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total nitrogen and community turnover determine phosphorus use efficiency of phytoplankton along nutrient gradients in plateau lakes

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Journal of Environmental Sciences 2023年第2期124卷 699-711页

作者： Yun Zhang Hucai Zhang Qi Liu Lizeng Duan Qichao Zhou Institute for Ecological Research and Pollution Control of Plateau Lakes School of Ecology and Environmental SciencesYunnan UniversityKunming 650500China

Numerous studies support that biodiversity predict most to ecosystem functioning,but whether other factors display a more significant direct impact on ecosystem functioning than biodiversity remains to be *** investigated 398 samples of the phytoplankton phosphorus resource use efficiency(RUE_(P)=chlorophyll-a concentration/dissolved phosphate)across two seasons in nine plateau lakes in Yunnan Province,*** identified the main contributors to phytoplankton RUEP and analyzed their potential influences on RUEP at different lake trophic *** results showed that total nitrogen(TN)contributed the most to RUEP among the nine lakes,whereas community turnover(measured as community dissimilarity)explained the most to RUEP variation across the two ***,TN also influenced RUEP by affecting *** richness(SR),functional attribute diversity(FAD2),and dendrogram-based functional diversity(FDc)were positively correlated with RUEP in both seasons,while evenness was negatively correlated with RUEP at the end of the rainy *** also found that the effects of biodiversity and turnover on RUEP depended on the lake trophic *** and FAD2 were positively correlated with RUEP in all three trophic *** showed a negative correlation with RUEP at the eutrophic and oligotrophic levels,but a positive correlation at themesotrophic *** had a negative influence on RUEP at the eutrophic level,but a positive influence at the mesotrophic and oligotrophic ***,our results suggested that multiple factors and nutrient states need to be considered when the ecosystem functioning predictors and the biodiversityecosystem functioning relationships are investigated.

关键词： Community turnover Biodiversity Phytoplankton Resource use efficiency Taxonomic diversity total nitrogen

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^137Cs tracing dynamics of soil erosion,organic carbon,and total nitrogen in terraced fields and forestland in the Middle Mountains of Nepal

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Journal of Mountain Science 2016年第10期13卷 1829-1839页

作者： SU Zheng-an XIONG Dong-hong DENG Wei DONG Yi-fan MA Jing PADMA C Poudel GURUNG B Sher Key Laboratory of Mountain Hazards and Earth Surface Processes Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China University of Chinese Academy of Science Belting 100049China College of Water Conservancy and Hydropower Engineering Sichuan Agricultural UniversityYa'an 625014China Central Department of Geography University CampusTribhuvan UniversityKirtipur 8212Nepal

The Middle Mountains is one of the regions of Nepal most vulnerable to water erosion, where fragile geology, steep topography, anomalous climatic conditions, and intensive human activity have resulted in serious soil erosion and enhanced land degradation. Based on the 137 Cs tracing method, spatial variations in soil erosion, organic carbon, and total nitrogen(TN) in terraced fields lacking field banks and forestland were determined. Soil samples were collected at approximately 5 m and 20 m intervals along terraced field series and forestland transects respectively. Mean 137 Cs inventories of the four soil cores from the reference site was estimated at 574.33 ± 126.22 Bq m-2(1 Bq(i.e., one Becquerel) is equal to 1 disintegration per second(1 dps)). For each terrace, the 137 Cs inventory generally increased fromupper to lower slope positions, accompanied by a decrease in the soil erosion rate. Along the entire terraced toposequence, 137 Cs data showed that abrupt changes in soil erosion rates could occur between the lower part of the upper terrace and the upper part of the immediate terrace within a small distance. This result indicated that tillage erosion is also a dominant erosion type in the sloping farmland of this area. At the same time, we observed a fluctuant decrease in soil erosion rates for the whole terraced toposequence as well as a net deposition at the toe terrace. Although steep terraces(lacking banks and hedgerows) to some extent could act to limit soil sediment accumulation in catchments, soil erosion in the terraced field was determined to be serious. For forestland, with the exception of serious soil erosion that had taken place at the top of slopes due to concentrated flows from a country road situated above the forestland site, spatialvariation in soil erosion was similar to the "standard" water erosion model. Soil organic carbon(SOC) and TN inventories showed similar spatial patterns to the 137 Cs inventory for both toposequences investigated.

