Growth, Yield and Nutritional Performance of Sweet Sorghum and Legumes in Sole and Intercropping Influenced by Type of Legume, Nitrogen Level and Air Quality

Sweet sorghum is a drought-tolerant cereal widely grown as pure stand in water-scarce areas. In the context of ongoing climate change, some agronomic adjustments are required for sustainable food production. Intercropping sweet sorghum with mungbean and soybean was assessed under three N levels (30, 60, 120 kg ha(-1)) and two types of air quality environments (charcoal filtered air and ambient air). Grain yield of sweet sorghum was significantly (P=0.001) reduced in intercropping with mungbean (4.5 t ha(-1)), but remained on par (P>0.05) between sole cropping (5.1 t ha(-1)) and intercropping with soybean (5.1 t ha(-1)). Nitrogen application at 60 kg ha-1 optimized the grain yield, LER (1.8-1.9) and nutritional outputs of carbohydrate, protein, fat, and energy in intercropping (4.7 t, 1.0 t, 0.2 t, and 102.5 MJ ha(-1), respectively) compared to that in sole cropping of sweet sorghum (3.6 t, 0.5 t, 0.1 t, and 74.6 MJ ha(-1), respectively). Charcoal-filtered air with reduced air pollutants of O-3, NO2 and SO2 significantly (P=0.05) improved the growth and seed yield of intercropped mungbean (2.1 tha(-1)) and soybean (1.8 tha(-1)), and overall land productivity compared to ambient air (1.7 and 1.2 t ha(-1), respectively).