Soil degradation is a serious environmental problem in Ethiopia. However, little information is documented on indicators such as variations in soil properties across different landforms in a catchment. This study was ...Soil degradation is a serious environmental problem in Ethiopia. However, little information is documented on indicators such as variations in soil properties across different landforms in a catchment. This study was aimed to assess soil properties and their changes across sites with different erosion statuses, and identify landscape positions that require prior management attention in the Mai-Negus catchment, northern Ethiopia. Three types of erosion-status sites(stable, eroding and aggrading) were identified using reconnaissance surveys, and then the corresponding soil samples were collected and analyzed. The major soil properties were significantly varied(P ≤ 0.05) among the three erosion-status sites. The highest soil p H, organic carbon, total nitrogen, cation exchange capacity, iron and zinc were recorded from the aggrading sites in the reservoir and valley landforms of the study catchment. A higher bulk density was generally recorded in the eroding sites, whereas a lower value was observed in the aggrading sites. The highest sand content was observed in the eroding sites of the mountain followed by the central ridge landform. The paired mean difference and the correlation matrix of most soil properties between the different erosion statuses also showed significant differences. About 95% of the erosionstatus sites were correctly classified by the discriminant function, indicating that the field survey-based classification was acceptable for decision making. On the basis of this study, suitable interventions should thus be introduced to the prioritized landforms, which are the mountain and central ridge, and eroding sites with severely degraded soil properties across the catchment.展开更多
Soil-erosion-induced land degradation is a great challenge in the Ethiopian highlands. Consequently, the government has invested in soil and water conservation measures to tackle the problem where farmland terracing i...Soil-erosion-induced land degradation is a great challenge in the Ethiopian highlands. Consequently, the government has invested in soil and water conservation measures to tackle the problem where farmland terracing is one of the commonly implemented measures in the country. The purpose of this study was to analyze the role of farmland terracing in maintaining soil fertility and to evaluate its performance within a terrace, across terrace age and slope of terrain. The study was conducted in the Lake Maybar watershed in Wello, northern Ethiopia. Composite topsoil samples were collected from plots representing four slope categories across the terrain and three positions within a terrace. The samples were analyzed for selected soil physico-chemical properties and statistically tested using ANOVA （analysis of variance）. The study revealed that soil pH （△pH [H2O] = 0.6）, exchangeable K＋ （△K＋ = 0.33 cmol（＋）/kg） and clay （9%） content significantly increased towards the lower terrain position. Unlike other studies, all soil properties except bulk density （△ 0.40 g/cm3） showed non-significant differences within a terrace. Bench terrace formation reduced soil fertility gradients within a terrace for which it has been commented. Soil fertility also showed very slight change across terrace age, which indicates terracing reduced erosion-induced soil and nutrient loss. However, in order to optimize impact of farmland terracing on soil fertility maintenance, terracing should be complemented by fertility amendment considering site-specific conditions.展开更多
The objective of this paper is to propose a conceptual framework stimulating the sustainable management of natural resources in Central Africa. Based on the forest resources, we show how good identification and alloca...The objective of this paper is to propose a conceptual framework stimulating the sustainable management of natural resources in Central Africa. Based on the forest resources, we show how good identification and allocation of property rights strengthen the joint management of forest resources. Cameroon is selected as an example, since the country represents one of the most forest-intense areas in Africa. In doing so, we first evaluate the performance of institutions in fostering sustainable forest management. Second we show how good elaboration and allocation of property rights may contribute to improving efficiency in forest management. Using the New Institutional Economic (NIE) theory we provide an outline of the potential relationships between forest management and property rights allocated to stakeholders involved in forest exploitation. Finally we provide two forms of institutional structures that could improve forest management efficiency: public-private partnership and multi-stakeholder management approaches. Public-private partnerships are joint project management processes operated by both private businesses and public entities in order to combine public prescriptive mechanisms with private operational roles. Multi-stakeholder management approach is also a co-management initiative combining public entities, private actors and local population to increase the involvement of local dwellers living in forest areas in the decision process.展开更多
The purpose of this paper is to make a contribution to the use of diatomite as a mineral additive in the composition of compressed earth blocks. The aim is to study the influence of diatomite on the hygrothermal behav...The purpose of this paper is to make a contribution to the use of diatomite as a mineral additive in the composition of compressed earth blocks. The aim is to study the influence of diatomite on the hygrothermal behaviour of composites based on clay soils. For this reason, two clay soils with different physicochemical and mineralogical compositions were incorporated with diatomite at percentages ranging from 5% to 50% with a step of 5 to produce compressed earth blocks. After assessing the hydric and thermal characteristics of the composites, it was found that the incorporation of diatomite into the clay matrix favours the absorption of water by capillary action for all the composites. The diatomite-amended blocks subjected to the rain erosion test were less eroded than the unamended blocks. In addition, BYD composites were found to be more resistant than BTD composites, due to the high percentage of clay in T soil. The thermal conductivity of the latter decreases respectively from 0.72 to 0.29 W/m∙K for BTD composites and from 0.52 to 0.21 W/m∙K for BYD composites. This reduction proves the thermal insulating properties of diatomite. Despite the high capillary absorption capacity of these composites, they have good thermal properties, enabling them to be used in the construction of buildings for improved indoor thermal comfort.展开更多
