Pavel Krasilnikov

Perspectives on utilitarian ethnopedology

Folk taxonomies can provide a common language, establish value, and assure quality of soil investigations for scientists, extension agents, and development workers. Vernacular soil names have been used throughout history and helped provide the basis of scientific classification. The Chinese were classifying soils 4000 years ago for tax assessment. Dokuchaev and others used vernacular soils like chernozem, solonetz, and gley as central concepts for their scientific soil classification. Scientific systems and detailed soil mapping are replacing folk taxonomies, especially in the more developed countries, because folk systems, if they still exist, are only locally valid and have relatively limited uses compared to scientific systems. In spite of these limitations folk taxonomies can still provide information that is useful for understanding landscape structure, function, and change, especially in developing countries with limited resources for research. Opportunities for using folk taxonomies to improve scientific soil classification, mapping, and environmental impact monitoring are not being exploited. These systems are disappearing; the last two centuries have seen rapid loss of this potentially useful information. The disconnection between folk and scientific soil classification and the resulting land management decisions that occur have wasted resources and caused severe economic hardship on communities. Examples from Africa, Asia, Europe, and the Americas are provided, especially the Senegal River Valley, United States, and Saudi Arabia.

Pedodiversity in mountainous tropical semideciduous forests of Sierra Madre del Sur, Mexico.

We studied pedodiversity in mountainous tropical semideciduous forests at three key sites in Sierra Madre del Sur, Southern Mexico, at the altitudes from 600 to 1400 m a.s.l. Using detailed soil maps, we recorded the total number and the areas of soil delineations at each site, and calculated the pedodiversity indices. We found that pedodiversity increases with an increase in the absolute height within the zone of semideciduous forests, and interpreted this phenomenon as an evidence for a smaller development of erosion at higher altitudes. The areas of soil delineations reach their minimum within the intermediate part of this zone, because large delineations of strongly weathered clayey soils are developed at the higher altitudes, and large delineations of recent soils on strongly eroded surfaces are found at the lower altitudes. A conclusion about the need to take into account the particular composition of the soil cover upon the interpretation of pedodiversity data is made.

Soil diversity and properties in mountainous subtropical areas, in Sierra Sur de Oaxaca, Mexico

Agroforestry is a new practice of sustainable soil use in the mountainous Sierra Sur de Oaxaca area of Mexico. Coffee is also a common cash crop grown in the region. The objective of this study was to investigate the pedodiversity in the area. Soil development is very complex, and is influenced by slope parameters and parent materials. Several soil groups are found in the area investigated: Alisols, Umbrisols, and Cambisols. Morphology, chemical properties, and mineralogical composition of the clay fraction of these soils were studied. The soils vary in the extent of weathering, morphology, and chemical properties, which are important to farming in the area. Most of the soils have heterogeneous parent material. The distribution of major soil types of the area is related to mass movement along the slopes, both past and present. The studied soils represent a chronosequence from unleached and unweathered Cambisols to Alisols, characterized by strong clay illuviation and dominance of kaolinite and gibbsite in...

Artificial chinampas soils of Mexico City: their properties and salinization hazards

