Su, Y.
Presented at the All Scientist Meeting (2013-04-04 to 2013-04-05 )
The production of biofuel grown more than ten times in the past two decades and
expected to grow in the future. Bioenergy assumed to mitigate the greenhouse gas (GHG) emissions due to the sequestration of CO during the biofuel crops growing can neutralize the emission when it combusts. However, There are still many uncertainties on the “climate neutrality” of biofuel crop plantation. Land use change creates carbon debt that may need decades to repay and the payback time dependent on the net ecosystem exchange (NEE) of CO. Net ecosystem production (NEP) of a terrestrial ecosystem is largely determined by its carbon loss (i.e., respiration) instead of gain through photosynthesis. However, recent advancements in ecosystem carbon studies revealed that belowground carbon loss through soil respiration is cohesively linked to the aboveground carbon gain because of stimulated autotrophic respiration (SR). I measure total and heterotrophic soil respiration rate (SRR and SRR) to explore how the soil respiration respond to climate across crops and LUH. Soil respiration rate may be determined by the plant allocation on belowground carbon pool and litter fall which is positive related to photosynthetic rate and NEE. Our results show that the patterns of SRR and SRR are related to plant growth. However, the difference between SRR and SRR are different between two LUH. SRR and SRR are very closed in CRP while SRR is obvirously lower than SRR at the peak of SRR (late July to early August) in AG and reference sites in 2011. However, the value of SRR and SRR at peak in all sites seems very closed in 2012. This may due to the hot and dry climate in 2012. The relationship between log SRR and soil temperature (Ts) and soil water content (VWC) are hump shape. The future work may develop a regression model to fit the relationship of SRR and climate and year. The production of biofuel grown more than ten times in the past two decades and expected to grow in the future. Bioenergy assumed to mitigate the greenhouse gas (GHG) emissions due to the sequestration of CO during the biofuel crops growing can neutralize the emission when it combusts. However, There are still many uncertainties on the “climate neutrality” of biofuel crop plantation. Land use change creates carbon debt that may need decades to repay and the payback time dependent on the net ecosystem exchange (NEE) of CO. Net ecosystem production (NEP) of a terrestrial ecosystem is largely determined by its carbon loss (i.e., respiration) instead of gain through photosynthesis. However, recent advancements in ecosystem carbon studies revealed that belowground carbon loss through soil respiration is cohesively linked to the aboveground carbon gain because of stimulated autotrophic respiration (SR). I measure total and heterotrophic soil respiration rate (SRR and SRR) to explore how the soil respiration respond to climate across crops and LUH. Soil respiration rate may be determined by the plant allocation on belowground carbon pool and litter fall which is positive related to photosynthetic rate and NEE. Our results show that the patterns of SRR and SRR are related to plant growth. However, the difference between SRR and SRR are different between two LUH. SRR and SRR are very closed in CRP while SRR is obvirously lower than SRR at the peak of SRR (late July to early August) in AG and reference sites in 2011. However, the value of SRR and SRR at peak in all sites seems very closed in 2012. This may due to the hot and dry climate in 2012. The relationship between log SRR and soil temperature (Ts) and soil water content (VWC) are hump shape. The future work may develop a regression model to fit the relationship of SRR and climate and year.
Back to meeting | Show |