Evaluation of Soil Solarisation for Management of Soilborne Pathogens in Vegetable Production in Rivers State, South South Nigeria

Soilborne pathogens including Fusarium oxysporum, Pythium spp., Sclerotium rolfsii, and root-knot nematodes (Meloidogyne spp.) are pervasive constraints on vegetable production in Rivers State, where the humid South South climate facilitates year-round pathogen survival and build-up. Soil solarisation, the process of covering moist soil with transparent polyethylene film to trap solar heat, offers a non-chemical management option suited to the high solar radiation available in the Niger Delta zone. This professional study evaluated the effectiveness of soil solarisation applied for 4-week and 6-week periods prior to planting tomato and pepper crops in four production sites in Rivers State. Soil temperature profiles under solarised and non-solarised plots were monitored, and bioassays conducted on pre- and post-solarisation soil samples assessed pathogen viability. Marketable crop yield and soil nematode egg counts at harvest were measured as outcome indicators. Six-week solarisation raised soil temperatures to above 50 degrees Celsius at 15 cm depth for sustained periods, resulting in 79 percent reduction in F. oxysporum colony-forming units and 84 percent reduction in Meloidogyne egg counts relative to unsolarised controls. Tomato yield in 6-week solarised plots exceeded control plots by 43 percent. The 4-week treatment provided intermediate benefits. Economic analysis confirmed profitability of both durations when applied in commercial-scale vegetable systems. The study recommends 6-week solarisation as a standard pre-planting practice for intensive vegetable farms in the South South zone. Keywords: soil solarisation, soilborne pathogens, Fusarium, vegetable production, Rivers State.