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A spatial frequency/spectral indicator-driven model for estimating cultivated land quality using the gradient boosting decision tree and genetic algorithm-back propagation neural network

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International Soil and Water Conservation Research 2022年第4期10卷 635-648页

作者： Ziqing Xia Yiping Peng Chenjie Lin Ya Wen Huiming Liu Zhenhua Liu College of Natural Resources and Environment South China Agricultural UniversityGuangzhou510642China

Cultivated land quality(CLQ)is related to national food security.Rapid and high-precision monitoring of CLQ is crucial for the sustainable development of agriculture.However,current satellite image-based evaluation methods that only consider the crop's spatial spectrum characteristics in the key growth stages cannot accurately estimate CLQ.This study proposes a new method based on time-series spectral data of crop growth to improve the accuracy of CLQ estimation.This study was conducted in the Conghua District of Guangzhou,Guangdong Province,China.The results showed that seven spectral indicators were determined as the optimal indicators based on the gradient boosting decision tree(GBDT)and variance inflation factor(VIF).And the genetic algorithm-back propagation neural network(GA-BPNN)model provided more accurate CLQ estimates than the partial least squares regression(PLSR)model,indicating a nonlinear relationship between CLQ and the indicators.In addition,the GA-BPNN model with a normalized root mean square error(NRMSE)of 9.91%demonstrates the excellent potential for mapping CLQ over large areas.The model based on the seven optimal indicators of crop phenology provided higher accuracy than the GA-BPNN model based on the normalized difference vegetation index(NDVI)indicators in the spatial domain,significantly decreasing the NRMSE of the CLQ estimates by 3.17%.This further implied that the spectral indicators in the spatial frequency domain can improve the accuracy of estimating CLQ.

关键词： Cultivated land quality Time-series spectral data Spectral indicators Spatial frequency domain Conghua district

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Biogas residue biochar integrated with phosphate from its ash for the effective recovery of nutrients from piggery biogas slurry

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Biochar 2022年第1期4卷 800-816页

作者： Zifeng Luo Hongping Wen Haotian Zhang Yunliang Li Xueyi Mai Yulong Zhang Jinjin Wang Yongtao Li Zhen Zhang College of Natural Resources and Environment South China Agricultural UniversityGuangzhou 510642China

Magnesium ammonium phosphate(MAP)precipitation generally requires an external phosphorus source to increase the recovery of NH_(4)^(+)-N from biogas slurry.However,P-rich piggery biogas residue has been ignored as a phosphorus source.In this study,biogas residue was carbonized into biogas residue biochar(BRC),followed by acid leaching to synthesize functionalized BRC and release PO_(4)^(3−)-P from its ash as the phosphorus source.The effects of different acids on the leaching efficiency and morphological changes of P in BRC were investigated,and NH_(4)^(+)-N and PO_(4)^(3−)-P in the biogas slurry were recovered with functionalized BRC and MAP precipitation.The results showed that oxalic acid-hydrochloric acid mixed acid could leach more than 96%of P in BRC,while weakening the inhibitory effect of Ca^(2+)on MAP precipitation.The BRC was mainly composed of inorganic P,and most nonapatite IP and apatite P(Ca_(3)(PO_(4))2)were leached during acid leaching,with the latter more easily leached.Under optimal recovery conditions,the method had a significant recovery effect on NH_(4)^(+)-N(96.4%)and PO_(4)^(3−)-P(99.3%)in biogas slurry.The recovery of NH_(4)^(+)-N and PO_(4)^(3−)-P by functionalized BRC was mainly through chemical precipitation(forming NH_(4)MgPO_(4)·H_(2)O precipitate)while bonding with-OH,C=O and C-H functional groups.The final recovery product was also a BRC-based slow-release N-P fertilizer rich in struvite.This study solved the disposal problems of P-rich biogas residue and N-rich biogas slurry while providing an innovative technology for the resource utilization of faecal sewage at pig farms.

