Records 1 - 20 / 258
Water allocation under future climate change and socio-economic development : the case of Pearl River Basin
Yan, Dan - \ 2017
Wageningen University. Promotor(en): P. Kabat, co-promotor(en): S.E. Werners; F. Ludwig; H.Q. Huang. - Wageningen : Wageningen University - ISBN 9789463438193 - 140
water allocation - climatic change - socioeconomics - china - watertoewijzing - klimaatverandering - sociale economie - china
Water shortage has become a major challenge in many parts of the world due to climate change and socio-economic development. Allocating water is critical to meet human and ecosystem needs in these regions now and in the future. However, water allocation is being challenged by uncertainties associated with climate change and socio-economic development. This thesis aims to assess the combined effects of climate change and socio-economic development on water supply and demand in the Pearl River Basin (PRB) in China, and identify water allocation plans, which are robust to future climate change and socio-economic development. To do so, the impact of climate change on future water availability is first assessed. Next, different model frameworks are developed to identify robust water allocation plans for improving reservoir management, ensuring sufficient flow into the delta to reduce salt intrusion, and providing sufficient freshwater for human and industrial consumption under future climate change and socio-economic development.
Results show that water availability is becoming more variable throughout the basin due to climate change. River discharge in the dry season is projected to decrease throughout the basin. For a moderate climate change scenario (RCP4.5), low flows reduce between 6 and 48 % depending on locations. For a high climate change scenario (RCP8.5), the decreases of low flows can reach up to 72%. In the wet season, river discharge tends to increase in the middle and lower reaches and decreases in the upper reach of the Pearl River Basin. The variation of river discharge is likely to aggravate water stress. Especially the reduction of low flow is problematic as already the basin experiences water shortages during the dry season in the delta.
The model frameworks developed in this study not only evaluate the performance of existing water allocation plans in the past, but also the impact of future climate change on robustness of previous and newly generated water allocation plans. The performance of the four existing water allocation plans reduces under climate change. New water allocation plans generated by the two model frameworks perform much better than the existing plans. Optimising water allocation using carefully selected state-of-the-art multi-objective evolutionary algorithms in the Pearl River Basin can help limit water shortage and salt intrusion in the delta region. However, the current water allocation system with six key reservoirs is insufficient in maintaining the required minimum discharge at two selected gauge stations under future climate change. More reservoirs, especially in the middle and lower reaches of the Pearl River, could potentially improve the future low flow into the delta.
This study also explored future water shortage in the Pearl River Basin under different water availability and water use scenarios. Four different strategies to allocate water were defined. These water allocation strategies prioritize upstream water use, Pearl River Delta water use, irrigation water use, and manufacturing water use, respectively. Results show that almost all the regions in the Pearl River Basin are likely to face temporary water shortage under the four strategies. The increasing water demand contributes twice as much as the decreasing water availability to water shortage. All four water allocation strategies are insufficient to solve the water scarcity in the Pearl River Basin. The economic losses differ greatly under the four water allocation strategies. Prioritizing the delta region or manufacturing production would result in lower economic losses than the other two strategies. However, all of them are rather extreme strategies. Development of water resources management strategies requires a compromise between different water users. Optimization algorithms prove to be flexible and useful tool in adaptive water resources allocation for providing multiple approximate Pareto solutions. In addition, new technologies and increasing water use efficiency will be important to deal with future water shortage in the Pearl River Basin.
Water use in a heavily urbanized delta : scenarios and adaptation options for sectorial water use in the Pearl River Basin, China
Yao, Mingtian - \ 2017
Wageningen University. Promotor(en): P. Kabat, co-promotor(en): S.E. Werners; R.W.A. Hutjes; Huang Heqing. - Wageningen : Wageningen University - ISBN 9789463438230 - 175
water use - water management - water resources - socioeconomics - salt water intrusion - water deficit - china - watergebruik - waterbeheer - watervoorraden - sociale economie - zoutwaterindringing - watertekort - china
Water use is increasing globally to meet the growing demand for food and industrial products, and the rising living standard. Water scarcity has been reported in many regions, questioning the long-term sustainability of water use. The objective of this thesis is to better understand sectorial water use development in an urbanizing river delta, and to explore the potential of water use management as an adaptation option to reduce water shortage. The Pearl River Basin in Southern China is taken as study area. The upstream part of the basin is one of the poorer regions of China, whereas the Pearl River Delta (PRD) is the world’s largest urban region in both population and area. This study presents the first consistent analysis of sectorial water use in the PRD. Results show that during the period of 2000-2010, the PRD managed to stabilize its annual total water use. Nevertheless, severe salt intrusion induced water shortages occur. Assessment of water use at a monthly resolution shows that water use contributes to salt intrusion by further reducing the already low dry season river discharge.
To investigate the possible future development of water use, this study proposed a method to derive region specific water use scenarios from a global assessment of water use. Scenarios based on regionalised assumptions project substantially lower water use than those based on national assumptions. Nevertheless, hydrological challenges remain for the PRD. The total water use of the PRD may still increase by up to 54% in 2030 in the regionalized scenarios. Also, water use in the upstream regions increases with socio-economic development. To address water shortage, four extreme water allocation strategies were analysed against water use and water availability scenarios under climate change. None of these strategies proved to be sufficient to fully avoid water scarcity in the Pearl River Basin.
