Rice single cropping or ratooning agro-system: which one is more environment-friendly?

Sustainable development of food production depends on damping the environmental impacts of agricultural production. The aim of this study was to investigate the environmental performance of rice production in single crop and ratooning (main rice + ratoon crop) agro-systems through life cycle assessment (LCA) methodology in Guilan province, Northern Iran, in 2015. The flooding irrigation regime was the dominant irrigation method for single cropping system and main crop rising in ratooning agro-system. The data were gathered through a face to face interview with 215 single crop and 115 ratoon breeder paddy farmers. The environmental risks were determined in six impact categories including global warming, terrestrial eutrophication, acidification, and depletion of fossil fuels, phosphate, and potash resources. The functional unit (FU) was set as 100 kg protein. Results indicated that the CO2, N2O, and CH4 emissions of the rice ratooning agro-system (661.44, 1.96, and 5.42 kg 100 kg−1 protein) were less than the corresponding values in the rice single cropping agro-system (1341.63, 2.88, and 9.20 kg 100 kg−1 protein, respectively). Among all the environmental impact categories, the terrestrial eutrophication had the widest negative environmental effect followed by depletion of phosphate resources in single cropping agro-system with weighted indices of 0.51 and 0.41, respectively. Moreover, the terrestrial eutrophication had the largest negative environmental effect followed by acidification in rice ratooning agro-system with weighted indices of 0.48 and 0.29, respectively. Overall, the results highlighted that the rice ratooning ago-system is more environmentally beneficial than the single cropping system, particularly in terms of depletion of fossil fuels, global warming, and depletion of phosphate and potash resources categories. This priority may be improved through adopting proper management of agronomic practices for main and ratoon rice in ratooning agro-system.