To address global challenges
, 193 countries have committed to the 17 United Nations Sustainable Development Goals (SDGs)
. Quantifying progress towards achieving the SDGs is essential to track ...global efforts towards sustainable development and guide policy development and implementation. However, systematic methods for assessing spatio-temporal progress towards achieving the SDGs are lacking. Here we develop and test systematic methods to quantify progress towards the 17 SDGs at national and subnational levels in China. Our analyses indicate that China's SDG Index score (an aggregate score representing the overall performance towards achieving all 17 SDGs) increased at the national level from 2000 to 2015. Every province also increased its SDG Index score over this period. There were large spatio-temporal variations across regions. For example, eastern China had a higher SDG Index score than western China in the 2000s, and southern China had a higher SDG Index score than northern China in 2015. At the national level, the scores of 13 of the 17 SDGs improved over time, but the scores of four SDGs declined. This study suggests the need to track the spatio-temporal dynamics of progress towards SDGs at the global level and in other nations.
Abstract
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–CO
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nexus. Here we studied impacts of irrigated agriculture on food–energy–water–CO
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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–CO
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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–CO
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nexus in other parts of the world to achieve global sustainability.
•DO concentration and MNBO application period affected tomato and cucumber yield, IWUE and fruit quality.•MNBO application improved soil quality by increasing rhizosphere soil enzyme contents and ...soil microbial species.•15 mg/L and the fruiting stage were the optimal DO concentration and application period of MNBO for tomato and cucumber.
Micro-nano bubble water oxygation (MNBO) has been recognized an effective way to increase crop yield and quality, but the effects and potential mechanism of dissolved oxygen (DO) concentration and application period on crops are unknown yet. Consequently, experiments within two consecutive growing seasons were conducted to determine the effects of two MNBO application period (SF: seeding and flowering stage, FR: fruiting stage) and two DO concentration (15 mg/L and 25 mg/L) on the yield, IWUE, fruit quality of tomato and cucumber as well as the soil quality under two kinds of water source (RW: reclaimed water, GW: groundwater). The results indicated that application of MNBO resulted into higher yield and IWUE of tomato and cucumber compared to no-oxygation treatments (CK) and RW irrigation showed higher production than GW treatments. Significant differences on fruit quality (p < 0.05) were recorded between MNBO application at FR and CK, particularly for vitamin C for two crops and tomato lycopene. DO15 was more effective on yield and quality improvement than DO25. Additionally, MNBO application improved soil quality by increasing rhizosphere soil urease and phosphatase contents and soil microbial species, which promised to stimulate crop root growth and accumulate soil available nutrients. Comprehensive consideration of IWUE, yield and quality, DO15_FR was recommended as the optimal MNBO pattern for greenhouse tomato and cucumber.
Coordination of water saving, yield and quality increase remains an attractive problem in agricultural production. Transporting irrigation water rich in micro-nano bubbles and fertilizers to the crop ...root zone through subsurface drip irrigation is expected to be an effective technique. In present study, cucumber and tomato cultivated in greenhouse were subjected to investigate the effects of three mixing ratios of micro-nano bubble water and groundwater combined with three different oxygation frequencies on irrigation water use efficiency, crop yield and quality. The results indicated that micro-nano bubble water oxygation could significantly increase their yield, irrigation water use efficiency and fruit quality (p < 0.05) without increasing the amounts of irrigation water and fertilizer, which demonstrated a cleaner production being friendly to soil ecological environment and sustainability using water saving technology. In the optimal treatment, the yield, irrigation water use efficiency, vitamin C, and soluble sugar of tomatoes increased by 16.9%, 16.9%, 17.7% and 39.2%, while those for cucumbers were 22.1%, 22.1%, 16.7% and 19.4%, respectively. This was mainly due to the increased soil oxygen content, longer retention time and stronger mass transfer ability of micro-nano bubbles. The recommended micro-nano bubble water oxygation mode for tomato plantation was the mixing ratio of 1:4 combined with the frequency of once every 5d, while that of cucumber being the mixing ratio of 1:0 with the same frequency with tomato. The study aims to provide a novel concept for the synergistic realization of water saving, yield increases and quality improvements in greenhouse crop production using subsurface drip irrigation.
