Researches

Irrigated agriculture has important implications for achieving the United Nations Sustainable Development Goals. However, there is a lack of systematic and quantitative analyses of its impacts on food–energy–water–CO2 nexus. Here we studied impacts of irrigated agriculture on food–energy–water–CO2 nexus across food sending systems (the North China Plain (NCP)), food receiving systems (the rest of China) and spillover systems (Hubei Province, affected by interactions between sending and receiving systems), using life cycle assessment, model scenarios, and the framework of metacoupling (socioeconomic-environmental interactions within and across borders). Results indicated that food supply from the NCP promoted food sustainability in the rest of China, but the NCP consumed over four times more water than its total annual renewable water, with large variations in food–energy–water–CO2 nexus across counties. Although Hubei Province was seldom directly involved in the food trade, it experienced substantial losses in water and land due to the construction of the South-to-North Water Transfer Project which aims to alleviate water shortages in the NCP. This study suggests the need to understand impacts of agriculture on food–energy–water–CO2 nexus in other parts of the world to achieve global sustainability.

Nanosized fertilizers are the new frontier of nanotechnology towards a sustainable agriculture. Here, an efficient N-nanofertilizer is obtained by post-synthetic modification (PSM) of nitrate-doped amorphous calcium phosphate (ACP) nanoparticles (NPs) with urea. The unwasteful PSM protocol leads to N-payloads as large as 8.1 w/w%, is well replicated by using inexpensive technical-grade reagents for cost-effective up-scaling and moderately favours urea release slowdown. Using the PSM approach, the N amount is ca. 3 times larger than that obtained in an equivalent one-pot synthesis where urea and nitrate are jointly added during the NPs preparation. In vivo tests on cucumber plants in hydroponic conditions show that N-doped ACP NPs, with half absolute N-content than in conventional urea treatment, promote the formation of an equivalent amount of root and shoot biomass, without nitrogen depletion. The high nitrogen use efficiency (up to 69%) and a cost-effective preparation method support the sustainable real usage of N-doped ACP as a nanofertilizer.

This paper analytically characterizes the four main environmental sustainability paradigms (i.e., WS, weak sustainability; AG, a-growth; DG, de-growth; and SS, strong sustainability) by introducing uncertainty about future preferences for consumption and future technologies. SS represents an ethical approach because of its maximum aversion to inter-generational inequality of resources, whereas DG depicts preference changes, AG depicts technology changes, and WS represents the reference paradigm without accounting for preference or technology changes. By comparing the costs and benefits of these paradigms, solutions derived for the whole parameter domains based on data for a globally representative individual suggest that whenever environmental sustainability is pursued for welfare reasons within a utilitarian perspective (i.e., WS, AG, DG), it is not worth pursuing. In contrast, if environmental sustainability is achieved for ethical reasons within an egalitarian perspective (i.e., SS), it is worth pursuing, even with an increased world population. In terms of feasibility (i.e., whether there are realistic parameter values such that a given sustainability paradigm can achieve its goal), solutions are ranked ethics > preference > technology (i.e., SS > DG > AG), whereas WS is unfeasible. Thus, WS, AG, and DG are inconsistent sustainability paradigms, SS empirically solves the theoretical dispute on absolute rights, and environmental sustainability must be treated as an ethical issue.