The dynamics of organic matter, carbon and nitrogen were studied during leaf decomposition over a three annual cycles period using the litterbag method at three permanently untilled and unfertilised plots. Our hypothe...The dynamics of organic matter, carbon and nitrogen were studied during leaf decomposition over a three annual cycles period using the litterbag method at three permanently untilled and unfertilised plots. Our hypothesis is to determine if each litter type influences the decomposition and C and N releases from each other litter type （three plots and two species）. The main objective of this study is the comparison of decomposition dynamics in a climax forest with respect to that occurring in the chestnut managed plots on terrain suitable for oak to have further insight into the recycling of above ground organic matter and these two associated bioelements. As for the loss of dry matter, two-way analysis of variance, involving the treatment and year factors, revealed the existence of significant differences only for year, while no differences were observed for either treatment or interaction. At the end of the 2.4 years of the study, most of the treatment assays higher nitrogen concentrations than the initial ones were recorded. These three treatments the samplings prior to the last one revealed nitrogen concentrations higher than the initial ones, such that it may be concluded that the trend was towards an increase in concentration.展开更多
Climate change and elevated atmospheric CO2 should affect the dynamics of soil organic carbon （SOC）. SOC dynamics under uncertain patterns of climate warming and elevated atmospheric CO2 as well as with different so...Climate change and elevated atmospheric CO2 should affect the dynamics of soil organic carbon （SOC）. SOC dynamics under uncertain patterns of climate warming and elevated atmospheric CO2 as well as with different soil erosion extents at Nelson Farm during 1998-100 were simulated using stochastic modelling. Results based on numerous simulations showed that SOC decreased with elevated atmospheric temperature but increased with atmospheric CO2 concentration. Therefore, there was a counteract effect on SOC dynamics between climate warming and elevated CO2. For different soil erosion extents, warming 1℃ and elevated atmospheric CO2 resulted in SOC increase at least 15%, while warming 5 ℃ and elevated CO2 resulted in SOC decrease more than 29%. SOC predictions with uncertainty assessment were conducted for different scenarios of soil erosion, climate change, and elevated CO2. Statistically, SOC decreased linearly with the probability. SOC also decreased with time and the degree of soil erosion. For example, in 2100 with a probability of 50%, SOC was 1 617, 1 167, and 892 g m^-2, respectively, for no, minimum, and maximum soil erosion. Under climate warming 5 ℃ and elevated CO2, the soil carbon pools became a carbon source to the atmosphere （P 〉 95%）. The results suggested that stochastic modelling could be a useful tool to predict future SOC dynamics under uncertain climate change and elevated CO2.展开更多
文摘The dynamics of organic matter, carbon and nitrogen were studied during leaf decomposition over a three annual cycles period using the litterbag method at three permanently untilled and unfertilised plots. Our hypothesis is to determine if each litter type influences the decomposition and C and N releases from each other litter type （three plots and two species）. The main objective of this study is the comparison of decomposition dynamics in a climax forest with respect to that occurring in the chestnut managed plots on terrain suitable for oak to have further insight into the recycling of above ground organic matter and these two associated bioelements. As for the loss of dry matter, two-way analysis of variance, involving the treatment and year factors, revealed the existence of significant differences only for year, while no differences were observed for either treatment or interaction. At the end of the 2.4 years of the study, most of the treatment assays higher nitrogen concentrations than the initial ones were recorded. These three treatments the samplings prior to the last one revealed nitrogen concentrations higher than the initial ones, such that it may be concluded that the trend was towards an increase in concentration.
基金Supported by the National Natural Science Foundation of China(Nos.51039007 and 51179212)the Fundamental Research Funds for the Central Universities
文摘Climate change and elevated atmospheric CO2 should affect the dynamics of soil organic carbon （SOC）. SOC dynamics under uncertain patterns of climate warming and elevated atmospheric CO2 as well as with different soil erosion extents at Nelson Farm during 1998-100 were simulated using stochastic modelling. Results based on numerous simulations showed that SOC decreased with elevated atmospheric temperature but increased with atmospheric CO2 concentration. Therefore, there was a counteract effect on SOC dynamics between climate warming and elevated CO2. For different soil erosion extents, warming 1℃ and elevated atmospheric CO2 resulted in SOC increase at least 15%, while warming 5 ℃ and elevated CO2 resulted in SOC decrease more than 29%. SOC predictions with uncertainty assessment were conducted for different scenarios of soil erosion, climate change, and elevated CO2. Statistically, SOC decreased linearly with the probability. SOC also decreased with time and the degree of soil erosion. For example, in 2100 with a probability of 50%, SOC was 1 617, 1 167, and 892 g m^-2, respectively, for no, minimum, and maximum soil erosion. Under climate warming 5 ℃ and elevated CO2, the soil carbon pools became a carbon source to the atmosphere （P 〉 95%）. The results suggested that stochastic modelling could be a useful tool to predict future SOC dynamics under uncertain climate change and elevated CO2.
