Water footprint coupled economic impact assessment for maize production in China

Spatiotemporal evolution and decoupling effects of sustainable water resources utilization in the Yellow River Basin: Based on three-dimensional water ecological footprint

Clarifying the spatiotemporal evolution of sustainable water resources utilization (SWU) and its decoupling effects from economic growth (EG) is essential for the effective management of water ecosystems and sustainable development of basins. However, the traditional Ecological Footprint model limits the ability to compare SWU within a basin, and existing studies need to pay more attention to the importance of water renewability in quantifying SWU. Based on the capital flow and capital stock perspectives, this study constructed an evaluation method for SWU and its decoupling effect from EG by combining the three-dimensional Water Ecological Footprint (WEF), sustainable reclassification, and the Tapio model, and explored different types of SWU enhancement strategies. The results indicate that: (1) From 2010 to 2022, the SWU of the Yellow River Basin (YRB) shows a decreasing and then increasing trend and is generally in water ecological deficit, with a lower SWU in the middle and lower reaches. Overall, the per capita WEFsize decreased by 0.73% per year, while the WEFdepth increased by 0.26% per year, the pressure and stress on the SWU of the YRB are still significant. (2) Agricultural freshwater use and domestic greywater discharge dominate the WEF of the basin, and the problem of inversion of the water use structure with the industrial structure is evident. (3) Spatial differentiation within the basin is apparent, and SWU shows a spatial distribution of western strength and eastern weakness, with significant consumption of water capital stock due to insufficient water capital flow as the main reason. (4) Topio decoupling analysis shows that WEF and EG are mainly strongly decoupled, with WEF lagging behind EG; the decoupling relationship between SWU and EG evolves from END-SD-WD, reduces the consumption of water capital stock and increasing water capital flow is a reasonable way to realise its stable strong decoupling. This study is essential for SWU studies of large river basins in arid and semi-arid regions. It provides insights into the sustainable management and rational allocation of water resources in the YRB and other similar basins worldwide.

Growth and yield of maize in response to reduced fertilizer application and its impacts on population dynamics and community biodiversity of insects and soil microbes

In the North China Plain, farmers are using excessive amounts of fertilizer for the production of high-yield crop yield, which indirectly causes pollution in agricultural production. To investigate an optimal rate of fertilizer application for summer maize, the fertilizer reduction experiments with 600 kg/ha NPK (N: P2O5: K2O = 28: 8: 10) as normal fertilizer application (NFA), (i.e., 100F), were conducted successively during 2020 and 2021 to study the effects of reduced fertilizer rates, including 90% (540 kg/ha; i.e., 90F), 80% (480 kg/ha; i.e., 80F), 62.5% (375 kg/ha; i.e., 62.5F) and 50% (300 kg/ha; i.e., 50F) of NFA, on the plant growth of maize, the dynamics of key population abundances and community diversity of insects, and the composition and diversity of microbial community and finally to find out the N-metabolic enzymes' activity in soil. Our findings revealed that the fertilizer reduction rates by 10% - 20% compared to the current 100% NFA, and it has not significantly affected the plant growth of maize, not only plant growth indexes but also foliar contents of nutrients, secondary metabolites, and N-metabolic enzymes' activity. Further, there was no significant alteration of the key population dynamics of the Asian corn borer (Ostrinia furnacalis) and the community diversity of insects on maize plants. It is interesting to note that the level of N-metabolic enzymes' activity and microbial community diversity in soil were also not affected. While the fertilizer reduction rate by 50% unequivocally reduced field corn yield compared to 100% NFA, significantly decreased the yield by 17.10%. The optimal fertilizer application was calculated as 547 kg/ha (i.e., 91.17% NFA) based on the simulation analysis of maize yields among the five fertilizer application treatments, and the fertilizer application reduced down to 486 kg/ha (i.e., 81.00% NFA) with a significant reduction of maize yield. These results indicated that reduced the fertilizer application by 8.83% - 19.00% is safe and feasible to mitigate pollution and promote sustainable production of maize crops in the region.

