Zero Tillage Systems Conserve Arbuscular Mycorrhizal Fungi, Enhancing Soil Glomalin and Water Stable Aggregates with Implications for Soil Stability

Arbuscular Mycorrhizal (AM) fungi form mutualistic symbiotic relationships with approximately 80% of terrestrial plant species, while producing the glycoprotein glomalin as a structural support molecule along their mycelial network. Glomalin confers two benefits for soils: (1) acting as a carbon and nitrogen storage molecule; (2) the binding of soil microaggregates (<250 µm) to form larger, more stable structures. The present study aimed to test the hypothesis that a correlation between glomalin and soil aggregation exists and that this is influenced by the method of seedbed preparation. The soils from two crops of winter wheat in Hertfordshire, UK, practising either conventional (20 cm soil inversion) or zero tillage exclusively, were sampled in a 50 m grid arrangement over a 12 month period. Glomalin and water stable aggregates (WSA) were quantified for each soil sample and found to be significantly greater in zero tillage soils compared to those of conventional tillage. A stronger correlation between WSA and glomalin was observed in zero tillage (Pearson’s coeffect 0.85) throughout the cropping year compared to conventional tillage (Pearson’s coeffect 0.07). The present study was able to conclude that zero tillage systems are beneficial for AM fungi, the enhancement of soil glomalin and soil erosion mitigation.