Biochar and NPK fertilizer effects on flavonoids and vitamins composition of okra, Abelmoschus esculentus (L.) Moench grown in Tashkent region of Uzbekistan

This study aimed to assess the effects of biochar and mineral fertilizers (NPK) on the composition of flavonoids and vitamins in okra fruit (Abelmoschus esculentus (L.) Moench). Six treatments were applied: T-control (without biochar or mineral fertilizers), T2 (1% biochar), T3 (N80P50K50 kg/ha), T4 (N120P75K75 kg/ha), T5 (biochar + N80P50K50 kg/ha), and T6 (biochar + N120P75K75 kg/ha). After sixty days, the flavonoid and vitamin content in the okra fruit was analyzed. The findings indicated that the use of biochar and its combination with mineral fertilizers positively affected the flavonoid and vitamin levels. In particular, the treatment that included both biochar and NPK (120:75:75 kg/ha) resulted in a significant increase in apigenin content in the okra. The results also showed that the biochar-only treatment significantly enhanced the levels of flavonoids, specifically rutin and hyperoside, compared to the control. Moreover, the combination of biochar and NPK (120:75:75 kg/ha) had a more beneficial effect on the gallic acid content of the okra fruit. Biochar alone significantly elevated the levels of vitamin B2 and vitamin B12 in the okra fruit compared to the control group. Since organic fertilization can improve the levels of rutin, hyperoside, vitamin B2, and vitamin B12 in okra fruit, it is advisable to utilize biochar (an organic fertilizer) instead of chemical fertilizers to support environmentally sustainable production of high-quality okra.