Influence of different fertilization treatments on yield components and vitamin C content of okra
Okra is a thermophilic vegetable crop with short vegetation whose cultivation is possible in all areas with hot summer months, including Croatia. Although okra is a valuable source of protein, carbohydrate and vitamin C, it is rarely grown in Croatia and research related to cultivation technology and nutritional value is very scarce. The aim of this research was to determine the influence of genotypes and fertilization treatments on the number of fruits per plant, marketable yield, share of non-marketable fruits and vitamin C content in okra. Different genotypes represented three population groups collected at two sites in Croatia (Karlovac and Vukovar-Srijem county). Fertilization treatments included: commercial organic fertilizer 'Siforga', traditional plant based formulations made from nettle and comfrey, followed by NPK 7-20-30 mineral fertilizer and control without fertilizer application. The two-factor field experiment was set up according to the randomized block design with 3 repetitions during the spring-summer growing season. The use of NPK fertilizer and nettle formulation had a positive effect on vitamin C content in young okra fruits (24.0 mg 100 g‑1 fw), while the smallest quantity of vitamin C was found in fruits of okra plants fertilized with organic commercial fertilizer (17.6 mg 100 g‑1 fw). Furthermore, the application of NPK fertilizer resulted in the highest marketable yield (266 g m‑2), but at the same time, this treatment resulted in the highest share of non-marketable fruits per plant (31%). The yields obtained in this study are slightly lower than expected, which can be explained by unfavorable weather conditions during the growing season, whereas yielding potential of okra could reach considerably higher values.
Opačić, N., Betlach, S., Šic Žlabur, J., Toth, N. and Radman, S. (2021). Influence of different fertilization treatments on yield components and vitamin C content of okra. Acta Hortic. 1320, 255-260
Abelmoschus esculentus, comfrey, genotype, nettle, NPK, organic fertilizer