Evaluation And Investigation Of Cultivated Land Fertility And Soil Environmental Quality In Taohua Districts Of Shihezi

[Object] Quantity and quality of cultivated land are the base and guarantee of agriculture. Under thebackground of cultivated land quantity decreasing, the cultivated land quality plays the vital role on thequantity and quality of agricultural products. The quality of cultivated land has become an importantbottleneck and security of agricultural development in china. Cultivated land fertility and soilenvironmental quality in Taohua district of Shihezi were investigated in this study. Change trend andnutrient status in soil of cultivated land were analyzed, and the cultivated land fertility was evaluated bygrading. Meanwhile, the contents of heavy metals in soil of cultivated land were investigated, and thepotential ecological risk and soil environment quality of cultivated land were also evaluated. The objectiveof this study is to promote the cultivated land quality construction and sustainable development ofagricultural production of Taohua.[Method] Soil nutrient status of cultivated land was analyzed through the historical data collection andfield sampling. Comparison of the second national soil survey, the change trend of soil nutrient in Taohuawas assessed. The field plots were used for the evaluation unit, and three categories of soil physical andchemical properties, soil nutrient and obstacle including12factors were selected as the evaluation index.The cultivated land fertility was evaluated using the Delphi method and analytical hierarchy process. Thecultivated land soils in Taohua districts of Shihezi were selected with130sampling points to evaluate thecontent and the distribution characteristics of seven heavy metals of Cu, Zn, Cr, Cd, Pb, As and Hg. Theaccumulation status and potential ecological risk of the heavy metals in soil of cultivated land wereassessed.[Result]（1） The average contents of the organic matter, total N, and total P in soil were13.61,0.66and0.49gkg^-1, and belonged to the fourth level, fifth level and fourth level, respectively. The average contents of theavailable N, available P, and available K in soil were52.04,26.83and298mg kg^-1, and belonged to thefifth level, second level and first level, respectively. The average contents of the available Cu, available Zn,available Mn, available B and available Fe in soil were2.43,0.85,10.94,1.21and26.12mg kg^-1, andbelonged to the first level, third level, third level, second level and first level, respectively.（2） Overall, the contents of organic matter, available N and available P in soil showed rising trend.Compared with the second national soil survey, the average contents of organic matter, available N andavailable P were increased by40.02%,34.47%and211.98%, respectively. The average content of availableK decreased, compared with the second national soil survey was reduced by22.40%. The average contentsof available Zn and Cu remained stable. Available Mn and available B were decreased, and the averagecontent of available Mn and available B were decreased by21.91%and28.82%, respectively.（3） The cultivated land fertility of Taohua was divided into six grades. The area of first grade is534hm², accounting for7.18%of the total cultivated land. The second grade accounted for11.03%ofcultivated land, and the area is820hm². The area of third grade is1429hm², accounting for19.23%. Thefourth grade of cultivated land area is1563hm², accounting for21.03%. The fifth grade of arable land areais1506hm², accounting for20.26%. The sixth grade cultivated land area is1582hm², accounting for21.28%.（4） The average concentrations of the Cu, Zn, Cr, Cd, Pb, As and Hg in soil were33.34,102.64,58.77,0.46,13.72,18.89and0.036mg kg^-1. They were higher than background values of soil in Xinjiang,especially for Cd, Hg, Pb and As showed a significant accumulation trend. The average concentrations ofseven heavy metals in the cultivated land soils did not exceed the national standards GradeⅡ, but the exceeding standard rate of Cd and As reached16.92%and9.23%, respectively.（5） The soil environment quality of cultivated land in Taohua was influenced significantly by humanactivities. The seven heavy metals in soils showed certain accumulation effects; especially Cd and Hg hadthe high pollution index. Soil environmental quality was still in accordance with the national soilenvironmental quality standard （level two） requirements. The average integrated pollution index ofcultivated land soil was0.71, belonging to the warning limit.（6） The multi-factor comprehensive potential ecological risk index of heavy metal in the low potentialecological risk accounted for27%of the soil samples, middle potential ecological risk accounted for50%,accounting for23%of the higher potential ecological risk. Cd was the main factor of potential ecologicalrisks and then was Hg. Other metals were at the low potential ecological risk level.[Conclusion] The soil nutrient of cultivated land in Taohua showed low organic matter, N deficiency, highavailable P and B, available K, Cu and Fe rich, available Zn and Mn moderate. The level of cultivated landfertility was low, first and second grade of cultivated land were less than20%, but the third grade and thefollowing grade accounted for more than80%. Overall, soil environment quality was still clean （warninglimit）. The heavy metal of soil was in the middle potential ecological risk; especially Cd and Hg had thehigh potential ecological risk.