•Oxygaiton achieves water saving, yield increasing and quality improving.•Explaining mechanism of synergistic increase of vegetables yield and quality.•Proposing optimal oxygation pattern for cucumbers and tomatoes.
Climate variability and trends have significant environmental and socioeconomic impacts. Global challenges such as food security, biodiversity loss, water scarcity and human health are affected by ...reference evapotranspiration, temperature, solar radiation, and precipitation together, but nonlinear dynamics of these four climatic factors have not been assessed simultaneously at the national scale. This leads to unclear climatic dynamics and limited applications. To address this knowledge gap, we analyzed the daily variability and trends of four climatic factors (reference evapotranspiration, temperature, solar radiation, and precipitation) in China simultaneously using high spatial resolution data from 1960 to 2013. The results indicate that the daily variability of climate system dynamics (quantified by multiplying fractal dimensions of the four climatic factors) in north China was higher than that in south China. For example, the climate system dynamics were more chaotic and with higher nonlinear variation in north China, most notably in Heilongjiang Province, the major grain base of China, posing threats to food security in the context of growing national population. Spatial distribution of variability varies among different climatic factors. Our study highlights the need for a more holistic study of climate variability and trends in other countries with multiple climate types to address challenges of sustainable development.
The axial compression behaviour of fibre-reinforced polymer (FRP)-confined concrete-core-encased rebar (FCCC-R) was investigated by performing monotonic axial compression tests on seven groups of ...FCCC-R specimens and three groups of pure rebar specimens. The research parameters considered were the FRP winding angle (0°, ±45°, and 90°), number of layers (2, 4, and 6 layers), and slenderness ratio of specimens (15.45, 20, and 22.73). The test results showed that FCCC-R's axial compression behaviour improved significantly compared with pure rebar. The axial load-displacement curves of the FCCC-R specimens had a second ascending branch, and their carrying capacity and ductility were enhanced substantially. The best buckling behaviour was observed for the FRP winding angle of 90°. The capacity and ductility of the specimens were positively related to the number of FRP-wrapped layers and inversely related to the slenderness ratio of the specimens. A finite element model of FCCC-R was constructed and agreed well with the test results. The finite element model was used for parametric analysis to reveal the effect of the area ratio, FRP confinement length, internal bar eccentricity, and mortar strength on the axial compression behaviour of FCCC-R. The numerical results showed that the area ratio had the most significant impact on the axial compression behaviour of FCCC-R. The confinement length of the FRP pipe and internal bar eccentricity had similar effects on the axial compression behaviour of FCCC-R. Both of them had a significant impact on the second ascending branch, with the post-peak behaviour exhibiting minimal differences. The influence of mortar strength on the axial compression behaviour of FCCC-R was observed to be minimal.
Iron is one of the essential elements for crop growth. Traditional iron fertilizer application method by injecting iron into soil results in low utilization efficiency of iron fertilizer and a ...considerable amount of iron residue in the soil. Applying iron fertilizer by drip irrigation system could effectively improve the utilization efficiency of iron fertilizer. However, emitter clogging seriously restrict this technology. Here, the effects of different types of iron fertilizers Ferrous sulfate (FeSO4); Ferric citrate (FC-Fe); Sodium ferric ethylenediamine tetraacetate (EDTA-Fe); And no iron fertilizer (CK) on emitters clogging were assessed. The components of emitter clogging substances were detected through X-ray Diffraction and Fourier Transform Infrared Spectrometer. The results showed that different types of iron fertilizers significantly affected emitter clogging. EDTA-Fe application significantly mitigated emitter clogging, reduced the total amount of clogging substances by 49.6% on average, and increased the emitter flow rate by 21.0%. This is due to EDTA-Fe chelated scaling cations (e.g., Ca2+) in water through its functional groups, thereby reducing the contents of calcite, monohydrate calcite and dolomite. However, FeSO4 and FC-Fe application aggravated emitter clogging, and increased the total clogging substances by 52.3% and 105.8%, respectively. Surprisingly, iron precipitation was not detected in the clogging substances. FeSO4 and FC-Fe aggravated clogging mainly by increasing the formation of particulate fouling (e.g., muscovite) and chemical precipitation (e.g., calcite). This study suggested choosing EDTA-Fe in drip irrigation systems to reduce emitter clogging. The research results are of significance for improving the utilization efficiency of iron fertilizer and promoting the application of iron fertilizer drip irrigation technology.
