Human-altered and human-transported (HAHT) soils in the U.S. soil classification system

ABSTRACT

Human-altered and human-transported (HAHT) soils are widespread across the globe and are concentrated near where people live and work. Although some of the HAHT soils are significant because they can be hazardous to human, animal, and plant health, most are not mapped or classified to the same extent as agricultural soils. The purpose of this article is to discuss the occurrence, types, and importance of HAHT soils and to document the historical and proposed classification of HAHT soils in Soil Taxonomy. There are two main forms of materials that define HAHT soils: human-altered soils formed in human-altered materials (HAM) from the soil surface to 50 cm (or to bedrock if shallower) or more and human-transported soils formed in human-transported materials (HTM) from the soil surface to 50 cm (or to bedrock if shallower) or more. The HAHT soils mainly occur in urban areas, transportation corridors, mined lands, landfills, filled shallow water, and agricultural areas on anthropogenic landforms. Hazards include danger from radioactivity, pollution, content of hazardous artifacts, or presence on unstable landforms that may fail during heavy rains or earthquakes. The HAHT soils are extensive, and their extent is growing. In the past, few HAHT soils were described or classified adequately because the U.S. Soil Taxonomy system was established for agricultural and other naturally occurring soils. However, HAHT soils are now being recognized and classified in many soil classification systems at very high levels. A new soil order is proposed for U.S. Soil Taxonomy that would include the most obvious profoundly and intentionally altered HAHT soils. A discussion and justification is given for an unofficial proposal. Input will be collected from international groups of scientists, and modifications of the unofficial proposal are expected. The long-term result of establishing a new soil order will be to enable proper classification, allocation, and mapping of HAHT soils worldwide.     

Palevye (pale) soils of Central Yakutia: Genetic specificity,properties, and classification

Permafrost-affected palevye (pale) soils of Central Yakutia are developed from mantle calcareous deposits of different textures and are characterized by the common mica-chloritic association of clay minerals with a higher content of chlorite in comparison with the soils developed from mantle loams and loess-like loams in the European part of Russia. In the pale soils, the distribution of clay minerals in the profile has an even pattern in the loamy variants and a differentiated pattern typical of podzols in the loamy sandy variants. Data on the chemical extracts and Mössbauer spectroscopy indicate that the iron in the pale soils is mainly fixed in silicate minerals. The content of nonsilicate iron represented by the amorphous and weakly crystallized compounds in the pale soils is relatively low. The humus-accumulative horizon in these soils is close to the gray-humus (soddy) AY horizon according to its acid-base characteristics (the soil pH and the degree of base saturation) despite the presence of exchangeable sodium and the shallow occurrence of the calcareous horizon.     

Patterns and classification by soil taxonomy of the soils of the southern cook islands

The soil patterns of the six larger islands of the Southern Cook Group in the South Pacific are described. Classification is according to Soil Taxonomy, and six soil orders are recognised: Oxisols, Ultisols, Mollisols, Alfisols, Inceptisols and Entisols, which are further subdivided into 12 suborders, 15 great groups, and 25 subgroups. Classification to series level is outlined in tabular form. The soil pattern on individual islands is basically one of concentricity. The older, more weathered soils (Oxisols and Ultisols) occur on remnant surfaces and grade with either decreasing altitude or age of land surface to Alfisols, Mollisols, Inceptisols, and Entisols, respectively. Many of the soils associated with the coralline makateas have shallow contacts to the underlying limestone and have been separated in lithic subgroups.     

Study of Pedo Genesis of soils of Bundi district (Rajasthan)

The soils of Rajasthan vary from desert sand to heavy clay with all intermediate stages like sandy loam, loam and clay loam. The last two textural groups are more prevalant on the eastern, northeastern and southeastern part of the Aravallies which run almost in the middle of the State from southeast to northeast. The latter groups of soils have more potential from the point of agricultural development in the State. These soils are widely termed as alluvial soils which is a general term to indicate the nontaxonomic group of soils that have parent material of alluvial origin, Riecken ¹⁷, Kelloog ⁸ has referred to the soils developed from the alluvium as classified under variety of world soil groups. In our country many of the alluvial soils have not yet been studied from the soil genesis point of view as a measure to classify the soils under taxonomic groups. Ray Chawdhary and Mukerji ¹⁵, concluded that the alluvial soil groups of our country are ill defined and the classification of these soils need more study. Basu ³ was able to distinguish the genetic characteristics of the soils of Deccan. Agrawal and Mukherji ¹⁾ established that distinct genetic soil types have come into expression under Gangetic alluvium. Agarwal ² has concluded about the three types of soils in the toposequence with precipitated calcium throughout, zone of calcium accumulation in the bottom of the profile and soils free of calcium, and suggests that the soils of Gangetic plain be called as derived from alluvium. A process of reclassifying the alluvial soil series into taxonomic groups is a common trend in the United States since the last two decades.     

