Moscow University Soil Studies Bulletin. 2019. 2.

Forest litter of some coniferous and deciduous plantations within the Botanical Garden of the Moscow State University is studied. It is established that in the conditions of the deciduous plantations, forest litters of destructive types develop, whereas in the coniferous plantations - fermentative and humified ones. The total reserves of forest litters range from 500-800 g/m² in deciduous plantations, up to 1000-5000 g/m² in coniferous ones. It is shown that small-leaved plantations are characterized by high rates of cycling, with a significant decrease in the coniferous ecosystems. It was shown for the first time that with an increase in the proportion of leaves in the litter, the overall decomposition rate of terrestrial litter increases substantially, which is confirmed by the theory of “hot points” proposed in the scientific literature.

The joint development of sod-podzolic and lightgray forest soils is investigated on the land released from agricultural use situated within the southern slope of Gorokhovetsky spur of the North-East of the Vladimir region. Morphological and physico-chemical properties of light gray forest and sod-podzolic soils influenced by both natural and anthropogenic factors are analyzed.

The concentrations of potassium were measured in 1 М NH₄OAc, 2 M HCl, and hot 10% HCl extracts from samples of the rhizosphere of Norway maple ( Acer platanoides ) and of bulk soil taken in five replicates from the (AO)EL horizon of a podzolic soil. The rhizosphere soil was found to contain reliably more exchangeable potassium due to higher content of OM and more potassium compounds extractable with hot 10% HCl. According to the existing guidelines on growing the leaf-bearing trees the rhizosphere soil and the bulk soil can be referred to highly and moderately provided with available potassium respectively. The higher content of potassium soluble in hot 10% HCl in the rhizosphere soil can be explained by the dissolution of the finest poorly crystallized illite particles. These particles can be accumulated in the rhizosphere soil due to intensification of two processes: illitization and physical disintegration of illite particles enhanced by growing roots.

The degree of spatial variation of agrochemically important properties of plowing horizon (pH KCl, hydrolytic acidity, absorption capacity, the degree of saturation of bases, humus content, mobile phosphorus and exchange potassium) is estimated. It is shown that the partition of the set into subsets corresponding to classification units significantly reduces the degree of variation of humus and physico-chemical properties, practically without changing the variability of pH, the content of mobile phosphorus and exchange potassium. Discriminant analysis shows that the arable horizons of sod-medium podzolic, gray forest and dark gray forest soils are satisfactorily classified for a given set of properties. Poorly classified bog-podzolic and gray forest gleyed soils. Light gray forest soils occupy an intermediate position, gravitating toward gray forest soils.

The article is dedicated to the analysis of content and distribution of oil hydrocarbons in the soils of geochemical landscapes of the southern Sakhalin. It is discussed the main types of soil formed in this region, and the parameters determining the migration of oil hydrocarbons in the landscapes. It was shown that the soils of transit-accumulative and accumulative landscapes are characterized by the highest content and the depth of oil hydrocarbons penetration into the soil profile. In the case of accidental oil spills, along with lateral migration significant role will play vertical migration of oil hydrocarbons to the accumulative landscapes.

The levels of phthalate esters in the upper soil layers of Moscow-city were considered. The sum of concentrations of five phthalate esters (dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, di-n-butyl phthalate, di-(2-ethylhexyl) phthalate) in the soils falls in the range 4,39-397,00 mg/kg (with mean value of 62,70 mg/kg and median of 31,22 mg/kg) and was characterized by lognormal distribution. The shares of those phthalates in the sum of concentrations were 0,6; 0,7; 14,2; 57,9, and 26,6% correspondently. The significant positive correlations were found between concentrations of the phthalate esters. The sum of phthalate concentrations was higher in the soils of reserve and residential areas than that in the soils of roadside and park areas.