关键词： Nepal 137Cs inventory Soil erosion/deposition Soil organic carbon total nitrogen

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A Modified HF-Kjeldahl Method for Determining total nitrogen in Soil

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Pedosphere 1997年第4期7卷 375-378页

作者： CHENBIYUN CHENGLILI 等 InstituteofSoilScience ChineseAcademyofSciencesP.O.Box821Nanjing210008（China） InstituteofSoilScienc

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Spatially distributed modelling and mapping of soil organic carbon and total nitrogen stocks in the Eastern Mau Forest Reserve,Kenya

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Journal of Geographical Sciences 2016年第1期26卷 102-124页

作者： Kennedy WERE Bal Ram SINGH ?ystein Bjarne DICK Department of Mathematical Sciences and Technology Norwegian University of Life Sciences Kenya Agricultural and Livestock Research Organisation Kenya Soil Survey Department of Environmental Sciences Norwegian University of Life Sciences

Detailed knowledge about the estimates and spatial patterns of soil organic carbon(SOC) and total nitrogen(TN) stocks is fundamental for sustainable land management and climate change *** study aimed at:(1) mapping the spatial patterns,and(2) quantifying SOC and TN stocks to 30 cm depth in the Eastern Mau Forest Reserve using field,remote sensing,geographical information systems(GIS),and statistical modelling *** is a critical ecosystem offering essential services,but its sustainability is threatened by deforestation and *** revealed that elevation,silt content,TN concentration,and Landsat 8 Operational Land Imager band 11 explained 72% of the variability in SOC stocks,while the same factors(except silt content) explained 71% of the variability in TN *** results further showed that soil properties,particularly TN and SOC concentrations,were more important than that other environmental factors in controlling the observed patterns of SOC and TN stocks,*** stored the highest amounts of SOC and TN(3.78 Tg C and 0.38 Tg N) followed by croplands(2.46 Tg C and 0.25 Tg N) and grasslands(0.57 Tg C and 0.06 Tg N).Overall,the Eastern Mau Forest Reserve stored approximately 6.81 Tg C and 0.69 Tg *** highest estimates of SOC and TN stocks(hotspots) occurred on the western and northwestern parts where forests dominated,while the lowest estimates(coldspots) occurred on the eastern side where croplands had been ***,the hotspots need policies that promote conservation,while the coldspots need those that support accumulation of SOC and TN stocks.

关键词： soil organic carbon total nitrogen carbon sequestration climate change digital soil mapping East-ern Mau

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The enrichments of organic matter and total nitrogen in sediment as affected by relavant factors

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Journal of Geographical Sciences 2004年第4期14卷 495-502页

作者：张兴昌郑纪勇李世清 State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest Sci-tech University of Agriculture and ForestryYangling 712100China

Serious soil erosion has already resulted in degradation of the Loess Plateau of China. Soil erosion is commonly accompanied by extensive soil nutrient loss. Because of enrichment processes,sediment nutrient content is often higher than that of natural soil. The objective of this study is to determine the enrichments of organic matter and total nitrogen in sediment in hilly and gully loess areas on the Loess Plateau of China. Measurements of enrichment ratios (ER) of organic matter (EROM) and total nitrogen (ERTN) in sediment as affected by rainfall, slope gradient, tillage, and fertilization were made in the field under natural rainfall conditions. The results showed that the enrichment of clay in sediment resulted in the enrichment of organic matter (OM) and total nitrogen (TN) in sediment. The averages of sediment clay ER, EROM and ERTN for the various slope gradients were 1.77, 2.09 and 1.61, respectively. The soil erosive module was negatively correlated with EROM and ERTN. Our results indicate that measures to reduce soil erosion, i.e. reducing rainfall erosivity, decreasing soil slope gradient, decreasing fertilizer use, and using level trenches, may increase EROM and ERTN. Both quantity and quality of sediment yield should be considered when implementing erosion control measures.