This study obtains a better understanding of the sectorial water use development and its impact on salt intrusion induced water shortage in a heavily urbanized river delta. The water use framework and methods used to derive regional water use scenarios are transferable to other regions, provided that data is available. Water use scenarios are crucial to sustainably manage water resources in a changing world.
A blooming business : Identifying limits to Lake Taihu's nutrient input
Janssen, Annette B.G. - \ 2017
Wageningen University. Promotor(en): Wolf Mooij, co-promotor(en): J.H. Janse; A.A. van Dam. - Wageningen : Wageningen University - ISBN 9789463431897 - 268
lakes - freshwater ecology - aquatic ecosystems - nutrients - cycling - nutrient flows - biodiversity - algae - models - critical loads - limnology - spatial variation - ecological restoration - china - meren - zoetwaterecologie - aquatische ecosystemen - voedingsstoffen - kringlopen - nutriëntenstromen - biodiversiteit - algen - modellen - critical loads - limnologie - ruimtelijke variatie - ecologisch herstel - china
Last century, Lake Taihu (China) became serious eutrophic due to excessive nutrient input. During the 1980s, the first algal blooms emerged in the lake, reaching disastrous proportions in 2007. During that year, the intake of drinking water had to be shut down and millions of people had to look for an alternative source of drinking water. This raises the question whether such problems can be avoided. Of crucial importance in avoiding and reducing toxic algal blooms is the identification of the maximum nutrient load ecosystems can absorb, while remaining in a good ecological state. In this thesis, I aim to determine the critical nutrient load for Lake Taihu. I approach the search for critical nutrient loads of Lake Taihu in five steps with diversity as an overarching topic throughout this thesis: diversity in lakes, diversity in models, diversity in spatial distribution of nutrient and water sources, diversity in the development of lakes around the earth and finally diversity within specific lakes. From the long list of available models I chose the model PCLake to use in my analysis because it is the most extensively used food web model applied for bifurcation analysis of shallow aquatic ecosystems. The approach has resulted in a range of critical nutrient loads for different parts of Lake Taihu. Furthermore, critical nutrient loads depend on management goals, i.e. the maximum allowable chlorophyll-a concentration. According to the model results, total nutrient loads need to be more than halved to reach chlorophyll-a concentrations of 30-40 μg.L-1 in most sections of the lake. To prevent phytoplankton blooms with 20 μg.L-1 chlorophyll-a throughout Lake Taihu, both phosphorus and nitrogen loads need a nearly 90% reduction. This range contrasts to the single point of recovery that is often found for small shallow lakes. The range in critical nutrient loads found for Lake Taihu can be interpreted as providing a path of recovery for which each step leads to water quality improvement in certain parts of the lake. To reach total recovery, nutrient reduction seems to be the most promising management option.
China’s grassland policies and the Inner Mongolian grassland system
Liu, Min - \ 2017
Wageningen University. Promotor(en): Wim Heijman, co-promotor(en): J. Huang; Liesbeth Dries; Xueqin Zhu. - Wageningen : Wageningen University - ISBN 9789463430241 - 156
grassland management - livestock farming - china - rural development - policy evaluation - social systems - ecological restoration - sustainable agriculture - mongolia - nei mongol - normalized difference vegetation index - graslandbeheer - veehouderij - china - plattelandsontwikkeling - beleidsevaluatie - sociale systemen - ecologisch herstel - duurzame landbouw - mongolië - nei monggol - genormaliseerd verschil in de vegetatie-index
Grasslands play a significant role in the global ecosystem, livestock production and millions of household livelihoods. However, grassland degradation has become a worldwide problem, and rural poverty has become exacerbated in some pastoral areas. The sustainable management and use of grasslands that maintain the productive and adaptive capacity of ecosystems while providing for the well-being of human communities are crucial concerns. In practice, various policy interventions have been initiated by governments all over the world to devote to grassland conservation, livestock production and improving local household livelihoods. This research aims to evaluate the effectiveness of the policy interventions for grassland ecosystems and livestock production in the pastoral areas of China. The conceptual framework for this research is based on Ostrom’s Social-Ecological Systems (SESs) framework. Four specific research questions are addressed. It is hoped that the research findings of this thesis can make a contribution to providing some references for policy development in light of the sustainable management and use of grasslands.
River export of nutrients to the coastal waters of China: the MARINA model to assess sources, effects and solutions
Strokal, Maryna - \ 2016
Wageningen University. Promotor(en): Carolien Kroeze, co-promotor(en): S. Luan; Lin Ma. - Wageningen : Wageningen University - ISBN 9789462579729 - 226
cum laude - nutrients - rivers - coastal water - models - eutrophication - coastal areas - water pollution - china - voedingsstoffen - rivieren - kustwateren - modellen - eutrofiëring - kustgebieden - waterverontreiniging - china
Rivers export increasing amounts of nitrogen (N) and phosphorus (P) to the coastal waters of China. This causes eutrophication problems that can damage living organisms when oxygen levels drop and threaten human health through toxic algae. We know that these problems result from human activities on land such as agriculture and urbanization. However, the relative importance of these human activities for river export of nutrients to Chinese seas is not well studied. There are two important issues that need further investigation: the relative importance of upstream pollution on downstream impacts and the relative importance of typical sources of nutrients in Chinese rivers that are often ignored in existing modeling studies.
