Organic manures and biostimulants: A synergistic approach to boosting ashwagandha growth and yield

Abstract

This study investigated the effects of organic manures and biostimulants on the growth and root yield of ashwagandha (Withania somnifera (L.) Dunal), a valuable medicinal herb widely used in Ayurvedic and Unani medicine. A field experiment was conducted at the Kerala Agricultural University, Vellanikkara from 2023 to 2024. The experiment followed a Factorial Randomized Block Design (FRBD) with 16 treatment combinations and three replications. The treatments included two factors: organic manures and biostimulants. Factor A consisted of four levels of organic manures: A1: FYM @ 5t/ha, A2: FYM @ 10 t/ha, A3: Vermicompost @ 2.5 t/ha, A4: Vermicompost @ 5 t/ha. Factor B included four levels of biostimulants: B1: Water spray (control), B2: Seaweed extract @ 0.4% at 1 and 3 MAP, B3: Humic and fulvic acid @ 0.4% @ 1 and 3 MAP, B4: Chitosan @ 0.1% at 1 and 3 MAP. Results demonstrated that vermicompost application at 5 t/ha resulted in significantly greater plant height (59.34 cm), biomass (141.35 g fresh and 53.98 g dry), and root development compared to other treatments. Seaweed extract as a biostimulant yielded the highest root growth and plant biomass, showing a 28.5% increase in root biomass. The findings indicate that organic farming significantly improves ashwagandha growth and yield, resulting in substantial export potential.