Changes in the properties of cultivated gray forest soils after their abandoning

Changes in the physical, physicochemical, and biological properties of cultivated gray forest soils after their abandoning and overgrowing with meadow and forest vegetation for 8–10 years are clearly seen in the upper part of the former plow layer. The organic matter content and the content of available forms of phosphorus and potassium increase; a significant increase in the root biomass and in the soil biological activity is observed. Changes in the physical properties—an increase in the degree of soil aggregation and a decrease in the bulk density values—are seen in the upper and middle parts of the former plow layer. The biological factor is the major factor of transformation of formerly cultivated gray forest soils upon their abandoning and overgrowing with meadow and forest vegetation. At the same time, a significant role in the improvement of the structural state of the soils belongs to the physical shrink-swell and freezing-thawing processes.     

Carbon Stock in Sandy and Loamy Soils of Coniferous–Broadleaved Forests at Different Succession Stages

Eurasian Soil Science - A comparative assessment of the carbon stock in loamy soils (Albic Retisols) of coniferous–broadleaved forests on the Moskvoretsko-Oksky Plain and sandy soils (Albic...     

Assessment of Intra-Biogeocenotic Variability of Forest Litters and Dwarf Shrub–Herbaceous Vegetation in Spruce Stands

Eurasian Soil Science - The differences in the species composition of the ground cover in spruce forest in dependence on the position in tessera are identified. Tessera is perceived as a...     

Collembolan community organization and its temporal predictability

Long-term investigations on Collembola in Russian forests revealed that both stable and fluctuating communities can exist in natural ecosystems. Stable collembolan communities are characteristic of mesic moisture conditions, whilst fluctuating communities are typical of either xeric or hygric habitats. Stable communities are determined by between-year constancy in species and ecological structures, though other characteristics (for instance, total collembolan abundance or number of species) can vary. Stability of collembolan communities is externally stimulated by the constancy of environmental conditions or by their cyclic changing. Stable collembolan communities are best suited for the bioindication of long-term anthropogenic impacts on natural ecosystems, whereas fluctuating communities better reflect short-term environmental changes. A temporal predictability is possible only for stable communities.     

Quantitative assessment of effectiveness of soil conservation measures using a combination of Cs radioactive tracer and conventional techniques

Quantitative assessment of soil redistribution in landscapes remains a challenging task. In this study we used radioactive soil redistribution tracer ¹³⁷Cs together with soil morphological characteristics and empirically-based modeling for quantitative assessment of long-term soil conservation effectiveness. Three pairs of arable slopes were selected, all located within the territory of the Novosil experimental station (the Orel Region, central European Russia). One slope in each pair undergone creation of artificial terraces with forest shelter belts located parallel to topography contour lines and spaced at approximately 100 m from each other.Preliminary results have shown that slopes with soil-protective measures are characterized by a 11–80% reduction of average soil redistribution rates, as shown by soil profile morphology and ¹³⁷Cs methods. Discrepancy in values obtained can be attributed to differences in temporal resolution of methods as well as possible influence of individual extreme events on results yielded by the ¹³⁷Cs method. On the other hand, more significant decrease in average soil degradation rates on slopes with soil conservation (62–75% for each pair of slopes) was predicted by the model.The ¹³⁷Cs method overestimates gross and net soil redistribution rates, as a result of the influence of extreme erosion prior to tillage mixing of a fresh fallout isotope, not accounted for by calibration models used. Another shortcoming of the estimations obtained is that sediment redeposition directly within forest belts was not taken into account. Therefore, net erosion rates obtained for slopes with forest belts should be regarded as overestimation. Nevertheless, it can be generally concluded that the multi-technical approach has allowed acquiring much more detailed information on temporal and spatial variability of soil redistribution rates than single method-based studies.     

Contribution of plant root respiration to the CO2 emission from soil

The respiration activity of roots was studied in field experiments on gray forest and soddy-podzolic soils and under cropland and natural vegetation. It was shown that the contribution of roots to the CO₂ emission from the soil surface depends significantly on the method of determination. The contributions of fine and coarse roots to the total root respiration were approximately similar in forest ecosystems. The use of the method of substrate-induced respiration made it possible to obtain the best estimates of the contributions of root respiration and respiration of microorganisms. The application of glucose in the form of a dry mixture with sand or talc instead of in the water-soluble form appeared to be the optimal procedure for determining the root respiration under field moisture conditions.     

Experimental determination of the active organic matter content in some soils of natural and agricultural ecosystems

In incubation experiments, the soil supply with carbon of mineralizable (C_min), potentially mineralizable (C_pm), and active (C_ac) organic matter, and of microbial mass (C_mb) in natural and agricultural ecosystems of Moscow region (gray forest soil) and Catalonia (Xerochrept) was assessed based on the measurements of the C-CO₂ emission. In the gray forest soil, the C_pm and C_ac contents decreased in the following sequence of ecosystems: forest > meadow > unfertilized agrocenosis; in the Xerochrept, forest > pasture > scrub > agrocenoses with organic fertilizer > unfertilized agrocenosis. A method for measurement of the C_mb according to the C-CO₂ emission during an 11-to 14-day incubation of previously dried soils is proposed.     

Changes in the canopies of Pinus sylvestris and Picea abies under alkaline dust impact in the industrial region of Northeast Estonia

Studies were carried out in 1999, 2005 and 2007 in the area of Kunda cement plant in Northeast Estonia on sample plots 3 km W and 2.5 and 5 km E of Kunda. As control stands, two plots for pine and spruce were established in Lahemaa National Park (34-38 km W of Kunda). The selected pine and spruce stands were 75-85-year-old Myrtillus site type, of 0.7-0.8 density and II quality class, with moderately dense or sparse understorey. The values concerning needle density and number of needle scars were higher for shoots formed in the period of higher pollution than for the shoots grown under a considerably lower pollution load. Although the cement dust pollution has notably decreased from year to year, the number of needle pairs per 1 cm of the shoot was 1.8-2.1 times greater in the shoots formed in 1998 than in those formed in 2003, whereas the changes were statistically reliable. Possibly the low temperatures at the time of shoot and needle formation affected the density of needles on all sample plots, and thus the number of needles on shoots formed in 2003 was many times smaller. After the significant fall in the pollution load since 1996 the length growth of needles intensified around Kunda cement plant, at the same time no changes occurred in the length growth of needles in the control area. As compared to the data from 1998, the length growth of pine needles had improved, especially 2.5 and 5 km E from the cement plant, needles being respectively 1.5 and 1.1 cm longer than 6 years ago. The stimulation of the growth of pine and spruce needles 2.5 and 5 km E of the cement plant may be a sign of a positive effect of reduced doses of cement dust in soil. The greater length of pine and spruce needles is the reason for the larger biomass of the needles.