Bioavailability Evaluation of Dissolved Organic Matter Derived from Compost-Amended Soils

Area of Science:

• Environmental Chemistry
• Soil Science
• Spectroscopy

Background:

• Dissolved organic matter (DOM) plays a crucial role in soil nutrient cycling and carbon sequestration.
• Understanding the impact of different compost amendments on DOM composition and transformation is vital for sustainable soil management.
• Compost quality significantly influences soil properties and microbial community structure.

Purpose of the Study:

• To investigate the changes in dissolved organic matter (DOM) components in soil amended with seven distinct compost types.
• To elucidate the relationships between compost amendments, soil organic matter, nutrient content, and microbial community composition.
• To rank compost sources based on their effectiveness in altering DOM characteristics and improving soil functions.

Main Methods:

• Hetero-two-dimensional correlation spectroscopy (hetero-2DCOS) was used to analyze DOM fluorescence.
• Parallel factor analysis (PARAFAC) was employed to resolve DOM components.
• Structural equation models (SEMs) and projection pursuit regression (PPR) were utilized to assess component dynamics and rank compost sources.

Main Results:

• Four distinct DOM components were identified, exhibiting varied fluorescence dynamics during mineralization.
• Compost amendments significantly altered the correlations between total organic carbon (TOC), total nitrogen (TN), bacterial community, and DOM components.
• Cabbage waste (CW) was ranked as the most effective compost source for improving DOM bioavailability, followed by chicken manure (CM), dairy cattle manure (DCM), tomato stem waste (TSW), and peat (P), with municipal solid waste (MSW) and sewage sludge (SS) being least effective.

Conclusions:

• Compost amendments modulate DOM transformations and microbial interactions in soil.
• The source and type of compost significantly influence DOM bioavailability and soil functions.
• Ranking compost sources provides valuable insights for selecting effective amendments to enhance soil health and nutrient cycling.