Rangelands of Central Asia (referring to Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan in this study), the largest contiguous area of grazed land in the world, serve as an important source of livelih...Rangelands of Central Asia (referring to Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan in this study), the largest contiguous area of grazed land in the world, serve as an important source of livelihood for pastoral and agro-pastoral communities in this region. They also play an important role in absorbing CO<sub>2</sub> as a global carbon sink. However, unsustainable management of rangelands has led to their degradation hugely by downgrading their potential agro-ecological, environmental and socio-economical roles. This paper reviewed the rangeland degradation in Central Asia, a topic which so far has received only scant coverage in the international scientific literature. It also provided examples of successful experiences and outlined possible options that land managers can adopt to enhance the sustainable management of these vast degraded rangelands. The experiences and lessons described in this paper may also be relevant for other degraded rangeland areas, especially in the developing countries. The causes of rangeland degradation within the Central Asian region are numerous, complex and inter-related. Therefore, while addressing the factors associated with improper rangeland management may shed some light on the causes of rangeland degradation, the scope of this paper would not be all-encompassing for the major causes of degradation. There is a need to develop and widely apply the viable and locally accepted and adapted packages of technical, institutional and policy options for sustainable rangeland management. Incentivizing the collective action of small-scale pastoralists who group together to facilitate access to remote pastures can reduce the degree of overgrazing within community pastures, such as those near the settlements. We also found that migratory grazing through pooling of resources among small-scale pastoralists can increase household income. After their independence, most Central Asian countries adopted various rangeland tenure arrangements. However, the building of enhanced capacities of pasture management and effective local rangeland governance structures can increase the likelihood, which will be sustainable and equitable. Finally, this paper presented several promising technical options, aiming at reversing the trend of rangeland degradation in Central Asia.展开更多
The poor distribution of meteorological stations results in a limited understanding of the precipitation pattern in the Tianshan Mountains. The spatial patterns of precipitation over the mid Tianshan Mountains were ch...The poor distribution of meteorological stations results in a limited understanding of the precipitation pattern in the Tianshan Mountains. The spatial patterns of precipitation over the mid Tianshan Mountains were characterized based on the TRMM 3B43 monthly precipitation data. By comparing satellite estimates with observed data, it shows that TRMM 3B43 data underestimate the precipitation in mountain region. Regression models were developed to improve the TRMM 3B43 data, using geographic location and topographic variables extracted from DEM using GIS technology. The explained variance in observed precipitation was improved from 64% (from TRMM 3B43 products alone) to over 82% and the bias reduced by over 30% when location and topographic variables were added. We recalculated all the TRMM 3B43 monthly precipitation grids for the period 1998 to 2009 using the best regression models, and then studied the variation patterns of precipitation over the mid Tianshan Mountains. The results are well explained by a general understanding of the patterns of precipitation and orographic effects. This indicated that the Tianshan Mountains strongly influences the amount and distribution of precipitation in the region. This is highlighted by the confinement of the precipitation maxima to the windward (northern slope). And complex vertical changes in the provenance and distribution of precipitation, like that a negative increasing rate of precipitation in the vertical direction exists in the north but does not in south. The results have also revealed large gradients and different patterns in seasonal precipitation that are not simply related to elevation, the distribution of precipitation may also be affected by other seasonal factors such as the sources of moist air, wind direction and temperature.展开更多
Rice crop growth and yield in the north Iran are affected by crop duration and phenology.The purpose of this study was to calibrate and validate the ORYZA2000 model under potential production based on experimental dat...Rice crop growth and yield in the north Iran are affected by crop duration and phenology.The purpose of this study was to calibrate and validate the ORYZA2000 model under potential production based on experimental data for simulating and quantifying the phenological development,crop duration and yield prediction of rice crop influenced by different seedling ages.In order to calibrate and validate the crop parameters of ORYZA2000 model,a two-year field experiment was conducted under potential growth condition for transplanted lowland rice during the 2008-2009 rice growing seasons,using three rice varieties with three seedling ages(17,24 and 33 days old).The results showed that the seedling age changed crop duration from 7 to 10 d.The ORYZA2000 model could predict well,but consistently underestimated the length of growing period.The range in normalized root mean square error(RMSEn) values for each phenological stage was between 4% and 6%.From our evaluation,we concluded that ORYZA2000 was sufficiently accurate in simulation of yield,leaf area index(LAI) and biomass of crop organs over time.On average,RMSEn values were 13%-15% for total biomass,18%-21% for green leaf biomass,17%-20% for stem biomass,16%-23% for panicle biomass and 24%-26% for LAI.The RMSEn values for final yield and biomass were 12%-16% and 6%-9%,respectively.Generally,the model simulated LAI,an exceeded measured value for younger seedlings,and best-fit was observed for older seedlings of short-duration varieties.The results revealed that the ORYZA2000 model can be applied as a supportive research tool for selecting the most appropriate strategies for rice yield improvement across the north Iran.展开更多
