Productivity, quality and economics of ashwagandha (Withania somnifera) as influenced by planting methods, spacings and nutrient management under drip irrigation

A field experiment was conducted during the winter (rabi) seasons of 2010–11 and 2011–12 at Rahuri, Maharashtra, to study the response of ashwagandha [Withania somnifera (L.) dunal] to 3 methods of planting (broad bed and furrow, ridge and furrow and flat bed), 2 levels of spacing (30 cm × 20 cm and 45 cm × 20 cm) and 4 levels of nutrient management (75, 37.5, 37.5 kg N, P₂O₅, K₂O + 5 t FYM/ha; 50, 25, 25 kg N, P₂O₅, K₂O + 5 t FYM/ha; 25, 12.5, 12.5 kg N, P₂O₅, K₂O + 5 t FYM/ha and control) under drip irrigation. Broad bed and furrow planting method recorded significantly higher values of yield attributes, viz. number of roots, root length, root diameter, dry root weight, number of berries and seed yield/plant, and consequently higher dry root (790 kg/ha) and seed yield (1.15 t/ha), nutrient uptake and total withanolide content as compared to ridge and furrow and flat bed. The closer spacing of 30 cm × 20 cm resulted in significantly maximum dry root yield (762 kg/ha), seed yield (1.13 t/ha), nutrient uptake and total withanolide content than wider spacing of 45 cm × 20 cm. At 30 cm × 20 cm spacing, the increase in dry root yield and seed yield was 19.89 and 15.20% over 45 cm × 20 cm respectively. Significant increase in dry root yield, seed yield, nutrient uptake and total withanolide content was noticed with increase in fertilizer levels from control to 75, 37.5, 37.5 kg N, P₂O₅, K₂O + 5 t FYM/ha. Application of 75, 37.5, 37.5 kg N, P₂O₅, K₂O + 5 t FYM/ha recorded significantly higher yield attributes as well as dry root yield (837 kg/ha), seed yield (1.28 t/ha), N, P and K uptake and total withanolide content than rest of the fertilizer levels. The broad bed and furrow planting registered higher gross returns (2, 20, 379/ha), net returns (1, 60, 796/ha) and benefit: cost ratio (3.67), followed by ridge and furrow and flat bed. The spacing of 30 cm × 20 cm and fertilized with 75, 37.5, 37.5 kg N, P₂O₅, K₂O + 5 t FYM/ha resulted in the maximum gross returns, net returns and benefit: cost ratio than the others.