Study On Integration Of Land Quality Geochemical Assessment And Agricultural Land Gradation Results In Luojiang County In Sichuan Province

Land quality geochemical assessment is carried out through investigating distributing condition of nutrient elements, harmful elements, health elements in the topsoil and content character of heavy metal elements in irrigation water, atmosphere and crop. The achievement, which integrates geochemical assessment and agricultural land gradation results, can provide scientific basis for basic farmland protection and land using planning, and upgrade management and service level of land resource.The condition of abundance or deficiency of the nutrient elements and environmental contamination in soil of the studied area has been mastered by grading of various elements. For essential macro elements, the serious deficiency of?, moderation of N and plenty of K in soil were observed. Essential trace elements generally have low content, and deficiency of Fe is obvious. For physicochemical properties, the light alkaline soil is primary, which accounts for 85% of evaluating area, and organic matter content is very low, whose deficient area accounts for near 60%. Contents of heavy metal elements generally are low, and the area percentage of As, Cr, Hg whose contents are under natural background values is higher than 90%. But Pb and Cd have higher contents, whose area percentage under natural background values is 84.01% and 20.56%, respectively. For health elements, Se represents absent, whose area accounts for 66.57%.After the assessment indices are screen out, membership function linearity model and Analysis Hierarchy Process are applied to assess. The results show that as a whole soil fertility has common level, and the one, two and three grade account for 26.41%, 61.95% and 11.64% of evaluating area, respectively. The one, two and three grade of environmental quality account for 22.06%, 64.46% and 13.48%. According to land quality geochemical assessment results, excellent grade soil is mainly distributed, and the percentage of high-quality, excellent, good, moderate and poor grade are 2.45%, 86.51%, 10.86%, 12.70% and 0.78%, respectively.The quality of atmosphere, irrigation water and crop safety in studied area is found well. The 2210 in geochemical assessment class and grade is primary, which have 202.80 square kilometers and account for 50.92%. Secondly, the percentage of 2210, 4110 and 3110 is 19.33%, 8.80% and 7.52%, respectively.A technique route of integrates geochemical assessment and agricultural land gradation results is put forward. The integrated achievement can basically reflect the spatial difference of agricultural gradation result and new grades are higher by physical and chemical superposition.