In the Shennongjia National Nature Reserve of Central China, the vegetative growth behavior of henon bamboo （Phyllostachys nigra var. henonis （Mitford） Stapf. ex Rendle） was studied from shoot recruitment to culm ...In the Shennongjia National Nature Reserve of Central China, the vegetative growth behavior of henon bamboo （Phyllostachys nigra var. henonis （Mitford） Stapf. ex Rendle） was studied from shoot recruitment to culm establishment. In May, bamboo shoots emerg- ing from the ground achieved an average density of 2.7 shoots m^-2 during the sprouting phase of 16 days. However, about 32% of the new shoots died back before maturity. Insect damage, withering death and rodent predation were responsible for 57%, 29 % and 14% of the total shoot mortality, respectively. From May to June, the shoots attained 400 ± 23 cm during the height growth phase of 34 days, with a daily rate varying from 1 to 56 cm. All branches and leaves unfolded during the branch spreading phase from June to August. Shoot production was positively related to the density of standing culms, but negatively to both coverage and height of herb layers.展开更多
Flowering pattern and seedling establishment of umbrella bamboo （Fargesia murieliae （Gamble） Yi） were studied in its native habitat, Mount Shennongjia in Central China. Here in 1996-2000, over 95% of the bamboo pl...Flowering pattern and seedling establishment of umbrella bamboo （Fargesia murieliae （Gamble） Yi） were studied in its native habitat, Mount Shennongjia in Central China. Here in 1996-2000, over 95% of the bamboo plants simultaneously flowered and died, extending from lower elevations to the higher mountains along the altitude and from southwest to northeast along the mountain settings. Bamboo seedlings emerged after the simultaneous flowering, achieving an average density of 5 460 seedlings·m^-2 in the autumn of the year following the flowering. After a high mortality throughout the first winter, bamboo seedlings remained a stable density in following 2-4 years （1130-1230 seedlings·m^-2）. Seedling density positively related to the coverage of parent bamboo, but negatively to the herb layers.展开更多
In spite of receiving a significant amount of food aid, achieving food security has been a major problem in Ethiopia. The claim is evidenced from the 2010 Global Hunger Index where the country fared dismally, coming o...In spite of receiving a significant amount of food aid, achieving food security has been a major problem in Ethiopia. The claim is evidenced from the 2010 Global Hunger Index where the country fared dismally, coming only fourth from the bottom. There are several factors attributing to this problem of food insecurity in a country like Ethiopia which depends highly on agriculture and allied activities. Some of the factors can be linked to low food production and productivity thereby leading to pervasive poverty. In order to assess these factors, the study was conducted on some selected members of agro-pastoral communities of Somali and Oromia regions in Ethiopia. Using availability of food in the household for the last one month as a proxy for food security, the estimated results of a logistic regression model indicated that the most significant factors affecting household food security are educational level of the spouse and that of the household head, size of farm land, availability of household assets including livestock, peace and security. The paper suggests some leads to how these amenities and resources can be provided to household members as they endeavor to reduce food insecurity.展开更多
The dynamic nature and inaccessibility of wetland ecosystems restricts in situ data collection and promote the use of various remote sensing platforms. This is because of their ability to record large areas in compara...The dynamic nature and inaccessibility of wetland ecosystems restricts in situ data collection and promote the use of various remote sensing platforms. This is because of their ability to record large areas in comparatively short time periods and map physically unreachable areas. Sensors in the optical and microwave range of the electromagnetic spectrum play a critical role in wetlands detection and delineation, as they complement each other in data collection. This study examined the potential of optical and microwave remote sensing in detecting the diversity of small wetlands ( ha) in the semi-arid and sub humid parts of Laikipia and Pangani plains and the humid parts of Mt. Kenya and Usambara highlands in Kenya and Tanzania, respectively. An intensive field survey was conducted to supplement the remotely sensed data. Decision tree, supervised and unsupervised classification techniques, facilitated the detection of floodplains and inland valley wetlands within the study sites. The results reveal that although optical and microwave data work effectively in the detection of wetlands the latter would be more effective in larger wetlands than those in the scope of this study.展开更多
Introduction:Land use intensification and urbanisation processes are degrading hydrological ecosystem services in the Guapi-Macacu watershed of Rio de Janeiro.A proposal to pay farmers to restore natural watershed ser...Introduction:Land use intensification and urbanisation processes are degrading hydrological ecosystem services in the Guapi-Macacu watershed of Rio de Janeiro.A proposal to pay farmers to restore natural watershed services might be an alternative to securing the water supply in the long-term for the around 2.5 million urban water users in the study region.This study quantifies the costs of changing current land use patterns to enhance watershed services and compares these costs to the avoided costs associated with water treatment for public supply.Methods:We use farm-household data to estimate the opportunity costs of abandoning current land uses for the recovery of natural vegetation;a process that is very likely to improve water quality in terms of turbidity due to reduced inputs from erosion.Opportunity cost estimates are extrapolated to the watershed scale based on remote sensing land use classifications and vulnerability analysis to identify priority zones for watershed management interventions.To assess the potential demand for watershed services,we analyse water quality and treatment cost data from the main local water treatment plant.Results:Changing agricultural land uses for watershed services provision generally comes at high opportunity costs in our study area near to the metropolis of