Growth, yield, andrographolide content and total antioxidant activity of Kalmegh [Andrographis paniculata (Burm. f.) Wall. ex Nees] under variable nitrogen rates and organic manures application in Indo-Gangetic plains of India

Abstract

Kalmegh is an important medicinal crop because of the most important biologically active phyto-chemical called andrographolide. Production of higher herbage yields with appropriate quality in terms of andrographolide is largely dependent upon efficient nutrient management. This study aimed to assess the effect of organic manures application and variable nitrogen rates on growth, yield, andrographolide content and total antioxidant activity of Kalmegh. The experiment was laid out in split plot design with three levels of organic manures [M1- Control, M2- vermicompost @ 5 t ha−1 and M3- poultry manure @ 5 t ha−1] and four fertility levels [F1- 0: 50: 50, F2- 50: 50: 50, F3- 75 (37.5 + 37.5): 50: 50 and F4- 75: 50: 50 kg ha−1 N, P2O5 and K2O, respectively] replicated thrice. The highest dry herbage yields and andrographolide content of kalmegh were recorded with vermicompost @ 5 t ha−1 + 75 (37.5 + 37.5): 50: 50 N, P2O5 and K2O kg ha−1 followed by poultry manure @ 5 t ha−1 + 75 (37.5 + 37.5): 50: 50 N, P2O5 and K2O kg ha−1 during both the years while, lower yields due to control. Dry herbage and andrographolide yield were found to be highest in M2×F3 compared with M1×F1. Our study concluded that the application of vermicompost @ 5 t ha−1 along with 75 kg ha−1 N in two splits and 50 kg ha−1of each P2O5 and K2O resulted higher yield and andrographolide content which, would provide better soil nutrient status in sustainable manner without affecting ecological balances.