Nutritional Quality of Tomato ( Lycopersicon lycopersicum L.) Varieties as Influenced by Combined Application of Human Urine and Rock Phosphate

Abstract

There has been increasing interest in the quality of food produced in the sub-Saharan Africa and organic fertilizers can be used as palliative for eradicating malnutrition and improving the livelihood of the populace. A study was conducted in two phases, 4 × 5 × 2 and 2 × 4 factorial experiments in a completely randomized design with three replicates at the Department of Agronomy screenhouse, University of Ibadan, Nigeria. In the first experiment, five N levels (0, 20, 40, 60 and 80 kgN/ha) were combined with two P levels (0 and 20 kgP/ha) using urea and single superphosphate, respectively and four varieties (Roma VF, UC82B, Rio grande and Roma savana) of tomatoes were used. In the second experiment, optimum rates (60 kgN and 20 kgP/ha) from the first experiment formed the basis for the application of urea + SSP, urine + ORP, urea + SSP + urine + ORP and control. The best-performing varieties (Rio grande and Roma savana) in the first experiment were used. Data were subjected to analysis of variance. Combined application of N and P had higher N use efficiency and nutrient uptake than sole application of N or P. Urine + ORP based fertilizer mixtures were best for nutrient uptake and crop utilization of N and P. Increasing N levels led to decrease in nutrient use efficiency. Application of urine + ORP and urea + SSP gave better fruit qualities. The descending order of varietal superiority with respect to nutrient uptake, utilization and quality was: Rio grande > Roma savana > Roma VF > UC82B. Thus, urine + ORP based fertilizer mixtures have great potentials as substitutes for urea + SSP in the production of tomatoes.