Rio de Janeiro.Alternative low cost watershed conservation options do exist in the livestock production sector.These options have the potential to directly reduce the amount of sediments and nutrients reaching the water bodies,and in turn decrease the costs of treatment needed for drinking water.Land cover changes at the scale needed to improve water quality will,nonetheless,likely exceed the cost of additional investments in water treatment.Conclusions:The state water utility company’s willingness to pay for watershed services alone will not be enough to induce provision of additional watershed services.We conclude that monetary incentives conditioned on specific adjustments to existing production systems could still have a complementary role to play in improving watershed services.However,we note that our willingness to pay analysis focusses on only one of the potentially wide range of ecosystem services provided by natural vegetation in the Guapi-Macacu watershed.Factoring these ecosystem services into the willingness to pay equation is likely to change our assessment in favour of additional conservation action,be it through PES or other policy instruments.展开更多
Introduction:Current land use in the Federal District,Western Central Brazil,causes problems related to the water supply which are linked to the regulation of ecosystem services(ES).In scope of an Integrated Water Res...Introduction:Current land use in the Federal District,Western Central Brazil,causes problems related to the water supply which are linked to the regulation of ecosystem services(ES).In scope of an Integrated Water Resources Management concept,we further developed the web-based planning support tool GISCAME for the Pipiripau river basin case study.Methods:We introduced analyses on ecosystem potentials in the raster-based tool to assess,in a spatially explicit manner,the scenario impact on water purification,sediment retention,water retention,and provision of food and fodder in order to identify potential pathways for conserving water resources.To demonstrate the method,we assess ES depending on a number of land use/land cover change(LULCC)scenarios.Results:We found that a considerable increase of water purification and sediment retention is difficult to achieve with realistic small scale LULCC,mainly because in areas with a low potential to provide hydrological ES and thus with a high demand for sustainable land use,such as native Savanna(Cerrado)and natural forests(Mata),favorable land uses were often already existing.We observed synergies in the response of regulating hydrological ES to LULCC but at the same time also trade-offs with provision of food and fodder.Conclusions:Our findings suggest that further degradation and loss of Cerrado and Mata must be avoided and their restoration should be promoted in order to safeguard water resources.We suggest that restoration measures should be focused on arable land located at steep slopes near surface waters to effectively increase hydrological ES through the marginal reduction of provision services.展开更多
Introduction:Many conservation initiatives for managing social-ecological landscapes factor in the best available biophysical information.However,insufficient consideration of social aspects can render such initiative...Introduction:Many conservation initiatives for managing social-ecological landscapes factor in the best available biophysical information.However,insufficient consideration of social aspects can render such initiatives ineffective.By incorporating stakeholders'perceptions and values,and by involving stakeholders(transparently)in decision-making processes,conservation plans and efforts can better achieve desired goals and targets.Results:In this paper,we present and analyze three case studies within different ecological and land use contexts.Each case study uses different participatory approaches to elicit stakeholders'perceptions and values,while seeking to involve stakeholders in the decision-making process.The case studies are the following:(1)participatory scenario planning for a protected area in Doñana coastal wetland in Southwestern Spain;(2)assessment of ecosystem services trade-offs and social responses on rewards for agro-biodiversity in the rubber agroforest landscape in Jambi,Indonesia;and(3)socio-cultural evaluation,through visual stimuli,of ecosystem services provided by transhumance cultural landscapes in Central Spain.We discuss how stakeholders perceive and value their environments and to what extent participatory approaches are useful for capturing information relating to land use and ecological processes.Conclusions:Social-ecological systems are inherently complex,having a variety of interacting actors with different types of ecological knowledge,interests,and values.Different participatory tools or approaches are appropriate for various and specific contexts and objectives.Determining and integrating the various types of knowledge and values of different actors can contribute to a more comprehensive understanding of social-ecological systems.展开更多
Burden statements on non-communicable diseases(NCDs)across the globe suggest that they pose a constant threat to human development.There are two different types of NCD interventions:population-based interventions addr...Burden statements on non-communicable diseases(NCDs)across the globe suggest that they pose a constant threat to human development.There are two different types of NCD interventions:population-based interventions addressing NCD risk factors and individual-based interventions addressing NCDs in the primary care setting.Most of the individual-based interventions are based on NCD-care models,as opposed to population-based interventions targeting risk factors through independent vertical programmes.We explored the relevant Indian policy documents including the recent National Health Policy 2017,to get an overview of the Indian NCD-care model and to find out how physical activity(PA)promotion stands in the year 2019 in the current policy documents on NCDs.We conducted a review with two perspectives;first to capture the NCD-care models and second to document the PA promotion and its integration in the current NCD-care model specific to the Indian context.Indian NCD programme is an evolving healthcare programme with a definite NCD-care model,where the individual-based and population-based care are thoroughly linked.Despite having good NCD-care policy and methodical planning,PA promotion seems to be lacking in the policy perspective and currently physical inactivity as a risk factor is not considered seriously.The structure of the NCD-care model should be detailed and strengthened by incorporating lessons from other successful NCD models from across the globe.Indian NCD model must provide sufficient scope of interfacing individual care to that of population-based risk factor strategies like physical activity promotion.展开更多