My PhD thesis, therefore, aims to better understand trends in river export of nutrients to the coastal waters of China by source from sub-basins, and the associated coastal eutrophication. To this end, I developed the MARINA model: Model to Assess River Inputs of Nutrients to seAs. For this, I used the existing Global NEWS-2 model (Nutrient Export from WaterSheds) as a starting point.
I formulated five sub-objectives to achieve the main objective:
To analyze the original Global NEWS-2 model for river export of nutrients and the associated coastal eutrophication (Chapter 2);
To develop a sub-basin scale modeling approach to account for impacts of upstream human activities on downstream water pollution, taking the Pearl River as an example (Chapter 3);
To quantify the relative share of manure point sources to nutrient inputs to rivers at the sub-basin scale (Chapter 4);
To quantify the relative share of sources to river export of nutrients at the sub-basin scale (Chapter 5);
To explore optimistic futures to reduce river export of nutrients and coastal eutrophication in China (Chapter 6).
The study area includes rivers draining roughly 40% of China. This includes the most densely populated areas, and areas with intensive economic activities. The rivers include the Yangtze (Changjiang), Yellow (Huanghe), Pearl, Huai, Hai and Liao. In the MARINA model, the drainage areas of the large Yangtze, Yellow and Pearl rivers are divided into up-, middle- and downstream sub-basins. The principle of the sub-basin approach of MARINA is that nutrients from human activities are transported by tributaries to outlets of sub-basins and then to the river mouth (coastal waters) through the main channel. The model takes into account nutrients that are partly lost or retained during transport towards the river mouth. The model quantifies river export of nutrients by source from sub-basins for 1970, 2000 and 2050.
The main six findings of the MARINA results for China are:
Finding 1: Dissolved N and P export by Chinese rivers increased by a factor of 2-8 between 1970 and 2000;
Finding 2: The potential for coastal eutrophication was low in 1970 and high in 2000 in China;
Finding 3: Most dissolved N and P in Chinese seas is from middlestream and downstream human activities;
Finding 4: Manure point sources are responsible for 20-80% of dissolved N and P in Chinese rivers;
Finding 5: In the future, river export of nutrients may increase in the Global Orchestration (GO) scenario of the Millennium Ecosystem Assessment. Current policy plans (CP scenario) may not sufficient to avoid this increase;
Finding 6: In optimistic scenarios (OPT-1 and OPT-2), the potential for coastal eutrophication is low in 2050, mainly as a result of assumed full implementation of: (1) high recycling rates of animal manure (OPT-1 and OPT-2), and (2) high efficiencies of nutrient removal in sewage systems (OPT-2, see Figure 1).
Figure 1. Illustration of future scenarios for coastal water quality in China. GO is Global Orchestration of the Millennium Ecosystem Assessment and assumes environmental actions that are either absent or ineffective in reducing water pollution. CP is based on GO, but incorporates the “Zero Growth in Synthetic Fertilizers after 2020” policy. OPT-1 and OP-2 are optimistic scenarios that assume high nutrient use efficiencies in agriculture (OPT-1, OPT-2) and sewage (OPT-2).
My PhD thesis reveals novel insights for effective environmental policies in China. It shows the importance of manure point sources in water pollution by nutrients. Clearly, managing this source will likely reduce coastal eutrophication in the future. Furthermore, the implementation of advanced technologies is essential when dealing with urban pollution. My PhD thesis may also be useful for other world regions with similar environmental problems as in China. The new, sub-basin scale MARINA model is rather transparent and thus can be applied to other large, data-poor basins that may benefit from the allocation of effective management options. With this I hope to contribute to future availability of sufficiently clean water for next generations, not only in China, but also in other world regions.
Pesticide use and off-site risk assessment : a case study of glyphosate fate in Chinese Loess soil
Yang, X. - \ 2016
Wageningen University. Promotor(en): Coen Ritsema; Violette Geissen, co-promotor(en): Hans Mol; Fei Wang. - Wageningen : Wageningen University - ISBN 9789462576759 - 152
pesticides - risk assessment - pesticide residues - glyphosate - loess soils - soil pollution - erosion - china - pesticiden - risicoschatting - pesticidenresiduen - glyfosaat - lössgronden - bodemverontreiniging - erosie - china
Pesticide use and off-site risk assessment: a case study of glyphosate fate in Chinese Loess soil
Abstract: Repeated applications of pesticide may contaminate the soil and water, threatening their quality within the environmental system and beyond it through water erosion related processes and leaching. Taking into account the situation of intense farming, pesticide use and erosion in China, and in the loess area in particular, this study aims to further the science of pesticide risk assessment by increasing the understanding of the fate of glyphosate and its main metabolite AMPA while also assessing their risks related to soil erosion in Chinese loess soil. Four main objectives are conducted:
1) Assessment of farmers’ knowledge and awareness of pesticide use in the Wei River catchment
In this study, we presented the information for the knowledge and awareness of pesticide risks via face-to-face interview among farmers (209) and retailers (20) in two rural regions (Qianyang County (S1) and Chencang County (S2)) of the Wei River catchment in China where the modes of farming and the state of erosion are very different. The results showed that farmers learned about the use and risk related to of pesticide use mainly by oral communication (p<0.01), rather than by introduction labelled on pesticide package bag/bottle and media tools (TV/newspaper/Internet/books). Protective measures were inadequate and washing hands (>70%) was the most common mode of personal hygiene after spraying, comparing to wearing masks, showering, and changing clothes. Regarding to dealing with the packages or containers of pesticide, farmers dumped them directly onto the land or into water, and over 85% of farmers claimed to use illegal pesticides. Compared to farmers, pesticide retailers were well-informed and highly conscious of their responsibility for the safe use of pesticides. Educational programmes targeted to age groups, proper disposal of pesticide waste, and sufficient supervision from authorities should consequently be considered for improving the levels of knowledge and awareness of the dangers of pesticides to human health and environmental pollution in the Wei River catchment, China.
