Exergy Analysis of a Bio-System: Soil-Plant Interaction

Area of Science:

• Thermodynamics
• Soil Science
• Plant Biology

Background:

• Soil functions as a dynamic system facilitating the movement of various substances.
• The second law of thermodynamics explains resource degradation via exergy destruction.
• Understanding exergy in soil-plant interactions is crucial for resource management.

Purpose of the Study:

• To develop and apply a novel method for assessing exergy in soil and plant formation processes.
• To quantify exergy destruction in key soil-plant reactions.
• To evaluate resource efficiency and degradation within soil ecosystems.

Main Methods:

• Conducted a thorough exergy analysis of critical soil-plant interactions.
• Developed a new methodology to assess exergy in soil and plant formation.
• Quantified exergy destruction percentages for various soil reactions, including mineralization, nutrient uptake, photosynthesis, and humus formation.

Main Results:

• Soil solution reactions destroy approximately 62.5% of input exergy.
• Photosynthesis exhibits low efficiency (around 15%), causing significant exergy destruction in the biota-atmosphere subsystem.
• Humus and protonation reactions are major contributors to exergy destruction (14% and 13%, respectively).
• Respiratory, weathering, and reverse weathering reactions show minimal exergy destruction (<1%).

Conclusions:

• The soil system exhibits a total exergy yield of approximately 37.45%.
• Significant exergy is lost during soil-plant processes, emphasizing the need for efficient resource utilization.
• The developed exergy analysis method provides valuable insights into soil ecosystem functioning and resource degradation.