


Vol 7, No 3 (2017)
- Year: 2017
- Articles: 10
- URL: https://journals.rcsi.science/2079-0961/issue/view/12822
Applied Problems of Arid Lands Development
Short-term exclusion of degraded pasture in the permafrost zone: aspects of soil microbial community
Abstract
The properties of alas soils were studied in short-term isolation (4–5 years). According to the speed of the response to the isolation of degraded pastures, components of the cryoarid–alas ecosystem form the following decreasing series: above-ground vegetation—functional range of cultivated soil microbial community—colony-forming units—underground phytomass, total mobile soil carbon, and nitrification activity. The response rates, respectively, are equal to 1, 4, 5, and over 5 years. The biodynamic features of degraded grasslands in the early years of isolation indicate that these ecosystems have a high regenerative potential. The high activity of autotrophic nitrification indicates a continuing imbalance in the circulation of substances in the isolated area.



Characteristics of ecological and faunistic complex of soil nematodes in dry-steppe landscapes in Manych valley
Abstract
The ecological and faunal similarity between different communities of soil nematodes have been established in samples of dry-steppe soils with close genetic positions and soil-forming processes. Seventyeight species of soil nematodes from 41 genera, 24 families, and seven orders have been identified in seven model plots with different habitats. It has been shown that specific features of soil nematodes communities are manifested in the species diversity and dominance of certain trophic groups and genera. On the whole, nematode fauna can be evaluated as diverse (Shannon diversity index was 1.53‒2.35) and sufficiently mature (Bongers maturity index of communities was 2.83‒4.9); our data indicates the stability and weak disturbance of the living conditions of nematodes.



Diversity and taxonomic composition of weeds in olive orchards in Tabuk Region, Saudi Arabia
Abstract
The introduction of weeds into the agricultural landscape is considered a major problem that threatened the cultivated plants as weeds compete with them for water, nutrients, space and light. The information about taxonomic diversity of weeds in olive orchards in Saudi Arabia is still incomplete. The present study aims to investigate the diversity patterns and taxonomic composition of the weeds in olive orchards in four sites located in Tabuk Region in the northern part of Saudi Arabia: Juraydah, Tayma, Qulaybah, and Tabuk. A total of 46 weeds species were identified from olive orchards in the four districts. The weeds communities in the Tabuk region is dominated by Pulicaria undulata, Anisosciadium lanatum, Cynodon dactylon, Emex spinosa, and Euphorbia granulata. The highest species richness of weeds was reporte in Juraydah, followed by Qulaybah, with values of 30 and 24 taxa, respectively. However, the lowest number of weed species was reported in Tayma. The highest values of Shannon-Weiner (H') and Simpson’s (1-D) indices were reported in Juraydah and Qulaybah. The diversity of species within the locations, expressed as beta diversity (β), was also measured. The olive orchards in Qulaybah and Tayma are characterized with high diversity within sites as indicated by the high values of beta diversity of 3.231 and 3.226, respectively. The diversity measures did not show significant differences among the sites (ANOVA, P > 0.05). Based on cluster analysis, olive orchards in Qualybah showed a strong relationship in the taxonomic composition of weeds with other orchards in Juraydah and Tabuk. Further studies concerning other biological and ecological aspects of weeds in the olive orchards of Saudi Arabia are urgently needed. This will facilitate the development of effective control strategies to manage the weed communities and increase the crop yield in olive orchards of Saudi Arabia.



Analyzing bedrock shore degradation at the Tsimlyansk reservoir
Abstract
This study traces and analyzes the evolution of the upper edge of a bedrock shore (retreat of the bedrock valley side crest) of the Tsimlyansk reservoir for the period from the beginning of the reservoir operation until 2012. The predicted and observed rates of retreat of the bedrock shore edge are collated for the time intervals of 12.5, 25, and 50 years of the reservoir’s operation.



