Fluctuations of nitrogen levels in soil profile under conditions of a long-term fertilization experiment
2008
Sadej, W.,University of Warmia and Mazury, Olsztyn (Poland). Dept. of Environmental Chemistry | Przekwas, K.,University of Warmia and Mazury, Olsztyn (Poland). Dept. of Environmental Chemistry
The present study is focused on the correlation between varied long-term fertilization and changes in soil nitrogen concentrations. All fertilization systems significantly increased the levels of total, mineral and organic N in the soil profile. Organic fertilizers (manure and slurry) contributed to a more considerable increase in the concentrations of total N and N undergoing hydrolysis in 6M HCl than mineral fertilizers. Ammonia N dominated over nitrate N among mineral N forms. Organic fertilization contributed to nitrate N accumulation while mineral fertilization to ammonia N storage. The highest accumulations of nitrate N and ammonia N were observed after the application of slurry and manure, respectively. Hydrolyzable N content and its proportion in total N generally decreased with soil depth. An increase in the levels of organic N forms, i.e. N contained in amino sugars and amino acids as well as ammonia N from decomposition of amides, amino sugars and amino acids, was conditioned primarily on the application of organic fertilizers, particularly manure. Amino acid N dominated among hydrolyzable N compounds (77%) while amino sugar N accounted for 5.6% only.
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