2) Investigation of off-site transport of glyphosate and AMPA by runoff and erosion in Chinese loess soil
In this study, we assessed the short-term transport (1h duration, 1 mm min-1 rainfall) of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) related to erosion and runoff on bare loess soil with different slopes (10° and 20°)and application rates (3.6 kg ha-1 and 7.2 kg ha-1) in hydraulic flumes. Significant power and exponent function described a significantly negative relation between rainfall duration and the content of glyphosate and AMPA (p<0.01) in runoff and suspended load, respectively. The transport rate of glyphosate (including AMPA) by runoff and suspended load was approximately 4% and 10% of the applied amount, respectively indicating that it mainly underlies particulate transport. The glyphosate and AMPA content in the flume soil at the end of the experiment (after 1h) decreased significantly with depth (p<0.05), and 72, 2, and 3% of the applied glyphosate (including AMPA) remained in the 0-2, 2-5, and 5-10 cm soil layers, respectively. Thus, the risk of leaching was low. In view of loss of 14 % of the initially applied glyphosate after 1 h, “buffer zone”, referred as the protection area for ecosystem discharge between farming land and public rivers, is strongly recommended, especially in regions where rain-induced soil erosion is common.
3) Investigation of the on-site fate of glyphosate and AMPA formation in Chinese loess soil
In this study, we observed glyphosate decay, erosion and runoff related transport of glyphosate and AMPA at different slopes (10° and 20°) and application rates (3.6 kg ha-1 and 7.2 kg ha-1) under field condition during 35 d, September-October in 2012 (16.8±2.1°C with 35 mm rainfall in total) and July-August in 2013 (27 ± 2.3°C with 74 mm rainfall in total). The initial glyphosate decayed rapidly (half-life of 3.5 d) in the upper 2 cm of soil following a first-order rate of decay. AMPA content in the 0-2 cm soil layer correspondingly peaked 3 d after glyphosate application and then gradually decreased. The residues of glyphosate and AMPA decreased significantly with soil depth (p<0.05) independently of the slope inclination and application rate. About 0.36% of the glyphosate initially applied was transported off-site plots after one erosive rain 2 days after the application. Glyphosate and AMPA concentration in runoff were low while the contents in the sediment was much higher than in the upper 2 cm of the soil. This suggested that even though the transported glyphosate is limited, the off-site risk of glyphosate and AMPA is high. Consequently, a realistic erosion-pesticide model should be developed that can simulate the particulate-facilitated transport of glyphosate and its off-site risks involving decay processes.
4) Off-site risk assessment of particle-facilitated pesticide transport related to erosion
In this study, we have developed a parsimonious integrative model of pesticide displacement by runoff and erosion that explicitly accounts for water infiltration, erosion, runoff, and pesticide transport and degradation in soil. The conceptual framework was based on broadly accepted assumptions such as the convection-dispersion equation and lognormal distributions of soil properties associated with transport, sorption, degradation, and erosion. To illustrate the concept, a few assumptions are made with regard to runoff in relatively flat agricultural fields: dispersion is ignored and erosion is modelled by a functional relationship. A sensitivity analysis indicated that the total mass of pesticide associated with soil eroded by water scouring increased with slope, rain intensity, and water field capacity of the soil. The mass of transported pesticide decreased as the micro-topography of the soil surface became more distinct. The timing of pesticide spraying and rate of degradation before erosion negatively affected the total amount of transported pesticide. The mechanisms involved in pesticide displacement, such as runoff, infiltration, soil erosion, and pesticide transport and decay in the topsoil, were all explicitly accounted for, so the mathematical complexity of their description can be high, depending on the situation.
Overall, the outcome of this study indicates that it is urgent to improve farmers knowledge and awareness on pesticide use in order to reduce pesticide risks before they are applied in environmental system. The rapid decay of glyphosate to AMPA in loess soil suggests that on-site risks of glyphosate is mainly related to AMPA, especially under warmer climatic conditions. The off-site transport of glyphosate in our study was about 14% of the applied dose after 1 h of rainfall indicating that the off-site risks of glyphosate should be taken into account in regions highly prone to soil erosion. The concept of particulate transport elaborated in objective 4 should be incorporated in existing erosion models, such as LISEM, to predict off-site effects of glyphosate applications.
Spoor naar China wacht op exporteurs
Zhang, Xiaoyong - \ 2016
long distance transport - transport - exports - agricultural products - china - rail transport - logistics
Zonde, al die treinen die vanuit Europa halfleeg terugkeren naar China, dacht Xiaoyong Zhang van Wageningen UR. China vormt namelijk een grote afzetmarkt voor Nederlandse zuivelproducten, groente, fruit en bloemen. Vervoer over de Nieuwe Zijderoute is sneller dan over zee en goedkoper dan door de lucht.