Content and distribution pattern of dichlorodiphenyltrichloroethane (DDT) in soils of Moscow

The content and distribution pattern of dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDE and DDD) in the surface layers of soils in Moscow are studied. The residual content of these substances in the soils varies within 2.22–1440 µg/kg (at a mean value of 158.9 ± 314.1 µg/kg and median 42.53 µg/kg). The correlation between the contents of DDT and its metabolites and DDD and organic matter is revealed. The highest contents of the pollutants are seen in the residential–transport and industrial zones of Moscow, while their lowest contents are revealed in the soils of the yards of preschool facilities and schools. With respect to the residual contents of the pesticide, most of the soils of Moscow can be considered uncontaminated (80.0%) and acceptably contaminated (7.5%).     

Inclusion of soils and soil-like bodies of urban territories into the Russian soil classification system

The results of the Internet discussion on the classification of urban soils aimed at evaluating their possible inclusion into the modern Russian soil classification system adopted by a wide range of specialists are presented. The first step was to address the urban diagnostic horizons as the basis for identifying soil types according to the rules of the Russian soil classification. New diagnostic horizons were proposed for urban soils: urbic (UR), filled compost-mineral (RAT), and filled peat (RT). The combination of these horizons with other diagnostic horizons and layers of technogenic materials correspond to different soil types. At the subtype level, the diagnostic properties (qualifiers) that may reflect both natural phenomena (gley, alkalinity) and technogenic impacts on the soils (urbistratified; phosphatic; or poorly expressed urban—ur, rat, rt) are used. Some corrections were proposed for the system of parent materials in urban environments. Urban soils formerly described in another nomenclature—urbanozems, urbiquasizems, and culturozems—are correlated with the taxa in all the trunks of the system. The proposals accepted can be used for the next updated version of the new Russian soil classification system.     

Micromorphology of diagnostic horizons in aridic soils (complementary to the new classification system of soils of Russia)

The micromorphological data on aridic soils are far from numerous; therefore, the information presented here contributes to the development of pedogenetic ideas and characterization of diagnostic horizons and genetic properties in substantive-genetic classification systems. The diversity, functioning, and resilience of aridic soils are basically determined by the properties of their topsoils, which are regarded as recent dynamic formations as opposed to subsoils that formed under a different paleoclimatic environment; topsoil properties are more important for soil classification. Each of the two upper horizons in the new system of soil classification (the light-humus and xero-humus) has the same micromorphological features in different soils; however, in a sequence of soils, some individual micromorphological properties were revealed that indicate increasing aridity. The micromorphological properties of topsoils make it possible to identify the mechanisms of certain phenomena: aeolian deposition, structural rearrangement, the dynamics of secondary carbonates, and cryptosolonetzic manifestations.     

草原土壤：分布、分类与演化

草原土壤系指草原、湿草原和森林草原植被下形成的富含有机质、盐基饱和度高的暗色土壤.世界上此类土壤面积约900万km2,我国约76万km2,是粮食生产的重要基地.本文比较了国际上草原土壤分类.不论俄罗斯或中国,均腐土开垦以后土壤有机质开始下降迅速,而后减缓,逐步达到与当地生物气候相适应的水平.所以至今仍保持一定厚度的黑土层.在均腐土资源的利用和保护上,一方面应保持其有机质平衡,另一方面更重要的是严防水土流失,以保证其生产能力.     

松嫩平原土壤线性膨胀系数的研究初探

<正>2013年4月国务院将黑龙江省确定为现代农业综合配套改革试验区后[1-2],以提升耕地质量为重点的土地整理、标准粮田建设、中低产田改良、农田水利工程等建设项目日益增多,研究掌握松嫩平原土壤的膨胀性和分散性,对指导田间工程建设和科学合理耕翻、免耕播种、节能降耗显得尤为迫切,并具有现实意义。     

Long-term dynamics of the anthropogenic salinization of soils in Moscow (by the example of the Eastern district)

The long-term (1989–2010) and seasonal dynamics of the anthropogenic salinization of soils related to the use of deicing mixtures in the Eastern Administrative District of Moscow were examined. Data on the chemical composition of deicing mixtures and on the contents of soluble salts in the snowmelt and in the soil profiles of different functional zones were analyzed. The maps of soil salinization were compiled for 1989, 2005, and 2010; on their basis, the resulting map of the degree of soil degradation was developed. The areas with abnormal concentration of salts in the soils expanded during the study period (21 yrs), and the average content of salts in such areas increased by 3.2 times. The maximum total content of salts was found in the spring season in the soils along major highways.     

