Changes in the soil's biological and chemical properties due to the land use

Increasing the soil productivity is challenged by the increasing biotic threat to plants and microorganisms, by the resistance to agrochemicals, and by the declining soil health. Soil management strategy is, therefore, aimed at erosion prevention and the minimisation of soil organic matter losses. A key factor in an agroecosystem is the appropriate biological stability. It is essential not only at present, but also for further sustainable agriculture. This study was based on the hypothesis that afforestation and conversion from arable land to permanent grassland improves the organic matter status and biological stability in the agroecosystem. The experiment was conducted from 2014 to 2018 in the Uhrice bio-corridor (Kromerii region, the Czech Republic). Haplic Luvisol has been investigated for its basic biological and chemical proper ties after the arable land was converted to a natural vegetation system. The afforested segment (F), permanent grassland segment (G), and arable land segment (A) have been sampled in the upper soil horizon (0-0.30 m). Standard analytical methods were applied for the determination of the basic soil properties. A principal component analysis and factor analysis were used for interpreting the connection between the parameters of the soil organic carbon, the humic substances, the humic acids, and the fulvic acids, the agrochemical properties of the soil (the pH, the content of the nitrogen, phosphorus and potassium, etc.), and the soil biological properties (basal soil respiration (BSR), the ratios of the N/BSR, NG/BSR, etc.). After five years of investigation, the differences in the studied parameters were evident. The factor analysis and multivariate exploratory techniques showed that the soil properties were grouped based on the management into three different categories F, G and A. The different land use directly influenced the quality and stability of the humic substances, basal soil respiration, and carbon and nitrogen utilisation. In comparison to the arable land, the forest and grassland were considered to have a higher accumulation potential of carbon and nitrogen. A negative correlation between the soil basal respiration (r =-0.95); total nitrogen (r =-0.93); total organic carbon (C-ox) content (r =-0.82); and partial Ca (r =-0.82) was found. A positive correlation (r = 0.80) between the humic substances (C-HS) and soil reaction (pH) was determined.