The changes of soil nitrogen and carbon contents in a long-term field experiment under different systems of nitrogen fertilization
2008
Nedved, V.,Ceska Zemedelska Univ., Prague (Czech Republic). Fakulta Agrobiologie, Potravinovych a Prirodnich Zdroju | Balik, J.,Ceska Zemedelska Univ., Prague (Czech Republic). Fakulta Agrobiologie, Potravinovych a Prirodnich Zdroju | Cerny, J.,Ceska Zemedelska Univ., Prague (Czech Republic). Fakulta Agrobiologie, Potravinovych a Prirodnich Zdroju | Kulhanek, M.,Ceska Zemedelska Univ., Prague (Czech Republic). Fakulta Agrobiologie, Potravinovych a Prirodnich Zdroju | Balikova, M.,Ceska Zemedelska Univ., Prague (Czech Republic). Fakulta Agrobiologie, Potravinovych a Prirodnich Zdroju
The aim of this study was to compare the hot water extraction method and the 0.01 M CaCl2 extraction, and to evaluate the changes in contents of different N and C forms in long-term experiments under different systems of N fertilization, especially focused on fertilization with sewage sludge. Chernozem and Cambisol were extracted using hot water (Nhws, Chws) and 0.01M CaCl2 (NCaCl2, CDOC). The Ct/Nt ratio in Chernozem was 9.6:1 and in Cambisol 6.1:1. The lowest Ct/Nt ratio in both experiments was found in the control treatment. C and N compounds are less stable in Cambisol, which leads to a higher rate of mineralization. In the Chernozem, Nhws formed 3.66% from the total N content in the soil, whereas NCaCl2 formed only 0.82%. Chws formed 2.98% and CDOC 0.34% from the total C content. Cambisol contained 4.81% of Nhws and 0.84% of NCaCl2 from the total N amount and 5.76% of Chws and 0.70% of CDOC from the total C content, respectively. N extracted by 0.01M CaCl2 formed only 22.4% of N extractable by hot water in Chernozem and 17.5% in Cambisol. The lowest C/N ratios were obtained after the CaCl2 extraction (3.0-6.2:1). The application of manure increased the content of soil organic N and C compared to the sewage sludge treatments.
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