Food security and climate change in drought-sensitive savanna zones of Ghana

Desertification, climate variability and food security are closely linked through drought, land cover changes, and climate and biological feedbacks. In Ghana, only few studies have documented these linkages. To establish this link the study provides historical and predicted climatic changes for two drought sensitive agro-ecological zones in Ghana and further determines how these changes have influenced crop production within the two zones. This objective was attained via Markov chain and Fuzzy modelling. Results from the Markov chain model point to the fact that the Guinea savanna agro-ecological zone has experienced delayed rains from 1960 to 2008 while the Sudan savanna agro-ecological zone had slightly earlier rains for the same period. Results of Fuzzy Modelling indicate that very suitable and moderately suitable croplands for millet and sorghum production are evenly distributed within the two agro-ecological zones. For Ghana to adapt to climate change and thereby achieve food security, it is important to pursue strategies such as expansion of irrigated agricultural areas, improvement of crop water productivity in rain-fed agriculture, crop improvement and specialisation, and improvement in indigenous technology. It is also important to encourage farmers in the Sudan and Guinea Savanna zones to focus on the production of cereals and legumes (e.g. sorghum, millet and soybeans) as the edaphic and climatic factors favour these crops and will give the farmers a competitive advantage. It may be necessary to consider the development of the study area as the main production and supply source of selected cereals and legumes for the entire country in order to free lands in other regions for the production of crops highly suitable for those regions on the basis of their edaphic and climatic conditions.     

Vulnerability of agro-ecological zones in India under the earth system climate model scenarios

India being a developing economy dependent on climate-sensitive sector like agriculture is highly vulnerable to impacts of global climate change. Vulnerability to climate change, however, differs spatially within the country owing to regional differences in exposure, sensitivity, and adaptive capacity. The study uses the Hadley Centre Global Environment Model version 2-Earth System (HadGEM-ES) climate projections to assess the dynamics in vulnerability across four climate change exposure scenarios developed using Representative Concentration Pathways (RCPs). The analysis was carried out at subnational (district) level; the results were interpreted and reported for their corresponding agro-ecological zones. Vulnerability of each district was quantified using indicators capturing climatic variability, ecological and demographic sensitivity, and socio-economic capacity. Our analysis further assigns probabilities to vulnerability classes of all the 579 districts falling under different agro-ecological zones. The results of the vulnerability profile show that Western plains, Northern plains, and central highlands of the arid and semi-arid agro-ecological zones are the most vulnerable regions in the current scenario (1950–2000). In the future scenario (2050), it extends along districts falling within Deccan plateau and Central (Malwa) highlands, lying in the arid and semi-arid zones, along with regions vulnerable in the current scenario, recording the highest vulnerability score across all exposure scenarios. These regions exhibit highest degree of variation in climatic parameters, ecological fragility, socio-economic marginality, and limited accessibility to resources, generating conditions of high vulnerability. The study emphasizes on the priority to take up adaptive management actions in the identified vulnerable districts to not only reduce risks of climate change, but also enhance their inherent capacity to withstand any future changes in climate. It provides a systematic approach to explicitly identify vulnerable regions, where regional planners and policy makers can build on existing adaptation decision-making by utilizing an interdisciplinary approach in the context of global change scenario.     

Implications of a changing climate on food security and smallholders’ livelihoods in Bogotá, Colombia

