Zero Till Water Use Efficient Rabi Sorghum (Sorghum bicolour L. Moench), an Effective Alternative to Water Guzzling Summer Rice (Oryza sativa), under Changing Climatic Scenario

Abstract

As temperature rises, the yields of food and cash crops in South Asia are expected to decline, putting pressure on food security in the region. India, home to 1.4 billion people, is ranked 101 out of 116 countries in the Global Hunger Index, indicating a serious problem. Scientists and researchers project that a 2.5 to 4.90C increase in temperature across the country could lead to a decrease of 41%-52% in the wheat yield, and 32%-40% in rice. Under changing climate conditions, hybrid sorghum is an effective solution for food security, which can withstand high temperatures and grow with less water over water guzzling summer rice. It has versatile utility as food grains, feed, fodder, and an important feedstock for first-generation biofuel or bioethanol production. Zero till hybrid sorghum cultivars CSH 14, CSH 16, and CSH 23 were sown after Kharif rice in jute-rice-Rabi sorghum sequence, in winter, on 1st January 2010. The crop matured with 52.5 cm irrigation water at 120 days (30th April) and consumed 7 irrigations, 7.5 cm each. The highest sorghum grain yield was obtained from cv. CSH 14 i.e., 6.5 tonnes/ha. Its water productivity was high, 808 litre water/kg grain whereas for summer rice with the same productivity (6.5t/ha) the water productivity was low, 2308 litre water/kg rice grain (irrigation requirement 150 cm). Thus, with the same water, the area under sorghum will be thrice over summer rice. Gross return from hybrid sorghum was Rs.193050/ha over Rs. 132600/ha from summer rice. Rabi sorghum saved 65% (97.5 cm/ha) of irrigation water which is drawn from groundwater only. From 6.5 tons of sorghum grain, approximately 2470 litre of ethanol can be produced/ha which is used as biofuel. Replacement of summer rice by profitable drought-resistant Rabi sorghum will ensure food security under changing climatic scenarios and maintain a sustainable groundwater position in traditional rice growing belts.