Towards sustainability: An integrated life cycle environmental-economic insight into cow manure management

Waste management signifies an equilibrium between environmental and economic factors. However, a comprehensive understanding of the integrated life cycle environmental-economic performance of waste management activities remains unclear. To facilitate a systematic linkage between the economic and environmental sectors, a regionalized life cycle assessment-based life cycle costing method was developed based on China's actual status quo. The cow manure utilization was set as an entry point to explored long-term environmental-economic performance of milk production under various manure utilization pathways. The results show that trade-offs were observed between internal and external costs as well as various environmental indicators. The choice of waste utilization is the focal point of environmental-economic trade-offs in the cow raising system. The optimal environmental-economic performance was achieved through the manure fertilizer utilization pathway, yielding a remarkable three-fold increase in marginal environmental benefits. Compared with fertilizer utilization, the manure direct returning to field reduced the carbon footprint by 12% while induced an external cost of $14.3. The wastewater treatment pathway is $ 5.5 lower in internal costs but $ 11.7 higher in external costs than those of fertilizer utilization. Overall, utilizing manure has potential to mitigate the upward trend of carbon footprint and external costs. However, achieving the carbon peak remains a significant challenge. A promising solution is the recycling of straw resources within cropping systems, particularly in hotspot regions (e.g., Inner Mongolia, Heilongjiang, Hebei, and Shandong). A comprehensive analysis of the dynamic interplay between cropping systems and cow raising systems is critical steps towards realizing a carbon-neutral future within the dairy production.

Decoupling of water resources utilization and coordinated economic development in China's Hexi Corridor based on ecological water resource footprint

The rapid growth of population and economy leads to a further increase in demand for water resources. The contradiction between supply and demand of water resources has become the main bottleneck restricting sustainable development of a regional social economy. Accurate measurement of regional water usage and the harmonious balance between water consumption (WC) and economic growth (EG) are the premise of regional high-quality development. Based on this premise, this paper studied the arid oasis region, Hexi Corridor, as the research object; utilized the theory of ecological footprint to calculate the ecological footprint (EFW) and ecological carrying capacity (ECCW) of water resources from 2005 to 2019; and quantitatively analyzed the water utilization situation in Hexi Corridor in the past 15 years. Then, combining with the coordinated development decoupling evaluation model, the connection between WC and EG was evaluated. The main results of this study were as follows: (1) During the study period, EFW has shown a fluctuating downward trend, decreasing from 1.745 in 2015 to 1.588 hm²/person in 2019. The average annual EFW per capita of 10,000 yuan of GDP decreased by 10.18%, which showed that the water resources utilization efficiency was gradually increasing. However, there was still a large water deficit. The average water ecological pressure index was 16.55; water resources were under great pressure. (2) From 2005 to 2019, the relationship between WC and EG experienced stages of strong decoupling-weak decoupling-weak negative decoupling-strong decoupling in Hexi Corridor, and the coordination between the two was gradually strengthened. (3) The decoupling status of the Hexi Corridor cities was gradually optimized. Zhangye was the best and in a stable decoupling state, followed by Wuwei and Jiuquan. The number of decoupling years accounted for 85.7% and 78.6% of the evaluation period, respectively. The cities with poor decoupling status were Jiayuguan and Jinchang, and the number of decoupling years accounted for 71.4% and 57.1%, respectively. This study provides some highlights for the formulation of arid oasis regional water strategy.

Integrated crop-livestock-bioenergy system brings co-benefits and trade-offs in mitigating the environmental impacts of Chinese agriculture

Agricultural bioenergy utilization relies on crop and livestock production, favouring an integrated crop-livestock-bioenergy production model. Yet the integrated system's exact contribution to mitigating various environmental burdens from the crop production system and livestock production system remains unclear. Here we inventory the environmental impacts of each process in three subsystems at both national and regional scales in China, ultimately identifying key processes and impact categories. The co-benefits and trade-offs in nine impact categories are investigated by comparing the life cycle impacts in the background scenario (crop production system + livestock production system) and foreground scenario (integrated system). Freshwater eutrophication is the most serious impact category in both scenarios. Except terrestrial acidification, the mitigation effects on the other eight impact categories vary from 1.8% to 94.8%, attributed to fossil energy and chemical fertilizer offsets. Environmental trade-offs should be deliberated when expanding bioenergy utilization in the identified critical regions.

Environmental footprints of soybean production in China

As a significant protein source for humans and animals, soybean (Glycine max) has experienced a fast growth with the rapid development of population and economy. Despite broad interest in energy consumption and CO2 emissions generated by soybean production, there are few impact-oriented water footprint assessments of soybean production. This study evaluates the fossil energy, carbon, and water footprints of China's soybean production so that key environmental impacts can be identified. To provide reliable results for decision-making, uncertainty analysis is conducted based on the Monte Carlo model. Results show that the impact on climate change, ecosystem quality, human health, and resources is 3.33 × 103 kg CO2 eq (GSD2 = 1.87), 6.18 × 10-5 Species·yr (GSD2 = 1.81), 3.26 × 10-3 Disability-adjusted Life Years (GSD2 = 1.81), and 81.51 $ (GSD2 = 2.28), respectively. Freshwater ecotoxicity is the dominant contributor (77.69%) to the ecosystem quality category, while climate change (85.22%) is the dominant contributor to the human health category. Key factors analysis results show that diammonium phosphate and diesel, and on-site emissions, are the major contributors to the overall environmental burden of soybean production. Several policy recommendations are proposed, focusing on trade structure optimization, efficient resource use, and technological improvements. Such policy recommendations provide valuable insights to those decision-makers so that they can prepare appropriate mitigation policies.

