Organic Matter Content and Humus Reserves in Natural Soils of Rostov Agglomeration

Abstract

The research aims to study the content of organic matter in typical chernozem, its distribution in the soil profile under herbaceous and wooden phytocenoses. Organic matter plays a key role in the functioning of soils and their stable performance of ecological functions, including – the protection function. This is particularly relevant in the growing urbanization. The research analysis includes 40 full-profile sections of migration-segregated chernozems (typical carbonate) laid on the upland soil of the Rostov agglomeration. We determined organic matter by high-temperature catalytic combustion on a TOC-L CPN Shimadzu in an SSM-5000A solid sample combustion unit. Based on the data obtained, we calculated the organic carbon reserves. Statistical analysis included the calculation of the Mann-Whitney U-test to consider significant differences in the samples of indicators under wooden and herbaceous phytocenoses and descriptive statistics. The research results showed the influence on the organic carbon content of such a widespread type of anthropogenic impact as planting trees in the steppe zone. Comparison of the total organic carbon content values in similar genetic horizons under herbaceous and wooden phytocenoses indicates the spatial heterogeneity of this indicator, associated primarily with the type of land use. The supply of humus for Rostov chernozems under herbaceous phytocenoses was assessed as low and under wooden phytocenoses – as average. In the one-meter layer of natural chernozems of the Rostov agglomeration, humus reserves are 387 t/ha, which corresponds to the average supply level. Thus, the park and recreational zone, where wooden vegetation grows, plays a special ecological role in the city as a place of accumulation of an increased amount of organic matter of natural origin compared to other soils of the Rostov agglomeration.