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Effects of land-use and climate change on sediment and nutrient retention in Guizhou,China

Ecosystem Health and Sustainability 2020年第1期6卷 185-197,184页

作者： Huiqing Han Jianqiang Yang Geng Ma Yue Liu Linan Zhang Siying Chen Shuliang Ma School of Architecture and Urban Planning Guizhou Institute of TechnologyGuiyangPR China School of Economics and Management Guizhou Institute of TechnologyGuiyangPR China

Introduction:Sediment and nutrient retention have significant impacts on agricultural productivity and water quality.Obvious changes of climate and land-use have deeply affected freshwater ecosystem services in the last several decades.Nevertheless,it is unclear what the differences are in the impact of climate and land-use changes on freshwater ecosystem services.Outcomes:The impacts of climate and land-use change on sediment and nutrient retention(two essential freshwater ecosystem services)were evaluated with the help of the Integrated Valuation of Environmental Services and Tradeoffs(InVEST)model.The results from the study area suggest a decreasing trend in sediment and nutrient retention from 1995 to 2015 when climate and land-use were changed simultaneously.A decreasing trend in sediment retention and an increasing trend in nutrient retention were presented under scenario A(climate change from 1995 to 2015 with land-use unchanged),while the sediment exported and nutrient retention exhibited a decreasing trend except sediment retained under scenario B(land-use change from 1995 to 2015 with unchanged climate).Rainfall erosivity and soil erodibility were more sensitive to the output of sediment retention,while retention efficiency produced more of an effect on nutrient retention.Discussion and Conclusion:Climate change played a dominant role in the change in sediment retention,while land-use change had a more significant effect on nutrient retention change than climate change.The results of this study provide explicitinformation for land-use managers to reduce the negative effects associated with sediment and nutrient retention.

关键词： Climate change land-use change InVEST model nutrient retention scenario analysis sediment retention

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Embedded reservoir and constructed wetland for drinking water source protection:Effects on nutrient removal and phytoplankton succession

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Journal of Environmental Sciences 2020年第1期32卷 260-271页

作者： Changtao Yang Jing Nan Huaiyong Yu Jianhua Li College of Environmental Science and Engineering Tongji University

An embedded reservoir that provides an efficient nutrient removal system protects drinking water.However,embedded reservoirs are rarely used in eutrophic shallow lakes because of their undetermined nutrient retention efficiency and unknown effects by the phytoplankton community.In this study,we aim to investigate the nutrient retention and algae succession in an embedded reservoir and adjacent wetland from April 2017 to September 2018 in the eastern part of Lake Taihu,China.More than 40%of total phosphorus(TP)and 45%of particulate phosphorous entering the reservoir were retained semiannually,and the highest TP removal efficiency was achieved in the reservoir during autumn with an average value of 53.3%±9.9%.The overall nitrogen retention efficiency(21.7%±37.8%)was lower than that of TP(41.8%±27.8%).Similar trends were obtained in the wetland area.An important pathway for phosphorus removal is through particulate matter retention.Our study revealed that nutrient retention mechanisms in the reservoir were primarily via macrophyte absorption,particulate substance sedimentation,and prolonged water residence time.Consequently,the phytoplankton biomass(Chl-a)in the reservoir decreased(from 48.0 to 25.2μg/L)and water transparency improved,due to the decreased P level and transformation of the phytoplankton group into simple structures with good ecological status.Therefore,the combination of embedded reservoir and constructed wetland ecosystem can be used successfully to protect surface water.The results will be advantageous to groups seeking to preserve drinking water sources.

关键词： Drinking water source Eutrophication Embedded reservoir Constructed wetland nutrient retention Phytoplankton succession

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Comparative efficacy of a phytogenic feed additive and an antibiotic growth promoter on production performance, caecal microbial population and humoral immune response of broiler chickens inoculated with enteric pathogens

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Animal Nutrition 2015年第3期1卷 213-219页

作者： Toshi Wati Tapan K.Ghosh Basharat Syed Sudipto Haldar Department of Animal Nutrition Faculty of Veterinary and Animal Sciences West Bengal University of Animal and Fishery Sciences BIOMIN GmbH

The aim of this work was to compare the efficacy of a commercially available phytogenic feed additive(PFA) and an antibiotic growth promoter, which was bacitracin methylene disalicylate(BMD), on performance, nutrient retention, caecal colonization of bacteria and humoral immune responses against Newcastle disease in broiler chickens challenged orally with Salmonella enteritidis and Escherichia coli.One-day-old male Cobb 400 broiler chicks(n = 120) were fed with 1) a negative control(NC) diet, which is the basal diet without any added growth promoter, 2) a positive control(PC) diet, the basal diet supplemented with BMD, 500 mg/kg and 3) a diet supplemented with PFA(150 mg/kg) for 39 days and the birds were inoculated with S. enteritidis and E. coli on d 28. Supplementation of PFA improved body weight, feed conversion ratio, retention of N and crude fiber, increased fecal moisture content and decreased digesta transit time as compared with the NC and PC groups(P <0.01). Both the PC and the PFA was found to be equally effective in controlling the surge in numbers of Salmonella and E. coli following oral inoculation of these bacteria as compared with the NC group(P <0.05) at 24 h past inoculation. Caecal content analysis on d 39 indicated lower numbers of Salmonella, E. coli and Clostridium in the PC and PFA groups as compared with the NC group(P <0.05). The number of Lactobacillus in the PFA group was higher than those in the NC and PC groups(P <0.05). Humoral immune response,measured as hemagglutination inhibition titer against Newcastle disease, was better in the PC and PFA groups compared with the NC group(P <0.05) at d 21 but the difference did not last till d 39. The heterophil to lymphocyte ratio was narrower(P <0.001) and alkaline phosphatase activity was higher(P <0.01) in the PFA group as compared with the NC and PC groups on d 39. It was concluded that the PFA, which is animal, environment and consumer friendly, may be used as an effective replacement for common in-feed antibiotics like BMD to enhance broi

关键词： Broilers Phytogenic feed additives Performance nutrient retention Enteric challenge Intestinal microbiology

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