Integrated nitrogen and weed management: A comprehensive approach to essential oil yield and quality in Monarda citriodora Cerv. ex Lag

A two-year experiment (2021-22 and 2022-23) was conducted at the CSIR-Indian Institute of Integrative Medicine, Jammu, using a split-plot design with three replicates to evaluate three nitrogen regimes: 100 14; 14;kg/ha recommended dose of nitrogen (RDN), farm yard manure (FYM) 20 14;t/ha and combined RDN 50% + FYM 10 14;t/ha, with five weed control measures: weed check, weed free, mulch 5 14;t/ha, mulch 5 14;t/ha + hand weeding 30 days after transplanting (DAT) and mechanical weeding twice (30 and 60 DAT). Mechanical weeding proved most effective in weed suppression, reducing weed density by 31.00‒42.65% in 2021-22 and 36.23‒45.23% in 2022-23 with corresponding reduction in weed dry biomass by 41.00‒51.58% in 2021-22 and 44.00‒56.90% in 2022-23 compared to the control. It also recorded the highest weed control efficiency (73.00%) with a weed index below 10.00% in both years. Maximum herbage yield (12.87 and 12.65 14;t/ha), essential oil yield (87.70 and 88.65 14; 14;kg/ha) were obtained in 100% RDN, but statistically at par with RDN 50% + FYM 10 14;t/ha treatment. Mechanical weeding increased herbage yield by 91.00–109.00% and essential oil yield by 106.00–128.00% over the weedy check. Thymol (61.48–76.65%) was the major oil component with the highest concentration under FYM 20 14;t/ha with mechanical weeding, accompanied by 33.50% reduction in monoterpene hydrocarbons. This study offers an efficient solution for reducing nitrogen fertiliser and enhancing mechanization to scale up an eco-friendly strategy for sustainable advancement of agricultural practices in India.