CAJ | 학술논문

为探明生态脆弱区土地利用方式转换对土壤有效态微量元素的影响,以贵州喀斯特地区草地及其相应开垦的农田为对象,采用成对设计的方法研究了草地开垦对土壤微量元素(铜、锰、铁、钼、硼、锌)的影响,并探索基于土壤微量元素密度的区域土壤微量元素丰缺评价指标.结果表明:研究区土壤有效态微量元素在土壤剖面上呈表面富集现象,其含量随土层深度的增加而降低;草地开垦导致土壤有效态铜、铁、硼和钼的含量出现不同程度的降低,降幅为4.97%~79.17%,而土壤有效锌含量则增加,增幅为11.76%~46.06%;开垦导致土壤有效锰含量在剖面上的下降速率加快.建立了研究区6种有效微量元素的丰缺评价指标,该指标以土壤微量元素密度为参数,以参数值的不同范围界定微量元素的丰缺程度,消除了微量元素空间异质性对判定结果的影响.根据该评价指标,研究区土壤有效铁、锰处于极高水平,草地开垦导致土壤有效铜、钼、硼的丰度下降,而有效锌的丰度上升;结合微量元素有效性评价指数,整个研究区土壤有效硼处于低水平,不能够满足植物正常生长发育的需要.该研究结果可为生态脆弱区土地的科学管理和土壤微量元素科学评价体系的建立提供参考.
위탐명생태취약구토지이용방식전환대토양유효태미량원소적영향,이귀주객사특지구초지급기상응개은적농전위대상,채용성대설계적방법연구료초지개은대토양미량원소(동、맹、철、목、붕、자)적영향,병탐색기우토양미량원소밀도적구역토양미량원소봉결평개지표.결과표명:연구구토양유효태미량원소재토양부면상정표면부집현상,기함량수토층심도적증가이강저;초지개은도치토양유효태동、철、붕화목적함량출현불동정도적강저,강폭위4.97%~79.17%,이토양유효자함량칙증가,증폭위11.76%~46.06%;개은도치토양유효맹함량재부면상적하강속솔가쾌.건립료연구구6충유효미량원소적봉결평개지표,해지표이토양미량원소밀도위삼수,이삼수치적불동범위계정미량원소적봉결정도,소제료미량원소공간이질성대판정결과적영향.근거해평개지표,연구구토양유효철、맹처우겁고수평,초지개은도치토양유효동、목、붕적봉도하강,이유효자적봉도상승;결합미량원소유효성평개지수,정개연구구토양유효붕처우저수평,불능구만족식물정상생장발육적수요.해연구결과가위생태취약구토지적과학관리화토양미량원소과학평개체계적건립제공삼고.
@@@@With population growth, most of the grasslands in China were converted into croplands. The structure, process and function aspects of the ecosystem changed as a result from the conversion of the grassland, and led to a decline in soil quality and productivity, soil erosion acceleration, and destruction of the vegetation. These phenomena are especially obvious in karst areas, because the typical characteristics of karst areas are harsh habitats and ecological vulnerabilities. Nowadays, most investigations mainly focus on biodiversity, soil and water conservation, soil productivity, and soil carbon density. However, the studies of soil trace elements are scarce. The available trace elements of soil are very important for plant growing, especially when major elements, such as N, P, and K are rich. In order to explore the effects of the conversion of grassland into cropland on soil trace elements (Cu, Fe, Mn, Zn, B, and Mo), a paired-site design was employed between grasslands and corresponding croplands of karst area in Guizhou. At the same time, the regional indices of trace soil elements were developed based on trace soil element density. In this study, the contents of available trace soil elements in different depths were measured and the element densities were calculated for the grasslands and their counterpart croplands, and consequently the regional indices of trace soil element was built for evaluating the study area. The results showed that trace soil elements decreased with soil depth. The soil contents of available Cu, Fe, B, and Mo decreased, ranging from 4.97% to 79.17%, resulting from the conversion of grassland to cropland. The soil content of available Zn in every soil depth in cropland was higher than in grassland, increasing in range from 11.76%to 46.06%;also, the declining rate of available Mn content in cropland areas was faster than in grassland areas after the grassland conversion. As the contents of trace soil elements varied with soil depth, the previous evaluation standard, based on the trace soil element content, could not eliminate the spatial heterogeneity. Therefore, the regional indices of abundant trace soil elements, based on soil trace element densities, were developed, in which the different range of parameter values were defined as trace element’s abundance degree, and the trace element density was calculated as the weight of trace elements in unit area in a certain depth. This method is proven better than previous evaluation methods, since it could avoid the side effect of soil trace element’s spatial heterogeneity. According to this evaluation, the available Fe and Mn were at a very high level in the study area, the abundance of soil available Cu, Mo and B decreased, and available Zn increased due to the grassland conversion. Combining with the trace elements effectiveness evaluation index, available B in the soil was at a below medium level and could not meet the demands of plant growing. The findings provide references for developing scientific strategies of land use in fragile ecological areas, and will be helpful for developing a scientific evaluation system of soil trace elements’abundance indices.