Relationship between Selected Soil Physico-Chemical Characteristics and Mycorrhizal Status under Triumfetta cordifolia in the Cameroon Western Highlands

There is limited information on the pedological requirements of Triumfetta cordifolia. A starting point for establishing such information requires knowledge on the growing environment of the species. The aim of this study was to assess the physicochemical properties and mycorrhizal status in the rhizosphere of Triumeffa cordifolia. Soil and root samples from the rhizosphere of T. cordifolia were collected from three localities (Santchou, Bandjoun, and Balatchi) in the West Region of Cameroon. The results show that the soils are dominated by a loamy texture and have a mean porosity > 50%. Mean bulk density ranges from 0.91 ± 0.02 to 1.26 ± 0.04 g⋅cm−3. The sum of exchangeable cations ranges from medium (6.45 ± 1.02) to high (11.21 ± 1.35) and are evident of the satisfactory soil organic matter (OM) content in the various localities (5.90% ± 0.42% to 10.65% ± 0.73%). Total nitrogen (TN) content of the soils ranged from low (0.10%) to very high (0.41%). Biological activity is low due to very poor OM quality (mean C/N > 20). The average available phosphorus status ranged from medium (18.32 ± 3.91 ppm) to very high (69.39 ± 26.09 ppm). The Cationic Exchange Capacity (CEC) was moderate (19.28 - 29.28 cmol⋅kg−1) and was mainly contributed by soil organic matter. Base saturation ranged from low (28.0%) to medium (48.83%). Assessment of endomycorrhizal colonization showed that the intensity (I), frequency (Fr) and specific density of spores (Ds) were not significantly different among sites. A high level of available P in the Santchou soils appears to be the major cause for the lowest values of Fr, I, and Ds observed. These results reaffirm the link between soil physicochemical properties and endomycorrhizal infection in T. cordifolia. Site characteristics and soil OM quality are factors to be considered in promoting the establishment of mycorrhizal symbiosis for profitable and sustainable cultivation of T. cordifolia.