关键词： Biogas slurry Biogas residue biochar Phosphorus source Ammonium and phosphorus Simultaneous recovery

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House dust mite allergens and nitrated products: Identification and risk assessment in indoor dust

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Journal of environmental Sciences 2023年第2期124卷 198-204页

作者： Fan Xu Jingyi Tian Fangxing Yang Key Laboratory of environment Remediation and Ecological Health Ministry of EducationCollege of Natural Resources and Environmental ScienceZhejiang UniversityHangzhou 310058China

Air pollutants can potentially lead to nitration of allergic proteins,thus promoting sensitization of these allergens.However,little is currently known about the nitration status of house dust mite(HDM)allergens.We identified the occurrence of nitrated products of two major HDM allergens Der f 1 and Der p 1 in dust samples collected from college dormitories in eastern China and assessed their associated health risk.The results showed that both non-nitrated and nitrated forms of the two allergens were detected in the dust in the range of non-detected(ND)-10.6,1.44-15.4,ND-22.4,ND-7.28μg/g for non-nitrated Der f 1,nitrated Der f 1,non-nitrated Der p 1 and nitrated Der p 1,respectively.The median rates of nitration were determined as 74.0%for Der f 1 and 20.4% for Der p 1 at consideration of one nitration site.Further analysis reveals that the levels of HDM allergens and their nitrated products were found to be generally higher during winter,in dormitories of lower altitude and with female occupants.Furthermore,the calculated risk indexes were at considerably high levels.Our findings suggest that nitrated HDM allergens have already accumulated in the environment at such significant levels and their associated health risk calls for our immediate attention.

关键词： Allergen Air pollution Health risk House dust mite(HDM) Nitration

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Significant loss of soil inorganic carbon at the continental scale

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National Science Review 2022年第2期9卷 13-20页

作者： Xiao-Dong Song Fei Yang Hua-Yong Wu Jing Zhang De-Cheng Li Feng Liu Yu-Guo Zhao Jin-Ling Yang Bing Ju Chong-Fa Cai Biao Huang Huai-Yu Long Ying Lu Yue-Yu Sui Qiu-Bing Wang Ke-Ning Wu Feng-Rong Zhang Ming-Kui Zhang Zhou Shi Wan-Zhu Ma Gang Xin Zhi-Ping Qi Qing-Rui Chang En Ci Da-Gang Yuan Yang-Zhu Zhang Jun-Ping Bai Jia-Ying Chen Jie Chen Yin-Jun Chen Yun-Zhong Dong Chun-Lan Han Ling Li Li-Ming Liu Jian-Jun Pan Fu-Peng Song Fu-Jun Sun Deng-Feng Wang Tian-Wei Wang Xiang-Hua Wei Hong-Qi Wu Xia Zhao Qing Zhou Gan-Lin Zhang college of environmental and Resource Sciences Zhejiang University Institute of Digital Agriculture Zhejiang Academy of Agricultural Sciences college of Agriculture Heilongjiang Bayi Agricultural University Tropical Crops Genetic resources Institute Chinese Academy of Tropical Agricultural Sciences College of Natural Resources and Environment Northwest A & F University college of resources and environment Southwest University college of resources Sichuan Agricultural University college of resources and environment Hunan Agricultural University Institute of Agricultural Product Quality Standard and Testing Research Tibet Academy of Agricultural and Animal Husbandry Sciences School of Agricultural Sciences Zhengzhou University State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Institute of Agriculture environment and resources Research Shanxi Academy of Agricultural Sciences college of resources and environment Henan Agricultural University college of resources and environment China Agricultural University college of resources and environmental Sciences Nanjing Agricultural University college of resources and environment Shandong Agricultural University Agricultural college Guangxi University college of Grassland and environment Science Xinjiang Agricultural University college of Geographical Science Qinghai Normal University Key Laboratory of Watershed Geographic Sciences Nanjing Institute of Geography and Limnology Chinese Academy of Sciences college of Advanced Agricultural Sciences University of Chinese Academy of Sciences college of resources and environment Huazhong Agricultural University Institute of Agricultural resources and Regional Planning Chinese Academy of Agricultural Sciences College of Natural Resources and Environment South China Agricultural University Northeast Institute of Geography and Agroecology Chinese Academy of Sciences college of Land and environment Shenyang Agricultural University School of Land Sc

