Study On Soil Geochemical Characteristics And Environmental Problems Of Farmlands In Ruijin,Jiangxi Province

The geochemical evaluation of land quality is an important project for the quality of land resources and ecological management.It is based on geochemical indicators,including nutrient beneficial elements,heavy metal elements,atmospheric deposition and irrigation.In order to obtain soil geochemical maps and geochemical grade maps,we conducted geochemical analysis and discussion on soil nutrient elements and environmental elements in the Xianghu District of Ruijin City.The geochemical maps are completed by the ArcGIS,taking the research area as the benchmark,applying the inverse distance weighting method,and plotting theachieved data on the benchmark.Besides,the geochemical grade maps are produced with the aid of the ArcGIS and its subsystem software.Thesubsystem software,which is self-developed by the China Geological Survey Development Center,focuses on geochemical observation and evaluation of soil quality.The geochemical grade maps are obtained by using two modulation spot as the benchmark,and dividing,coding,spot-interpolating,interpolation-combining and spot-assigning of the extreme value processed data.The results show that comprehensive soil nutrient status of the study area is extremely scanty,and the proportions of relatively lack and lack of soil area are 34.47% and 54.18%,with the proportion of abundant area is only 2.39%.The nutrientelements of N,P and K arerelatively lacking in the study area,especially the elements of N and P are exceedingly poor.Therefore,attention should be paid to increase the use of nitrogen and phosphate fertilizers,and synchronously rationally adjust the proportion of potassium fertilizers in the agricultural production process.Meanwhile,the organic matter of the study area is relatively scarce,and the proportions of the lack and the less lack for land are 33.16% and 60.23% respectively in geochemical grade evaluation.Attention should be also paid to the supplement of organic matter.However,the proportion of selenium rich soil in the study area is relatively high.Three selenium rich lands are found in Shazhouba town,Huangbaicountry and the east of Xianghu town.The selenium contentexceeds 0.4mg/kg in the soil,which is suitable for developing the local selenium-rich products.The comprehensive environmental quality for soil is high in the study area,with slight pollution(0.74%),and heavy metal content of arsenic,chromium,cadmium,mercury,lead and nickel are also extremely low.The high-value areas of soil heavy metal elements are generally distributed in dense population areas of cities and towns,where the mercury and cadmium elements have high coefficient variation.Attention,thus,should be paid to the prevention of mercury and cadmium pollution in Xianghu town and Shazhoubatown.The soil in the study area is mainly neutral-acidic,with an average pH of 5.57.The area ratios of acidic and strongly acidic lands are 20.73% and 73.84%,respectively.Overall,the geochemical comprehensive grade of soil quality in the study area is mainly medium and low soils,with area ratios of 35.03% and 54.18% respectively.Furthermore,it is an urgently needmeasure to ameliorate the soil nutrient status,particularly the elements of N,P,and K.