EFFECT OF LEGUME TYPE, NITROGEN DOSE AND AIR QUALITY ON BIOMASS AND BIOETHANOL PRODUCTION IN SWEET SORGHUM-LEGUME INTERCROPPING

Sweet sorghum is grown as a sole and potential energy crop in water limited areas. It has inherent potential to be intercropped with legumes for the production of both food and bioethanol. To explore this potential, several intercropping patterns composed of two legumes (viz. mungbean and soybean), three nitrogen doses (viz. 30, 60 120 kg ha^-1) and two air quality environments (viz. filtered air ambient air) with three sole crops (sweet sorghum, mungbean and soybean), in a completely randomized design with three replicates in dry season were studied. Dry matter (DM), grain, above ground biomass (AGB), and calculated bioethanol (BEY) yields of sweet sorghum and legumes in sole and intercropping stands and within intercropping were compared. The DM, grain yield and AGB of sweet sorghum were significantly (p ≤ 0.001) reduced when intercropped with mungbean (36.2, 4.5 40.7 t ha^-1, respectively) but remained at par (p 0.05) in intercropping with soybean (40.3, 5.2 45.5 t ha^-1, respectively) compared to sole crop of sweet sorghum (41.8, 5.1 46.9 t ha^-1, respectively). Nitrogen treatment of 60 kg ha^-1 produced optimized DM, grain/seed, AGB, and BEY compared to other N levels. Influence of ambient air (polluted) on sweet sorghum crop was not significant (p 0.05); however filtered air significantly (p≤0.05) improved the dry matter and seed yields in intercropped legumes. Establishing sweet sorghum with mungbean or with soybean in simultaneous seeding and provided with 60 kg ha^-1 of N under filtering of air pollutants enhanced the performance of legume, crop yields and bioethanol production.