Widespread soil acidification due to atmospheric acid deposition and agricultural fertilization may greatly accelerate soil carbonate dissolution and CO2release.However,to date,few studies have addressed these processes.Here,we use meta-analysis and nationwide-survey datasets to investigate changes in soil inorganic carbon(SIC) stocks in China.We observe an overall decrease in SIC stocks in topsoil(0-30 cm)(11.33 g C m-2yr-1) from the 1980 s to the 2010 s.Total SIC stocks have decreased by～8.99±2.24%(1.37±0.37 Pg C).The average SIC losses across China(0.046 Pg C yr-1) and in cropland(0.016 Pg C yr-1) account for～17.6%-24.0% of the terrestrial C sink and 57.1% of the soil organic carbon sink in cropland,respectively.Nitrogen deposition and climate change have profound influences on SIC cycling.We estimate that～19.12%-19.47% of SIC stocks will be further lost by 2100.The consumption of SIC may offset a large portion of global efforts aimed at ecosystem carbon sequestration,which emphasizes the importance of achieving a better understanding of the indirect coupling mechanisms of nitrogen and carbon cycling and of effective countermeasures to minimize SIC loss.

关键词： China soil inorganic carbon stocks global change carbonate soil acidification

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Soil surface roughness change and its effect on runoff and erosion on the Loess Plateau of China

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Journal of Arid Land 2014年第4期6卷 400-409页

作者： LongShan ZHAO XinLan LIANG FaQi WU College of Natural Resources and Environment Northwest A&F University

As an important parameter in the soil erosion model, soil surface roughness（SSR） is used to quantitatively describe the micro-relief on agricultural land. SSR has been extensively studied both experimentally and theoretically; however, no studies have focused on understanding SSR on the Loess Plateau of China. This study investigated changes in SSR for three different tillage practices on the Loess Plateau of China and the effects of SSR on runoff and erosion yield during simulated rainfall. The tillage practices used were zero tillage（ZT）, shallow hoeing（SH） and contour ploughing（CP）. Two rainfall intensities were applied, and three stages of water erosion processes（splash erosion（I）, sheet erosion（II） and rill erosion（III）） were analyzed for each rainfall intensity. The chain method was used to measure changes in SSR both initially and after each stage of rainfall. A splash board was used to measure the splash erosion at stage I. Runoff and sediment data were collected continuously at 2-min intervals during rainfall erosion stages II and III. We found that SSR of the tilled surfaces ranged from 1.0% to 21.9% under the three tillage practices, and the order of the initial SSR for the three treatments was ZT〈SH〈CP. For the ZT treatment, SSR increased slightly from stage I to III, whereas for the SH and CP treatments, SSR decreased by 44.5% and 61.5% after the three water erosion stages, respectively, and the greatest reduction in SSR occurred in stage I. Regression analysis showed that the changes in SSR with increasing cumulative rainfall could be described by a power function（R2〉0.49） for the ZT, SH and CP treatments. The runoff initiation time was longer in the SH and CP treatments than in the ZT treatment. There were no significant differences in the total runoff yields among the ZT, SH and CP treatments. Sediment loss was significantly smaller（P〈0.05） in the SH and CP treatments than in the ZT treatment.

关键词： tillage practice soil surface roughness overland flow water erosion Loess Plateau

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Structure and evolution of the submarine cable network of Chinese mainland

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Journal of Geographical Sciences 2022年第5期32卷 932-956页

作者： XIE Yongshun WANG Chengjin HUANG Jie Institute of Geographic Sciences and natural resources Research CASBeijing100101China college of resources and environment University of Chinese Academy of SciencesBeijing100049China

Submarine cable network is one of the most important connectivity infrastructures in the digital era.In the past 20 years,the submarine cable network of Chinese mainland has formed a complex connectivity structure.This paper focuses on exploring the structure and evolution of the submarine cable network of Chinese mainland.The results show that the evolution can be divided into four stages:an initial stage(1993-1998),a developmental stage(1999-2002),a stagnation stage(2003-2015)and an accelerated stage(2016-2018).The connectivity structure can be analyzed at micro,meso and macro scales.Statistically,the connectivity increased significantly overall,but showed significant differences in space.For the microscale,the landing cities were characterized by“extensive but low,exclusive and high”;for the mesoscale,the connectivity of countries or regions was characterized by“distance attenuation”as a whole,but,in part,by a“regional identity”;for the macroscale,intercontinental connectivity differences have been declining.The hierarchy has been upgraded from a“3 system”to a“2+3 system”.Finally,this paper discusses the interaction between submarine cable network construction and international relations,and puts forward policy suggestions for China’s submarine cable construction.