基金the financial support by Deutscher Akademischer Austausch Dienst (DAAD)/Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) (Germany) through the Centre for Development Research (ZEF), University of Bonn (Germany)the support of Aksum University (Ethiopia) for the first author’s field work
文摘Soil degradation is a serious environmental problem in Ethiopia. However, little information is documented on indicators such as variations in soil properties across different landforms in a catchment. This study was aimed to assess soil properties and their changes across sites with different erosion statuses, and identify landscape positions that require prior management attention in the Mai-Negus catchment, northern Ethiopia. Three types of erosion-status sites(stable, eroding and aggrading) were identified using reconnaissance surveys, and then the corresponding soil samples were collected and analyzed. The major soil properties were significantly varied(P ≤ 0.05) among the three erosion-status sites. The highest soil p H, organic carbon, total nitrogen, cation exchange capacity, iron and zinc were recorded from the aggrading sites in the reservoir and valley landforms of the study catchment. A higher bulk density was generally recorded in the eroding sites, whereas a lower value was observed in the aggrading sites. The highest sand content was observed in the eroding sites of the mountain followed by the central ridge landform. The paired mean difference and the correlation matrix of most soil properties between the different erosion statuses also showed significant differences. About 95% of the erosionstatus sites were correctly classified by the discriminant function, indicating that the field survey-based classification was acceptable for decision making. On the basis of this study, suitable interventions should thus be introduced to the prioritized landforms, which are the mountain and central ridge, and eroding sites with severely degraded soil properties across the catchment.
文摘Soil-erosion-induced land degradation is a great challenge in the Ethiopian highlands. Consequently, the government has invested in soil and water conservation measures to tackle the problem where farmland terracing is one of the commonly implemented measures in the country. The purpose of this study was to analyze the role of farmland terracing in maintaining soil fertility and to evaluate its performance within a terrace, across terrace age and slope of terrain. The study was conducted in the Lake Maybar watershed in Wello, northern Ethiopia. Composite topsoil samples were collected from plots representing four slope categories across the terrain and three positions within a terrace. The samples were analyzed for selected soil physico-chemical properties and statistically tested using ANOVA （analysis of variance）. The study revealed that soil pH （△pH [H2O] = 0.6）, exchangeable K＋ （△K＋ = 0.33 cmol（＋）/kg） and clay （9%） content significantly increased towards the lower terrain position. Unlike other studies, all soil properties except bulk density （△ 0.40 g/cm3） showed non-significant differences within a terrace. Bench terrace formation reduced soil fertility gradients within a terrace for which it has been commented. Soil fertility also showed very slight change across terrace age, which indicates terracing reduced erosion-induced soil and nutrient loss. However, in order to optimize impact of farmland terracing on soil fertility maintenance, terracing should be complemented by fertility amendment considering site-specific conditions.
文摘The objective of this paper is to propose a conceptual framework stimulating the sustainable management of natural resources in Central Africa. Based on the forest resources, we show how good identification and allocation of property rights strengthen the joint management of forest resources. Cameroon is selected as an example, since the country represents one of the most forest-intense areas in Africa. In doing so, we first evaluate the performance of institutions in fostering sustainable forest management. Second we show how good elaboration and allocation of property rights may contribute to improving efficiency in forest management. Using the New Institutional Economic (NIE) theory we provide an outline of the potential relationships between forest management and property rights allocated to stakeholders involved in forest exploitation. Finally we provide two forms of institutional structures that could improve forest management efficiency: public-private partnership and multi-stakeholder management approaches. Public-private partnerships are joint project management processes operated by both private businesses and public entities in order to combine public prescriptive mechanisms with private operational roles. Multi-stakeholder management approach is also a co-management initiative combining public entities, private actors and local population to increase the involvement of local dwellers living in forest areas in the decision process.
文摘The purpose of this paper is to make a contribution to the use of diatomite as a mineral additive in the composition of compressed earth blocks. The aim is to study the influence of diatomite on the hygrothermal behaviour of composites based on clay soils. For this reason, two clay soils with different physicochemical and mineralogical compositions were incorporated with diatomite at percentages ranging from 5% to 50% with a step of 5 to produce compressed earth blocks. After assessing the hydric and thermal characteristics of the composites, it was found that the incorporation of diatomite into the clay matrix favours the absorption of water by capillary action for all the composites. The diatomite-amended blocks subjected to the rain erosion test were less eroded than the unamended blocks. In addition, BYD composites were found to be more resistant than BTD composites, due to the high percentage of clay in T soil. The thermal conductivity of the latter decreases respectively from 0.72 to 0.29 W/m∙K for BTD composites and from 0.52 to 0.21 W/m∙K for BYD composites. This reduction proves the thermal insulating properties of diatomite. Despite the high capillary absorption capacity of these composites, they have good thermal properties, enabling them to be used in the construction of buildings for improved indoor thermal comfort.
