| 摘要 | 土壤是人类赖以生存的最基本和最重要的自然资源。近年来，由于人类大规模生产、生活等活动，破坏了影响土壤发育的生态环境，工业三废的排放、大量使用农药、不适当施用化肥等使土壤环境遭受不同程度的污染，而土壤环境状况对发展农业生产以及提高农产品品质与安全起着举足轻重的作用。贵州岩溶山区是生态环境脆弱带的重要组成部分，境内山多地少，没有平原支撑的耕作条件，农业生产条件差、水平低，耕地资源严重不足。而近百年来岩溶山区人口迅速增加,自然植被破坏以及工业污染加剧,导致土壤退化以及土地生产力的下降，严重制约岩溶山区经济、社会的可持续发展。因此，开展岩溶山区土壤与环境问题的研究将有利于促进岩溶地区经济发展，缓解岩溶山区人口-资源-环境之间的矛盾，为合理发展山区立体农业种植提供科学依据。因此，本文选取贵州省毕节市威奢乡基本农耕土壤为研究区域，通过实地调查，采用GPS定位方法对研究区土壤进行样品采集，并选用玻璃电极法、PE-2400元素分析仪法、马尔文激光粒度测试仪法、ICP-MS及 X荧光光谱法对样品进行测试分析，运用 SPSS12.0 和 EXCEL2010 软件进行样品数据的统计处理，分析了研究区土壤理化性质及元素地球化学特征，最后采用单因子指数法和综合污染指数法对威奢乡土壤环境质量进行科学评价，得出如下主要研究结果：毕节市威奢乡农耕土壤主要土壤类型为黄壤及黄棕壤，耕作土壤总体呈弱酸性，pH平均值为6.12；土壤有机质含量丰富,可以满足农作物生长需要；研究区土壤以粘土至中粉砂为主，根据美国制土壤质地命名标准,研究区土壤质地为粉质黏壤土。对比全国第二次土壤普查养分分级标准，研究区土壤全氮、全磷含量为一级,无需补充,但全钾含量为五级,因此,应适量施加含钾元素肥料，以提高土壤肥力，此外，研究区土壤Ca、Mg元素含量均低于贵州省表层土壤平均值,也应注意适量补充；研究区土壤植物必需微量元素含量具有Fe>Mn>Zn >Cu>Mo的区域特征，且研究区除Mo元素含量低于贵州省表层土壤平均值外，其余元素均高于贵州省平均值；研究区土壤有害重金属元素Cr、Cd、As、Pb含量具有Cr＞Pb＞As＞Cd的区域特征，且重金属Cr、Cd含量均大于贵州省表层土壤平均值，而As、Pb含量则小于此平均值；此外，研究区土壤Na元素、Ti元素以及Al元素含量均大于贵州省表层土壤平均值，应注意预防土壤盐碱化以及Ti、Al元素含量过高对研究区农耕土壤造成污染。研究区土壤有机碳含量及全N、全K、全Mg含量随土壤深度的增加均呈现逐步下降的变化趋势，而土壤全P、全Ca具有随深度增加呈现出先降低后又上升的变化趋势；研究区土壤植物必须微量元素（除Zn元素外）及重金属Cr均随土壤深度增加大致呈现出上升的变化趋势，而重金属Zn、Cd、Pb等元素具有随土壤深度增加逐步下降的变化趋势，重金属Ni、As随土壤深度增加无明显变化规律。据GB15618－1995 环境质量标准，采用单因子污染指数法及综合污染指数法对研究区土壤环境质量进行科学评价，结果表明研究区土壤存在严重的重金属污染，不符合国家一级及二级土壤环境质量标准。研究区土壤有机碳、全磷、全镁含量随海拔高度增加总体呈上升趋势，全氮、全钾含量随海拔高度变化较小且无明显变化规律，而全钙含量则随海拔高度增加呈下降趋势。研究区土壤Fe元素含量随海拔高度增加呈现出先上升后下降随后又上升的变化规律，且最高值出现在海拔最高处，而Mo元素随海拔高度增加无明显变化规律。 Mn、Cu、Zn元素随海拔高度增加呈明显上升趋势，这可能与大气沉降有关。研究区土壤重金属元素Cr含量随海拔高度增加呈明显上升的变化规律，而重金属元素Cd含量在海拔1400-1700m之间，具有随海拔高度增加呈明显下降的变化趋势，而在海拔1700m以上含量突然增加。Ni元素含量随海拔高度增加总体上呈现逐步上升的变化趋势，而 As元素含量随海拔高度增加则无明显变化规律。Pb元素含量在海拔1500m以上，具有随海拔高度增加明显上升的变化特征，最大值位于海拔最高处。土壤有机碳同位素随海拔高度增加总体上呈现出逐步变轻的变化趋势。一般而言，海拔升高，气温呈下降趋势而降水呈上升趋势，而温度降低及降水增加均可导致植物碳同位素变轻。此外，海拔高度不同，分布的植被类型不同，这也可能成为影响土壤有机碳同位素值产生变化的因素之一。本文通过对研究区土壤环境特征进行综合研究，对该区土壤环境质量提出一些规划建议：即针对土壤过酸过碱采取合理治理措施；针对土壤营养元素缺乏状况应合理调配施肥给予适量补充；针对不同地貌单元土壤应采取不同改良措施；针对山地草原土壤应大力发展山区牧业经营，以提高农民生活水平。 |
| 其他摘要 | Soil is the most fundamental and important natural resource which people rely on to live. In recent years, the ecological environment which influents the development of soil has been damaged due to human mass production and activities. What’s more, emissions of industrial “three waste”, extensive use of pesticides, inappropriate application of chemical fertilizer caused different degree pollution of soil environment. However, the condition of soil environment is of great importance to develop agricultural production and improve the quality and safety of agricultural products. The Karst mountain area of Guizhou Province is an important component of fragile ecological environment. There are many forest land and few cultivated land, and there’s no cultivated conditions supported by plain. As a result, the conditions of agricultural production is bad and the productive level is very low. What’s more,the cultivated land is seriously insufficient.Over the last one hundred years, due to the rapid population growth,forest damage as well as serious industrial pollution, the soil