The content and quality of soil carbon and nitrogen as well as enzymatic activity in soils with diverse texture following different land use and management practices

A detailed knowledge concerning the responses of different carbon pools and the activity of soil enzymes to various land uses is critical for maintaining soil health and quality. Accordingly, the aim of this study was to determine the effects of different soil uses and management practices on the contents of total, dissolved and microbial biomass C and N as well as the fractional composition of humus and the set of enzyme activities. This study was conducted to compare the status of soil properties in the surface horizons of 24 soils with diverse textures, following the different land uses. Thus, arable lands, short-term cultivation, vineyards, orchards, hop plantations and grasslands were compared. The contents of total and dissolved carbon and nitrogen, the fractional composition of humus, the content of microbial biomass C and N and the enzymatic activity were assessed. The application of various land uses affects the C and N content of the soils and their humus fractions as well as their enzymatic activities differently. Generally, both grass-based systems (grasslands and orchards) revealed the most positive effects in most of the studied properties as compared to other land use systems. By contrast, long-term tillage and/or the lack of permanent plant cover (cereals, grapevine and hop cultivation) adversely affects the studied properties of the soils. No clear pattern of changes was detected in terms of the fractional composition of the SOM. The enzymatic activity changed because of their different functions in SOM transformation and because of the differences in the complexities of the enzymatic substrates occurring in the soil. Most of the studied properties were significantly higher in soils with a loamy texture as compared to the sandy loam and loamy sand soils. Differently managed soils presented a distinctive response in terms of organic matter content and quality as well as extracellular enzyme activity as a function of the tillage regime applied and different cultivated plants. In general terms, both land uses which were based on permanent grass cultivation revealed that the most positive effects occurred on these studied properties as compared to other land use systems. Therefore, we may conclude that permanent grasslands play a special role in the status of soil organic matter, microbial content and enzymatic activity.