Khoroshev A.V. STABILITY OF PHYTOMASS DYNAMICS IN PROTECTED LOW MOUNTAIN-STEPPE LANDSCAPES AND PASTURES IN THE SOUTHERN URALS // Arid ecosystems. 2022. V.28. № 3 (92). P. 3-13. | PDF
In the steppe zone, the high sensitivity of the vegetation cover to humidification contrasts raises the question of the dependence of the intraseasonal dynamics of phytomass on the spatial pattern of vegetation cover and relief in a landscape. We performed a case study in the Aituarskaya steppe (Orenburg region) to test the hypothesis about the inequality of the spatial factors of variability of functioning under the conditions of the reserve regime and pasture impact. Based on the frequency of occurrence of five gradations of deviations of the intraseasonal increments of the vegetation index NDVI from the mean values, the measure of instability of the types of dynamics of green phytomass (Shannon’s index) was calculated. The relationship between the types of dynamics and the types of natural boundaries, due to belonging to the relief forms with the characteristic types of phytocenoses, has been established. Areas of the most unstable phytoproductive functioning are characteristic of valleys with meadow steppes. The reserve regime stabilizes the dynamics of phytomass due to a higher subordination to landscape-scale climatic processes. On grazed areas, frequent changes in the variants of phytomass increments are more characteristic and dependence on local factors (e.g., stoniness, groundwater level) increases. In the pasture area, in some places, the dominant dynamics becomes with an intensive late spring accumulation of phytomass and a small decrease or renewal by the end of summer due to an increase in the proportion of non-palatable and grazing-resistant species.
Acknowledgements. Expressing gratitude to D.E. Sharova, O.M. Podgorny, I.V. Volovinsky, G.M. Leonova for participation in field research and arrangement of remote materials and to reviewers for constructive comments.
Financing. The study was carried out with the financial support of the Russian Foundation for Basic Research, project No. 20-05-00464 «Spatial structure as a factor of stability of landscape functioning», 2020-2022.
Zalibekov Z.G., Mamaev S.A., Biarslanov A.B., Asgerova D.B., Magomedov R.A. POTENTIAL OF SOIL COVER BIOPRODUCTIVE RESOURCES: USE AND RENEWABLE SOURCES // Arid ecosystems. 2021. V. 27. № 1 (86). P. 15-23. | PDF
Soil resources are identified by regional factors of soil genetic differences. This approach is a multifunctional basis for soil resources accounting on a global, regional and local scale. Regional factors include the areas of functioning soils and their detailing characteristics: the contours’ dimensions, space measure, their quantity, principles of crossing lines and the turnover frequency. The purpose of this work is to identify the potential of bioproductive processes, where inherent potential of soil areas is marked by an unlimited increase in productivity within the existing soil dimensions and geometric outlines. The main difference is an increase of phytomass and photosynthetic activity of plants on a naturally limited area of soils from using the inexhaustible resources of the sun cosmic energy and the physical and geographical environmental processes. Combinations generated by soil properties and their usage lead to formation of renewable sources categories, compensating for the scarcity of new areas allocated for development.
Kaplina N.F., Kulakova N.Yu. Phytomass and stocks of carbon and nitrogen in the upland oak groves contrasting in productivity in the southern forest-steppe // Arid ecosystems. 2021. V. 27. № 1 (86). P. 35-42. | PDF
The current state of upland oak groves of saline and glague-sedge types in the Tellerman forest has been studied. The phytomass of stands is estimated by model trees taking into account the types of their development according to the original classification based on the morphological indicators. The content and stocks of carbon and nitrogen in the phytomass, litter, and soil were determined. It was found that the phytomass of saline and glague-sedge oak stands was 2 and 1.3 times lower, respectively than in similar stands before the period of oak mass drying in the 1970s — early 1980s. The mass of fallen leaves and litter corresponded to previous values due to development of the lower layer of the forest. The studied oak groves differ most of all in their carbon (7 times) and nitrogen – (5 times) stocks in the phytomass and much less in their stocks in the soil – in 1.4 times, the indicators of capacity — (1.4 times), and rate (1.2 times) of the annual biological cycle. The content of carbon, nitrogen, and non-structural carbohydrates in the oak organs in these groves is similar.
Keyword: phytomass, fallen leaves, litter, carbon and nitrogen stocks in ecosystem, capacity, and rate of the annual biological cycle, type of tree development, recovery of productivity of oak forests.