Wild geese of the Yangtze River : their ecology and conservation
Zhang, Y. - \ 2016
Wageningen University. Promotor(en): Herbert Prins; Fred de Boer; L. Cao. - Wageningen : Wageningen University - ISBN 9789462576049 - 147
geese - anatidae - anser - animal ecology - wildlife management - nature conservation - hydrology - habitat selection - rivers - china - ganzen - anatidae - anser - dierecologie - wildbeheer - natuurbescherming - hydrologie - habitatselectie - rivieren - china
Habitat selection is a process in which organisms decide to choose a suitable site for nesting, roosting or foraging. The question where the organisms are, and when they will leave are two of the fundamental questions frequently asked by ecologists. Habitat selection is affected by various abiotic and biotic determinants, varying over different spatial and temporal scales. In addition, an animal’s body size, determining its daily demands and its digestion capacity, plays an important role in foraging and habitat selection. This is because forage quality often decreases with increasing forage quantity. Therefore, herbivores often face a trade-off between forage quality and quantity. Although studies on habitat selection have offered substantial insights into the effect of various ecological factors, myriad effects of habitat and its’ surrounding are still not clearly understood, as former studies concerning this topic normally focus on a single species or a single spatial scale.
Migrating goose species are herbivorous with more or less similar habitat requirements and hence often mix in the field. Studying habitat selection of different goose species is attractive as they are from the same guild but differ in body size. In this thesis, I study the effects of various variables on habitat selection of different Anatidae species over different spatial scales, answering the question how ecological and anthropogenic variables affect Anatidae species habitat selection and population sizes and if these effects vary over different spatial scales.
First, I studied the habitat selection of Anatidae species under the condition with and without interference competition using an experimental approach in Chapter 2. To do this, I offered geese and ducks foraging patches with various swards heights. My results showed that all three species acquired the highest nitrogen intake at relatively tall swards (on 6 or 9 cm, but not on 3 cm) when foraging in single species flocks in the functional response experiment. When they were offered foraging patches differing in sward height with and without competitors, their mean percentage of feeding time did not change, whereas all species increased their percentage of time being vigilant except for the dominant swan goose. All species utilized strategies that increased their peck rate on patches across different sward heights when foraging together with other species, resulting in the same instantaneous and nitrogen intake rate than when foraging in a single species flocks. My results suggest that variation in peck rate over different swards height permits Anatidae herbivores to increase nitrogen intake under competition to compensate for the loss of intake, illustrating the importance of behavioural plasticity in heterogeneous environments when competing with other species for resources.
In Chapter 3, using a correlative field study, I analysed the habitat selection of two differently sized grazing goose species at site level. I found that both species selected lower lying area where the swards became recently exposed, due to receding water levels. However, the smaller species was more sensitive to this elevation gradient. Moreover, sward height negatively affected both species habitat selection with a stronger effect on the smaller species. This result highlighted the importance of body size on facilitating species coexistence and habitat segregation. Not in agreement with the results from most experimental studies, I found that nitrogen content did not influence habitat selection of both species. This conflicting result suggests that additional factors should be carefully considered when applying outcomes from experimental studies to field situations.
In Chapter 4, I studied habitat selection of the two goose species at a lake level by analysing the effect of ecological and anthropogenic variables. My results supported the individual-area relationship as only patch area had a significant effect on both species habitat selection, and other variables that were related to food availability and disturbance, were not significant. In addition, a facilitation effect of grazing livestock on geese habitat selection was detected, indicating that larger grazing herbivores can facilitate geese foraging by removing the taller and lower quality food from the top. As patch area size in wetlands is directly linked to water levels fluctuations, this result demonstrated that modifying hydrological regimes can enlarge the capacity of wetlands for migratory birds.
In Chapter 5, I further expanded my study area to the flood plain level of the Yangtze, testing for the effect of various abiotic and biotic variables on several Anatidae species habitat selection and population trends. I showed that slope and climate factors were the most important ones affecting habitat selection and distribution of Anatidae species. Furthermore, I demonstrated that the current protection policies may not stop the declining population trends but might buffer to some extent against a rapid decline in numbers in wetlands with a higher level protection status. This result points out that the conservation effectiveness is still low and larger conservation efforts are urgently needed to maintain the Anatidae populations, especially in wetlands with a lower level protection status. I recommend several protection measures to stop the decline of Anatidae species in wetlands of the Yangtze River flood plain and I called for more research efforts in this area in particularly, but also at a larger scale, the entire East Asian-Australasian Flyway.
In Chapter 6, I synthesized these results and draw conclusions from the preceding chapters, and highlighted the importance of spatial scales when studying the effect of abiotic and biotic variables on animals’ habitat selection. I also propose to modify hydrological regimes, aimed at creating enhanced habitat and improved forage accessibility conditions over the entire wintering period for herbivorous birds species in the Yangtze River flood plain. In summary, this thesis offers a framework for the effects of various variables on habitat selection and population sizes of herbivorous Anatidae species over different spatial scales, and a scientific basis for policy-makers and managers to enhance the efficiency of conservation actions in wetlands along the Yangtze River flood plain and also for similar ecological systems.
