Soil Properties Shape the Arbuscular Mycorrhizal Status of Common Bean (Phaseolus Vulgaris) and Soil Mycorrhizal Potential in Kabare and Walungu Territories, Eastern DR Congo

Abstract

Common bean (Phaseolus vulgaris L.) stands as the main leguminous crop cultivated in South-Kivu Province, DR Congo. However, there is a scarcity of information regarding the soil mycorrhizal potential, natural mycorrhization, and the spore density of arbuscular mycorrhizal fungi (AMF) associated with P. vulgaris in South-Kivu Province. Sample of rhizospheric soil and roots were collected from famer’s field in three localities in two territories namely Kabare and Walungu. The goal was to determine the natural mycorrhization rate of common beans, AM fungi spore density, and the soil mycorrhizal potential in relation with soil chemical properties. Our findings revealed that bean root colonization was notably high in Katana, Kavumu and Miti, while being comparatively low in Lurhala, Walungu centre, and Nduba. Katana and Kavumu exhibited a high number of spores (242.9 ± 37.8 and 183 ± 13.1 spores.100 g⁻¹ soil, respectively) compared to other sites. Soil mycorrhizal potential was higher in Katana, Kavumu, and Miti sites, located in Kabare territory (10.8 ± 0.7, 9 ± 1.3 and 8.8 ± 0.9 AM fungi propagula g⁻¹ soil). The AM fungi potential was positively and significantly correlated with bean mycorrhizal colonization (p < 0.0001). As soil phosphorus (P) content increased, mycorrhization frequency and intensity significantly decreased (r = − 0.69, p < 0.0001 and r = − 0.54, p = 0.002, respectively), along with the soil mycorrhizal potential (r = -0.87, p < 0.0001), regardless the study sites. Conversely, soil pH positively influenced mycorrhizal colonization (r = 0.73, p < 0.0001 and r = 0.54, p = 0.002, respectively), and the soil mycorrhizal potential (r = 0.78, p < 0.0001). This study underscores a substantial variation in common bean mycorrhizal status and soil mycorrhizal potential across sites. To enhance common bean productivity, it is recommended to consider site-specific identification of AM fungi morphotypes and inoculum production.