Estimating organic carbon in soils from Gulyantsi Municipality, Pleven District

The aim of the present study is to evaluate soil organic carbon in Gulyantsi Municipality, Pleven District. The case study area of “Ulpia Eskus” Reserve was chosen for the research. The composition of soil organic substance of Arenosols + Fluvisols is distinguished by the use of a chemical analysis and the application of the Turin method. The results show a prevalence of humic acids over fulvic acids in the sampled soil profile. Keywords: soil organic carbon, soil horizons, excavations.

Ecological and Agrochemical Assessment of the Kamennaya Steppe Soils under Forest Cenosis

A set of parameters of soils under forest belts was studied. The objects of research were old-growth (65–68 yrs) ravine and shelterbelt forest plantations of the Kamennaya Steppe. The results allow assessing the trends of changes in soil characteristics over a long period of time. Key plots of 100×100 m were laid out using a regular sampling grid. The sampling interval is 15–25 m. A positive effect of forest shelterbelts on the properties of chernozems was found. There is an increase in thickness of the humus horizon from 42.3 cm (arable land on the slope) to 72.6±5.1 cm (under forest). The maximum values are typical for chernozems of watershed areas: 59.6±2.4 cm (arable land) and 85.6±3.9 cm (forest belt). Chernozems leached due to the activation of migration processes of carbonates into the underlying soil horizons have the maximum depth of soil effervescence. Chernozems zooturbated due to mechanical transport and mixing of accumulative-carbonate horizon have the lowest depth of soil effervescence. A general trend to decrease the depth of soil effervescence under the forest cenosis was found. The highest humus content is observed in watershed areas: 7.14±0.24 % (arable land) and 8.56±0.18 % (forest belt). A ravine forest belt reduces the risk of erosion processes. A fairly strong humus profile with a high content of organic matter: 7.03±0.27% (under forest) and 6.10±0.10% (on arable land), was possible to preserve on arable lands in the zone of the belt’s influence. The planting of forest belts causes a change in the nature of vegetation. The influence of acidic products of litter decomposition formed soil horizons with a moderately acidic reaction of the environment in the humus layer. Despite the leading position of calcium, an increased content of magnesium was found in the composition of exchange-absorbed cations. Forest belts have become especially important in recent decades due to changing climatic conditions. In the steppe regions of Russia, such plantations are a powerful soil conservation factor that helps stabilize and increase soil fertility. It is necessary to intensify the planting of artificial forest stands in the steppe regions of Russia. For citation: Cheverdin Yu.I., Bespalov V.A., Sautkina M.Yu., Titova T.V. Ecological and Agrochemical Assessment of the Kamennaya Steppe Soils under Forest Cenosis. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 5, pp. 76–91. DOI: 10.37482/0536-1036-2021-5-76-91

Metagenomic Sequencing of Multiple Soil Horizons and Sites in Close Vicinity Revealed Novel Secondary Metabolite Diversity

This study helped uncover the biosynthesis potential of forest soils via exploration of shotgun metagenome and amplicon sequencing methods and showed that both methods are needed to expose the full microbial diversity in soil. Based on our metagenome mining results, we suggest revising the historical strategy of sampling soils from far-flung places, as we found a significant number of novel and diverse BGCs and domains even in different soils that are very close to each other.

PSXI-21 Soil emission of carbon dioxide and behavior of microorganisms in soils of Western Kazakhstan

Kazakhstan Western ecosystems are intensively used in agricultural production. Assessing greenhouse gas emissions from soils, especially CO2, is important. In the upper stages, microbiology, characteristics and condition of the soil change. Biological intensity indicators are soil respiration processes, numerous microbiocenoses species composition. Soil CO2 emissions were measured 5 times monthly during three years. The CO2 flow rate from soil surface is measured by a closed dynamic chamber method with Li-8100A field respirometer. Metagenomic soil testing used bacteria DNA, archaea, real-time PCR, 16SrRNA sequencing. The soil CO2 monthly dynamics fluxes varied among the lands, within the season. In 2020, the CO2 emissions soil peak noted in the pasture. There is a slight decline in summer with a decrease towards the cold season. Comparison between the CO2 flux pasture soils is less in virgin soil. The minimum CO2 flux was recorded in November - February; in the spring, the flux increases. The above CO2 emissions were recorded in summer. In soils, there is wide variety of microorganisms with opposite and incompatible properties for one habitat. The microbial communities structure identified at the family level. The taxonomic samples structure ominated by phylae - Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteria, Gemmatimonadetes, Firmicutes, Actinobacteria. The spread explained by increased actinomycetes resistance characteristic to low moisture content with long dry period. For comparative evaluation microbial communities results comparing by cenoses of upper horizons with dark chestnut soil indicators. This violation caused microorganisms resistance to disturbing factors. On anthropogenically disturbed saline soils, the bacteria found were specific and resistant to critical conditions. CO2 emission in soil varied cenosis type. The CO2 intensity factors were precipitation deficit, high temperature. The profile microorganisms distribution corresponded to the soil horizons humus content. During summer soil drying, the deep soil horizons abundance occurred where moisture is retained.

Динамика накопления хлорофилла в листьях Triticum aestivum L. в зависимости от глубины залегания узла кущения

This research paper presents the results of the dynamics of the accumulation of the chlorophyll in-dex in winter soft wheat plants, depending on the depth of the tillering node. In conditions of lack of moisture, the deepening of the tillering node leads to the development of roots in more moisture-rich soil horizons, which reduces the risk of cultivating winter soft wheat. With the help of the chlorophyll index, it was possible to evaluate the effect of the deepening of the tillering node in the soil, as well as to assess the condition of plants and the rate of maturation.

Development and Evaluation of Pedotransfer Functions to Estimate Soil Moisture Content at Field Capacity and Permanent Wilting Point for South African Soils

This study was undertaken to develop new pedotransfer functions (PTFs) for the estimation of soil moisture content at field capacity (FC, at −33 kPa) and permanent wilting point (PWP, at −1500 kPa) for South African soils based on easily measurable soil physico-chemical properties. The new PTFs were developed using stepwise multiple linear regressions with the dependent variable (either FC or PWP) against clay, silt, sand and soil organic carbon (SOC) content from a total of 3171 soil horizons as the explanatory variables. These new PTFs were evaluated and compared with five well-established PTFs using a total of 3136 soil horizons as an independent dataset. The coefficient of determination (r2) values for the existing PTFs ranged from 0.65–0.72 for FC and 0.72–0.81 for PWP, whilst those developed in this study were 0.77 and 0.82 for FC and PWP, respectively. The root mean square error (RMSE) values for the well-established PTFs ranged from 0.052–0.058 kg kg−1 for FC and 0.030–0.036 kg kg−1 for PWP, whilst those developed in this study were 0.047 and 0.029 kg kg−1 for FC and PWP, respectively. These findings suggest that PTFs derived locally using a large number of soil horizons acquired from different agro-climatic locations improved the estimation of soil moisture at FC and PWP. Due to the range of conditions and large soil datasets used in this study, it is concluded that these new PTFs can be applied with caution in other regions facing data scarcity but with similar soil types and climatic conditions.