Transformation of old-plowed gray forest soils under the influence of differently aged pine forests in the middle Angara River region

The long-term (55–85 years) influence of pine forests on old-plowed gray forest soils (in the middle Angara River basin) has been reflected in the character of the biological cycle and intensity of the biological processes. The population of actinomycetes decreased, and that of fungi increased, within the whole profiles of these soils. The soil profiles became more differentiated according to eluvial-illuvial types. The thickness of the humus (former plowed) horizons decreased. The thicker differently decomposed litter with the abundant fungal mycelium was formed. The most conservative were relic morphological characteristics: plow sole, humus tongues, and the illuvial-metamorphic horizon.     

Thermophysical Properties of Histosols on Lowmoor Peat

Eurasian Soil Science - The temperature regime and the dependence of thermal diffusivity on the volumetric water content in high-ash drained peat soils (Sapric Drainic Histosols (Lignic)) on woody...     

Nomothetic taxonomy of the genus Triticum

The nomothetic taxonomy of species in the genus Triticum based on phylogenetic studies at subgenomic level of their quantitative traits and the law of homologous series of genetic variability is proposed, taking into account features of genomic (chromosomal) composition of the species, structure of the ear, and its real level of quantitative traits.     

The dose dependence of 15N-incorporation in organ proteins of newborn rats after pulse labeling with different tracers

A short-chain 15N-peptide mixture characterized by an average chain length of 2.3 was obtained when 15N-labeled yeast protein has hydrolyzed enzymatically by thermitase from Thermoactinomyces vulgaris. Fifteen newborn Wistar-rats were given a single pulse of [15N]glycine. [15N]H4Cl and [15N]yeast protein-thermitasehydrolysate (YPTH) in a dosage of 50 mg 15N excess kg-1 by gastric tube. In comparison with [15N]glycine the 15N-incorporation rates of brain, muscle and liver were approximately 150% higher after [15N]YPTH-application. Uniform labeling, high 15N-enrichment, almost complete absorption, avoidance of imbalances and the low price make this tracer substance superior to other tracers conventionally used for organ labeling.     

Hydrophysical Properties of the High-Ash Lowmoor Peat Soils

The water retention curve (WRC), density, botanical composition, and ash contents were determined for high-ash lowmoor peat soils (Rheic Sapric Histosols) developing on the floodplain of the Yakhroma River (Moscow oblast) from the herb–hypnum and hypnum peat enriched in carbonates, agromineral peat soils (Rheic Drainic Sapric Histosols (Mineralic)), and peat soils developed from woody peat underlain by herb, sedge, and woody peat layers (Rheic Sapric Histosols (Lignic)). The WRC was determined by capillarimetric method in the range of water pressure from 0 to 80–90 кPa. For the studied peat soils, the WRC represents a close to linear dependence of the water content on the water pressure in semilogarithmic scale. In contrast to mineral soils, a characteristic point of the air-entry pressure is virtually absent on the WRC of peat soils. The WRC of peat largely depended on their density: denser peat samples were characterized by a higher water content at the same water pressure, which attests to the increased water retention capacity. An increase in the degree of decomposition of peat and its ash content also leads to the rise in the water retention capacity, but the effect of these factors is considerably smaller than the effect of peat density.     

Experience in digital mapping of soil cover patterns

Methodological problems of large-scale soil mapping with the use of digital mapping technologies are discussed. Two variants of obtaining the maps of soil combinations for a test polygon (30 km²) in the area of soddy-podzolic soils with 996 studied soil pits are described. In the first variant, the initial state of soils at studied points was characterized by the taxonomic name of the soil (at the level of soil subtypes); the probability of occurrence of different subtypes within operation cells of the digital map was estimated, and the most probable soil subtypes were assigned to them. This approach was tested for the first time. In the second variant, the initial state of soils at studied points was described with the help of the grades of ecologically meaningful features of soil morphology; the degree of soil gleying and the degree of soil erosion or aggradation were indicated. The integral digital map represented the areas of different agroecological groups of soil combinations. The maps obtained with the help of these two approaches show a satisfactory agreement with the maps of soil cover patterns compiled by traditional methods earlier.     

Clay minerals in a denudation-accumulative soil catena

Chernozems and agrochernozems of the Kamennaya Steppe agroforest landscape have a silty clay or clay texture and similar associations of clay minerals. The plow horizons of the agrochernozems on a slope of 2°–3° to the Talovaya Balka have an increased content of the smectite phase (50–70%) compared to the upper horizons of the chernozems on flat watersheds (30–50%) due to the lithological discontinuity of the soil-forming material and the possible total removal of material on the slope by denudation. On slightly eroded areas, the clay minerals display a more intense disturbance of their crystal lattice structures by pedogenetic processes, which increase the degree of disorder in their layers and the accumulation of fine quartz in the clay fraction. In the areas with more significant erosion of the humus horizon, the clay minerals are characterized by their perfect structure and clean reflections, which are indicative of the outcropping of less weathered material from the middle part of the chernozem profile less transformed by pedogenesis.     

Diagnostic parameters of soil formation in gray forest soils of abandoned fields overgrowing with pine forests in the middle reaches of the Angara River

The content, differentiation in the profile, and dynamics of the mobile iron compounds can serve as adequate diagnostic parameters of the direction of the pedogenesis upon the overgrowing of abandoned fields with pine forests in the middle reaches of the Angara River Region in the area affected by the Bratsk water reservoir. The bulk chemical composition of the soil remains relatively stable in the entire profile against the background of the eluvial-illuvial redistribution of the finest particle-size fractions and mobile iron compounds under the impact of the long-term seasonal freezing, the percolative soil water regime, and the alternating redox conditions. The development of accumulative processes in the soil is accompanied by the weak manifestation of eluvial and pulsating gley processes as the initial stages of podzolization under the influence of the growing pine forests.