Effect of indigenous organic fertilizers in plant-parasitic nematodes control and yield improvement in soyabean fields.

The current research hypothesized that three new commercial Nigerian-based organic fertilizers have the propensity to reduce phytonematodes in soyabean fields in Nigeria. Neem, Sunshine and Gateway are organic fertilizers that were applied at the rate of 5 t ha-¹ 14 days pre-plant against phytonematodes in Abeokuta and Ayetoro fields grown to TGx 1019-2EN soyabean variety known for its susceptibility to Meloidogyne incognita. Application of N₁₅P₁₅K₁₅ at 120 kg ha-¹ 14 days' post planting and the untreated plots served as check and control, respectively. The experimental plots were assayed prior to planting and found to be naturally infested with Meloidogyne spp., Pratylenchus spp., Scutellonema spp., Helicotylenchus spp. and Longidorus spp. Results showed that organic fertilizer amendments resulted in 9.2–78.2% suppressions in the population densities of all the five genera of the plant-parasitic nematodes found. In contrast, there were unprecedented increases of these nematodes from 3.6% to 498% in NPK-fertilized and control plots. Grain yield was significantly (P<0.05) higher by 26–149% in organic fertilized plots compared to a mere 14.4–18.1% increase in the NPK-treated plots. All the five genera of nematodes recovered correlated negatively (r = -0.49 to r = -0.85) and significantly (P<0.05) with soyabean grain yield. In conclusion, all three novel organic fertilizers were more efficacious in reducing phytonematodes compared with NPK and the control. [ABSTRACT FROM AUTHOR]