growth,but also are regarded as the “food source” of crops.It brings both positive and negative effect with the rapid development of the economic level.In agriculture,excessive use of fertilizers and pesticides have seriously polluted environment and increased economic costs for farmers.In addition,the cultivated land area was decreasing and the dropping cultivated land quality.It has been many year since our country's second soil survey,which is insufficient to direct current quality of farmland and crop production.In response to this problem,this study collected representative farmland soils in each agricultural county in Xi'an.Through the analysis of soil nutrient elements,the purpose was to find out the nutrient status of cultivated soil in Xi'an and improve the storage of soil nutrients.Reduce and control pollution of the soil environment and agricultural and sideline products,reasonably manage the existing cultivated land resources,and increase the utilization rate.The experimental results are as follows:1.The followings are overall condition of cultivated soil nutrients in Xi'an city.The content of arable soil organic matter is abundant which the average content is 19.86g/kg,ranging from 8.91g/kg to 31.61g/kg.It is believed that the content of organic matter has reached a high level.The average concentration of alkaline dissolved nitrogen in soil is about 72.94mg/kg,varying from 19.25 to 127.75 mg/kg,which belongs to the middle level.The content of available phosphorus is also plentiful in soil of Xi'an city which the mean value can reach 30.51 mg/kg at a high level.In addition,the varied extent is between 2.28 to 76.7mg/kg.The average content of available potassium in soil is 245.24mg/kg in the range of 71.05 to 470.44mg/kg.The value is at a high level extremely,indicating that the available potassium content of cultivated land in Xi'an is sufficient.2.In all counties and districts of Xi'an,the nutrient content of farmland in Baqiao District is the lowest,which is the lowest compared with other regions;followed by the Eyi District,where the organic matter is high,and the content of other nutrients is generally low;the overall nutrient content of cultivated land is rich in Yanliang district.The average organic matter content is 21.65g/kg,and it is between 15.47-27.98g/kg,and the average available potassium content is 344.96mg/kg,which is between 218.6~620.66mg/kg,and they are both significantly higher than others.The highest available phosphorus content is in Gaoling,with an average of 41.98mg/kg,between 13.83 and 108.34mg/kg;and the alkali nitrogen content is the highest in Lantian,with an average of 86.89 mg/kg,between 54.25 and 147mg/kg.