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Limited and fragmented information is available about the effects of conservation agriculture, increasingly adopted by grain producers in sub-Saharan African countries, on nematode assemblages in maize-based cropping systems. Rhizosphere samples were obtained from three treatments, viz. conservation (CA) and conventional maize (CTA) fields, as well as from natural veld (NV) areas (serving as the reference) adjacent to maize fields in South African production areas. Forty-nine nematode genera (12 plant-parasitic and 37 non-parasitic/beneficial) were identified. Prominence values (PV) showed that Rotylenchulus and Meloidogyne (in descending order) dominated in 50 g roots of all three treatments, Pratylenchus in 5 g roots, and Rotylenchulus and Scutellonema in 200 g soils from CA and CTA maize, as opposed to Helicotylenchus and Rotylenchulus in soils from NV. Pratylenchus abundance in 5 g roots was significantly higher in CA and CTA maize compared to NV, with the Shannon diversity index values (H') also being the highest for species of this genus in CA, followed by CTA and NV. Rotylenchulus abundance/50 g roots was significantly higher in CA compared to both CTA and NV, while Meloidogyne abundance/50 g roots did not differ significantly among the three treatments. For soil nematodes, the H' was highest for NV, but not significantly compared to CA and CTA. Ninety-one percent of beneficial nematode genera and families were associated with NV soils, generally with higher PV and significant higher abundance (for bacterivores and predators) and diversity (for bacterivores, omnivores and predators) compared to CA and CTA. Nonetheless, most soils from the three treatments represented resource-depleted soil nematode communities indicating that soil health should be improved by using strategies such as cover cropping, incorporation of organic materials and inclusion of crop rotation sequences using cultivars with poor-host status or resistance to the dominating, target plant-parasitic nematode species to enable sustainable crop production. Associations of nematode assemblages, plant-parasitic and beneficial, with selected soil properties are also illustrated. [ABSTRACT FROM AUTHOR]