Arbuscular mycorrhizae fungi community structures in Conservation Agriculture soils amended with organic and inorganic fertilizers in a sub-humid region of Zimbabwe

This study investigated AMF community response to tillage and soil amendment regimes from rhizospheric soil of maize roots at 0-10 cm and 10-20 cm at Hunyani farm, Zimbabwe. Two tillage systems (conservation agriculture: CA) and conventional tillage: CT), and six soil fertility amendments [Control (C), High fertilizer (HF-120), Low fertilizer (LF-60), Manure (M), Manure + low fertilizer (MLF-60), Manure + 60 kg N ha-1 (M-60)] were laid in a split plot design with three replications. Twelve morpho-species were identified at the study site. Species richness was highest for CA+C (11.7) and CA+ M (11.7) at 10-20 cm depth. Control plots of CT had more diverse AMF species in the surface layers (Shannon-Weaver index = 2.12) compared to the subsurface soil layer (Shannon-Weaver index = 1.86). The tillage x fertility interaction showed that in CA, A. dilatata spore populations were higher in MLF-60 amended plots than all other plots, followed by LF-60 plots, while in CT systems MLF-60 promoted higher spore populations than all other treatments. All plots amended with manure plus inorganic fertilizer had lower (P<0.05) G. clavisprum spore populations than C, HF-120 and M amended plots under both CA and CT, however LF-20 promoted higher populations than in plots with a combination of manure and inorganic fertilizer in CT only. Tillage x fertility amendment x depth interactions (P<0.05) were observed on A. denticulate, A. schenkii, and C. Luteum, E. infrequens, R. clarus, and S. calospora spore populations. Medium term effects of CA+ manure, and CA + no amendments may include increasing species richness and diversity. Application of relatively large amounts of inorganic fertilizers increase populations of C. luteum populations in CA and decrease in CT. Manure reduces populations of some species e.g. C. luteum in both CA and. CT.