基金the Asian Development Bank,the International Center for Agricultural Research in the Dry Areas,Russian Scientific Fund(14-38-00023)the CGIAR Research Program on Dryland Systems for their support and funding
文摘Rangelands of Central Asia (referring to Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan in this study), the largest contiguous area of grazed land in the world, serve as an important source of livelihood for pastoral and agro-pastoral communities in this region. They also play an important role in absorbing CO<sub>2</sub> as a global carbon sink. However, unsustainable management of rangelands has led to their degradation hugely by downgrading their potential agro-ecological, environmental and socio-economical roles. This paper reviewed the rangeland degradation in Central Asia, a topic which so far has received only scant coverage in the international scientific literature. It also provided examples of successful experiences and outlined possible options that land managers can adopt to enhance the sustainable management of these vast degraded rangelands. The experiences and lessons described in this paper may also be relevant for other degraded rangeland areas, especially in the developing countries. The causes of rangeland degradation within the Central Asian region are numerous, complex and inter-related. Therefore, while addressing the factors associated with improper rangeland management may shed some light on the causes of rangeland degradation, the scope of this paper would not be all-encompassing for the major causes of degradation. There is a need to develop and widely apply the viable and locally accepted and adapted packages of technical, institutional and policy options for sustainable rangeland management. Incentivizing the collective action of small-scale pastoralists who group together to facilitate access to remote pastures can reduce the degree of overgrazing within community pastures, such as those near the settlements. We also found that migratory grazing through pooling of resources among small-scale pastoralists can increase household income. After their independence, most Central Asian countries adopted various rangeland tenure arrangements. However, the building of enhanced capacities of pasture management and effective local rangeland governance structures can increase the likelihood, which will be sustainable and equitable. Finally, this paper presented several promising technical options, aiming at reversing the trend of rangeland degradation in Central Asia.
基金supported by the 973 Program of China(Grant No. 2010CB951002)Natural Science Foundation of China (Grant No. 41130641)
文摘The poor distribution of meteorological stations results in a limited understanding of the precipitation pattern in the Tianshan Mountains. The spatial patterns of precipitation over the mid Tianshan Mountains were characterized based on the TRMM 3B43 monthly precipitation data. By comparing satellite estimates with observed data, it shows that TRMM 3B43 data underestimate the precipitation in mountain region. Regression models were developed to improve the TRMM 3B43 data, using geographic location and topographic variables extracted from DEM using GIS technology. The explained variance in observed precipitation was improved from 64% (from TRMM 3B43 products alone) to over 82% and the bias reduced by over 30% when location and topographic variables were added. We recalculated all the TRMM 3B43 monthly precipitation grids for the period 1998 to 2009 using the best regression models, and then studied the variation patterns of precipitation over the mid Tianshan Mountains. The results are well explained by a general understanding of the patterns of precipitation and orographic effects. This indicated that the Tianshan Mountains strongly influences the amount and distribution of precipitation in the region. This is highlighted by the confinement of the precipitation maxima to the windward (northern slope). And complex vertical changes in the provenance and distribution of precipitation, like that a negative increasing rate of precipitation in the vertical direction exists in the north but does not in south. The results have also revealed large gradients and different patterns in seasonal precipitation that are not simply related to elevation, the distribution of precipitation may also be affected by other seasonal factors such as the sources of moist air, wind direction and temperature.
基金supported by HARAZ-Extension and Technology Development Center (HETDC) in Amol City,Iran
文摘Rice crop growth and yield in the north Iran are affected by crop duration and phenology.The purpose of this study was to calibrate and validate the ORYZA2000 model under potential production based on experimental data for simulating and quantifying the phenological development,crop duration and yield prediction of rice crop influenced by different seedling ages.In order to calibrate and validate the crop parameters of ORYZA2000 model,a two-year field experiment was conducted under potential growth condition for transplanted lowland rice during the 2008-2009 rice growing seasons,using three rice varieties with three seedling ages(17,24 and 33 days old).The results showed that the seedling age changed crop duration from 7 to 10 d.The ORYZA2000 model could predict well,but consistently underestimated the length of growing period.The range in normalized root mean square error(RMSEn) values for each phenological stage was between 4% and 6%.From our evaluation,we concluded that ORYZA2000 was sufficiently accurate in simulation of yield,leaf area index(LAI) and biomass of crop organs over time.On average,RMSEn values were 13%-15% for total biomass,18%-21% for green leaf biomass,17%-20% for stem biomass,16%-23% for panicle biomass and 24%-26% for LAI.The RMSEn values for final yield and biomass were 12%-16% and 6%-9%,respectively.Generally,the model simulated LAI,an exceeded measured value for younger seedlings,and best-fit was observed for older seedlings of short-duration varieties.The results revealed that the ORYZA2000 model can be applied as a supportive research tool for selecting the most appropriate strategies for rice yield improvement across the north Iran.