From freight trains to cold chains : Building China's new supply chains for fresh food
Bosch, P. ; Zhang, Xiao Yong ; Chew, Ping ; Pan, Chenjun ; Sawyer, Wil ; Chiang, Lief ; Fan, Ning - \ 2015
Wageningen UR - 55
fresh products - supply chain management - refrigerated transport - logistics - rail transport - china - verse producten - ketenmanagement - koeltransport - logistiek - railtransport - china
Agrofood-trein naar China
Guiking, K. ; Zhang XiaoYong, Xiaoyong - \ 2015
Resource: weekblad voor Wageningen UR 10 (2015)6. - ISSN 1874-3625 - p. 4 - 4.
china - voedingsmiddelen - bloemen - transport - railtransport - agro-industriële sector - nederland - china - foods - flowers - transport - rail transport - agroindustrial sector - netherlands
Transport van voedingsmiddelen en bloemen van Nederland naar China kan goed via het spoor, zegt LEI-onderzoeker Xiaoyong Zhang. Ze presenteerde haar bevindingen op 28 oktober aan een handelsdelegatie in China, met toehoorders als de Rotterdamse burgemeester Ahmed Aboutaleb en koning Willem-Alexander.
Phylogenetic analysis of highly pathogenic avian influenza A (H5N8) virus outbreak strains provides evidence for four separate introductions and one between-poultry farm transmission in the Netherlands, November 2014
Bouwstra, R.J. ; Koch, G. ; Heutink, C.G. ; Harders, F.L. ; Spek, A. van der; Elbers, A.R.W. ; Bossers, A. - \ 2015
Eurosurveillance 20 (2015)26. - ISSN 1025-496X
mitochondrial-dna - a viruses - sequence - amplification - china - h5
Phylogenetic analysis of highly pathogenic avian influenza A(H5N8) virus strains causing outbreaks in Dutch poultry farms in 2014 provides evidence for separate introduction of the virus in four outbreaks in farms located 16–112 km from each other and for between-farm transmission between the third and fourth outbreak in farms located 550 m from each other. In addition, the analysis showed that all European and two Japanese H5N8 virus strains are very closely related and seem to originate from a calculated common ancestor, which arose between July and September 2014. Our findings suggest that the Dutch outbreak virus strain ‘Ter Aar’ and the first German outbreak strain from 2014 shared a common ancestor. In addition, the data indicate that the Dutch outbreak viruses descended from an H5N8 virus that circulated around 2009 in Asia, possibly China, and subsequently spread to South Korea and Japan and finally also to Europe. Evolution of the virus seemed to follow a parallel track in Japan and Europe, which supports the hypothesis that H5N8 virus was exchanged between migratory wild waterfowl at their breeding grounds in Siberia and from there was carried by migrating waterfowl to Europe.
Daqu : a traditional fermentation starter in China: microbial ecology and functionality
Zheng, X. - \ 2015
Wageningen University. Promotor(en): Marcel Zwietering; E.J. Smid, co-promotor(en): Rob Nout. - Wageningen : Wageningen University - ISBN 9789462572805 - 175
fermentatieproducten - fermentatie - optimalisatie - starterculturen - micro-organismen - kwaliteit - china - fermentation products - fermentation - optimization - cultured product starters - microorganisms - quality - china
Fermented products have high nutritional value and constitute an important part of the Chinese dietary profile; they are also gaining popularity throughout the world. Daqu is a traditional natural fermentation starter culture that has a significant impact on the quality and flavour of Chinese liquor and vinegar.
A review of the literature was conducted focusing on the classification, composition, and manufacture of Daqu. The review provided a preliminary understanding of the link between the fermentation process and the characteristics of the final Daqu product. Then the occurrence, levels, and diversity of microorganisms were studied in different types of Daqu produced by various fermentation processes. The results showed that Bacillus licheniformis and Saccharomycopsis fibuligera were present in all the tested samples of Daqu. Regional comparisons showed Staphylococcus gallinarum and Staphylococcus saprophyticus in southern Daqu. The fungi Sm. fibuligera and Lichtheimia ramosa were found in low/medium-temperature Daqu and Thermomyces lanuginosus occurred in high-temperature Daqu.
In order to study the functionality of Daqu and the contribution of the predominant microorganisms to alcoholic fermentation, the mesophilic and thermophilic bacteria and spores, Enterobacteriaceae, lactic acid bacteria, yeasts, and moulds present in the core and outer portions of Fen-Daqu were isolated. The isolates were identified by culture-dependent sequencing of rRNA genes (16S rRNA for bacteria; 18S rRNA, 26S rRNA, and ITS rRNA for fungi). A succession of fungi, lactic acid, and Bacillus spp. was associated with prevailing acidity, moisture content, and temperature during Daqu fermentation. The predominant species in fermentation were B. licheniformis, Pediococcus pentosaceus, Lactobacillus plantarum, Pichia kudriavzevii, Wickerhamomyces anomalus, Sacchromyces cerevisiae, and Sm. fibuligera.
One strain of the each of the above-mentioned predominant species, with the highest starch degrading ability and alcohol tolerance, was selected and used in different combinations to perform alcoholic fermentation. Metabolite composition differed significantly between various fermentation trials. S. cerevisiae provided superior ethanol production. Sm. fibuligera and B. licheniformis provided the amylolytic activity that converted starch and polysaccharides into fermentable sugars. Finally, W. anomalus was found to be an important contributor to formation of the liquor aroma.
Understanding the microbial diversity and functional activity, as well as the production dynamics and safety of Daqu will enable commercial producers to improve and/or scale-up traditional processes and enhance product quality and safety, thus facilitating entry into international markets.
