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Vegetation restoration is an effective measure to cope with global climate change and promote soil carbon sequestration. However, during vegetation restoration, the turnover and properties of carbon within various aggregates change. The effects of plant source carbon input on surface soil and subsurface soil may be different. Thus, the characteristics of carbon components in aggregates are affected. Therefore, the research object of this study is the Robinia pseudoacacia forest located in 16–47a of the Loess Plateau, and compared with farmland. The change characteristics of organic carbon functional groups in 0–20 cm, 20–40 cm, and 40–60 cm soil layers were analyzed by Fourier near infrared spectroscopy, and the relationship between the chemical structure of organic carbon and the content of organic carbon components in soil aggregates was clarified, and the mechanism affecting the distribution of organic carbon components in soil aggregates was revealed in the process of vegetation restoration. The results show the following: (1) The stability of surface aggregates is sensitive, while that of deep aggregates is weak. Vegetation restoration increased the surface soil organic carbon content by 1.97~3.78 g·kg−1. (2) After vegetation restoration, the relative contents of polysaccharide functional groups in >0.25 mm aggregates were significantly reduced, while the relative contents of aromatic and aliphatic functional groups of organic carbon were significantly increased. The opposite is true for aggregates smaller than 0.25 mm. (3) With the increase in soil depth, the effect of litter on organic carbon gradually decreased, while the effect of root input on the accumulation of inert carbon in deep soil was more lasting. [ABSTRACT FROM AUTHOR]

Cereal + legume rotation is an integrated system that facilitates soil fertility and sustainable agricultural production. However, research on the management compatibility affecting soil physico-chemical properties yields overall agro-ecosystem sustainability, but profitability is lacking, especially under straw retention and potential reductions in fertilizer application. An 11-year field experiment investigated three treatments: no straw retention + traditional mineral fertilization (TNS), straw retention + traditional mineral fertilization (TS), and straw retention + reduced mineral fertilization (DS). Compared with TNS, TS significantly improved soil physico-chemical properties, including macro-aggregates (R > 0.25 mm), porosity, field water capacity (FWC), soil organic carbon (SOC) storage, total nitrogen storage, microbial biomass carbon (MBC), and microbial biomass nitrogen (MBN) by 17.3%, 3.2%, 13.0%, 5.5%, 3.2%, 15.5%, and 13.8%, respectively. TS also significantly increased total (wheat + soybean) yields (TYs), economic profits, and emergy sustainability index (ESI) by 15.8%, 25.0%, 3.7 times that of TNS, respectively. Surprisingly, compared with TS, DS further significantly improved R > 0.25 mm, porosity, FWC, SOC storage, MBC, MBN, TY, economic profits, and ESI by 11.4%, 1.5%, 6.1%, 3.0%, 10.6%, 7.2%, 5.7%, 11.1%, and 36.5%, respectively. Overall, retaining straw with reduced fertilization enhances soil properties, yields, and emergy sustainability in wheat–soybean rotation systems. [ABSTRACT FROM AUTHOR]

In deep-sea mixed transmission mining systems, the mixed transmission hard pipe plays an important role in mineral transport. To speed up the process of connecting the hard pipe, a quick disassembly and assembly system was designed. By model analysis, the key focus of the rapid disassembly and assembly system was the clamp connector. On the basis of vibration theory and finite-element simulations, the connector underwent static and vibration analysis, and the fatigue life was predicted. Finally, laboratory and sea test tests were conducted on the rapid disassembly and assembly system. The quick disassembly and assembly system can realise quick disassembly and assembly under the target working conditions and maintained smooth operation during two 24-h cycle tests. [ABSTRACT FROM AUTHOR]

The appearance of tea leaves is the most intuitive factor in assessing their quality and is an important indicator of the price. The study utilizes machine vision and hyperspectral image technology to develop a rapid method for assessing the appearance quality of seven grades of Dianhong Congou black tea samples based on shape, color, texture, and feature fusion. Using the shape metrics of length, width, perimeter, narrowness, area, and rectangularity, 88 texture values, and nine color values as features, the effectiveness of intelligent recognition algorithms such as support vector machine, random forest, and least squares support vector machine (LSSVM) in classifying single features (shape, color, and texture) and fused data models of the categories of Dianhong tea samples was explored. The results showed that the accuracy of the feature fusion-based appearance quality evaluation models was all higher than the modeling results of the corresponding single features, and the accuracy of the LSSVM model based on the fused data was 100%. This study showed that feature data fusion reflects the external information of tea leaves more comprehensively and that intelligent classification algorithms combined with image analysis techniques were an effective strategy for the identification of regional black tea. [ABSTRACT FROM AUTHOR]

