摘要
Elevated CO2 can stimulate wetland carbon （C） and nitrogen （N） exports through gaseous and dissolved pathways, however, the consequent influences on the C and N pools are still not fully known. Therefore, we set up a free-air CO2 enrichment experiment in a paddy field in Eastern China. After five year fumigation, we studied C and N in the plant-water-soil system. The results showed： （1） elevated CO2 stimulated rice aboveground biomass and N accumulations by 19.1% and 12.5%, respectively. （2） Elevated CO2 significantly increased paddy soil TOC and TN contents by 12.5% and 15.5%, respectively in the 0-15 crn layer, and 22.7% and 26.0% in the 15-30 cm soil layer. （3） Averaged across the rice growing period, elevated CO2 greatly increased TOC and TN contents in the surface water by 7.6% and 11.4%, respectively. （4） The TOC/TN ratio and natural 5ISN value in the surface soil showed a decreasing trend under elevated CO2. The above results indicate that elevated CO2 can benefit C and N accumulation in paddy fields. Given the similarity between the paddies and natural wetlands, our results also suggest a great potential for long-term C and N accumulation in natural wetlands under future climate patterns.
Elevated CO2 can stimulate wetland carbon （C） and nitrogen （N） exports through gaseous and dissolved pathways, however, the consequent influences on the C and N pools are still not fully known. Therefore, we set up a free-air CO2 enrichment experiment in a paddy field in Eastern China. After five year fumigation, we studied C and N in the plant-water-soil system. The results showed： （1） elevated CO2 stimulated rice aboveground biomass and N accumulations by 19.1% and 12.5%, respectively. （2） Elevated CO2 significantly increased paddy soil TOC and TN contents by 12.5% and 15.5%, respectively in the 0-15 crn layer, and 22.7% and 26.0% in the 15-30 cm soil layer. （3） Averaged across the rice growing period, elevated CO2 greatly increased TOC and TN contents in the surface water by 7.6% and 11.4%, respectively. （4） The TOC/TN ratio and natural 5ISN value in the surface soil showed a decreasing trend under elevated CO2. The above results indicate that elevated CO2 can benefit C and N accumulation in paddy fields. Given the similarity between the paddies and natural wetlands, our results also suggest a great potential for long-term C and N accumulation in natural wetlands under future climate patterns.
基金
supported by the National Natural Science Foundation of China (No. 31200369)
the Lecture and Study Program for Outstanding Scholars from Home and Abroad, Chinese Academy of Forestry (CAFYBB2011007)
