Impact of Different Nitrogen Sources and Plant Spacing on the Growth Characteristics of Kalmegh (Andrographis paniculata Nees) under the Malwa Agro-Climatic Region of Madhya Pradesh

A field experiment titled “Effect of Nitrogen Sources and Plant Geometry on Herbage Yield and Nutrient Uptake in Kalmegh (Andrographis paniculata Nees.) under the Malwa Plateau of Madhya Pradesh” was conducted during the Kharif season of 2024–25. The study was undertaken at the Herbal Garden, Department of Plantation, Spices, Medicinal and Aromatic Crops, KNK College of Horticulture, Mandsaur (M.P.). Observations on various growth parameters were systematically recorded using established scientific methodologies. The study assessed key growth parameters, including Leaf Area (cm2 plant-1) Fresh weight (g plant-1) and Dry weight (g plant-1). Observations were recorded from five randomly selected plants at intervals of 30, 60, 90, and 120 days after transplanting (DAT), as well as at the time of harvest. The results indicated that among the nitrogen treatments, N1 (40 kg N through vermicompost + 40 kg N through urea) showed the highest values for leaf area (8.75, 45.10, 104.54, 134.45, and 134.37 cm²), fresh weight (9.13, 25.51, 45.00, 64.41, and 63.72 g), and dry weight (2.68, 6.81, 23.06, 41.77, and 44.17 g). In terms of plant spacing, the S1 geometry (20 × 10 cm) resulted in the greatest leaf area (9.12, 45.80, 105.33, 135.12, and 134.43 cm²), fresh weight (9.22, 26.70, 45.15, 64.95, and 64.34 g), and dry weight (2.76, 6.92, 22.98, 41.70, and 44.22 g). Furthermore, the combined treatment of S1 × N1 produced the most significant results, with maximum leaf area (10.82, 48.23, 108.83, 139.01, and 137.53 cm²), fresh weight (10.50, 32.49, 48.83, 68.50, and 70.06 g), and dry weight (3.49, 8.54, 28.68, 46.61, and 47.79 g) at 30, 60, 90 DAT, and at harvest.