Agrogeochemical cycles of plant nutrients in the territory of Russia

The contribution of mineral fertilization to the agrogeochemical cycles of major nutrients (N, P, K) was estimated. The agrogeochemical budgets of major nutrients (NPK) in the territory of Russia are unfavorable for agricultural production for the present and the nearest future. The removal of major nutrients with crops significantly exceeds their input to the soil with fertilizers and other sources. The nutritional degradation of arable soils increases, which can result in irreversible catastrophic consequences within 20–30 years.     

Particle nucleation in the tropical boundary layer and its coupling to marine sulfur sources

New particle formation in a tropical marine boundary layer setting was characterized during NASA's Pacific Exploratory Mission-Tropics A program. It represents the clearest demonstration to date of aerosol nucleation and growth being linked to the natural marine sulfur cycle. This conclusion was based on real-time observations of dimethylsulfide, sulfur dioxide, sulfuric acid (gas), hydroxide, ozone, temperature, relative humidity, aerosol size and number distribution, and total aerosol surface area. Classic binary nucleation theory predicts no nucleation under the observed marine boundary layer conditions.     

Distribution of stable carbon isotopes in an agrochernozem during the transition from C3 vegetation to a corn monoculture

The distribution of carbon in an agrochernozem??s profile was studied by the natural ¹³C abundance method during the C₃-C₄ vegetation transition and the analysis of the soil phytolith complex under a continuous corn monoculture. A young pool of soil organic matter (SOM) formed during 43 years of monoculture growing was detected by the isotope analysis in the 0-to 60-cm layer, while the analysis of the phytolith complex identified this pool deeper: corn phytoliths were detected in the 0- to 80-cm layer. The maximum size of the young pool was found in the upper soil horizon; it reached 6.4% of the SOM in the 0- to 20-cm layer. The apparent time of the SOM turnover was 635 and 2225 years in the 0- to 20- and 40- to 60-cm layers, respectively. The high values of the mean residence time were related to the low input of plant residues to the soil at the growing of corn for silage and the high initial content of organic carbon in the chernozem. The changes in the isotope composition after the decalcification of the soil to remove carbonates and the variation of the ??¹³C in the corn biomass during the vegetation period significantly affected the calculated value of the mean residence time.     

Review and Update: Genomic and Molecular Advances in Sex Determination and Differentiation in Small Animals

Inherited disorders of sexual development are important to identify as a cause of inherited infertility or sterility in humans and animals. Investigation of these disorders in dogs and cats can identify new mutations, allowing us to eliminate inherited disorders from breeding populations, while contributing to the understanding of mammalian sexual development and differentiation. This review updates an overview of normal mammalian sexual development while discussing disorders of sexual development at three consecutive levels, as errors in sex chromosome constitution, gonadal sex determination or phenotypic sexual development. The molecular mechanisms controlling sexual development and current molecular methods to identify causative mutations are illustrated in three specific examples of abnormal sexual development reported in small animals: XX sex reversal, Persistent Mullerian Duct Syndrome and cryptorchidism. Identification of causative mutations and development of practical tests to identify carrier and affected animals will provide effective mechanisms to reduce the prevalence of these disorders in small animals.     

The Institute of Soil Science in Pushchino: Its forty-year history

The main stages of the 40-year-long history of the Institute of Physicochemical and Biological Problems of Soil Science of the Russian Academy of Sciences in Pushchino are considered.     

Global climate changes and the soil cover

The relationships between climate changes and the soil cover are analyzed. The greenhouse effect induced by the rising concentrations of CO₂, CH₄, N₂O, and many other trace gases in the air has been one of the main factors of the global climate warming in the past 30–40 years. The response of soils to climate changes is considered by the example of factual data on soil evolution in the dry steppe zone of Russia. Probable changes in the carbon cycle under the impact of rising CO₂ concentrations are discussed. It is argued that this rise may have an effect of an atmospheric fertilizer and lead to a higher productivity of vegetation, additional input of organic residues into the soils, and activation of soil microflora. Soil temperature and water regimes, composition of soil gases, soil biotic parameters, and other dynamic soil characteristics are most sensitive to climate changes. For the territory of Russia, in which permafrost occupies more than 50% of the territory, the response of this highly sensitive natural phenomenon to climate changes is particularly important. Long-term data on soil temperatures at a depth of 40 cm are analyzed for four large regions of Russia. In all of them, except for the eastern sector of Russian Arctic, a stable trend toward the rise in the mean annual soil temperature. In the eastern sector (the Verkhoyansk weather station), the soil temperature remains stable.     

Fertilizing effect of the increasing CO2 concentration in the atmosphere

The effect of three atmospheric CO₂ concentrations (ambient, 400 ppm; double, 800 ppm; and triple, 1200 ppm) on the productivity of cottonwood (Populus deltoides Barr.) and the activity of the soil microbial biomass in the root-inhabited zone was studied. The total biomass of the cottonwood increased with increasing CO₂ concentration (2.28, 5.28, and 3.78 kg/tree for 400, 800, and 1200 ppm, respectively). The strongest responses were observed for the trunk and coarse roots (three and two times higher as compared to the ambient CO₂ concentration). The triple concentration of CO₂ had a greater effect on the roots of the trees, but the growth of leaves and branches was insignificant or absent. The shoot-to-root ratio changed as follows: 2.86, 2.80, and 1.57 at 400, 800, and 1200 ppm, respectively. The rate of C-CO₂ release from the soil samples incubated for 70 days increased in the following order: 400, 800, and 1200 ppm CO₂; the average values of the CO₂ emission were 2.02, 2.33, and 2.76 mg/100 g per day, respectively. The greatest content of C_mb (75.1 mg/100 g) was observed in the treatment with the triple CO₂ concentration, and the lowest content (53.7 mg/100 g) was found for the ambient CO₂ concentration. This study suggests that the responses of the cottonwood biomass and soil microbial activity vary depending on the CO₂ concentration. The microbial biomass gradually increased with increasing CO₂ concentration; the total plant biomass showed the highest response at the double CO₂ concentration, and the triple CO₂ concentration was likely to suppress the growth of the above-ground plant biomass.