Rubber plantation ageing controls soil biodiversity after land conversion from cassava

•Rubber ageing had a stronger effect than land use conversion on soil biota diversity.•Land conversion from cassava to rubber had a positive effect on soil biota.•Rubber ageing affected negatively the soil bacterial richness.•Intercropping of cash crops affected negatively the soil biota and soil chemical parameters.•Rubber ageing shifted the soil biota to Firmicutes, Trichoderma and Earthworms.