Modifying the Soil and Water Assessment Tool to simulate cropland carbon flux: model development and initial...

Area of Science:

• Environmental Science
• Climate Modeling
• Agricultural Science

Background:

• Climate change necessitates accurate modeling of greenhouse gas emissions.
• Existing Soil and Water Assessment Tool (SWAT) carbon algorithms have limitations in assessing human impacts on CO2 emissions.
• Soil organic matter (SOM) dynamics and land-atmosphere carbon exchange are critical components of climate systems.

Purpose of the Study:

• To incorporate a revised CENTURY carbon model into SWAT, creating SWAT-C.
• To improve the simulation of soil organic matter dynamics and land-atmosphere carbon exchange.
• To assess the performance of the new SWAT-C model using eddy covariance data.

Main Methods:

• Integrated a revised CENTURY carbon model into the SWAT model.
• Tested the SWAT-C model against daily eddy covariance (EC) observations of net ecosystem exchange (NEE) and evapotranspiration (ET).
• Evaluated model performance across six U.S. Midwest sites with varying agricultural management practices.

Main Results:

• SWAT-C accurately simulates multi-year average NEE and ET across diverse sites.
• The model captures significant temporal variations in NEE and ET at a daily scale.
• Model performance is influenced by factors including crop management, data quality, and site-specific conditions.

Conclusions:

• The enhanced SWAT-C model demonstrates robust performance in simulating land-atmosphere carbon exchange in agricultural settings.
• SWAT-C is a valuable tool for incorporating carbon flux into sustainable watershed management under climate change.
• Further validation with extensive field data is recommended for refining the model and understanding regional uncertainties.