Determination of Nitrogen dose and PGPR concentration to promote growth and flavonoid content of Ocimum sanctum L. (Lamiaceae)

Ocimum sanctum L. is a plant that contains flavonoids and is often used as a side crop in cultivation. CBS data (2015) show that the number of O. sanctum horticulture business households is 195 with a planting area of 303,134 m2 and the average planting area cultivated per household is 1554 m2. The flavonoid content in O. sanctum plants has benefits, including counteracting free radicals and antibiotics. The problem of O. sanctum cultivation, which is only used as a side crop, causes less intensive maintenance, one of which is the lack of attention to nutrition. The application of nitrogen fertilizer and plant growth-promoting rhizobacteria (PGPR) can help spur growth and flavonoid content. The N fertilizer levels used were N 92 kg/ha, N 138 kg/ha and N 184 kg/ha while the PGPR concentration consisted of 0 mL/L, 20 mL/L and 40 mL/L. There was an interaction between the dose of N fertilizer and PGPR concentration on the number of leaves, leaf area and flower emergence time. The form of interaction between the dose of N fertilizer and PGPR concentration is an antagonistic interaction, where the addition of PGPR concentration can reduce the dose of N fertilizer, which is indicated by the lowest dose of N fertilizer accompanied by a higher concentration of PGPR that can increase the growth of O. sanctum. N fertilization produced significant differences in fresh weight consumption and flavonoid levels where the 92 kg/ha N fertilizer dose gave 16.33% higher flavonoid levels than the 184 kg/ha N fertilizer dose.