Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract only
Publication Acceptance Date: 5/3/2004
Publication Date: 11/1/2004
Citation: Chen, D., Molina, J.A., Clapp, C.E., Vial, R.S., Lee, D.T. 2004. Corn root influence on automated measurement of soil co2 concentrations. ASA-CSSA-SSSA Annual Meeting Abstracts. Paper No. 5784. Interpretive Summary:
Technical Abstract: Carbon dioxide (CO2) production is a more desirable indicator of soil carbon dynamics than CO2 flux at the soil-air interface which is significantly influenced by gas-transport conditions. The production of CO2 can be computed from the CO2 concentration profile if a high temporal measurement is achieved. Our objective was to design an automated CO2 measurement system that requires low maintenance with high temporal resolution of CO2 concentration in the soil. The CO2 sensors were located at different depths, both inside and outside the root zone of the soil, to document the effect of corn root activities on CO2 concentrations. The CO2 concentrations increased with depth. Computed CO2 production was highest in the topsoil layers. A peak of soil CO2 concentration occurred at each of the major rain events. The amplitude of the peaks decreased with depth. Differences between the CO2 concentrations in the corn row and root-excluded soils were small between rain events and large at and after rain. Soil CO2 concentrations showed diurnal variations at the 10-, 20-, and 40-cm depths, but were hardly detectable at the 60-cm depth. The data will be used to calibrate the model NCSOIL/NCSWAP for rhizodeposition.