Productivity, Weed Dynamics, Nutrient Mining, and Monetary Advantage of Maize-Legume Intercropping in the Eastern Himalayan Region of India

Despite the lack of scientific knowledge on plant density and its influence on component crops in intercropping, risk-averse smallholder farmers unabatedly continue growing crops in a mixture, which finally lowers the productivity of the system. Studies were conducted to evaluate the productivity, weed dynamics, nutrient mining, and monetary advantages in the maize-legume intertropping systems. The highest yield, maize equivalent yield (MEY), and per day productivity were recorded in the plot of sole cowpea (CP) and plots of maize (M) intercropped with CP at row proportions of 1:2 (1M:2CP) and 1M:5CP. Density and biomass of grasses, sedges, and broadleaved weeds were lowest in the plot of sole CP followed by 1M:5CP. Weed smothering efficiency was highest (88%) in the plot of sole CP followed by 1M:5CP, and lowest in the plot of 1M: 1frenchbean(FB) (8%). Nitrogen, phosphorus, and potassium were removed less by weeds by intercropping M with CP than with any other legume at row proportions of 1:5. Uptake of nitrogen and potassium was high in the plot of 1M: 5 blackgram (BG) The net return, net return per dollar of investment, and marginal returns were high in the plot of 1M:2CP followed by 1M:5CP. Intercropping M with CP at a row proportion of 1:2 gave a higher yield and nutrient uptake, and lowered nutrient mining by weeds with higher returns. In an area where weeds are the major competitor with M for site-specific resources, intercropping M with CP at a row proportion of 1:2 or 1:5 will help to suppress weeds and also to obtain higher MEY. Higher yield gave better returns. Inclusion of legumes increased the uptake of nutrients by maize. This intercropping system may be found efficient in similar situations or land use elsewhere, especially in Southeast Asia.