Glyphosate and previous crop residue effect on deleterious and beneficial soil-borne fungi from peanut-corn-soybean rotations

Summary

This study examined how glyphosate application and previous crop residue history influence soil-borne fungal communities in a peanut-corn-soybean rotation system using bean as a test crop. Corn residue consistently supported the highest populations of beneficial Trichoderma and Gliocladium species regardless of glyphosate dose, whilst pathogenic Fusarium and Pythium populations increased proportionally with glyphosate concentration in the field. In vitro testing confirmed direct inhibitory effects of glyphosate on mycelial growth of most fungi studied, suggesting both direct chemical toxicity and indirect residue-mediated effects on soil fungal ecology.

Regional applicability

The peanut-corn-soybean rotation is not a standard United Kingdom cropping pattern, though the methodology and findings regarding glyphosate impacts on soil fungi are relevant to UK herbicide use and soil health policy. The results would require validation in UK-specific crop rotations and soil conditions to inform UK practice.

Key measures

Soil fungal population counts (Trichoderma, Gliocladium, Fusarium, Pythium) over 24 days; glyphosate concentration levels; in vitro mycelial growth inhibition

Outcomes reported

The study monitored populations of beneficial (Trichoderma, Gliocladium) and pathogenic (Fusarium, Pythium) soil-borne fungi over 24 days following glyphosate treatment in soils with different crop residue histories. In vitro toxicity testing evaluated direct glyphosate effects on fungal mycelial growth.

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