INFLUENCE OF PHYSIOGRAPHIC POSITIONS AND NUTRIENT SOURCES ON LEAF YIELD AND QUALITY OF Telfairia occidentalis

Abstract Physiographic position has impact on the yield and quality of crops. The effects of physiographic positions and nutrient sources on the yield and quality of fluted pumpkin (Telfairia occidentalis) were studied at the Teaching and Research Farms, Federal University Oye-Ekiti (T&RF FUOYE) in 2019 and 2020 growing seasons. The treatments were main plots of upper slope (US) and valley bottom (VB) physiographical positions and sub-plots of 60 kg N ha -1 of sole urea (U), Tithonia diversifolia plant biomass (TPB), their combination (U+TPB) and Control. Fluted pumpkin seedlings were transplanted at 100 x 100 cm plant spacing at three weeks. Data on growth parameters, nitrate, nitrite and oxalate contents of the vegetable at vegetative and reproductive stages were statistically analysed. The US and VB were loamy sand and sandy loam respectively with slight to moderate soil acidity. At both growing seasons and stages, the VB significantly influenced the measured parameters better than the US except for the oxalate content, attributable to the wetland qualities. The nutrient sources significantly influenced the leaf yield, ranged from 0.42 - 0.65 t ha -1. The influence were in the order of U > U+TPB = TPB > Control in 2019 season and TPB > U+TPB = U> Control in the residual season of 2020, showcasing the prolonged effectiveness of organic nutrient sources. Generally, the nitrate and nitrite contents were lower in the year 2020 compared to 2019 with urea having significantly higher concentrations of nitrate (1130.61 mg kg -1) and nitrite (720.46 mg kg -1) at the vegetative stage with similar but lower concentrations at the reproductive stage. However, at both stages, soluble oxalate was not significantly different. The study therefore suggests the use of sole urea for single season but TPB and/or U+TPB for longer seasons which produced better and healthier growth of the Telfairia occidentalis than other nutrient sources. Keywords: fluted pumpkin, nitrate, nitrite, oxalate, physiographic position, Tithonia diversifolia