Biogas residue parameterization for soil organic matter modeling.

Area of Science:

• Agricultural Science
• Soil Science
• Environmental Science

Background:

• Biogas residues (BGRs) are increasingly used as organic fertilizers in agriculture.
• Assessing the impact of BGRs on soil organic matter (SOM) storage typically requires long-term studies.
• Predictive modeling offers an efficient alternative for estimating SOM changes if BGR parameters are known.

Purpose of the Study:

• To estimate organic matter (OM) turnover parameters for BGRs for process modeling.
• To determine the turnover coefficient (k) for fresh organic matter (FOM) decay and the synthesis coefficient (η) for SOM creation.
• To establish relationships between these parameters and the chemical properties of BGRs.

Main Methods:

• An incubation experiment was conducted using six BGRs to collect carbon mineralization data.
• An SOM turnover model was applied in inverse mode to calculate k and η values.
• Linear regression analysis was used to correlate k and η with BGR chemical properties (pH, C/N ratio).

Main Results:

• The turnover coefficient (k) ranged from 0.28 to 0.58 d⁻¹, influenced by FOM chemical composition.
• The synthesis coefficient (η) ranged from 0.8 to 0.89.
• The strongest linear relationship for k was with pH (R² = 0.863), and for η with the C/N ratio (R² = 0.696).

Conclusions:

• Specific k and η values, linked to BGR chemical properties, are crucial for accurate long-term SOM scenario simulations.
• The study provides preliminary parameters for BGRs, enabling more precise predictive modeling of SOM dynamics.
• Further research is necessary to validate and refine these findings for broader application.