Incorporation of carbon dioxide production and transport module into a soil-plant-atmosphere continuum model

Authors: BEEGUM, SAHILA - University Of Nebraska; SUN, WENGUANG - University Of Nebraska; Timlin, Dennis; WANG, ZHUANGJI - University Of Maryland; Fleisher, David; Reddy, Vangimalla; RAY, CHITTARANJAN - University Of Nebraska

Submitted to: Geoderma
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/27/2023
Publication Date: 9/1/2023
Citation: Beegum, S., Sun, W., Timlin, D.J., Wang, Z., Fleisher, D.H., Reddy, V., Ray, C. 2023. Incorporation of carbon dioxide production and transport module into a soil-plant-atmosphere continuum model. Geoderma. 437. Article e116586. https://doi.org/10.1016/j.geoderma.2023.116586.
DOI: https://doi.org/10.1016/j.geoderma.2023.116586

Interpretive Summary: Carbon dioxide (CO2) release from agricultural soils is a major source of Carbon in the global carbon cycle. CO2 production and transport through the soil are influenced by multiple factors (crop, soil, atmosphere, and environmental conditions). Computer simulation models of crop growth and soil processes can be a useful tool to study the interaction of all the processes that affect CO2 dynamics in the soil and plant and assess the effects of climate and agricultural management on these processes. In this study, an existing simulation model for simulating maize growth and related soil processes is improved to simulate CO2 production and transport from the soil. The developed model can be a valuable tool for estimating CO2 flux from agricultural soils as affected by soil management and climate. This research will be useful to scientists, agricultural managers and policy makers interested in assessing the effects of agricultural management on CO2 dynamics in the soil.

Technical Abstract: Carbon dioxide release from agricultural soils is influenced by multiple factors; soil (soil properties, soil-microbial respiration, water content, temperature, soil diffusivity), plant (carbon assimilation, rhizosphere respiration), atmosphere (climate, atmospheric carbon dioxide), etc. Accurate estimation of the carbon dioxide fluxes in the soil and soil respiration requires a process-based modeling approach that accounts for the influence of all these factors. In this study, a module for carbon dioxide production via root and microbial respiration and diffusion-based carbon dioxide transport is developed and integrated with MAIZSIM (a process-based maize crop growth model that accounts for detailed soil and atmospheric processes) based on a modularized architecture. The developed model simulates root respiration based on the root mass, root age, soil water content, and temperature. Microbial respiration is based on the soil microbial processes by accounting for the carbon dynamics in the litter, humus, and organic fertilizer pools as moderated by the soil water content, temperature, microbial synthesis, humification, and decomposition of the carbon pools. Illustrative examples include scenarios with different soil, climate, and carbon pools that simulated the soil respiration with an average index of agreement of 0.82 and root mean squared error of 5.4 kg carbon ha-1 between the measured and simulated soil respiration. The modular architecture used in the model development facilitates easy integration with other existing crop models and future modifications.