Influence of Different Irrigation Regimes on Physiological Growth and Yield Parameters of Stevia rebaudiana Bertoni under Subtropical Agro-climatic Conditions

The present investigation was conducted at Division of Agroforestry, Sher-e-Kashmir University of Agricultural Sciences and Technology, Jammu, to determine the effect of different irrigation depths and IW:CPE ratios on the growth and leaf yield of Stevia rebaudiana. The experiment included ten treatments comprising various combinations of irrigation water depths (40 mm, 50 mm, 60 mm) and IW:CPE ratios (0.8, 1.0, 1.2), along with a rainfed control. The irrigation had significant influence on all measured growth and yield parameters. Among the treatments, irrigation at 60 mm depth with an IW: CPE ratio of 1.0 (T9) resulted in the highest plant height, number of branches and leaves per plant, as well as fresh and dry leaf yield. Although IW60mm: CPE=1.2 was statistically at par with T9, showed slightly reduced growth and yield, possibly due to waterlogging and nutrient leaching. In contrast, rainfed conditions recorded the lowest values for all parameters. The findings suggest that optimal irrigation not only enhances physiological growth but also contributes to higher biomass accumulation in S. rebaudiana. Therefore, irrigation with 60 mm water depth at an IW: CPE ratio of 1.0 is recommended for maximizing leaf yield under subtropical conditions. Additionally, applying three irrigations per month during the critical summer months (May–June) at 8–10-day intervals is suggested to maintain optimum soil moisture and ensure superior crop performance.