利用遥感数据排序特征制作土壤侵蚀图的研究

本文介绍了土壤侵蚀类型的CCT排序特征,提出了利用该特征制作土壤侵蚀图的原理和方法。经实验,获得了实验区的土壤侵蚀图和各类面积数,与常规调查结果基本一致。讨论了该法确保制图精度的各项措施,分析了成本费用,得出该法具有制图精度高和成本费用低的优点,有着广为应用的前景。     

土壤样本分形几何特征的图像分析方法

土壤水分的持留与水分和溶质的运移,在很大程度取决于土壤孔隙的几何性质,而用数字图像处理方法能够较准确地加以识别。本文采用面积法和周长法分别计算了土壤样本图像的孔隙分形维数和多重孔隙轮廓线分形维数,并分析了它们同土壤质地之间的关系。结果表明,土壤孔隙空间在一定尺度范围内才存在明显的分形特征,土壤质地越细(粘粒含量越高)分形维数越大。与周长法相比较,用面积法计算的孔隙分形维数对土壤质地更为敏感。     

OPTIMAL INTERPOLATION AND ISARITHMIC MAPPING OF SOIL PROPERTIES

Soil properties mapped in two intensive surveys had large nugget variances, leading to large estimation variances and erratic isarithms when mapped by punctual kriging. It is likely that both surveyors and survey clients are interested in average values of soil properties over areas rather than point values, and such values can be obtained by block kriging. Estimation variances are very much smaller, and maps of sodium and stone content at Plas Gogerddan, Central Wales, kriged over blocks 920m², and thickness of cover loam at Hole Farm, Norfolk, kriged over blocks of 400m², are much smoother than the punctually kriged maps. The map of Hole Farm has a distinct and meaningful regional pattern.     

中国土壤信息共享研究——1:400万中国土壤分布式查询数据库

基于INTERNET网络的信息高速公路的开通,为土壤资源信息网络化和共享提供基础条件,从而避免低水平的重复投资、重复建设,充分发挥土壤信息在国家建设、农业发展、生态环境保护、资源合理利用、科学研究和国内外同行学术交流中的作用。本研究利用当前世界上最流行的客户端/服务器,分布式查询的网络通信模型,以标准化的土壤信息为基础,采用先进的 Web GIS、ASP和Frontpage等网页编辑和发布技术去达到并实现 1:400万中国土壤空间信息和属性信息的分布式动态查询、静态查询和远程用户进行图形查询与编辑的目的。通过本项目的研究为促进中国土壤信息的标准化、规范化和网络共享提供了理论与方法论。     

A COMPARISON OF DATA FROM AGRICULTURAL SOIL SURVEYS WITH ENGINEERING INVESTIGATIONS FOR ROADWORKS IN AYRSHIRE

Recently a number of outline soil survey maps, on a scale I: 25 000, each covering some IOO km square, have been made available by the Soil Survey of Scotland to County Advisory Officers) Planning Officers, and others who have specialist requirements. In North Central Ayrshire a number of major roadworks have been completed in recent years and the Kilmarnock and Hurlford Bypasses are at present under construction. Site investigations have been undertaken in connection with these works and construction records kept. These make possible the assessment of the usefulness of the soil survey maps for initial route and realignment planning of roads. The delineation of the various soil associations on the soil survey maps related very closely to the limits of the various engineering soils encountered. The groupings adopted by the soil surveyors for boulder clays have, however, been found to be narrower than presently required by engineers) while the groupings adopted with respect to the raised beach and alluvial deposits too wide. It is suggested that the engineering behaviour of boulder clays needs closer examination and any correlations between engineering and soil association groupings should be sought. Also if the grading, water content, and bulk density of the raised beach sands and gravels could be given by the soil survey, this information would permit engineers to make a much better judgement of the road-bearing capacity of these materials. Alluvial deposits should be similarly tested and distinguished as either riverine or lacustrine deposits. To avoid duplication of effort in the future when geotechnical maps are produced and to gain the maximum benefit of the information so far collected, a closer liaison between engineers and the Soil Survey of Scotland is suggested.     

