共查询到16条相似文献，搜索用时 125 毫秒
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河南省土壤系统分类中典型土系简介 总被引：1，自引：1，他引：0
《土壤通报》2015,(1):4-13
土系是我国土壤系统分类的最基层分类单元;而尽快建立健全覆盖我国各区域的典型土系是我国土壤系统分类的一项急迫工作。重点介绍河南省的土系建立情况,在222个典型单个土体的野外调查和实验测定数据基础上,依据《中国土壤系统分类检索(第三版)》和《中国土壤系统分类土族和土系划分标准》,共划分了5个土纲,11个亚纲,22个土类和39个亚类,建立了187个土系,并以农业耕作区的21个典型土系为例,介绍了河南省土系建立情况。 相似文献
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中国土壤系统分类土系描述的难点与对策 总被引：2，自引：0，他引：2
土系是土壤系统分类的最基层单元,我国现有土系约3 000个,距约3万个的估计总量还有巨大差距,因此土系建设在未来相当长时间内仍将是我国土壤系统分类研究和土系建设的一个重点。土系描述是土系建设最为重要的一环,是土系所有信息的直观具体展现,为确保土系描述的质量,国家科技基础性工作专项"我国土系调查与《中国土系志》编制(2008FY110600)"初步制订了土系描述标准,但其在描述规范上还存在一些问题有待明确和解决。为此,本文基于土系描述标准的介绍,剖析我国土系描述中存在的主要问题和产生原因,并提出相应对策,旨在进一步完善土系描述标准的科学性、规范性、全面性和系统性,提高我国土系描述的质量。 相似文献
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利用遥感(RS)和地理信息系统(GIS)技术能够快捷高效地进行景观解译。土系分布与景观特征密切相关,可以借助景观变异规律来辅助土系调查。本研究选择句容市某小区域为研究对象,首先以决策树分类方法对资源三号卫星影像进行土地利用类型的分类,将分类结果与原始影像叠加,并结合野外调查结果进行人工修正;精度达到要求后,再以修正后的土地利用类型图为底图,用决策树分类方法添加合适的坡度和高程信息,生成"高程-坡度-土地利用类型"的景观分类图;在此基础上,根据土壤-景观关系,结合数字高程模型(DEM)数据、资源三号卫星原始影像和景观分类图,对大比例尺土系调查进行调查路线的选择、剖面点的设置和土系界线的确定,并在研究区中选取核心区进行验证。结果证明:改进后的方法相对于传统土壤调查方法更加定量地考虑到景观变异情况,调查结果更具有代表性。 相似文献
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将土种资料转化为土系的必要性与可行性分析 总被引：1，自引：0，他引：1
在对我国土壤基层分类发展历程进行简短回顾的基础上,分析了将土种资料转化为土系的必要性,和将第二次全国土壤普查建立的土种转化为土系的可行性,并指出了在土种转化为土系过程中应当注意的问题。研究结果表明,经过大量土壤学家的多次讨论修改,全国第二次土壤普查最终汇总时所建立的土种(或称"新土种")已接近土系的涵义,以此为基础,辅以必要的野外实地补充调查,根据土系划分的原则、标准和方法,将土种转化为土系是可行的。如果能够通过认真分析、比较、归纳、总结已建立的"新土种"资料,将其转化的土系,就能够使大量宝贵的土壤普查资料充分发挥作用,节约大量的时间和资金,这是在大规模开展新一轮土壤普查前,加速我国土壤系统分类的基层分类研究进程,完善我国土壤系统分类体系,使土壤调查资料能够更好地为生产实际服务有效途径。 相似文献
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《国际水土保持研究(英文)》2020,8(4):430-439
Soil erosion is a major environmental problem in China. Planning for soil erosion control requires accurate soil erosion rate and spatial distribution information. The aim of this article is to present the methods and results of the national soil erosion survey of China completed in 2011. A multi-stage, unequal probability, systematic area sampling method was employed. A total of 32,948 sample units, which were either 0.2–3 km2 small catchments or 1 km2 grids, were investigated on site. Soil erosion rates were calculated with the Chinese Soil Loss Equation in 10 m by 10 m grids for each sample unit, along with the area of soil loss exceeding the soil loss tolerance and the proportion of area in excess of soil loss tolerance relative to the total land area of the sample units. Maps were created by using a spatial interpolation method at national, river basin, and provincial scales. Results showed that the calculated average soil erosion rate was 5 t ha−1 yr−1 in China, and was 18.2 t ha−1 yr−1 for sloped, cultivated cropland. Intensive soil erosion occurred on cropland, overgrazing grassland, and sparsely forested land. The proportions of soil loss tolerance exceedance areas of sample units were interpolated through the country in 250 m grids. The national average ratio was 13.5%, which represents the area of land in China that requires the implementation of soil conservation practices. These survey results and the maps provide the basic information for national conservation planning and policymaking. 相似文献
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慈溪市土壤系统分类研究 总被引：6，自引：0，他引：6
本文对浙江省慈溪市第二次土壤普查土壤分类系统进行了修订,并建立了慈溪市土壤系统分类,依据浙江省土系建立的原则和要求,初步建立了慈溪市土壤的土族和土系。 相似文献
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中国南方富铁铝化土壤土系建立进展 总被引：1，自引：0，他引：1
土壤基层分类单元划分，特别是土系建设是土壤系统分类的基础，也能直接为农业生产提供更详细的科学指导。富铁铝化土壤（砖红壤、赤红壤和红壤）在我国南方广泛分布，为了解其在中国土壤系统分类中归属以及土系建设情况，本文综述了自2008年以来土系研究的相关成果，系统分析了富铁铝化土壤诊断层和诊断特性检索、高级分类单元归属以及基层分类单元建设现状，并展望了土系建设的发展方向：进一步细化土系划分和描述标准，加强新土系建设，加强新技术和新方法在土系建设中的应用，加大和扩展土系建设成果的运用，旨在为我国南方富铁铝化土壤系统分类研究提供参考。 相似文献
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THE RELATION BETWEEN COST AND UTILITY IN SOIL SURVEY 总被引：1，自引：0，他引：1
This paper discusses how to compare the utility of soil maps. For three contrasting areas, in Southern England, it compares the utilities of a number of single-property and general purpose (series) soil maps, produced by free and grid survey, at map scales from 1 :20,000–1:70,000. The‘purity’of series mapping units increases with survey effort. Where the soil boundaries had fairly clear external expression free survey was superior to grid survey. On average the purity of maps by grid survey was higher than for maps by free survey at comparable survey effort. The uniformity of soil properties within mapping units was measured by relative variance (RV)= within-unit variance/total variance, (1–RV) indicates the increased precision achieved by the soil map. It increased with survey effort. For series maps by free or grid survey (1–RV) depended on how closely soil properties were associated with profile classes, and on the extent to which soil boundaries could be mapped on their external expression. Free survey was preferred at scales between 1: 100,000 and 1:30,000, when the soil boundaries could be mapped on their external expression, (1–RV) for the profile classes on which the mapping units are defined puts a ceiling to the utility of series maps (grid or free) which is already nearly achieved at map scales near 1:25,000. Except for properties very poorly associated with profile classes, single property maps do not have great advantage over series maps at medium map scales, but they attain higher values of (1–RV) at scales greater than 1: 25,000. 相似文献
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