关键词： submarine cable network structure connectivity evolution Chinese mainland

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京津冀城市韧性的时空演变特征及动态模拟研究

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Journal of Geographical Sciences 2022年第9期32卷 1766-1790页

作者：牟旭方方创琳杨智奇 Institute of Geographic Sciences and natural resources Research CASBeijing100101China college of resources and environment University of Chinese Academy of SciencesBeijing100049China

The continuous growth of urban agglomerations in China has increased their complexity as well as vulnerability. In this context, urban resilience is critical for the healthy and sustainable development of urban agglomerations. Focusing on the Beijing-Tianjin-Hebei(BTH) urban agglomeration, this study constructs an urban resilience evaluation system based on four subsystems: economy, society, infrastructure, and ecology. It uses the entropy method to measure the urban resilience of the BTH urban agglomeration from 2000 to 2018.Theil index, standard deviation ellipse, and gray prediction model GM(1,1) methods are used to examine the spatio-temporal evolution and dynamic simulation of urban resilience in this urban agglomeration. Our results show that the comprehensive evaluation index for urban resilience in the BTH urban agglomeration followed a steady upward trend from 2000 to 2018,with an average annual growth rate of 6.72%. There are significant differences in each subsystem’s contribution to urban resilience;overall, economic resilience is the main factor affecting urban resilience, with an average annual growth rate of 8.06%. Spatial differences in urban resilience in the BTH urban agglomeration have decreased from 2000 to 2018, showing the typical characteristic of being greater in the central core area and lower in the surrounding non-core areas. The level of urban resilience in the BTH urban agglomeration is forecast to continue increasing over the next ten years. However, there are still considerable differences between the cities. Policy factors will play a positive role in promoting the resilience level. Based on the evaluation results, corresponding policy recommendations are put forwar to provide scientific data support and a theoretical basis for the resilience construction of the BTH urban agglomeration.

关键词： urban agglomeration urban resilience Beijing-Tianjin-Hebei(BTH) evaluation system gray prediction model

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Mercury bioaccumulation in fish in an artificial lake used to carry out cage culture

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Journal of environmental Sciences 2019年第4期31卷 352-359页

作者： Yongmin Wang Qing Xie Qinqin Xu Jinping Xue Cheng Zhang Dingyong Wang college of resources and environment Southwest University Chongqing Key Laboratory of Agricultural resources and environment

As a global toxic pollutant,mercury(Hg)bioaccumulation within food chain could be influenced by human disturbance.Ten typical fish species were collected from Changshou Lake,an artificial lake used to carry out cage fish culture,to investigate the C/N isotopic compositions and Hg bioaccumulation in fish.The results showed that the total Hg(THg)and methylmercury(MeHg)levels in fish muscles((56.03±43.96)and(32.35±29.57)ng/g,wet weight),comparable with those in most studies in China,were significantly lower than the international marketing limit(0.5 mg/kg).Past human input for cage culture in this lake led to abnormal^(15)N enrichment in food chain,as the quantitative trophic levels based onδ^(15)N were different with that classified by feeding behaviors.This phenomenon subsequently demonstrated that it should be considered thoughtfully with respect to the application of the traditional method for understanding Hg bioaccumulation power by the slope of log_(10)[Hg]withδ^(15)N regression in specific water body(i.e.,Changshou Lake).In addition,no significant linear correlation between Hg and body weight or length of some fish species was observed,suggesting that the fish growth in the eutrophic environment was disproportionate with Hg bioaccumulation,and fish length or weight was not the main factor affecting Hg transfer with food web.The occurrence of human disturbance in aquatic system presents a challenge to a better understanding of the Hg bioaccumulation and biomagnification within the food chain.

