Impact of integrated nitrogen management and plant spacing on yield and phytochemical quality of Kalmegh (Andrographis paniculata)

Abstract

A field experiment entitled “Impact of Integrated Nitrogen Management and Plant Spacing on Yield and Phytochemical Quality of Kalmegh (Andrographis paniculata)” was conducted during the kharif season of 2024-25 at AICRP on Medicinal, Aromatic Plants and Betelvine, Nagarjun Medicinal Plants Garden, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola. The experiment was laid out in a factorial randomized block design (FRBD) with four nitrogen source treatments, viz., N₁: 75% N through vermicompost + 25% recommended dose of nitrogen (RDN) through inorganic fertilizer, N₂: 50% N through vermicompost + 50% RDN through inorganic fertilizer, N₃: 100% N through vermicompost, and N₄: 100% RDN through inorganic fertilizer, and three plant spacings, viz., S₁: 20 × 20 cm, S₂: 30 × 10 cm, and S₃: 30 × 15 cm, replicated thrice. Results revealed that nitrogen sources and plant spacing significantly influenced fresh foliage yield, dry foliage yield, and total andrographolide yield of Kalmegh. Among nitrogen treatments, application of 100% RDN through inorganic fertilizer (N₄) recorded the highest fresh foliage yield (8558 kg ha⁻¹), dry foliage yield (3388 kg ha⁻¹), and total andrographolide yield (44.41 kg ha⁻¹), which was statistically at par with N₂ (50% vermicompost + 50% RDN). Among spacing treatments, S₂ (30 × 10 cm) produced significantly higher fresh foliage yield (9627 kg ha⁻¹), dry foliage yield (3548 kg ha⁻¹), and total andrographolide yield (46.52 kg ha⁻¹).The interaction effect was significant, with the combination of N₄S₂ (100% RDN through inorganic fertilizer with 30 × 10 cm spacing) recording the maximum fresh foliage yield (12573 kg ha⁻¹), dry foliage yield (4910 kg ha⁻¹), and total andrographolide yield (61.07 kg ha⁻¹). The study clearly indicates that integrated nutrient management combined with optimum plant spacing plays a vital role in enhancing yield and quality of Kalmegh.