A classification scheme for earthworm populations (Lumbricidae) in cultivated agricultural soils in Brandenburg,Germany

Earthworm activity is observed at long‐term monitoring sites as an indicator of soil function to assess changes resulting from environmental and management conditions. In order to assess changes, characteristic values of earthworm populations under different site conditions have to be known. Therefore, a classification scheme for site‐specific earthworm populations was developed for soil in agricultural use, taking interactions between earthworm populations and soil properties into account. Characteristics of sites grouped by means of a cluster analysis after principal‐component analysis served as a basis for the derivation of the classification scheme. Soil variables found to characterize site differences with respect to earthworm populations were the texture of the topsoil, the texture of the subsoil, and the soil organic‐matter (SOM) content. The textural classes of the topsoil were divided into five groups comprising sandy soils (Ss), silty sand soils (Su), slightly loamy sand soils (Sl2), medium to strongly loamy sand soils (Sl3/Sl4), and loam and clay soils. Soil organic matter was divided into grades of equal size in a range from <1%, 1%–2% up to >6%. The variables “earthworm abundance” and “earthworm species” were selected to represent earthworm populations and were divided into six groups ranging from very low to extremely high. Defined groups of earthworm populations showed a clear structure in relation to soil textural groups and the content of SOM. From this distribution, a classification scheme was derived as basis for prognostic values of site‐specific earthworm populations, thus enabling the interpretation of changes over time. For some soil textural groups, selected variables appeared to enable the derivations of expected earthworm densities and species composition outside the range of the given database, but for some soil textural groups, broader databases will be needed to specify these derivations.     

Ecology of soil springtails (Collembola, Insecta) from pine woods and Rhododendron shrublands in the Central and Eastern Pyrenees (North Spain)

The collembological composition of samples from the Central and Western Pyrenees (Northern Spain) was studied. Soils from two biotopes (pine forest and Rhododendron shrub) were studied in Nuria and Vallibierna, using different diversity indices and multivariate analyses. Ten species were found that were endemic to the Iberian Peninsula. Three of these are exclusive to the Pyrenees: Ceratophysella elegans, Hypogastrura dasiensis and Protachorutes pyrenaeus. The greatest diversity was observed in the soils of Rhododendron, above all at Nuria. Collembola were most poorly represented in the pine forest of Vallibierna, where the endemic Hypogastrura meridionalis was the dominant species. Multivariate analyses indicated that the latter species characterizes this pine forest and separates it from all other biotopes studied. The evenness (E) was most pronounced in Nuria, where Folsomia manolachei was the characteristic species.     

模糊逻辑在土壤连续分类和制图表达中的应用及展望

土壤是复杂的历史自然综合体,在属性空间和地理空间上均是连续渐变的,因此基于"双清晰模型"的常规土壤调查制图理论基础明显存在不足,且随着精准农业的快速发展和环境模型模拟精度的提高,客观上对土壤调查输出信息的内容与精度提出了更高的要求。模糊逻辑应用于土壤分类和制图,是继地统计学之后土壤计量学领域又一创新性发展,为国外许多学者所推崇,但是国内在这一领域的研究还较少。因此,本文系统地介绍了模糊逻辑引入土壤分类研究中的必然性和科学意义,以及模糊逻辑在国内外土壤分类和连续制图领域的应用研究进展,并分析了基于模糊逻辑的土壤连续制图表达方法存在的不足及研究展望。     

Correction of a large-scale soil map with the use of the new classification system of Russian soils

A large-scale soil map of one of the farms in the south of Karelia has been analyzed. This map was initially compiled in 1979 on the basis of the official Classification and Diagnostics of Soils of the Soviet Union (1977). We have corrected it with the use of the new Classification and Diagnostics of Russian Soils. Both the names of the map units and the particular delineations on the map have been changed. These changes are related to differences in the principles of soil diagnostics in the old and new classification systems and to real changes in the soil cover that have taken place after the map’s compilation. In particular, large areas of peat bogs have been drained, and the cultivated peat soils have been subjected to accelerated mineralization. Surface planing works after digging drainage channels have also changed the soil cover pattern. The revised large-scale soil map developed on the basis of the new classification system gives more adequate information about the real soil cover.     

A tentative proposal for productivity classification of paddy soils in a detailed soil survey

In Japan, half of the total crop yield consists of rice grown in paddy fields as the nation's staple food. In the past ten years, serious consideration has been given to the stagnant production of rice, at a rate of about 450 kg unhulled rice to ten ares.