基金This research was financed by the Center for Development Research （ZEF） of the University of Bonn, Germany （P. 52015l, the National Natural Science Foundation of China （No. 30470284l and the Scientific Research Foundation for the Returned 0verseas Chinese Scholars （No. 2004-527）.
文摘In the Shennongjia National Nature Reserve of Central China, the vegetative growth behavior of henon bamboo （Phyllostachys nigra var. henonis （Mitford） Stapf. ex Rendle） was studied from shoot recruitment to culm establishment. In May, bamboo shoots emerg- ing from the ground achieved an average density of 2.7 shoots m^-2 during the sprouting phase of 16 days. However, about 32% of the new shoots died back before maturity. Insect damage, withering death and rodent predation were responsible for 57%, 29 % and 14% of the total shoot mortality, respectively. From May to June, the shoots attained 400 ± 23 cm during the height growth phase of 34 days, with a daily rate varying from 1 to 56 cm. All branches and leaves unfolded during the branch spreading phase from June to August. Shoot production was positively related to the density of standing culms, but negatively to both coverage and height of herb layers.
基金This research was financed by the National Natural Science Foundation (No. 30470284) and the Center for Development Research of the University of Bonn (P. 52015).
文摘Flowering pattern and seedling establishment of umbrella bamboo （Fargesia murieliae （Gamble） Yi） were studied in its native habitat, Mount Shennongjia in Central China. Here in 1996-2000, over 95% of the bamboo plants simultaneously flowered and died, extending from lower elevations to the higher mountains along the altitude and from southwest to northeast along the mountain settings. Bamboo seedlings emerged after the simultaneous flowering, achieving an average density of 5 460 seedlings·m^-2 in the autumn of the year following the flowering. After a high mortality throughout the first winter, bamboo seedlings remained a stable density in following 2-4 years （1130-1230 seedlings·m^-2）. Seedling density positively related to the coverage of parent bamboo, but negatively to the herb layers.
文摘In spite of receiving a significant amount of food aid, achieving food security has been a major problem in Ethiopia. The claim is evidenced from the 2010 Global Hunger Index where the country fared dismally, coming only fourth from the bottom. There are several factors attributing to this problem of food insecurity in a country like Ethiopia which depends highly on agriculture and allied activities. Some of the factors can be linked to low food production and productivity thereby leading to pervasive poverty. In order to assess these factors, the study was conducted on some selected members of agro-pastoral communities of Somali and Oromia regions in Ethiopia. Using availability of food in the household for the last one month as a proxy for food security, the estimated results of a logistic regression model indicated that the most significant factors affecting household food security are educational level of the spouse and that of the household head, size of farm land, availability of household assets including livestock, peace and security. The paper suggests some leads to how these amenities and resources can be provided to household members as they endeavor to reduce food insecurity.
文摘The dynamic nature and inaccessibility of wetland ecosystems restricts in situ data collection and promote the use of various remote sensing platforms. This is because of their ability to record large areas in comparatively short time periods and map physically unreachable areas. Sensors in the optical and microwave range of the electromagnetic spectrum play a critical role in wetlands detection and delineation, as they complement each other in data collection. This study examined the potential of optical and microwave remote sensing in detecting the diversity of small wetlands ( ha) in the semi-arid and sub humid parts of Laikipia and Pangani plains and the humid parts of Mt. Kenya and Usambara highlands in Kenya and Tanzania, respectively. An intensive field survey was conducted to supplement the remotely sensed data. Decision tree, supervised and unsupervised classification techniques, facilitated the detection of floodplains and inland valley wetlands within the study sites. The results reveal that although optical and microwave data work effectively in the detection of wetlands the latter would be more effective in larger wetlands than those in the scope of this study.
基金The authors acknowledge financial support of the IPSWAT Programme(financed from the German Federal Ministry of Research-BMBF)and the DINARIO Project:“Climate Change,Landscape dynamics,Land use and Natural Resources in the Atlantic Forest of Rio de Janeiro”。
文摘Introduction:Land use intensification and urbanisation processes are degrading hydrological ecosystem services in the Guapi-Macacu watershed of Rio de Janeiro.A proposal to pay farmers to restore natural watershed services might be an alternative to securing the water supply in the long-term for the around 2.5 million urban water users in the study region.This study quantifies the costs of changing current land use patterns to enhance watershed services and compares these costs to the avoided costs associated with water treatment for public supply.Methods:We use farm-household data to estimate the opportunity costs of abandoning current land uses for the recovery of natural vegetation;a process that is very likely to improve water quality in terms of turbidity due to reduced inputs from erosion.Opportunity cost estimates are extrapolated to the watershed scale based on remote sensing land use classifications and vulnerability analysis to identify priority zones for watershed management interventions.To assess the potential demand for watershed services,we analyse water quality and treatment cost data from the main local water treatment plant.Results:Changing agricultural land uses for watershed services provision generally comes at high opportunity costs in our study area near to the metropolis of Rio de Janeiro.Alternative low cost watershed conservation options do exist in the livestock production sector.These options have the potential to directly reduce the amount of sediments and nutrients reaching the water bodies,and in turn decrease the costs of treatment needed for drinking water.Land cover changes at the scale needed to improve water quality will,nonetheless,likely exceed the cost of additional investments in water treatment.Conclusions:The state water utility company’s willingness to pay for watershed services alone will not be enough to induce provision of additional watershed services.We conclude that monetary incentives conditioned on specific adjustments to existing production systems could still have a complementary role to play in improving watershed services.However,we note that our willingness to pay analysis focusses on only one of the potentially wide range of ecosystem services provided by natural vegetation in the Guapi-Macacu watershed.Factoring these ecosystem services into the willingness to pay equation is likely to change our assessment in favour of additional conservation action,be it through PES or other policy instruments.