La agricultura de chinampas es una practica tradicional de uso del suelo en el Valle de Mexico desde la epoca prehispanica. Los suelos de chinampas fueron construidas por la excavacion de sedimentos del lago que resulto en la creacion de un sistema de islas separadas por canales. La productividad agricola de estos suelos artificiales fue alta; tambien las practicas de uso del suelo incluyeron la silvicultura, la pesca y la caza. Actualmente, los suelos de chinampas estan afectados por una salinidad excesiva. Se estudiaron 10 perfiles de suelos representativos de la zona de chinampas de la Ciudad de Mexico con el objeto de caracterizar sus propiedades y origen, obtener su clasificacion, evaluar la salinizacion del suelo, la distribucion vertical de las sales y su composicion quimica. Los suelos se caracterizan por presentar una estructura en capas, de color gris oscuro uniforme, y una irregular distribucion vertical de carbono organico y arcilla. Algunos suelos muestran un aumento de la materia organica con la profundidad y otros perfiles presentan un contenido alto de esta en las capas superficiales y en el subsuelo. La dinamica de la sedimentacion como resultado de la disminucion de la materia organica en las capas superiores de los sedimentos lacustres se debe al aumento reciente en la tasa de erosion y al consiguiente aumento en la proporcion de particulas minerales en los sedimentos. El alto contenido de materia organica en las capas superficiales de algunos suelos se debe a la acumulacion de material del subsuelo rico en materia organica obtenida del fondo de los canales. La concentracion de sales solubles en los horizontes superficiales, expresada como conductividad electrica, varia de 5 a 50 dS⋅m-1. Las sales se concentran principalmente en las capas superficiales de los suelos. La abundancia de los cationes de las sales solubles es Na+>Mg2+>Ca2+>K+ y la de los aniones es SO42->Cl->HCO3->CO32-. La reaccion alcalina de los suelos se debe al Na+ intercambiable mas que por carbonatos de sodio libres. La recuperacion de las chinampas requiere de un planteamiento complejo, con la combinacion del suelo, agua y de la recuperacion de los ecosistemas.The chinampas agriculture is a traditional land use practice in the Valley of Mexico since Pre-Hispanic time. The chinampas soils were constructed by excavation of lake sediments that resulted in the creation of a system of islands separated by channels. The agricultural productivity of these artificial soils was high; also the land use practices included forestry, fish breeding and hunting. Nowadays, the chinampas soils are affected by excessive salinity. We studied 10 representative soil profiles in the chinampas zone of Mexico City in order to characterize their properties and origin, to provide their classification, and to evaluate soil salinization, vertical distribution of the salts and their chemical composition. The soils are characterized by a layered structure, uniform dark grey colour, irregular vertical distribution of organic carbon and clay, and high percentage of carbon. Some soils show an increase in organic matter with depth, and other profiles have maximum organic matter content in the surficial layers and in the subsoil. The dynamics of sedimentation resulted in the decrease in organic matter in the upper layers of lacustrine sediments, because of recent increase in erosion rate and consequent increase in the proportion of mineral particles in the sediments. Most probably high organic matter content in surficial layers of some soils is due to excavation and accumulation of organic-rich subsoil material in the course of digging the channels. The concentration of soluble salts in superficial horizons, expressed as electric conductivity, varies in a wide range from 5 to almost 50 dS·m -1 . The salts concentrate mainly in the superficial layers of soils. The abundance of the cations of soluble salts is Na + >Mg 2+ >Ca 2+ >K + and that of the anions is SO 4 2- >Cl - >HCO 3 - >CO 3 2- . The alkaline reaction of soils is caused by exchangeable Na rather than by free sodium carbonates. The restoration of chinampas requires a complex approach, combining soil, water and ecosystems remediation.

Soil legacy data rescue via GlobalSoilMap and other international and national initiatives

Legacy soil data have been produced over 70 years in nearly all countries of the world. Unfortunately, data, information and knowledge are still currently fragmented and at risk of getting lost if they remain in a paper format. To process this legacy data into consistent, spatially explicit and continuous global soil information, data are being rescued and compiled into databases. Thousands of soil survey reports and maps have been scanned and made available online. The soil profile data reported by these data sources have been captured and compiled into databases. The total number of soil profiles rescued in the selected countries is about 800,000. Currently, data for 117, 000 profiles are compiled and harmonized according to GlobalSoilMap specifications in a world level database (WoSIS). The results presented at the country level are likely to be an underestimate. The majority of soil data is still not rescued and this effort should be pursued. The data have been used to produce soil property maps. We discuss the pro and cons of top-down and bottom-up approaches to produce such maps and we stress their complementarity. We give examples of success stories. The first global soil property maps using rescued data were produced by a top-down approach and were released at a limited resolution of 1km in 2014, followed by an update at a resolution of 250m in 2017. By the end of 2020, we aim to deliver the first worldwide product that fully meets the GlobalSoilMap specifications.

Stable carbon compounds in soils: Their origin and functions

The sources, formation conditions, and composition of stable carbon compounds in soils are considered in this review. It has been shown that the stable carbon compounds contain lithogenic carbon-containing components and pyrogenic material, as well as some stable compounds resulting from the biochemical transformation of biomass in the soil. The presented data indicate that pyrogenic components (black carbon) play the major role in the formation of stable carbon compounds in the soil; in most soils, the products of biomass combustion prevail over the technogenic emissions resulting from the combustion of fossil fuel. Methods for the separation and analysis of stable carbon compounds have been considered; the specificity of markers used for the diagnostics of carbon compounds of different genesis has been discussed. A tentative scheme has been proposed for the classification of carbon compounds in the soil depending on their genesis and stability. The contribution of black carbon to the development of soil morphology and properties has been discussed; the hypothesis about the deciding role of pyrogenic components in the formation of chernozemlike soils in Middle Europe has been challenged. The suitability of biocarbon application to soils for improving their properties and fixing carbon in the soil has been shown.