西藏主要农区农田土壤肥力状况研究

西藏由于其特殊的地理位置、气候类型和地质历史以及耕作习惯,使其具有特殊的土壤特征。在2002~2004年间,我们对西藏主要农业区的林芝、拉萨、日喀则、山南等4地(市)的农田土壤进行了采样分析,分析结果显示:4地(市)农田土壤酸碱性由弱酸性至弱碱性(pH6.5~9.0);养分的基本状况是有机质含量在5~50g/kg之间,变幅较大,N素少(全N0.2~2g/kg,速效N20~80mg/kg),P素缺(全P0.22~1.42g/kg,速效P1~133mg/kg),K素(全K1.9~12.2g/kg,速效K80~1290mg/kg)和微量元素比较丰富(Cu10~443mg/kg,Zn47~266mg/kg,Fe1880~7550mg/kg,Mo0.2~6.6mg/kg,Mn196~736mg/kg,B0.5~138mg/kg)。     

OPTIMAL INTERPOLATION AND ISAR1THMIC MAPPING OF SOIL PROPERTIES

Kriging is a means of spatial prediction that can be used for soil properties. It is a form of weighted local averaging. It is optimal in the sense that it provides estimates of values at unrecorded places without bias and with minimum and known variance. Isarithmic maps made by kriging are alternatives to conventional soil maps where properties can be measured at close spacings. Kriging depends on first computing an accurate semi-variogram, which measures the nature of spatial dependence for the property. Estimates of semi-variance are then used to determine the weights applied to the data when computing the averages, and are presented in the kriging equations. The method is applied to three sets of data from detailed soil surveys in Central Wales and Norfolk. Sodium content at Plas Gogerddan was shown to vary isotropically with a linear semi-variogram. Simple punctual kriging produced a map with intricate isarithms and fairly large estimation variance, attributed to a large nugget effect. Sloniness on the same land varied anisotropically with a linear semi-variogram. and again the estimation error of punctual kriging was fairly large. At Hole Farm. Norfolk, the thickness of cover loam varied isotropically, but with a spherical semi-variogram. Its parameters were estimated and used to krige point values and produce a map showing substantial short-range variation.     

A REAPPRAISAL OF SOIL MAPPING IN AN AREA OF SOUTHERN SCOTLAND. PART I THE RELIABILITY OF FOUR SOIL MAPPING UNITS AND THE MORPHOLOCICAL VARIABILITY OF THEIR DOMINANT TAXA

A two stage random sample survey was made to study the composition of four common soil mapping units already mapped in the Central Lowlands of Scotland. The four mapping units were sampled at densities proportional to their mapped area. In terms of their A horizon textures, the mapping units had percentage reliabilities of 84, 96, 93 and 97 and drainage class reliability scores of 70, 80, 72 and 70. On the basis of taxonomic units within the mapping units, percentage reliabilities ranged from 43–66 but no minor constituent soil exceeded 16 per cent in any of the units studied. Although complex according to currently accepted guidelines, such mapping units should be named according to the dominant taxonomic unit. Errors of identification due to inadequate definitions of taxonomic units have contributed to some of the low levels of reliability of taxonomic units within mapping units and soil taxa should be defined more precisely in Scotland. Means and variances of the taxonomic units, upon which the above named mapping units are based, indicate that the four taxonomic units (and hence also mapping units) under study are not equally variable in the area of investigation.     

一种确定原状土样非饱和水力传导度的方法

提出了一种新的求参方法－“同定参数法”,按该方法求原状土样参数的原理设计制作了在装置,在求参过程中,通过迭代法修正水分特征曲线,求得原状土样非饱和水力传导度。     

THE DESCRIPTION OF DESORPTION OF PHOSPHATE FROM SOIL

After incubation with soil, phosphate was desorbed in dilute calcium chloride solutions. After short periods of incubation, the amount of phosphate desorbed increased rapidly at first but then net re-adsorption occurred. After long periods of incubation, desorption was slower and there was no net re-adsorption with prolonged desorption. Desorption was described in terms of two limiting values: the amount of phosphate (K) which would be desorbed as the concentration of phosphate approached zero, and the solution concentration of phosphate (C_o) at which no desorption occurred. Both values decreased as the period of incubation increased. The value of K increased during the desorption phase, but the value of C_o decreased. The decrease in C_o during desorption was most marked after short periods of incubation and was important in describing the trend for re-adsorption of phosphate.     

西藏主要农区农田土壤肥力研究

西藏地质历史比较年轻,因而土壤的形成也较晚。由于喜马拉雅山造山运动和多次的冰期和间冰期的发生,青藏高原不断加速抬升,气候变干变冷。洪积物、坡积物、冰积物、湖积物和冰水沉积物在气候、生物、物理、化学和人类活动的作用下不断演变,在不同的地型部位形成多种类型的土壤,且具有鲜明的高原特色。耕地是土壤资源的精华,它是在自然土壤的基础上,经过长期的人类耕作、灌溉、施肥等措施逐步演化而成的,由于各地气候、成土母质、成土条件、耕作方式、栽培历史等的不同,耕地的类型、质量、肥力状况差异较大[1,2]。西藏全区共有耕地约32万hm2,…     

