Potential of Organic Nutrient Sources for Improving Yield and Bioactive Principle of Ashwagandha (Withania Somnifera) through Enhanced Soil Fertility and Biological Functions

摘要

Ashwagandha (Withania somnifera L. Dunal) is an industrially important medicinal herb and root and is a rich source of bioactive withanolides. To investigate the impacts of different organic nutrient management practices on ashwagandha yield and quality, a field experiment was conducted for 2 consecutive years. The experiment was carried out in randomized bock designed (RBD) with treatments comprised of different organic manures (farmyard manure, vermicompost, and castor cake) and microbial consortium along with recommended doses of fertilizer and the control. The root yield parameters (root girth, length, and fresh and dry root weight) of ashwagandha were influenced significantly by the treatments containing organic manures and microbial consortium alone or in combination. The highest fresh (1505 kg ha(-1)) and dry (767 kg ha(-1)) root yields as well as total withanolide contents (0.947 mg g(-1)) were recorded under the treatment receiving castor cake + microbial consortium (T-7) followed by application of vermicompost + microbial consortium (T-8). Significant improvements in soil fertility status (mineral N, available P and S) and soil biochemical parameters (microbial biomass and enzymes) were observed under the treatments containing castor cake and vermicompost. A positive correlation coefficient (< 0.01) was found between dry root yield, withanolide content and soil properties (r = 0.34-0.64). Thus, the results indicate that castor cake and vermicompost could be promising nutrient source for production of quality medicinal herb by improving soil properties.