Relationship of nematodes in natural and disturbed land with physicochemical properties in Magoebaskloof, Limpopo Province, South Africa

Abstract

AbstractMagoebaskloof is an evergreen mountainous landscape covered with Afromontane forests. During a survey on soil nematode diversity, the soil samples were collected from the rhizosphere of a forest tree (no cultivation over 50 years), grassland, prepared kiwi land, oak tree, kiwifruits trees (37-year-old), and 8-year-old kiwifruit in the Limpopo Province, South Africa. Overall, results showed that a total of 30 nematode genera were found to be associated with the surveyed plant species. The frequency of occurrence showed Ditylenchus (100%), Acrobeloides (100%), and Nanidorus (100%), followed by Meloidogyne (83%) were the most distributed nematodes. The study of the relationship between nematodes with physicochemical properties in the soil using Pearson correlation revealed that clay percentage of the soil has a positive correlation with Pseudacrobeles (r = 0.684), Acrobeloides (r = 0.658) and Meloidogyne (r = 0.668) species. In contrast, clay percentage had a strong negative correlation (r = -0.900) with Filenchus. Soil pH showed no strong correlation with the nematodes. The principal component analysis placed kiwifruits and forest soil in two groups, indicating the biodiversity dynamics among the two locations. In conclusion, forest trees and grasslands showed a high diversity of free-living than disturbed land of kiwifruits. Additionally, plant-parasitic nematodes numbered more in the rhizosphere of kiwifruit trees. Our results suggest that the soil nematodes, especially free-living bacterivores, may mediate the effects of ecosystem disturbance on soil health.