Effect of soil solarization on tomato (Solanum lycopersicum L.) growth and impact on native microbial diversity of farm soil in Nigeria

Abstract Background Tomato plant leaves can be wilted by the presence of various species of soil-residing bacteria, especially Ralstonia solanacearum. Soil solarization has proven to be an environment-friendly method for disease management in various crops. Therefore, this study aimed to evaluate solarization as an effective and non-chemical way to control R. solanacearum population in farm soil cultivated with tomato plants. The tomato variety UC 82 was raised on a nursery bedding for 3 weeks, after which four solarization-based treatments were applied to the field plots where tomato plants were cultivated subsequently. Agronomic, pathological, and soil temperature data were recorded from the soil samples, while isolation, Gram staining, morphological, biochemical, and physicochemical analyses were carried out on the same soil samples. Results The bacterial species identified from the pre-experiment soil included Enterobacter cloacae, Serratia marcescens, and Proteus mirabilis, while for the post-experiment were Citrobacter freundii, Klebsiella pneumoniae, P. mirabilis, Salmonella sp., and Citrobacter diversus. Occurrences of bacteria and fungi populations in solarized soils were R. solanacearum, Aspergillus niger, Aspergillus flavus, Penicillium, Rhizopus spp., Actinomycetes, and yeast. Conclusions The results obtained showed that solarization reduced the native soil microbial populations since the solarized soils had a lower occurrence of bacteria and fungi than the non-solarized soils. Thus, the present study suggests that solarization is effective in reducing the pathogenic bacteria population on farm soils.