关键词： Mercury Methylmercury Human disturbed lake Bioaccumulation N enrichment

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Role of interfacial electron transfer reactions on sulfamethoxazole degradation by reduced nontronite activating H_(2)O_(2)

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Journal of environmental Sciences 2023年第2期124卷 688-698页

作者： Hao-Jie Cui Yaqi Ning CongWu Wei Peng Dong Cheng Lichu Yin Weijun Zhou Wenjuan Liao college of resources and environment Hunan Agricultural UniversityChangsha 410128China college of environment Zhejiang University of TechnologyHangzhou 310014China

It has been documented that organic contaminants can be degraded by hydroxyl radicals(•OH)produced by the activation of H2O2 by Fe(II)-bearing clay.However,the interfacial electron transfer reactions between structural Fe(Ⅱ)and H_(2)O_(2) for•OH generation and its effects on contaminant remediation are unclear.In this study,we first investigated the relation between•OH generation sites and sulfamethoxazole(SMX)degradation by activating H2O2 using nontronite with different reduction extents.SMX(5.2–16.9μmol/L)degradation first increased and then decreased with an increase in the reduction extent of nontronite from 22% to 62%,while the•OH production increased continually.Passivization treatment of edge sites and structural variation results revealed that interfacial electron transfer reactions between Fe(Ⅱ)and H2O2 occur at both the edge and basal plane.The enhancement on basal plane interfacial electron transfer reactions in a high reduction extent rNAu-2 leads to the enhancement on utilization efficiencies of structural Fe(Ⅱ)and H_(2)O_(2) for•OH generation.However,the•OH produced at the basal planes is less efficient in oxidizing SMX than that of at edge sites.Oxidation of SMX could be sustainable in the H_(2)O_(2)/rNAu-2 system through chemically reduction.The results of this study show the importance role of•OH generation sites on antibiotic degradation and provide guidance and potential strategies for antibiotic degradation by Fe(Ⅱ)-bearing clay minerals in H2O2-based treatments.

关键词： Reduced nontronite Electron transfer Sulfamethoxazole degradation Reaction sites Hydroxyl radicals

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Recovery of cyanophycin granule polypeptide from activated sludge: carbon source dependence and aggregation-induced luminescence characteristics

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Frontiers of environmental Science & Engineering 2024年第2期18卷 25-34页

作者： Kui Zou Hongyuan Liu Bo Feng Taiping Qing Peng Zhang college of environment and resources Xiangtan UniversityXiangtan 411105China

In the sewage treatment process,facilitating the conversion of pollutants into value-added resources holds great potential for reducing the amount of greenhouse gas emissions and promoting economic circulation.Cyanophycin granule polypeptide(CGP),a recently discovered high value-added biopolymer present in activated sludge,has provided new avenues for the recovery of resources.However,the mechanisms that regulate CGP synthesis and the characteristics of this biopolymer in activated sludge remain unclear thus far.This study investigated the synthesis of CGP,polyhydroxyalkanoates(PHA),and alginate-like exopolysaccharides(ALE)in various microbial aggregates under different carbon sources feeding conditions.Our results showed that the CGP yields was superior that of PHA and ALE when subjected to identical carbon source feeding conditions.Furthermore,biofilm was more conducive to CGP accumulation than floc sludge.Compared with glucose and methanol,sodium acetate significantly enriched the CGP synthetase-encoding gene(cphAabundance=~17419),resulting in the highest CGP yield(average 107.1 mg/g MLSS)in both biofilm and floc sludge.This study is the first to reported the characteristic fluorescence of CGP(Ex/Em=~360/450 nm)caused by the aggregated luminescence of arginine on the side chains.Overall,this study highlights the potential application of CGP as a fluorescent material and offers insights into CGP recovery from activated sludge in wastewater treatment plants.

关键词： Cyanophycin Polyhydroxyalkanoate Alginate-like exopolysaccharides Bioresource recovery Aggregation-induced luminescence

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