The impact of biochar and arbuscular mycorrhizal inoculation on garden egg (Solanum gilo L.) performance

Garden eggs are an important vegetable, but often yield poorly due to soil fertility depletion. Biochar has gained interest in mitigating nutrient loss, while arbuscular mycorrhizal fungi (AMF) reportedly enhance plant nutrition. However, limited information exists on garden egg responses to biochar application and their interactions with mycorrhizal inoculation. Therefore, the effects of biochar and AMF inoculation on garden egg performance were investigated. In a 3 × 2 factorial field experiment during the 2021 and 2022 cropping seasons, biochar (0, 2.5, and 5 t/ha) and AMF inoculation (−AMF and +AMF) were evaluated in a randomised complete block design with three replicates. Garden egg (NHSg−3) seedlings were transplanted at 60 cm × 60 cm spacing. Data were subjected to ANOVA at p < 0.05. Applying 5 t/ha biochar and AMF inoculation resulted in a significant leaf area increase compared with their respective controls. Fruit yield was significantly higher with 2.5 t/ha biochar than other treatments. The AMF-inoculated plants had significantly higher fruit yield (726.40 kg/ha) than the untreated plants (644.17 kg/ha). Fruit yield for biochar and AMF interactions ranged from 436.50 (− AMF) to 854.53 kg/ha (+AMF inoculation) at 5 t/ha biochar. However, 5 t/ha biochar resulted in significantly higher weed biomass and lower microbial count, while 2.5 t/ha biochar +AMF and −AMF treatments gave 771.63 and 802.08 kg/ha fruit yields, respectively, enhanced microbial counts, and reduced weed biomass. Applying 2.5 t/ha biochar without AMF inoculation was considered adequate for good garden egg performance and improved soil conditions.