Comparison of soil characteristics related to C and N processes in Eastern Hungarian and Central Japanese soils under different land use and nutrient supply. Issue 1 (2nd January 2022) - Kátai, János
ABSTRACT: This comparative investigation aimed to evaluate controlling factors for the changes of chemical and microbial properties in soils taken from chemical fertilizer experiments carried out mainly in Chernozem and Andosol in Hungary and Japan, respectively. The plant available nutrient content of the soil, the stock of C and N and the soil microbial parameters of the carbon and nitrogen cycles were examined under different land-use and vegetation. In the Japanese soils, there was about 2–3 times higher organic C content than in Hungarian soils. The average CO2 -production was about 1.5 times higher in Hungary soils than Japanese soils, and significantly increased (9–37%) in the fertilized treatments compared to control in all Hungarian long-term experiments. Regarding the Hungarian soils, the NPK-fertilization especially increased the nitrate and phosphorus content of soils, among the microbial parameters of the CO2 -production, MBC, MBN, net nitrification, saccharase and urease activities – in most cases significantly increased – among the six microbial examined parameters. With reference to Japanese soils, the nitrogen fertilization especially increased the nitrate and phosphorus content of soils and had the highest effect on the microbiological parameters in the forest soil, where the MBC, MBN, net nitrification, saccharase and urease activities increased significantly. Only the net nitrification increased significantly in the fertilized treatments in the all Numata experiments, and generally 10–100 times higher values were found in the Japanese soils than in the Hungarian ones. The microbial activity decreased according to land use in the following order: maize>forest>grassland in Hungary soils, and forest>grassland>apple orchards in Japanese soils. These results confirm that climate conditions and human activity have important impacts on the C and N cycles of the soil–plant–atmosphere system. Based on our results, it appears that land-use and chemical fertilization resulted in a larger change in the stock of organic matter and soil microbiological processes in the Hungarian long-term experiments compared to the Japanese experiments.