Архив метки: salinity

VARIABILITY OF SOIL SALINITY AND PHYTODIVERSITY OF HETEROCHRONOUS REGIONS OF THE CASPIAN LITTORAL PLAIN

Arid Ecosystems

Konyushkova M.V.,  Nukhimovskaya Yu.D.,  Gasanova Z.U.,  Stepanova N.Yu. VARIABILITY OF SOIL SALINITY AND PHYTODIVERSITY OF HETEROCHRONOUS REGIONS OF THE CASPIAN LITTORAL PLAIN // Arid ecosystems. 2020. V. 26. № 4 (85). P. 66-75. | PDF

The article discusses the results of soil and geobotanical studies at the plots on the coastal plain of the Caspian Sea (Northern Dagestan) of different ages: 1340 ± 36 years calBP (Kaspii-1) and 293 ± 13 years calBP (Kaspii-2). Changes in the biodiversity of the vegetation cover and the soil-salinity variation over time are assessed. It is shown that the variability of soil salinity (range, quartile scale, and standard deviation) at the local level (areas of nonuniformity with linear dimensions of meters or tens of meters) has increased, while the parameters of vegetation biodiversity (floristic richness, the species number, the families number, the number of long-vegetating herbaceous perennials and ephemers, the presence of species with different salinity tolerance, and differentiation of the intracoenotic diversity) have decreased. The plot with a Tamarisk community (Kaspii-2) is characterized by a statistically significant, moderate correlation (R2 = 0.29) between soil salinity and vegetation based on data on the distribution of dominant species, whereas this correlation is not significant on the older plot with a saltwort—suaeda community (Kaspii-1). The data show that, when the area dries up after sea regression, the variation in soil properties (salinity) and vegetation changes in different directions: the variation in soil salinity (functional pedodiversity) increases with age, while the variation in vegetation (phytodiversity) decreases. Moisture availability is obviously the main factor limiting the biodiversity on the older plot on the background of high salinization of soils on the both plots as evidenced with the smaller moisture reserve in the top 1-m soil layer on the older plot.

Keywords: solonchaks, biodiversity, functional pedodiversity, sea plain, Caspian Sea Region, nonuniformity, salinity.

DOI: 10.24411/1993-3916-2020-10120

EVALUATION OF ECOLOGICAL CONDITION AND PRODUCTIVITY LOSSES OF ARID PASTURES ECOSYSTEMS OF SARPINSKY LOWLAND

Arid Ecosystems

Vlasenko M.V., Kulik A.K., Salugin A.N. EVALUATION OF ECOLOGICAL CONDITION AND PRODUCTIVITY LOSSES OF ARID PASTURES ECOSYSTEMS OF SARPINSKY LOWLAND // Arid ecosystems. 2019. V. 25. № 4 (81). P. 71-81. | PDF

We monitored the pastures ecosystems of the semi-arid zone in Sarpinsky Lowland of Russia and registered some local problems. The experimental data was collected through 1999-2017. It is stated that the present agro-landscape conditions are critical. The degraded pastures account for more than 600 thousands ha (34%), more than the half of which are highly degraded. 35-40%, of the total area of the regional forage grounds (about 1870 thousands ha) are moderately overgrazed, 30-40% are highly overgrazed, and 15-20% are excluded from the agricultural management and have turned into broken sands and abandoned territories. The digression is severely high on the winter (year-round) pastures. The area of open and drift sands has increased to 20-30%. In some districts the pressure on the pastures exceeds the optimal index 5-7 times. Almost all pastures need resting periods and agricultural restoration. Desertification (salinity, erosion and deflation) is a severe problem of the region. As the result of it the productivity loss of the pastures is 1052.7 thousands hwt of feed-units per year. Agroforestry measures have a significant value for preventing of soil erosion and deflation and are considered to be the many-functional, long-term protection factor. A map of forest conditions was composed to achieve the maximal ecological- and economical result of agroforestation; it was based on the agroforestry classification which represents the natural characteristics of the territory and features of its agroforestry developing

Keywords: desertification, deflation, eroding, salinity, pastures, annual productivity loss.

DOI: 10.24411/1993-3916-2019-10075