Salinity-dependent potential soil fungal decomposers under straw amendment

Area of Science:

• Soil Science
• Microbiology
• Environmental Science

Background:

• Soil salinization severely limits plant productivity and ecosystem function.
• Straw amendment is a potential strategy to enhance saline soil fertility by improving microbial activity and carbon sequestration.
• The adaptation and ecological preferences of fungal decomposers in response to straw addition under varying soil salinities are not well understood.

Purpose of the Study:

• To investigate the impact of wheat and maize straw amendments on soil chemical properties and fungal community structure across a range of soil salinities.
• To identify specific fungal decomposers that respond to straw addition in different saline soil environments.
• To understand the relationship between soil chemical changes and fungal community dynamics under straw management.

Main Methods:

• A soil microcosm study was conducted using wheat and maize straws incorporated into soils with varying salinity levels.
• Soil chemical properties including microbial biomass carbon (MBC), soil organic carbon (SOC), dissolved organic carbon (DOC), and nitrogen fractions (NH4+-N, NO3--N) were analyzed.
• Fungal diversity (α- and β-diversity, Shannon diversity) and community composition were assessed using amplicon sequencing, and fungal co-occurrence networks were constructed.

Main Results:

• Straw amendment significantly increased MBC, SOC, DOC, and NH4+-N, while decreasing NO3--N, regardless of salinity level.
• Soil salinity had a greater impact on fungal diversity than straw amendment, but straw addition reduced fungal Shannon diversity and altered community composition, especially in severe saline soils.
• Straw amendment enhanced the complexity of fungal co-occurrence networks, and distinct fungal taxa were enriched in response to straw addition depending on the soil salinity level (e.g., Cephalotrichum and unclassified Sordariales in severe saline soil; Coprinus and Schizothecium in light saline soil).

Conclusions:

• Straw amendment positively influences key soil chemical properties and alters fungal community structure in saline soils.
• The responses of fungal decomposers to straw addition are soil-specific, with different fungal groups dominating under varying salinity conditions.
• Understanding these soil-specific fungal responses can inform targeted microbial strategies for optimizing straw decomposition and managing saline-alkali lands.