Diagnostics of hydromorphism in soils of autonomous positions on the Severo-Sos’vinsk Upland (Western Siberia)

The complex studies of hydromorphism features in taiga weakly differentiated soils using morphological (color), chemical (iron content in different extracts, indicators of reducing conditions (IRIS)), and geobotanic (using the Ramenskii scale) methods have led to ambiguous conclusions. In all the soils, surface gleying was manifested. According to the results obtained by different methods, the maximum reduction processes were related to either the sublitter or the next deeper horizon. The Schwertmann coefficient, the criterion of Bodegom, and the Ramenskii scale indicated an increase of hydromorphism in the soils studied in the following sequence: the lower part of the ridge slopes drained by the small gullies < the middle part of the slopes < the flat tops of the ridges < the depression between the ridges. The morphological diagnostics of gleying proved to be a less sensitive method, which can recognize only the most contrasting hydromorphic soils. The lower horizons in some taiga soils have a bluish gray color probably not related to the recent soil hydromorphism.

Biogeography of testate amoebae in the soils of Mexico

We studied testate amoebae (testates) in the soils of coniferous and deciduous forests and in the wetland and aquatic habitats of Mexico. In 141 samples we found 205 taxa identified to the species or intraspecies level and 68 testate amoebae, which could not be identified to the species level. The highest species diversity of testates was found in the soils of the tropical rainforest (126 species and intraspecific taxa, including spp.) and in tropical wetlands (144 species and intraspecific taxa, including spp.). The study documented testate amoebae with a limited geographical distribution (genera Centropyxis, Cornuapyxis, Ellipsopyxis, Hoogenraadia, Planhoogenraadia, Apolimia, Certesella, Apodera, and Alocodera). We found that testate amoebae in the soils of Mexico had a high level of polymorphism and individual variability. We discuss the value of soil testate amoebae for defining biogeographical regions of Mexico.

Effects of edaphic factors on the tree stand diversity in a tropical forest of Sierra Madre del Sur, Mexico

Two sites with similar environmental parameters, except for the edaphic factor, were selected in the mountainous tropical forest of southern Mexico. Site 1 was established on an Alisol; site 2, on a Phaeozem. Representative soil profiles were examined on each of the sites, and topsoil was sampled on a regular grid pattern. The soil of site 2 was richer in organic matter and major nutrients and had a less acid reaction than the soil of site 1. The species diversity of the trees at site 2 (30 species) was higher than that at site 1 (17 species). The species compositions of the trees were different on the two soils: there were only six species in common for both sites. The coefficients of species similarity on the sites were low. We concluded that the presence of different soils within the same type of forest ecosystem increases its β-diversity. The examination of edaphic preferences of the species showed that Alstonia longifolia and Thouinidium decandrum preferred rich soils, Inga punctata and Ocotea sinuata preferred poor soils, and Cupania dentata and Hamelia patens did not display preferences in the studied range of soil properties. Thus, the spatial variability of the soil properties affect the spatial pattern of tree species in the studied tropical forest ecosystems.

Soil-geographic interpretation of spatial variability in the chemical and physical properties of topsoil horizons in the steppe zone

The study of spatial variability in the chemical and physical properties of topsoil horizons of southern chernozems and chestnut soils at characteristic distances of less than 150, 150–800, and 800–2000 m proved that the spatial distribution of the studied properties is different for these two soils. In the southern chernozems, the maximum variability at short (<150 m) distances was observed for the organic carbon content and pH values. The contents of clay (<0.001 mm) and physical clay (<0.01 mm) fractions and the content of total nitrogen displayed the maximum variability at distances of 150–800 m. At distances of >800 m, the distribution of all the studied properties was characterized by quasiperiodicity. In the chestnut soils, the maximum variability in the contents of the clay, physical clay, and total nitrogen was observed at short distances, whereas the variability of the organic carbon content and pH values was maximum at distances of 150–800 m. At the distances of 800–2000 m, only the variability in the clay fraction content followed a quasiperiodic pattern.