Indian Journal of Agronomy

A field experiment was conducted at Annigeri (Karnataka) during rabi 2004–05 and 2005–06 to study the effect of 4 spacings (15 cm × 5 cm, 15 cm × 10 cm, 30 cm × 10 cm and 45 cm × 10 cm) and 4 N-P fertilizer levels (control, 12–10.6, 18–15.9 and 24–21.2 kg/ha) on performance of ashwagandha (Withania somnifera Dunal). The results indicated that dry root yield, nutrient uptake and total withanolide content were significantly higher at a spacing of 15 cm × 10 cm when compared with other spacings. At 15 cm × 10 cm spacing, the increase in dry root yield was 10.2, 54.9 and 107.4% over 15 cm × 5 cm, 30 cm × 10 cm and 45 cm × 10 cm respectively. Significant increase in dry root yield, nutrient uptake and total withanolide content was noticed with increase in fertilizer levels from control to 24–21.2 kg N-P/ha. Application of 24–21.2 and 18–15.9 kg N-P/ha, being comparable recorded significantly higher dry root yield, N and P uptake and total withanolide content than control and 12–10.6 kg N-P/ha. At 24–21.2 kg N-P/ha, the increase in dry root yield, N, P uptake and total withanolide content was 22.1, 51.5, 43.6 and 13.5% over control respectively. Further, there was remarkable improvement in root length, root diameter and dry root weight of ashwagandha which resulted in increase in dry root yield. Maximum dry root yield (1.55 t/ha), net returns (Rs 50,141/ha) and total withanolide content (0.62%) accrued when the crop was sown at 15 cm × 10 cm spacing along with fertilizer doze of 24–21.2 kg N-P/ha. Consequently, a spacing of 15 cm × 10 cm spacing along with fertilizer application of 24–21.2 kg N-P/ha was found optimum for ashwagandha in vertisols of Northern dry zone of Karnataka.