The nature of the patchiness of irrigated soils in the dry steppe zone (on example of the Svetloyarskaya irrigation system)
Abstract
Various variants of the patchiness of irrigated soils, which are reflected on remote sensing materials and associated with the results of field research, have been analyzed on the example of the Svetloyarskaya irrigation system. The system is located on the right-bank part of the Caspian lowland within the solonetz complexes of the dry steppe. It is revealed that the reasons for the formation of the patchiness of irrigated fields fixed on remote materials are not unambiguous. During studies at the Svetloyarskaya irrigation system, it was found that the patchiness depends on the depth of the groundwater table (GWT) and the state of the field (bare soil, cropland, and layland) and can be caused by soil properties, such as primary and secondary salinization, alkalization, the carbonate content, and others.



Searching for benchmark soils in the steppe zone of the Trans-Ural Plateau to compile the Red Book of Soils
Abstract
A large amount of soil works on the steppe zone of the Trans-Ural Plateau has been analyzed for the purpose of finding benchmark soils to compile the Red Book of Soils. In light of the theory of basic, local, rare, and complex benchmark soils (Kliment’ev et al., 1996), the upland site on virgin soil in the center of the Stepnoe site of the Il’men State Reserve in the Ural Branch of the Russian Academy of Sciences (UB RAS), should be referred to the basic benchmark soils as the most valuable soil object in the area. The upland site is a representative example of the steppe zone of the Trans-Ural Plateau. Brown earth soils and paleourbanozems soils marked by anthropogenic impact should be considered rare soils in the region. Other rare soils include natural fossil soils—the vertical chronological series of buried soils of terraces above the flood plain and soils buried under mounds and under the ramparts of the ancient settlement of Arkaim. The entire Stepnoe site, where different soils of the region are found, is considered a complex benchmark soil site.



Carbon reserves in postagrogenic dry steppe soils of Western Transbaikalia
Abstract
New data on carbon reserves in the postagrogenic chestnut soils of Western Transbaikalia are given. Quantitative and qualitative characteristics of the formation of element reserves in these soils have been revealed. It has been shown that the ratio between organic and inorganic carbon compounds in the total carbon reserves in dry steppe ecosystems varies significantly. The element reserves are gradually restored in postagrogenic successions and become close to those in similar virgin soils.



Systematic Study of Arid Territories
Desertification paradigm: 40 years of development and global efforts
Abstract
In light of the 40th anniversary of the United Nations Conference on Desertification and the 20th anniversary of the empowerment of the United Nations Convention to Combat Desertification (UNCCD), the periodization is given and the main stages in the development of international efforts to combat desertification and changes in the desertification paradigm are examined. The UNCCD initiatives, which require serious scientific study at the present stage, are reviewed, including the actively developed concept of land-degradation neutrality. A conclusion is drawn about the need to expand the mandate of the UNCCD beyond the narrow geographic scope of arid and dry regions.



Soil desiccation as indicator of desertification of forest–steppe ecosystems in the Barguzin depression
Abstract
This article presents study data on the status of plant and soil cover in the Barguzin Depression related to soil desiccation as the result of a 3-year drought, which caused the death of natural pine forests and shelterbelts composed of pine and balsam poplar. The main factors of tree death, as well as the soil conditions that favor survival under long-term air drought, have been revealed. A negative trend in the development of forest steppes under climate aridization in the North Baikal region was determined.



Background medical–geographical assessment of regions with high environmental tourism potential in the Republic of Kazakhstan
Abstract
This paper is dedicated to the medical–geographical assessment of seven regions in the Republic of Kazakhstan where national parks have been designated that have potential for ecotourism development. The authors have grouped the regions by the level of population morbidity in order to identify their regional medical–geographical parameters and background (reference) characteristics. A medical–geographical map chart of the Republic of Kazakhstan showing the complex of natural focal diseases has been produced. Administrative regions with different medical–geographical risk levels have been identified. This makes it possible to develop detailed medical–environmental monitoring programs, combined with organizational and management actions in areas visited by tourists.