关键词： sediment organic matter total nitrogen enrichment ratio

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Distribution of Soil Organic Carbon and total nitrogen of the Cultivated Layer under Different Tillage Practices

Distribution of Soil Organic Carbon and Total Nitrogen of th...

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2011 International Conference on New Technology of Agricultural Engineering(ICAE 2011)

作者： Xuekun Hou Heilongjiang Bayi Agricultural University Daqing,China Yaolei Wang,Siwei Jiang Institute of Applied Ecology,Chinese Academy of Sciences Shenyang,China

To evaluate the carbon and nitrogen sequestration capacity of different tillage practices,soil organic carbon and nitrogen concentrations and storages of the cultivated layer under different tillage practices(conventional tillage,no-tillage and fallow)were *** results showed that soil organic carbon under different tillage practices were significantly different among different soil depths and 0-5 cm >5-15 cm>15-30 cm(except for the conventional tillage in booting stage).The concentration of soil organic carbon in no-tillage was higher than that in conventional tillage and *** concentrations of soil total nitrogen were significantly different among different treatments in 5-15 cm of jointing stage and 0-5 cm of booting and ripening stage,and no-tillage >conventional tillage>*** organic carbon storage in the cultivated layer(0-30 cm)was increased by no-tillage practice,but soil nitrogen storage was not affected significantly by tillage *** organic carbon and total nitrogen were negatively correlated with pH,exchangeable K + and Ca 2+.

关键词： no-tillage organic carbon total nitrogen storage

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Variation Dynamics of total nitrogen and Nicotine of Burley Tobacco at Various Growing Stages under Different nitrogen Nutrition Levels

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Agricultural Science & Technology 2012年第11期13卷 2327-2331页

作者：柴家荣云南省烟草农业科学研究院云南玉溪653100

[Objective] This study aimed to investigate the variation dynamics of total nitrogen and nicotine of burtey tobacco at various growing stages under different ni- trogen nutrition levels to provide reference for optimizing fertilization technologies for burley tobacco. [Method] Fresh burley tobacco leaves were collected at various growing stages and dried to measure the content of total nitrogen, protein and nico- tine by using INTEGRAL automated chemical analyzer and analyze the correlation with nitrogen application level. [Result] Regardless of the nitrogen application level, the content of total nitrogen and protein showed a downward trend since root ex- tending stage and reached the minimum at mature stage; the content of nicotine showed an upward trend since early vigorous growing stage and increased to the maximum at mature stage; the content of total nitrogen, protein and nicotine all in- creased after air curing; the content of total nitrogen, protein and nicotine showed positive correlation with nitrogen application level, while total nitrogen/nicotine was negatively correlated. The results indicate that nitrogen level is closely related to the total nitrogen and nicotine of burley tobacco at growing period and post-air curing, rational application of nitrogen is an important measure to regulate the content of total nitrogen and nicotine of tobacco. [Conclusion] This study provides scientific ba- sis for rational fertilization of burley tobacco.

关键词： Burley tobacco nitrogen nutrition Growth period total nitrogen Nicotine

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Spatial distributions of soil nutrients affected by land use,topography and their interactions,in the Loess Plateau of China

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International Soil and Water Conservation Research 2024年第1期12卷 227-239页

作者： Wenxin Zhou Changjia Li Wenwu Zhao Lindsay C.Stringer Bojie Fu State Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijingChina Institute of Land Surface System and Sustainable Development Faculty of Geographical ScienceBeijing Normal UniversityBeijingChina Department of Environment and Geography University of YorkYorkUK York Environmental Sustainability Institute University of YorkYorkUK