基金The study is part of the project IWAS-ÁGUA DF,which is funded by the German Ministry of Education and Science(BMBF)in scope of the initiative‘Excellent research and innovation in the New Länder’(FKZ:02WM1166 and 02WM1070).
文摘Introduction:Current land use in the Federal District,Western Central Brazil,causes problems related to the water supply which are linked to the regulation of ecosystem services(ES).In scope of an Integrated Water Resources Management concept,we further developed the web-based planning support tool GISCAME for the Pipiripau river basin case study.Methods:We introduced analyses on ecosystem potentials in the raster-based tool to assess,in a spatially explicit manner,the scenario impact on water purification,sediment retention,water retention,and provision of food and fodder in order to identify potential pathways for conserving water resources.To demonstrate the method,we assess ES depending on a number of land use/land cover change(LULCC)scenarios.Results:We found that a considerable increase of water purification and sediment retention is difficult to achieve with realistic small scale LULCC,mainly because in areas with a low potential to provide hydrological ES and thus with a high demand for sustainable land use,such as native Savanna(Cerrado)and natural forests(Mata),favorable land uses were often already existing.We observed synergies in the response of regulating hydrological ES to LULCC but at the same time also trade-offs with provision of food and fodder.Conclusions:Our findings suggest that further degradation and loss of Cerrado and Mata must be avoided and their restoration should be promoted in order to safeguard water resources.We suggest that restoration measures should be focused on arable land located at steep slopes near surface waters to effectively increase hydrological ES through the marginal reduction of provision services.
文摘Introduction:Many conservation initiatives for managing social-ecological landscapes factor in the best available biophysical information.However,insufficient consideration of social aspects can render such initiatives ineffective.By incorporating stakeholders'perceptions and values,and by involving stakeholders(transparently)in decision-making processes,conservation plans and efforts can better achieve desired goals and targets.Results:In this paper,we present and analyze three case studies within different ecological and land use contexts.Each case study uses different participatory approaches to elicit stakeholders'perceptions and values,while seeking to involve stakeholders in the decision-making process.The case studies are the following:(1)participatory scenario planning for a protected area in Doñana coastal wetland in Southwestern Spain;(2)assessment of ecosystem services trade-offs and social responses on rewards for agro-biodiversity in the rubber agroforest landscape in Jambi,Indonesia;and(3)socio-cultural evaluation,through visual stimuli,of ecosystem services provided by transhumance cultural landscapes in Central Spain.We discuss how stakeholders perceive and value their environments and to what extent participatory approaches are useful for capturing information relating to land use and ecological processes.Conclusions:Social-ecological systems are inherently complex,having a variety of interacting actors with different types of ecological knowledge,interests,and values.Different participatory tools or approaches are appropriate for various and specific contexts and objectives.Determining and integrating the various types of knowledge and values of different actors can contribute to a more comprehensive understanding of social-ecological systems.
文摘Burden statements on non-communicable diseases(NCDs)across the globe suggest that they pose a constant threat to human development.There are two different types of NCD interventions:population-based interventions addressing NCD risk factors and individual-based interventions addressing NCDs in the primary care setting.Most of the individual-based interventions are based on NCD-care models,as opposed to population-based interventions targeting risk factors through independent vertical programmes.We explored the relevant Indian policy documents including the recent National Health Policy 2017,to get an overview of the Indian NCD-care model and to find out how physical activity(PA)promotion stands in the year 2019 in the current policy documents on NCDs.We conducted a review with two perspectives;first to capture the NCD-care models and second to document the PA promotion and its integration in the current NCD-care model specific to the Indian context.Indian NCD programme is an evolving healthcare programme with a definite NCD-care model,where the individual-based and population-based care are thoroughly linked.Despite having good NCD-care policy and methodical planning,PA promotion seems to be lacking in the policy perspective and currently physical inactivity as a risk factor is not considered seriously.The structure of the NCD-care model should be detailed and strengthened by incorporating lessons from other successful NCD models from across the globe.Indian NCD model must provide sufficient scope of interfacing individual care to that of population-based risk factor strategies like physical activity promotion.