condition has been degraded and the agricultural producing ability has been declined, and this situation has seriously constrained the economy and society sustainable development. So, researching the soil environmental problems in Karst mountain area is of great importance to develop the economy and society in studied area and it can also relieve the contradiction of the population,resource and environment.What’s more, it can also provides scientific basis for the mountain stereo-agriculture planting. So, in this paper, we select the basic cultivated soil in Weishe town,Bijiecity,Guizhou province as studied area and applied glass electrode method,PE-2400 elemental analyzer method, Marven laser particle size instrument method, ICP-MS and the X fluorescence spectrum method to test and analyze the soil samples. Using the SPSS12.0 and EXCEL2010 to deal with the statistical data. It uses the single factor index method and comprehensive pollution index method to evaluate the soil environment in Weishe town and the main results are as followes:The main type of the cultivated soil in Weishe town are yellow soil and yellow brown soil. The cultivated soil is of weak acidity in generally, the mean pH value is 6.12; the content of the soil organic matter is abundant which can meet the need of the plant growing; the soil in the studied area is mainly composed of clay and medium silt ,according to The American Soil Texture Naming Standard, soil in the studied area is silty clay loam soil.According to The Second National Soil Survey Standard, the content of the total nitrogen and the total phosphorus are in the first class which neen’t to be added, but the content of the total K is in the fifth grading which needs to be added in order to increase the soil fertilizer;the content of Ca、Mg element in studied area is lower than the average content of Guizhou province which should be added properly; the regional characteristic of the plant-essential trace element content in the soil is Fe>Mn>Zn >Cu>Mo and besides the content of Mo element is lower than the average content of Guizhou province, the rest are all higher than this value. The content characteristic of the harmful heavy metal Cr、Cd、As、Pb in the surface soil is Cr＞Pb＞As＞Cd and the content of Cr、Cd are higher than the average content of GuiZhou Province, but the content of As、Pb are lower than this value. What’s more, the content of the Na、Al、Ti elements are higher than the average content of Guizhou province, so it needs to pay attention to prevent the soil salinization and soil pollution caused by high value of Al、Ti element.The content of the soil carbon、total N、total P and total K all show a declining trend with the increasing of the soil profile depth, but the content of total P、total Ca firstly show a decreased trend and then begin to rise with the increasing of the soil profile depth; the plant-essential trace element (excludes Zn element) and heavy metal Cr all show a general rising tr |
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