Nutrient impact: Unveiling the growth and biochemical dynamics of Kalmegh (Andrographis paniculata Nees.) through zinc and iron nutrition

A field experiment at Kitturu Rani Channamma College of Horticulture, Arabhavi, assessed the impact of Zinc and Iron on Kalmegh (Andrographis paniculata Nees.) growth and biochemical attributes in the northern dry zone of Karnataka during 2019-2020. With ten treatments replicated thrice in an RCBD, observations at 30, 60, 90 days after planting, and harvest showed significant increases in plant height (19.72 cm to 40.88 cm), branches (17.43 to 28.15), north-south spread (8.79 cm to 29.00 cm), and east-west spread (11.32 cm to 32.86 cm) with Zinc (0.25%) and Iron (0.25%) foliar application alongside RDF. Chlorophyll-a, chlorophyll-b, and total chlorophyll content (1.37, 1.71, 3.08 mg g^-1 of tissue) peaked with Zinc (0.25%) and Feso4 (0.25%) foliar application alongside RDF (T₁₀). These findings highlight the positive influence of Zinc and Iron nutrition on Kalmegh, offering valuable insights for agricultural practices in similar agro-ecological contexts and enriching our understanding of nutrient management in horticulture.