Effect of Soil Collected under Eucalyptus camaldulensis Dehn on Peanut (Arachis hypogaea L.) Development and Soil Microbial Community Structure

Aims: The objective of this study was to determine the effect of soil sampled under E. camaldulensis on peanut development and microbial community.

Place and Duration of Study: Soil sampling at the 0-10 cm horizon was conducted at different distances: 1.5 m, 3 m, 4.5 m, 6 m and 30 m from 3 randomly selected E. camaldulensis plants in four sites: Karamba, Nicia, Rokout and Dioncome.

Methodology: A two-factor randomized complete block design was set up in a greenhouse experiment and parameters such as chlorophyll content, acetylene reducing activity, mycorrhization rate, number of nodules, mass of dry matter and microbial community structure were studied.

Results: No significant difference was noted among the parameters regardless of the sampling distance for the Karamba, Nicia and Dioncome sites (P>0.05). In the case of Rokout site, however, the chlorophyll content measured at 4.5 m was significantly different from the chlorophyll content measured at 1.5 m from the tree. For aboveground dry biomass, no significant difference was noted regardless of sampling distance at Karamba and Rokout sites except for samples collected at 4.5 m (Pa≤0, 045; Pc≤0.029). No significant difference was also noted for root biomass regardless of sampling distance at the Karamba, Rokout, and Dioncome sites (P>0.05). However, at Nicia, the biomass of the control treatment was significantly higher compared to others (P=0.021). Nodulation did not vary according to sampling distance (P>0.05). The amount of nitrogen fixed is higher at 6 m from Eucalyptus compared to other distances at the Karamba and Nicia sites (P<0.02). In contrast, at Boucotte it is higher at 1.5 m from the tree (P<0.03). Mycorrhization intensity was significantly higher at 6 m and 30 m from the tree compared to other distances.

Conclusion: Microbial community structure differed between soil collected under and outside of the canopy of E. camaldulensis.