VARIABILITY IN THREE AREAS OF THE DENCHWORTH SOIL MAP UNIT

Variability of soil within three areas of the Denchworth map unit in southern England Has been investigated by describing and analysing samples from thirty profiles located at the intersects of a randomly oriented grid. The Denchworth series has been mapped over several stratigraphically different clays, and the areas chosen provide three groups of profiles developed over Gault (Cretaceous), Kimmeridge, and Oxford (Jurassic) Clay respectively. Purity of the map unit, estimated as the percentage of profiles whose data agree with the definition of the Denchworth series, was 60 per cent, which is comparable with values for other map units both near by and elsewhere. The variability of individual properties as indicated by coefficients of variation differed widely. Generally, physical properties were more uniform than chemical properties. The Denchworth map unit can consequently be treated uniformly for aspects of land management related to soil physical properties but it provides little guidance for fertilizer application. A small amount of variability can be attributed to mapping together those soils developed in material derived from stratigraphically different clays, but is insufficient to justify separating them.     

小比例尺土壤制图理论和方法的研究

本文对小比例尺土壤制图理论和方法进行了总结,认为土壤制图是研究和表达土壤在空间分布的群体结构形式。提出了土壤组合发生的制图原则,以及提高定量化程度的单区与复区并重的制图方式。论述了土壤制图单元的组成分、确定的根据、相应的分类级别;土壤制图单元系统的等级及其排列;土壤制图单元与土壤分类单元的关系和异同。概括了单区与复区两种图斑结构形式及其形成因素,提出首先将复区图斑划分为地形、母质、历史演化、耕作等成因系列,然后再根据土壤群体组成分间的发生联系,细分为许多成因类型的分类观点和实例。还阐述了图斑组合所显示的我国土壤分布的地理规律性。概述了制图综合在小比例尺土壤制图中的重要意义,综合概括的途径和注意事项。最后简述了小比例尺土壤制图的展望。     

红壤性水稻土无机肥连施与土壤结构特性的研究

良好的土壤物理环境,是农业高产稳产的基础。通过9年定位研究阐明,红壤性水稻土无机肥连施特别是偏施,随着有机和无机胶结物质的数量减少,土壤结构性遭受破坏,容重增值,孔隙度降低,水稳性结构破坏率提高,微团聚体分数系数上升,致使土壤紧实,耕性变坏,土壤肥力衰退。无机肥与有机肥配合施用能有效地提高作物产量,改善土壤物理环境,为建立优化施肥结构展示了良好前景。     

低湿地与土壤湿度的卫星遥感监测与制图

本文介绍应用陆地卫生ＴＭ图象数据监测法国莱茵河谷地土壤湿度变化，绘制１：５０，０００低湿地分布图的技术方法。对夏、秋两个时相的ＴＭ图像进行Ｋ－Ｌ变换等应用处理，获得的第３主分量集中了土壤湿度差异的信息。把两个时相的第３主人量精确配准后，以Ｈｙｐｅｒｂｏｘｅｓ分类器进行湿度分类，分出水体、恒湿地、夏秋季潮湿地、冬春季潮湿地、恒干地等５个湿度类别。经实地检验准确可信，表明此方法适合于土壤湿度变化监测与     

VARIATIONS IN THE USEFULNESS OF RAPID SOIL MAPPING IN THE NIGERIAN SAVANNA

The rapid soil mapping required in developing countries can only be done by relating soils to land form and geology. A usefulness classification of mapping units is suggested. The most useful contain the least soil variation. Units with regular soil variation within them are more useful than those with random variation. In the Nigerian Savanna the most useful units are on hill remnants and homogeneous sediments, particularly coarse siliceous sandstones and fixed dunes. The least useful are on dissected areas, heterogeneous sediments, igneous and metamorphic rocks. The least fertile soils often dominate the most useful units. Rapid soil mapping should be useful in the north and the lower Niger and Benue valleys.     

DPTIMAL INTERPOLATION AND ISARITHMIC MAPPING OF SOIL PROPERTIES. IV SAMPLING STRATEGY

A sampling strategy is presented for soil survey in which an individual soil property is of interest and can be measured. It depends on first determining accurately the semi-variogram for the property, and this must be done in a prior reconnaissance stage of a survey. Then from the semi-variogram estimation variances can be found for any combination of block size and sampling density by the methods of kriging. Alternatively for a given block size the sampling density needed to achieve a predetermined precision (maximum estimation variance) can be determined. The strategy is optimal in the sense that the sampling effort is the least possible to achieve the precision desired. An equilateral triangular configuration of sampling points is best where variation is isotropic, but a square grid at the same density is very nearly as good, and will usually be preferred for convenience. Where there is simple anisotropic variation optimal sampling is achieved by choosing a rectangular grid with sides in the same proportion to one another as the slopes of the semi-variogram in the directions of maximum and minimum variation.