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