Soil nutrient availability and their spatial distributions are strongly related to land use and landscape *** study aims to address the knowledge gap regarding the interaction between these factors and the underlying *** selected five land uses(grassland with Artemisia gmelinii,woodland with Robinia pseudoacacia,shrubland with Caragana korshinskii and Hippophae rhamnoides,and apple orchard with Malus pumila)and nine slope positions across hillslopes in the Loess Plateau,China,to investigate their combined effects on the contents and stocks of soil organic carbon(SOC),total nitrogen(TN)and total phosphorus(TP).Parametric and non-parametric statistical tests were conducted to determine the significant differences in the means or the medians of the soil nutrient *** showed that the SOC and TN contents of shrubland with Caragana korshinskii were statistically significantly greater than those of the grassland(p<0.05).SOC and TN contents generally decreased from the upper slope to the middle slope,and to the foot slope for the grassland,woodland and shrublands,and on the contrary,an increasing trend from the upper slope,to the middle slope,and to the foot slope was identified for the apple *** study highlights that land use,slope position and their interaction have significant effects on the spatial distributions of soil *** provides essential empirical evidence for the identification of the optimal vegetation type and slope positions in land management and vegetation restoration activities.

关键词： Soil organic carbon total nitrogen total phosphorus Slope position Vegetation restoration

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nitrogen removal performance of municipal reverse osmosis concentrate with low C/N ratio by membrane-aerated biofilm reactor

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Frontiers of Environmental Science & Engineering 2018年第6期12卷 49-59页

作者： Xiao Quan Kai Huang Mei Li Meichao Lan Baoan Li Chemical Engineering Research Center School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China State Key Laboratory of Chemical Engineering Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Membrane Science and Desalination Technology Tianjin UniversityTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin300072China

MABR exhibits excellent TN removal performance for treating ROC with low C/N ratio. Operating conditions should be properly controlled to achieve optimal TN removal. Denitrifying bacteria and NOB are proved notably inhibited by high salinity stress. The TN removal rate remains over 70% when the NaCl addition amount is below 20 g/L.

关键词： Membrane-aerated biofilm reactor (MABR) Salinity total nitrogen Reverse osmosis concentrate

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nitrogen removal from summer to winter in a field pilot-scale multistage constructed wetland-pond system

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Journal of Environmental Sciences 2022年第1期34卷 249-262页

作者： Tao Wang Liping Xiao Hongbin Lu Shaoyong Lu Jiaxin Li Xiaochun Guo Xiaoliang Zhao National Engineering Laboratory for Lake Pollution Control and Ecological Restoration State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu(SEPSORSLD)State Environmental Protection Key Laboratory for Lake Pollution ControlState Key Laboratory of Environmental Criteria and Risk AssessmentChinese Research Academy of Environmental SciencesBeijing 100012China School of Environmental and Municipal Engineering Qingdao University of TechnologyQingdao 266033China College of Environmental Science and Engineering Liaoning Technical UniversityFuxin 123000China College of Water Sciences Beijing Normal UniversityBeying 100875China

A pilot-scale multistage constructed wetland-pond(MCWP)system with a"pre-ecological oxidation pond,two-stage horizontal subsurface flow constructed wetland(HSCW)and surface flow constructed wetland(SFCW)as the core and postsubmerged plant pond"as the process was used to treat actual polluted river water in the field,and the variation in nitrogen removal from summer to winter was *** results showed that the average total nitrogen(TN)removal efficiency in the MCWP was approximately 40.74%.The significant positive correlation between the daily highest temperature and the TN removal efficiency of the whole system was fitted with a nonlinear curve(R^(2)=0.7192).The TN removal load rate in the HSCWs was 2.7–3.7 times that in the *** SFCW,which had high-density plants(35 plants/m^(2)),increased the proportion of nitrogen removed by plant harvesting and microbial *** TN transformed by Iris pseudacorus *** for 54.53%in the ***,bacteria completed the nitrogen cycle in the SFCW through a variety of nitrogen removal *** research not only investigated the TN removal performance in an MCWP system but also made it possible to predict the TN removal efficiency according to the daily highest temperature from summer to winter in the field.

关键词： Multistage constructed wetland-pond total nitrogen Air temperature change Emergent plants Polluted surface water

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