Empty pockets, empty ponds? Disadoption of water harvesting technologies in Ethiopia
Wakeyo, M.B. ; Gardebroek, C. - \ 2015
Journal of Arid Environments 120 (2015). - ISSN 0140-1963 - p. 75 - 86.
supplemental irrigation - agricultural extension - semiarid region - adoption - systems - productivity - africa - impact - china - soil
This study analyses disadoption of water harvesting technologies in Ethiopia where the average disadiption rate in the sample areas is as high as 42%. Given that Ethiopia is a drought-prone country with 95% of its crop production being rain-fed, such a high disadoption rate for irrigation technologies is surprising and urges investigation. Using panel data on 332 Ethiopian farm households collected in 2005 and 2010 we estimate a logit model to identify factors underlying disadoption. We find farm-household, economic, technology-specific, and natural condition variables that relate to disadoption. Mainly, shortage of plastic-sheets, altitude, and distance to market increase disadoption whereas education, experience with water harvesting (learning-by-doing), farm profit, availability of family labour, access to credit, ease of selling output, growing perennial crops, and distance from natural water sources decrease the probability of disadiption. There is no evidence that malaria has a significant effect on disadoption. Based on these findings, improved supply of plastic sheets and motor pumps, and advise to afmers on appropriate crops, credit and improved market accesses could ontribute to decreasing disadoption of water harvesting technologies.
Mobile dune fixation by a fast-growing clonal plant: a full life-cycle analysis
Werger, M.J.A. ; During, H.J. ; Zuidema, P.A. - \ 2015
Scientific Reports 5 (2015). - ISSN 2045-2322 - 7 p.
integral projection models - inner mongolian dune - comparative demography - population-dynamics - psammochloa-villosa - relative importance - hedysarum-laeve - desert cactus - china - growth
Desertification is a global environmental problem, and arid dunes with sparse vegetation are especially vulnerable to desertification. One way to combat desertification is to increase vegetation cover by planting plant species that can realize fast population expansion, even in harsh environments. To evaluate the success of planted species and provide guidance for selecting proper species to stabilize active dunes, demographic studies in natural habitats are essential. We studied the life history traits and population dynamics of a dominant clonal shrub Hedysarum laeve in Inner-Mongolia, northern China. Vital rates of 19057 ramets were recorded during three annual censuses (2007–2009) and used to parameterize Integral Projection Models to analyse population dynamics. The life history of H. laeve was characterized by high ramet turnover and population recruitment entirely depended on clonal propagation. Stochastic population growth rate was 1.32, suggesting that the populations were experiencing rapid expansion. Elasticity analysis revealed that clonal propagation was the key contributor to population growth. The capacity of high clonal propagation and rapid population expansion in mobile dunes makes H. laeve a suitable species to combat desertification. Species with similar life-history traits to H. laeve are likely to offer good opportunities for stabilizing active dunes in arid inland ecosystems.
Progress Report China Potato GAP project; Late blight control, seed quality, storage facilities and sustainability studies in Heilongjiang province and communications
Kempenaar, C. ; Kessel, G.J.T. ; Wustman, R. ; Pronk, A.A. ; Haverkort, A.J. ; Ruijter, F.J. de; Lyu, D. ; Wan, S. ; Fan, G. ; Bai, Y. ; Min, F. ; Guo, M. ; Zhang, S. ; Yang, S. ; Gao, Y. - \ 2015
Wageningen : Plant Research International (Report / Plant Research International 608) - 73
potatoes - seed potatoes - solanum tuberosum - good practices - phytophthora infestans - disease resistance - decision support systems - seed quality - land use - water use efficiency - storage - storage equipment - china - aardappelen - pootaardappelen - solanum tuberosum - good practices - phytophthora infestans - ziekteresistentie - beslissingsondersteunende systemen - zaadkwaliteit - landgebruik - watergebruiksrendement - opslag - voorzieningen voor de opslag - china
In this report we describe the mid-term results of the R&D program of the PPS Potato GAP China. The aim of the Potato GAP China PPS is to exchange information on GAP in potato production and storage, and to set up experiments and demonstration farms in China with Dutch technology and know-how. This last objective, the setup of Centres of Dutch potato Expertise in China, has not been achieved yet, but still has high priority in 2015. In this report, we describe the results of experiments, investigations and communications within the PPS in 2013 and 2014. The R&D topics are potato late blight disease monitoring and control, potato seed quality evaluation, potato storage investigation and sustainability evaluation of potato production.
The molar H: Corg ratio of biochar is a key factor in mitigating N2O emissions from soil
Cayuela, M.L. ; Jeffery, S.L. ; Zwieten, L. van - \ 2015
Agriculture, Ecosystems and Environment 202 (2015). - ISSN 0167-8809 - p. 135 - 138.
greenhouse-gas emissions - rice - impact - straw - co2 - carbon - china - paddy - plant - denitrification
A previously published meta-analysis of biochar impacts on soil N2O emissions by Cayuela et al. (2014) found a “grand mean” reduction in N2O emissions of 54 ± 6% following biochar application to soil. Here we update this analysis to include 26 additional manuscripts bringing the total to 56 articles. The updated meta-analysis confirms that biochar reduces soil N2O emissions by 49 ± 5% (mean ± 95% confidence interval). Importantly, this meta-analysis has sufficient data to investigate the impact of biochar under field conditions, showing a statistically significant lower average reduction in the field (28 ± 16%) compared to controlled laboratory studies (54 ± 3%). A key finding is the importance of the molar H:Corg ratio of biochar in determining mitigation of N2O. Biochars with a molar H:Corg ratio 0.5 were less effective at 40 ± 16%. Together with previously published information, our new results suggest that a key mitigation mechanism is linked to the degree of polymerization and aromaticity of biochar.
