Techno-economic and environmental assessment of different rice-based cropping systems in an inceptisol of West Bengal, India

Abstract

Sustainable intensification in cereal-based cropping systems has become an important issue in present-day agriculture. Hence, finding sustainable cropping systems in terms of techno-economic and environmental dimensions will be a major focus of scientific inquiry in near future. The present study aimed at estimating system productivity, economics, energetics and GHGs emission of 12 rice-based cropping systems in selected areas of the lower Gangetic plain of West Bengal, India. Information was collected regarding the management of these twelve cropping systems through questionnaire survey of 36 farms in nine sampled villages. Energy and cost incurred during different processes at the farm level and use of different animate and inanimate energy sources to execute those processes were taken into consideration during the primary data collection through questionnaire survey. Among the different systems studied, the rice-cabbage system recorded the highest system yield (∼23 t/ha/yr) and benefit: cost ratio (4.44), followed by rice-garlic system and rice-cauliflower system. The highest specific energy was estimated in rice-wheat system (5.25 ± 0.035 MJ/kg); however, rice-garlic system showed highest energy productivity (981.29 ± 3.534 kg/GJ). Emission of both CO2 and N2O was maximum from the rice-potato system, resulting in highest estimated global warming potential (GWP) i.e. about 21.0 t CO2eq/ha/yr from the same. Following the rice-potato system, rice-rice system and rice-wheat systems witnessed maximum global warming potential (GWP). Lowest GWP was observed in rice-garlic system. Yield-scaled GHG emission was highest in the rice-wheat system (∼3.0 t CO2eq/t system yield) and lowest in rice-garlic system (<0.5 t CO2eq/t system yield). Sensitivity analysis performed through Monte-Carlo simulation was indicative of the manifested role of chemical fertilizer, followed by seed and irrigation towards increasing the yield-scaled GHG emission from different rice-based systems. Considering the higher system yield and benefit: cost ratio, highest energy productivity, and lowest GWP and yield-scaled GHG emission together, the rice-garlic system and rice-cabbage system can be good practices for ensuring sustainable resource utilization in the study region.