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Mulching and nitrogen (N) fertilization are the main drivers for sustainable crop production. The sole use of nitrogen fertilizer threatened both the physiology and production of maize in rain-fed areas. Therefore, we proposed that wheat straw mulching with N fertilization would increase maize yield by improving soil fertility, physiology, and nitrogen use efficiency. A two-year field study evaluated the effects of CK (control), N (nitrogen application at 172 kg ha−1), HS (half wheat straw mulch, 2500 kg ha−1), HS+N (half wheat straw, 2500 kg ha−1 plus 172 kg N ha−1), FS (full wheat straw, 5000 kg ha−1), and FS+N (full wheat straw, 5000 kg ha−1 plus 172 kg N ha−1) on maize growth, physiology, and biochemistry. Compared with the control, the FS+N treatment resulted in the increase of 56% photosynthetic efficiency, 9.6% nitrogen use efficiency, 60% nitrogen uptake, 80% soluble sugar, 59% starches, 48% biomass, and 29% grain yield of maize. In addition, the FS+N regime increased 47%, 42%, and 106% of soil organic carbon and available P and N content in comparison with the control. Maize grain and biomass yields were positively correlated with N uptake, photosynthesis, soil organic carbon, and soil available N and P contents. Conclusively, the use of wheat straw at 5000 kg ha−1, along with 172 kg N ha−1, is a promising option for building a sustainable wheat–maize cropping system to achieve optimal crop yield and improved plant and soil health in a semi-arid region of China. [ABSTRACT FROM AUTHOR]

China's biogas industry has experienced ups and downs over the past two decades, with various challenges pointing to misplaced expectations that biogas technology is overly focused on energy production. With the promotion of China's low-carbon strategy, a more rational and sustainable transformation strategy is crucial for the development of the biogas industry. To elucidate the sustainable development process of the biogas industry, this study applies the socio-technical transition theory and the strategic niche management (SNM) approach to understand the multi-regime interactions of biogas systems and their possible future paths. At present, the Chinese biogas industry needs to abandon the expectation of energy recovery and establish the expectation of multi-functional combination, especially including nutrient cycling. This study proposes a sustainable transformation path for the biogas industry and predicts three phases based on the type of socio-technological transformation path: a transformation path to 2030 to promote niche innovation and develop core technologies; a reconfiguration path from 2030 to 2050, which will require a lot of trials and errors; and the expansion of market share in 2050 through technology replacement. This study highlights the importance of niche experimentations and broad advocacy coalitions for the biogas industry. This research also illustrates how the transformation of China's biogas industry can be achieved through incremental innovation with consistent policy support. [ABSTRACT FROM AUTHOR]

The taste of tea is one of the key indicators in the evaluation of its quality and is a key factor in its grading and market pricing. To objectively and digitally evaluate the taste quality of tea leaves, miniature near-infrared (NIR) spectroscopy and electronic tongue (ET) sensors are considered effective sensor signals for the characterization of the taste quality of tea leaves. This study used micro-NIR spectroscopy and ET sensors in combination with data fusion strategies and chemometric tools for the taste quality assessment and prediction of multiple grades of black tea. Using NIR features and ET sensor signals as fused information, the data optimization based on grey wolf optimization, ant colony optimization (ACO), particle swarm optimization, and non-dominated sorting genetic algorithm II were employed as modeling features, combined with support vector machine (SVM), extreme learning machine and K-nearest neighbor algorithm to build the classification models. The results obtained showed that the ACO−SVM model had the highest classification accuracy with a discriminant rate of 93.56%. The overall results reveal that it is feasible to qualitatively distinguish black tea grades and categories by NIR spectroscopy and ET techniques. [ABSTRACT FROM AUTHOR]

Anaerobic digestion is a technology that converts complex organic matter into another form of matter, from which energy can be more easily extracted. The stability and digestion of anaerobic co‐digestion with multiple raw materials as substrates is better than the performance of anaerobic mono‐digestion. In the past two decades, there has been a large amount of literature on how to improve the performance of methane production in the anaerobic co‐digestion process, but few systematic reviews have been conducted. This paper summarizes the factors affecting the development of anaerobic co‐digestion. The process parameters, substrate optimization strategy, microbial community, and model application for improving anaerobic co‐digestion performance were systematically analyzed. Methane purification technology and policies to support digestion projects are also discussed. At present, the technological process is basically mature, but the interaction between various parameters can be studied in depth. Methane purification technology expands the market for the biogas industry and increases its economic benefits. Policy is the key to promoting process technology and the methane market. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Straw retention and wheat-soybean rotation play critical role in maintaining soil quality. However, the correlation between bacterial diversity and community structure, and soil nutrients is unknown, and a systematic understanding of their responses to straw retention is lacking. In the field experiment, the straw retention treatments included no straw (NS), half straw (HS), and total straw (TS) retention during long-term wheat-soybean rotation. The mean contents of soil total nitrogen (TN), nitrate-N (NO3−-N), and microbial biomass nitrogen (MBN) increased by 15.06%, 21.10%, and 38.23%, respectively, with straw retention relative to NS, while that of ammonium-N (NH4+-N) reduced by 3.68%. The concentration of carbon components increased as straw retention increased. The levels of soil dissolved organic carbon (DOC), microbial biomass carbon (MBC), and soil organic carbon (SOC) increased by 4.34%, 7.63%, and 9.34%, respectively, with straw retention relative to NS. Soil bacterial alpha diversity was reduced with straw retention. Soil pH and nutrient content were identified as the main factors affecting the soil microbial diversity and structure at the phylum level. Accordingly, straw retention and soybean-wheat rotation enable sustainable agriculture in the dryland of northern China. [ABSTRACT FROM AUTHOR]