Humus state of soils of Kiev region

Abstract

Among the types of soil degradation, one of the first in importance and globality is called dehumidification. So, nowadays annual average losses of humus of chernozems in the country exceed 1 t/ha. A significant part of other soil degradation is directly or indirectly due to a decrease in the amount of humus. The analysis of the change (deterioration) of the humus soil should be carried out to determine the inverse and irreversible degradation. Excess of mineralization of humus over its formation causes dehumidification of the soil profile. Dynamics of humus content in the soils of Kyiv region during six rounds (1986–2015) of agrochemical certification of agricultural land is generalized. Humus content index was changing significantly within this period. Research data designated the weighted average humus content to amount 2.7% in the soils of the region at the time of the first survey (1986–1990). The reducing the volume of organic fertilizer application in VІ, VІІ tours (1991–2000) didn’t lead to a significant decrease of humus. Though, during VІІІ–Х tours (2001–2015) a sharp increase of humus content in the soils of the region was observed against the background of not less sharp decrease in the norms of organic matter application. The humus content in the soils of the Kiev region increased by 0.38% for this period, namely: from 2.6 % in VІ tour to 2.98% in Х tour. Intensive growth of humus content in the soils of the region didn’t associated with level of application of organic fertilizers but took place seeing withdrawal from the treatment of infertile soils, especially the Polissya zone. Application of crop residues was an important base for increase of humus content in the soils of the region.