Evaluation of the relation between soil biomass of arbuscular mycorrhizal fungi and glomalin-related soil protein in conservation agriculture

Abstract

Arbuscular mycorrhizal fungi (AMF) are indicators of soil health and are associated with various soil benefits, primarily linked to glomalin accumulation from hyphal turnover. However, the direct connection between glomalin-related soil protein (GRSP) and AMF has been questioned. In addition, conservation agriculture (CA) stands out as a pivotal plant production system that promotes agricultural sustainability and enhances soil quality.  In particular, the combination of minimal soil disturbance with residue retention has been linked with alterations in microbial biomass. The study aimed to explore the correlation between various fractions of GRSP and fatty acid fractions in the soil, along with examining the long-term impact of conservation agriculture practices on AMF biomass and GRSP content. Findings revealed a positive correlation between easily extractable (EE) GRSP and phospholipid fatty acid (PLFA) 16:1ω5, while no significant correlations were found for difficultly extractable (DE) or total GRSP fractions. These results highlight the complexity of GRSP dynamics and the need for further research on different fractions and their relation to AMF biomass. Additionally, the study demonstrated that mechanical soil management had a more significant impact on AMF hyphal biomass and EE-GRSP compared to residue management. Direct seeding, a reduced tillage approach, led to higher hyphal biomass and EE-GRSP, indicating AMF sensitivity to tillage intensity. This suggests that tillage practices exert a more substantial influence on AMF abundance and GRSP content than residue management.