Quantitative Analysis Of Rice Rhizosphere Carbon Deposition

Plants-Carbon flow process is an important link in the terrestrial ecosystem carbon cycle. Based on summarizing rhizodeposition research advance, this paper focuses on the quantitative of the number of plant rhizodeposited carbon, and via expounding and proving the feasibility of applications on the study of plant carbon rhizodeposition by the carbon flux observations, then puts forward that the method to measure the number of plant rhizodeposited carbon.After that, as typical representative of the subtropical paddy ecosystem-Taoyuan Ecological Agriculture Experiment Station-its flux and meteorological data from2003-2011was gained, via processing and analysis, the changing characteristics of paddy CO2fluxes was discussed and the number of rice rhizodeposited carbon was measured and analyzed. The main conclusions are as follows:(1) As there is a strong artificial disturbance in the paddy ecosystem, rhizosphere carbon deposition process becomes the main cause on the gap between ecosystem biomass and net primary productivity, which can be used to estimate the amount of rhizodeposited carbon and its rhizodeposited rate of the whole ecosystem during the period of time, and provide an important theoretical and methodological support for the study of rhizosphere carbon deposition in situ conditions(2) The flux data were analyzed, the results showed that:Paddy ecosystem carbon fluxes showed significant variation from year to year and a day and night, mainly in:in the yearly change, showing from low to high to low, intermediate peak appears the law, due to the period between the early and late harvest and form a distinct "Twin Peaks" phenomenon; in the diurnal variation, showing a clear inverted U-shaped structure, with the passage of the month, the inverted U-shaped " trough " showing an increase from the beginning of the first and then to the end of the year and reduce. The resulets suggest that paddy ecosystem is an important carbon sink of the terrestrial ecosystem carbon cycle processes.(3) The soil respiration fluxes(Rs) were analyzed, the results showed that: Rs and soil temperature(Tsoil) exhibit correlation, the correlation between variations of the year is close to a normal distribution; Rs peak level performs different in different years, the corresponding Tsoii change remains approximately stable, indicating that stable ecological environment has an important role on the region stable; diurnal variation on, Rs showed good consistency with Tsoil change, but high temperatures may affect the sensitivity of Rs.(4) Quantitative analysis of rice rhizosphere carbon deposition has been conducted, the results showed that:Rice growing season has a higher carbon sequestration potential, the difference between the status of vegetation cover has changed the entire ecosystem carbon exchange situation; late rice period is the main period of rhizosphere carbon deposition, and there are14.01%～43.17%photosynthetic carbon getting into the soil through the rhizosphere deposition in the rice growing season, which is the confidence interval of rhizosphere carbon deposition rate(δ); in the one year, the rice in the whole growth period showed a greater rhizosphere carbon deposition rate.