An environmental and economic assessment of sustained cleaner production for double rice from the combination of controlled-released urea and water-saving irrigation

Abstract

Controlled-released urea (CRU) and water-saving irrigation are being extensively used to obtain higher rice (Oryza sativa) yields with lower greenhouse gas emissions. However, the environmental impact potential of their combined impacts is still unknown. Two-factor experiments, nitrogen practices with urea and CRU while irrigation practices with conventional irrigation (CI) and alternate wetting-drying water-saving irrigation (AWD), were used to clarify the potential impacts in the Jianghan Plain in China. Life cycle assessment (LCA) methodology was used to examine seven environmental impact categories, including non-renewable energy depletion, global warming potential (GWP), acidification potential, eutrophication potential (EP), human toxicity potential, freshwater toxicity potential (FTP) and soil toxicity potential in addition to an economic assessment. The largest contribution allocated to the comprehensive environmental impact indices included the GWP, EP (>26.28%) and FTP (>62.14%), while the other four indices contributed little, and CRU + AWD had the lowest weighting value (0.7981). The EP was affected by N fertilizer off and on the farm (7% and 68%–71%), nitrous oxide emissions from the planting season and winter fallow (7%–12% and 8%–12%) and the FTP differed slightly among the four treatments. Net ecosystem economic benefits (NEEB) (approximately 15,541 CNY ha−1) and benefit-cost ratio (52%) of CRU + AWD was similar to those of CRU + CI, and were increased by 18%–47% and 11%–41% compared with U + CI and U + AWD, respectively. Trade-off results found the combination of CRU and AWD had the lowest environmental load with a high grain yield, economic benefits and soil organic carbon storage to enable the sustainable production of rice.