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•Nanobubbles (NBs) effectively controlled biofouling in irrigation pipelines.•NBs shifted the bacterial communities and reduced their diversities in biofilm.•NBs drastically decreased ...the deposition of mineral precipitation in biofilm.•NBs treatment could provide an eco-friendly solution for biofouling control.
Biofouling poses considerable technical challenges to agricultural irrigation systems. Controlling biofouling with strong chemical biocides is not only expensive and sometimes ineffective, but also contributes to environmental pollution. This study investigated the application of nanobubbles (NBs) on minimizing biofouling in agricultural irrigation water pipelines. Treatment performances were assessed using low concentration bubbles (LCB) and high concentration bubbles (HCB) together with a negative control (CK: no-NBs). 16 s rRNA gene sequencing and X-ray diffraction were used to characterize the microbial community and mineral compositions of biofilms in water emitters. Results demonstrated that NBs effectively mitigated biofouling through reducing fixed-biomass by 31.3−52.1%. A significantly different microbial composition was found in the biofilm community with reduced biodiversity. Molecular ecological network analysis revealed that NBs were detrimental to the mutualistic interactions among microbial species – destabilizing the network complexity and size, which was expressed as decreasing in extracellular polymers and biofilm biomass. Furthermore, NBs significantly decreased the deposition of carbonate, silicate, phosphate, and quartz on the pipe surfaces, leading to reductions of total content of minerals in biofilms. Therefore, this study demonstrated that NBs treatment could be an effective, and eco-friendly solution for biofouling control in agricultural water distribution systems.
Global agricultural trade creates multiple telecoupled flows of nitrogen (N) and phosphorus (P). The flows of physical and virtual nutrients along with trade have discrepant effects on natural ...resources in different countries. However, existing literature has not quantified or analyzed such effects yet. Here we quantified the physical and virtual N and P flows embedded in the global agricultural trade networks from 1997 to 2016 and elaborated components of the telecoupling framework. The N and P flows both increased continuously and more than 25% of global consumption of nutrients in agricultural products were related to physical nutrient flows, while virtual nutrient flows were equivalent to one-third of the nutrients inputs into global agricultural system. These flows have positive telecoupling effects on saving N and P resources at the global scale. Reducing inefficient trade flows will enhance resource conservation, environmental sustainability in the hyper-globalized world.
Reusing reclaimed water through drip irrigation offers an effective way to overcome freshwater scarcity. However, biofilm accumulation in the flow channel of drip emitters is the primary obstacle. So ...far, biofilm development in the emitters remains largely unknown. Here, industrial computed tomography was used to quantify the emitter biofilm developments. Results showed that biofilm typically accumulated in the inlet of the emitter flow channel and decreased toward the flow direction. Biofilm was also typically accumulated in dead areas having low flow velocities, such as edge, corner, and adjacent surface zones in flow channels. The dynamics of the emitter biofilm variation mechanisms were also elucidated. Specifically, particle and nutrient transport appeared to be dominant in shaping the initial biofilm formation (i.e., 5% emitter clogging degree), resulting in biofilm abundant in the inlet of the flow channel. However, it changed the hydraulic conditions in emitter flow channels, increased local water shear stress, which made the biofilm easier to be washed away in the inlet, and caused biofilm to grow faster in the middle and outlet regions of the flow channel at 20% emitter clogging degree. At 50% clogging degree, biofilm in inlet regions grew faster again. Finally, some biofilm control approaches such as water quality management and emitter flow channel structure optimization were proposed. This study provided a better understanding of biofilm formation mechanisms in the emitter flow channels, which is critical for designing appropriate biofilm control technologies and will facilitate the reuse of reclaimed water in agricultural irrigation.
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•The biofilm developments in drip irrigation emitters were visualized and quantified.•The critical regions of biofilm accumulation in the emitter channel were identified.•The dynamics of the emitter biofilm variation mechanisms were elucidated.•Some approaches for controlling the biofilm in the emitter channel were proposed.
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