Organic Matter of the Air-Dry and Water-Stable Macroaggregates (2–1 mm) of Haplic Chernozem in Contrasting Variants of Land Use

Eurasian Soil Science - The content and the composition of soil structural units of different hierarchical levels were studied for Haplic Chernozems (Loamic, Pachic) of Kursk region under...     

Distribution of transformed organic matter in structural units of loamy sandy soddy-podzolic soil

The effect of land use types and fertilizing systems on the structural and aggregate composition of loamy sandy soddy-podzolic soil and the quantitative parameters of soil organic matter has been studied. The contribution of soil aggregates 2–1 mm in size to the total C_org reserve in the humus horizon is higher than the contributions of other aggregates by 1.3–4.2 times. Reliable correlations have been revealed between the contents of total (C_org), labile (C_lab), and active (C₀) organic matter in the soil. The proportion of C₀ is 44–70% of C_lab extractable by neutral sodium pyrophosphate solution. The contributions of each of the 2–1, 0.5–0.25, and <0.25 mm fractions to the total C₀ reserve are 14–21%; the contributions of each of the other fractions are 4–12%. The chemically labile and biologically active components of humic substances reflect the quality changes of soil organic matter under agrogenic impacts. A conceptual scheme has been proposed for the subdivision of soil organic matter into the active, slow (intermediate), and passive pools. In the humus horizon of loamy sandy soddy-podzolic soil, the active, slow, and passive pools contain 6–11, 34–65, and 26–94% of the total C_org, respectively.     

Optical Properties of the Extractable Organic Matter Fractions in Typical Chernozems of Long-Term Field Experiments

Eurasian Soil Science - The extractable fractions of organic matter (OM) differing in their mobility—water-extractable organic matter, labile humic substances, and humic substances—have...     

Detoxification of heavy-metal contaminated leached chernozems and ancient alluvial soils with the use of sorption materials

It is shown that the use of sapropel and mixtures based on it is effective as sorbent-ameliorants for detoxification of heavy metal-contaminated leached and podzolized chernozems in the Ryazan oblast, and for ancient alluvial soils in Vietnam, the application of natural bentonite.     

The effect of dissolved organic substances on the genesis of gley-podzolic soils in the northern taiga zone,Arkhangelsk oblast

The effect of dissolved organic substances on the genesis and functioning of gley-podzolic soils in the lower reaches of the Northern Dvina River (Arkhangelsk oblast) has been studied. It is shown that polyphenols and low-molecular (<1000 a.u.) fractions of fulvic acids bound with Fe (II, III) and Mn (II) ions are present in the EL_g and B_fg horizons of these soils and participate in alternating downward and upward migration processes. The presence of these compounds colors the soil mass into the dark gray color resembling the color of the proper humus horizon.     

Contents of Organic Carbon and Nitrogen in Particle-Size Fractions of Aggregates of Typical Chernozems (Protocalcic Chernozems)

Eurasian Soil Science - Specific features in the content and accumulation of organic carbon and nitrogen in the aggregates of typical chernozems (Protocalcic Chernozems) of long-term experimental...     

Pattern formation and shape changes in self-oscillating polymer gels

We developed an efficient model for responsive gels that captures large-scale, two-dimensional (2D) deformations and chemical reactions within a swollen polymer network. The 2D calculations allowed us to probe not only volume changes but also changes in sample shape. By focusing on gels undergoing the oscillatory Belousov-Zhabotinsky reaction, we observed traveling waves of local swelling that form a rich variety of dynamic patterns and give rise to distinctive oscillations in the gel's shape. The observed patterns depend critically on the gel's dimensions. The approach provides a useful computational tool for probing the dynamics of chemomechanical processes and uncovering morphological transformations in responsive gels.     

DNA adducts as biomarkers for oxidative and genotoxic stress from pesticides in crop plants

Plant studies have been carried out to identify the nature and extent of the formation of adducts with DNA bases when treated with pesticide formulations. DNA extracted from crop plants after treatment with pesticide formulations has yielded evidence of adduct formation. The extent of DNA modification has been established by (32)P postlabeling studies. The radiochromatograms from (32)P postlabeling of isolated plant DNA from grapes, bush beans, soybeans, pumpkins, and cucumbers show elevated adduct levels in treated vegetable plants as compared with untreated controls. A number of different adduct spots appear, likely indicating adduct formation with pesticide molecules or their metabolites. The DNA adducts from hexenal and 4-hydroxy-2-nonenal were clearly observed, indicating oxidative stress and lipid peroxidation in the plant.