Study On Geochemical Evalution Of Land Quality Of The Typical Area,Shanghai Province

The geochemical evaluation of land quality is an important project for land resources quality and ecological management.This project classifies geochemical land quality based on geochemical indicators,such as soil nutrient beneficial elements,heavy metal harmful elements,air and irrigation water.This study discusses the geochemical character of soil nutrient elements and soil environmental elements,also introduces the results for soil nutrient and soil environment geochemical classifications of Zhangyan Town,Zhuanghang Town,Tuolin Town,Nanqiao Town and Fengcheng Town in Shanghai.The results indicate that the comprehensive nutrient quality for soil is abundant in the study area,and the proportion of abundant and less abundant comprehensive nutrient quality for soil is between 69.5% and 98.23%.Zhangyan Town is the most abundant area of soil nitrogen;Tuolin Town and Fengcheng Town are deficient area of soil nitrogen,should increase the amount of nitrogen fertilizer in agricultural production activities.There is no deficiency area of soil phosphorus in the study area where should carefully apply phosphorus fertilizer to avoid economic loss and eutrophication.The proportion of selenium-enriched soil is abundant in the study area.The content of soil selenium is mainly related to the content of soil organic carbon that the content of soil selenium increases with the rising content of soil organic matter.Compared with the inland areas in China,the content of soil fluorine in Shanghai is relatively high which is necessary to pay close attention to the safety of fluorine in drinking water and the problem of excessive fluorine in food.The comprehensive environmental quality for soil is almost clean in the study area.The most pollution elements are Hg,Ni and Cu,which concentrate in populated villages and towns.The comprehensive environmental geochemical classification for soil is relatively poor in Zhangyan Town that the proportion of clean quality is only 91.39%.The comprehensive environmental geochemical classification for soil in Nanqiao Town and Tuolin Town are the highest that the proportions of clean quality are 99.95% and 99.37% respectively.The proportions of clean quality are 99.37% and 98.78% in Zhuanghang Town and Fengcheng Town respectively.This paper compare with 1:10000,1:50000 and 1:250000 different survey precision on the interpolation data error and quality error of Zhangyan Town in Shanghai,and give the suggestion of error identification and the range of allowable error.Error analysis mainly base on the error analysis of interpolation data and the error analysis of quality is secondary.Compared with 1:50000 survey precision,qualification rate of 1:10000 survey precision decreases.The interpolation error increases along with the sample collection density because the spatial variability of the elements which are affected by the local human activities(such as fertilization and biological debris)increase.Considered about the influence of sampling process and human activities,the survey precision of 1: 50000 and 1: 10000 can meet the requirements of the geochemical evaluation of land quality,and it is suitable to use IDW for the geochemical evaluation of land quality.