Zonal features of the dynamics of humus content in soils of Chernihiv region

The humus condition of soils of Chernihiv region has been studied. The dynamics of humus content in the soils of the region during six rounds (1986–2015) of agrochemical certification of agricultural lands is generalized and analyzed. In comparison with the 5th round (1986–1990), there was a discrepancy between the processes of stabilization and increase of humus content in most districts and in the region as a whole in the ninth round (2006–2010), and in some districts in the tenth round (2011–2015) against the background of a sharp decrease in the application of organic fertilizers. It was found that the stabilization of humus content in the soils of the region during the V–VIII rounds of agrochemical certification and a sharp increase in its content in the ninth round, against a significant reduction of organic matter, correlates with the withdrawal of eroded, low-yielding lands with low humus content (r=0.76). Analyzing the dynamics of humus content over thirty years of research,it was found that its content has increased in all climatic zones, as well as in nineteen of the twenty-two districts of the region. The increase of the indicator is in the range of 0.01–0.72%, while in all districts there is a significant reduction of the surveyed areas and only in three districts of the region there is a decrease in the humus content. According to the results of the 10th round of agrochemical certification, the soils of Chernihiv region are characterized by an average humus content of 2.41%. The highest humus content is characterized by the soils of Bakhmatsky (3.56%), Talalaivsky (3.33%) and Pryluky (3.32%) districts, and the lowest — NovgorodSiversky (1.57%). Increasing the sown area of green manure crops, plowing straw and the use of other elements of biologization of agriculture are important factors in increasing the weighted average humus content in the soils of Chernihiv region.