四川成都唐昌镇表层土壤元素地球化学特征及质量评价

Elemental Geochemical Characteristics of Topsoil in Tangchang Town,Chengdu,Sichuan Province and Quality Evaluation

土壤质量状况直接关系到农产品安全和人类健康,是农业种植和土地规划重要的参考依据。四川成都唐昌镇作为成都市重要的菜篮子基地,农业种植发达,目前该地区土壤质量状况尚不清楚。为了准确掌握当前唐昌镇农业种植区表层土壤元素含量特征和质量等级,本文通过开展1∶5万土壤质量地球化学调查,采集表层土壤810件,采用X射线荧光光谱法、电感耦合等离子体质谱法、原子荧光光谱法等方法测定了N、P、K、As、Cd、Hg、Pb、Cr、Ni、Cu、Zn、Se等元素含量和pH值,进行土壤养分等级、土壤环境质量等级、土壤地球化学综合等级评价。结果表明:(1)与全国表层土壤相比,研究区表层土壤略富集Zn、Pb,较富集Se,强烈富集N、P、Cd、Hg,土壤总体呈弱酸性。(2)土壤养分综合等级以二等较丰富为主,面积占比88.0%,土壤肥力较丰富;土壤8项重金属元素环境质量等级中的一等土壤面积占比均大于96.0%,综合环境质量等级以一等清洁型为主,占比达98.06%。土壤综合质量以一等优质级为主,占比85.85%。(3)区内富硒土壤面积2.49km~2,占比3.7%,零星分布于研究区中部;富铜土壤面积63.13km~2,占94.0%;富锌土壤面积63.31km~2,占比94.17%。综上所述,唐昌镇地区表层土壤养分较丰富,土壤环境整体清洁,土壤综合质量属优质级。

BACKGROUND: The quality of soil is directly related to human health and the safety of agricultural products, which has important references for agricultural planting and land planning. As an important vegetable basket base in Chengdu, Tangchang Town has developed agricultural planting, but the recent soil quality in the region is still unclear.OBJECTIVES: In order to accurately understand the current content of nutrient and heavy metal elemental characteristics and soil quality grade of topsoil in the Tangchang agricultural planting area.METHODS: According to 1∶50000 soil quality geochemical survey, 810 topsoil samples were collected. The contents of N, P, K, As, Cd, Hg, Pb, Cr, Ni, Cu, Zn, Se and pH in these soil samples were determined by X-ray fluorescence spectrometry, inductively coupled plasma-mass spectrometry, atomic fluorescence spectrometry, element analyzer and ion selective electrode method. The element geochemical characteristics and soil nutrient grade, soil environmental quality grade and comprehensive soil geochemical grade were then evaluated.RESULTS:(1) Compared with the general topsoil in China, Zn and Pb in the topsoil of the study area are slightly enriched, Se is relatively enriched, N, P, Cd and Hg are strongly enriched. The topsoil is generally weakly acidic.(2) The comprehensive grade of soil nutrients is rich in second grade, accounting for 88.0% of the area, and the soil fertility is rich. The proportion of the first grade soil area in the environmental quality grade of the eight heavy metal elements in the soil is more than 96.0%, and the comprehensive environmental quality grade is dominated by first grade clean type, accounting for 98.06%. The comprehensive quality of soil is mainly grade one, accounting for 85.85%.(3) The area of selenium-rich soil in the region is 2.49 km~2, accounting for 3.7%, sporadically distributed in the central study area. Copper-rich soil area is 63.13 km~2, accounting for 94.0%, and zinc-rich soil area is 63.31 km~2, accounting for 94.17%.CONCLUSIONS: In summary, the nutrients of topsoil in Tangchang Town are rich, the soil environment is clean and the comprehensive quality of the soil is high.