Co-evolution of soil and water conservation policy and human-environment linkages in the Yellow River Basin since 1949
Wang, F. ; Mu, X. ; Li, R. ; Fleskens, L. ; Stringer, L.C. ; Ritsema, C.J. - \ 2015
Science of the Total Environment 508 (2015). - ISSN 0048-9697 - p. 166 - 177.
sustainable land management - impact - framework - science - erosion - china - state
Policy plays a very important role in natural resource management as it lays out a government framework for guiding long-term decisions, and evolves in light of the interactions between human and environment. This paper focuses on soil and water conservation (SWC) policy in the Yellow River Basin (YRB), China. The problems, rural poverty, severe soil erosion, great sediment loads and high flood risks, are analyzed over the period of 1949–present using the Driving force–Pressure–State–Impact–Response (DPSIR) framework as a way to organize analysis of the evolution of SWC policy. Three stages are identified in which SWC policy interacts differently with institutional, financial and technology support. In Stage 1 (1949–1979), SWC policy focused on rural development in eroded areas and on reducing sediment loads. Local farmers were mainly responsible for SWC. The aim of Stage 2 (1980–1990) was the overall development of rural industry and SWC. A more integrated management perspective was implemented taking a small watershed as a geographic interactional unit. This approach greatly improved the efficiency of SWC activities. In Stage 3 (1991 till now), SWC has been treated as the main measure for natural resource conservation, environmental protection, disaster mitigation and agriculture development. Prevention of new degradation became a priority. The government began to be responsible for SWC, using administrative, legal and financial approaches and various technologies that made large-scale SWC engineering possible. Over the historical period considered, with the implementation of the various SWC policies, the rural economic and ecological system improved continuously while the sediment load and flood risk decreased dramatically. The findings assist in providing a historical perspective that could inform more rational, scientific and effective natural resource management going forward.
Polyfluorinated substances in abiotic standard reference materials
Reiner, J.L. ; Blaine, A.C. ; Higgins, C.P. ; Kwadijk, C.J.A.F. - \ 2015
Analytical and Bioanalytical Chemistry 407 (2015)11. - ISSN 1618-2642 - p. 2975 - 2983.
alkyl acid concentrations - perfluorinated compounds - temporal trends - perfluorooctane sulfonate - spatial trends - human plasma - house-dust - perfluorochemicals - contaminants - china
The National Institute of Standards and Technology (NIST) has a wide range of Standard Reference Materials (SRMs) which have values assigned for legacy organic pollutants and toxic elements. Existing SRMs serve as homogenous materials that can be used for method development, method validation, and measurement for contaminants that are now of concern. NIST and multiple groups have been measuring the mass fraction of a group of emerging contaminants, polyfluorinated substances (PFASs), in a variety of SRMs. Here we report levels determined in an interlaboratory comparison of up to 23 PFASs determined in five SRMs: sediment (SRMs 1941b and 1944), house dust (SRM 2585), soil (SRM 2586), and sludge (SRM 2781). Measurements presented show an array of PFASs, with perfluorooctane sulfonate being the most frequently detected. SRMs 1941b, 1944, and 2586 had relatively low concentrations of most PFASs measured while 23 PFASs were at detectable levels in SRM 2585 and most of the PFASs measured were at detectable levels in SRM 2781. The measurements made in this study were used to add values to the Certificates of Analysis for SRMs 2585 and 2781.
China geïnteresseerd in lelieveredeling
Arens, P.F.P. - \ 2014
china - lilies - ornamental bulbs - plant breeding - varieties - crop production - conferences
Improved Surface Reflectance from Remote Sensing Data with Sub-Pixel Topographic Information
Roupioz, L.F.S. ; Nerry, F. ; Jia, L. ; Menenti, M. - \ 2014
Remote Sensing 6 (2014)11. - ISSN 2072-4292 - p. 10356 - 10374.
landsat-tm data - satellite imagery - rugged terrain - atmospheric correction - spatial-resolution - illumination - products - albedo - china - model
Several methods currently exist to efficiently correct topographic effects on the radiance measured by satellites. Most of those methods use topographic information and satellite data at the same spatial resolution. In this study, the 30 m spatial resolution data of the Digital Elevation Model (DEM) from ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) are used to account for those topographic effects when retrieving land surface reflectance from satellite data at lower spatial resolution (e.g., 1 km). The methodology integrates the effects of sub-pixel topography on the estimation of the total irradiance received at the surface considering direct, diffuse and terrain irradiance. The corrected total irradiance is then used to compute the topographically corrected surface reflectance. The proposed method has been developed to be applied on various kilometric pixel size satellite data. In this study, it was tested and validated with synthetic Landsat data aggregated at 1 km. The results obtained after a sub-pixel topographic correction are compared with the ones obtained after a pixel level topographic correction and show that in rough terrain, the sub-pixel topography correction method provides better results even if it tends to slightly overestimate the retrieved land surface reflectance in some cases.