2025, Vol. 8, Issue 1, Part D

author(s)
Neeraj Kumar Gupt, Raushan Kumar and Anil Singh

abstract
The application of nitrogen (N) and phosphorus (P) fertilizers is critical for optimizing growth and yield in agricultural crops, yet the optimal combination for specific plants like Japanese mint (Mentha arvensis L.) remains underexplored. This study aimed to evaluate the effects of varying N and P levels on fresh herbage production, oil content, chlorophyll, and carotenoid levels in Japanese mint. The experiment involved five nitrogen levels (40-200 kg/ha) and three phosphorus levels (40-80 kg P₂O₅/ha), assessing growth parameters, oil yield, and chlorophyll content at 45 and 90 days after planting (DAP). Results revealed significant increases in fresh herbage production, chlorophyll, and carotenoid content with higher nitrogen and phosphorus application, particularly at N4 (160 kg/ha) and P3 (80 kg/ha). Fresh herbage production showed a marked increase from 12.39 g/plant at low N to 16.87 g/plant at high N levels. Oil content also improved with increased nutrient supply, with the highest oil production observed at N5P3 (200 kg N/ha, 80 kg P₂O₅/ha). Chlorophyll "a" and "b" contents exhibited positive correlations with nutrient application, especially at N4 and P2. Carotenoid levels increased significantly at higher nitrogen levels. Overall, nitrogen levels significantly influenced all parameters, whereas phosphorus had a less pronounced effect. This study highlights the importance of optimal N fertilization for enhancing both yield and quality in Japanese mint cultivation.