Comprehensive Water Footprint of a University Campus in Colombia: Impact of Wastewater Treatment Modeling

Protection of water resources implies the responsible consumption, and the return of this resource with the best physicochemical conditions. In organizations, water is consumed both directly in their facilities and indirectly in the products or services acquired for their operation, requiring a water accounting based on the life cycle perspective. This study aims to assess the comprehensive water footprint of the main campus of the Technological University of Pereira (Colombia), based on the ISO 14046:2014 standard, and analyze the influence of wastewater treatment. Impacts on water scarcity were evaluated using the AWARE method, while the impacts on human health and ecosystems were evaluated using the ReCiPe method. Specific modeling of the wastewater treatment plants on campus was conducted. A total of 102,670 m³.y^-1 of water scarcity was accounted for. Water consumption per person was 17.8 m³ of which 86.2% corresponded to indirect activities. Similarly, indirect activities were responsible for more than 98% of the impacts on human health and ecosystems, where more than 95% were due to infrastructure construction and 2% due to electricity consumption. Although the wastewater treatment on campus reduced the impact on ecosystems by 14%, if a tertiary treatment was added, these impacts would have a 40% of additional reduction. Efforts in recycling programs were also quantified in 712 m³ of avoided water scarcity for secondary users. The findings suggest focusing actions on sustainable construction and purchases to improve water management in organizations.

An insight into the drag effect of water, land, and energy on economic growth across space and time: the application of improved Solow growth model

Economies that depend on natural resources can experience a resource drag effect when economic growth is limited by constraints on the availability of those resources. Therefore, this study uses panel data and the improved Solow growth model to explore the resource drag effect on China's regional economic growth from 1987 to 2017 and makes innovative contributions to address these four gaps in the previous literature: the resources gap, the consistent measurement gap, the regional gap, and the temporal gap. The empirical results indicate that the resource drag effect reduced China's overall annual economic growth by 0.58% during the study period, with reductions of 1.07%, 0.29%, 0.79%, and 0.46% in the Eastern, Western, Central, and Northeastern regions, respectively. In the meantime, the resources drag effect changed in individual regions and across regions. The results on energy drag are most notable. Policies such as "West-to-East Electricity Transmission" and "West-to-East Gas Transmission" promoted economic growth of the Eastern and Western Region, facilitating continued growth in both regions and attracted the return of labor to the Western region. The results indicate that the policies such as west-to-east energy transfer for helping to even out the economic growth conditions in different regions. Labor force mobility has also been important to alleviate resource dependence of agricultural production in Central regain, while other regions have managed to continually grow through improvements in inefficiency. Also, growth in some regions/provinces continues to depend upon increases in water, land, and energy availability and export. This will become increasingly problematic as the social prices of these inputs rise to account for environmental damage. Therefore, the government should adjust the industrial structure of each region to optimize use of resource endowments, alleviate dependence on natural resources, and achieve sustainable economic development.

Water security assessment with the improvement of modifying the boundary consistency between footprint and provision

Clarifying specific water resources distribution and quantifying water security are vital for sustainable management. There is still unexplored gap regarding security indicators as the linkage between water footprint and availability. This study proposed a dynamic water security assessment framework considering the boundary consistency between green water footprint and provision at multi spatio-temporal scales and applied it to Yalong River Basin (YLRB) of southwest China. Results show: 1) The temporal variation of blue water was stronger than green water. Green water flow exhibited more homogeneous spatial distribution than blue water and green water storage. 2) The hotspots of green water crisis were observed in the middle reach with the higher scarcity/vulnerability. 3) Under anthropogenic disturbance, pastureland exhibited lower green water sustainability with scarcity >1 than forest. 4) Lower green water scarcity denoted the potential for rain-fed agriculture in the southeastern YLRB and higher blue water security indicated the water supply prospect for socioeconomic utilization. This work contributes to ensure water resources sustainable management in eco-socioeconomic nexus.