Sustainable maize intensification through green manure intercrops and nitrogen management

A field experiment was conducted during the Kharif and Rabi seasons of 2023-24 and 2024-25 at ZAHRS, Shivamogga, to evaluate the effect of green manure (GM) intercropping (I) and nitrogen (N) levels on growth and yield of maize in a maize-maize sequence. The experiment was laid out in a split-plot design with three N levels (75 %, 100 % and 125 % RDN) and four intercrops (sole maize, cowpea, horse gram and sun hemp). Green manures were raised in an additive series and incorporated at 45 DAS. Pooled results showed that increasing nitrogen beyond the recommended dose provided only marginal yield benefits, while GM intercropping significantly enhanced maize productivity. Among the systems tested, maize + sun hemp consistently produced the highest grain and straw yields across nitrogen levels, followed by maize + cowpea. The combination of higher nitrogen with sun hemp recorded the maximum productivity, whereas sole maize under the lowest nitrogen level recorded the lowest. The study demonstrates the strong potential of sun hemp-based intercropping to improve maize yields and contribute to the sustainable intensification of maize-based cropping systems.