Work

Rhizosphere Biochemical and Microbial Community Reorganisation Under Consecutive Multi-Year Penicillin Application in a Citrus Orchard

Year: 2026

Type: article

Abstract: Repeated penicillin application may alter citrus rhizosphere functioning. We compared nine soil biochemical variables and bacterial and fungal amplicon profiles among an untreated control and 1-, 2-, and 3-year trunk-infusion groups in one citrus orchard (three independent plots per group). All nine soil variables differed among groups after block adjustment (q ≤ 0.0086). Bacterial observed OTUs averaged 5315, 3582, 3772 and 4585, and Shannon indices averaged 7.421, 6.128, 6.215 and 6.876, respectively. Both indices were lower in treated groups than in controls, although the 3-year group exceeded the 1- and 2-year groups. Fungal richness did not differ significantly; the fungal Shannon result varied with the test. Bray–Curtis PERMANOVA detected bacterial and fungal group differences (R2 = 0.853 and 0.806; p = 0.00174), accompanied by heterogeneous multivariate dispersion. Trichoderma accounted for 57.57 ± 5.32% and 66.10 ± 6.23% of fungal reads in the 1- and 2-year groups and showed positive block-adjusted centred log-ratio contrasts. These findings indicate nonlinear associations between recorded treatment duration, soil biochemical potential and microbial community composition.

Source: Agronomy

DOI: 10.3390/agronomy16212250