[Soil Carbon Pool Allocation Dynamics During Soil Development in the Lower Yangtze River Alluvial Plain]

Area of Science:

• Soil Science
• Environmental Science
• Geochemistry

Context:

• Soil carbon dynamics are crucial for understanding global carbon cycling.
• Land use and soil development significantly influence soil carbon pool allocation.
• Alluvial plains are vital ecosystems for carbon sequestration.

Purpose:

• To investigate soil carbon pool distribution and trends during soil development and land use.
• To analyze soil organic carbon (SOC), soil inorganic carbon (SIC), particulate organic carbon (POC), and mineral-associated organic carbon (MAOC) dynamics.
• To assess carbon sequestration potential (CSP) under different reclamation ages and land use types in the Lower Yangtze River.

Summary:

• A soil reclamation chronosequence (0-1500 years) in the Lower Yangtze River floodplain revealed that SOC content increased by 4.9% after initial decline, while SIC leached significantly.
• Mineral-associated organic carbon (MAOC) contributed 48.0%-79.7% to SOC accumulation, exceeding particulate organic carbon (POC).
• Soil organic carbon density (SOCD) comprised 57.4%-100% of total carbon density, with carbon sequestration levels (CSL) ranging from 18.6% to 56.1%. Paddy-dryland rotation enhanced CSP by 20.8% compared to dryland.

Impact:

• Identifies MAOC as a critical component for SOC accumulation in developing soils.
• Highlights the importance of reclamation age and land use (e.g., paddy-dryland rotation) in determining soil carbon sequestration.
• Emphasizes the need for balanced fertilization and careful soil management in cultivated floodplain soils to sustain productivity and carbon sequestration capacity.