Sự khoáng hóa cacbon, nitơ trong đất phù sa sông Hồng

UMMARY CARBON AND NITROGEN MINERALIZATION IN RED RIVER ALLUVIAL SOIL VU VAN HIEN, NGUYEN THI NHU TRANG On the basis in results of researches which were carried out from 2005- 2006, the authors came to the following conclusions : 1. Amount of carbon mineralized after 28 days of incubation ranges from 294,39 mg CO2- C / kg to 404,33 mg CO2- C / kg. Amount of nitrogen mineralized after 45 days of incubation ranges from 118,63,39 mg N/kg to 181,28 mg N/kg. The highest content of carbon mineralized was noted in alternate rice and dry crops soil (404,33 mg CO2-C/kg). Thighest amount of nitrogen mineralized was observed in dry crops soil (181,63 mg N/kg). The lowest amount of carbon and nitrogen mineralized was evidenced in rice soil (294,39 mg CO2-C/kg and 118,63 mg N/kg respectively). 2. Rate of carbon and nitrogen mineralized tended to decrease during the period of incubation. Rate of carbon and nitrogen mineralized was greater in the alternate rice and dry crops soil and dry crops soil compared to the rice soil 3. Percentage soil carbon mineralized in the alternate rice and dry crops soil and dry crops soil was greater in comparation with rice soil by 1,7 times and 1,9 times respectively, percentage soil nitrogen mineralized by 1,2- 1,4 times 4. There was evident differences in rate of carbon and nitrogen mineralization between rainy and dry seasons.