Small farmers who supply the city of Bogotá with food are facing many challenges that are jeopardizing their livelihoods and by extension, the food security of Colombia’s capital. We expect future changes in climatic conditions to exacerbate the plight of the small farmers and this is expected to compromise Bogota’s food security even further. This paper specifically seeks to assess the impact of climate change (CC) on the livelihoods of smallholders who supply Bogota with most of its food. In our multidisciplinary methodology, we translated the exposure to CC into direct impact on crops and assessed sensitivity and adaptive capacity using the sustainable rural livelihoods framework. The results show that rainfall (by average of 100 mm) and temperature (by average of 2.1 °C) will increase over the study area, while the future climate suitability of the most important crops such as mango (Mangifera indica), papaya (Carica papaya), corn (Zea mays) and plantain (Musa balbisiana) shows a decrease of 19 % to 47 % climate suitability by the year 2050. The assessment of sensitivity and adaptive capacity demonstrates that farmers participating in a farmers’ market, initiated by several local and international non-governmental organizations (NGOs), are less vulnerable to CC than farmers who sell through intermediaries. Those farmers selling directly to consumers in the farmers’ market have a higher adaptive capacity (3 on a scale of 3) in social and financial capital than those selling to intermediaries with less adaptive capacity (1 on a scale of 3). In light of the reduction in overall climatic suitability of some of the major crops and the change of geographic location of suitability for others, there are likely to be serious threats for Bogotá’s food security, the ecological landscape around the city, and farmers’ livelihoods. We further conclude that unless proper adaptation measures are implemented, the geographical shift in climate suitability may also force farmers to shift their crops to higher elevations including remaining forests and páramos (the Colombian alpine tundra ecosystems), which may be threatened in the near future.     

土地用途管制下基本农田发展权受限的区域差异及经济补偿——以湖北省武汉、荆门、黄冈等地区为实证

以湖北省武汉、荆门、黄冈等地区为实证,分析重点开发区、农产品主产区及生态功能区农民收入及土地利用行为受土地用途管制的影响,测算基本农田发展受限下农民的福利损失及空间异质性。结果表明:① 农民收入及土地利用行为具有显著的空间差异,农产品主产区农业收入较重点开发区农业收入高30 929.29 元/(户·a),生态功能区农民倾向于种植经济作物,江汉平原农产品主产区农民更愿意种植粮食作物,农地经营意愿也最强烈,而重点开发区及生态功能区农民转入农地、扩大农业经营规模的意愿较弱;② 土地用途管制对农业收入较高、农地投入较大、农地经营意愿较低、单纯种植粮食作物和兼营粮食作物与经济作物农民的影响较大;③ 土地用途管制强度及其给农民福利带来的损失具有显著空间差异,重点开发区的管制程度最强,生态功能区的管制程度最弱,其中重点开发区农民的福利损失最大[23 839.34 元/(hm²·a)],其次为生态功能区[22 266.71 元/(hm²·a)],农产品主产区最低[14 445.58 元/(hm²·a)]。     

Vulnerability of exporting nations to the development of a carbon label in the United Kingdom

Carbon labels inform consumers about the amount of greenhouse gases (GHGs) released during the production and consumption of goods, including food. In the future consumer and legislative responses to carbon labels may favour goods with lower emissions, and thereby change established supply chains. This may have unintended consequences.We present the carbon footprint of three horticultural goods of different origins supplied to the United Kingdom market: lettuce, broccoli and green beans. Analysis of these footprints enables the characterisation of three different classes of vulnerability which are related to: transport, national economy and supply chain specifics.There is no simple relationship between the characteristics of an exporting country and its vulnerability to the introduction of a carbon label. Geographically distant developing countries with a high level of substitutable exports to the UK are most vulnerable. However, many developing countries have low vulnerability as their main exports are tropical crops which would be hard to substitute with local produce.In the short term it is unlikely that consumers will respond to carbon labels in such a way that will have major impacts in the horticultural sector. Labels which require contractual reductions in GHG emissions may have greater impacts in the short term.     

Farmers’ nutrient management practices in indigenous cropping systems in southern Cameroon

With increasing population densities, food production needs to be increased. A common response of farmers is to shorten fallow periods, which can lead to a decline in crop yields, due to incomplete nutrient replenishment. However, whether farmers change their management of soil and nutrients according to the fallow length is not known. A survey was carried out in southern Cameroon in 1995 to establish factors determining farmers’ nutrient management practices (NMPs). Three classes of indigenous NMPs were identified: crop placement, mulching, and the use of inputs. Crop placement comprised intentional cultivation of certain crops in ash patches or near to tree trunks and stumps. Mulching was done with weeds and crop residues, on the soil surface next to crops or in planting holes. Crop placement was found in 88.8% of fields and mulching in 57.4%, while inputs were used in only 1.7%. Nutrient management seemed to be restricted to an optimal allocation of crops to nutrient sources in the field.Relationships were weak between the frequency of crop placement or mulching and indices of land or labor availability. Fallow length seems to be negatively correlated to crop placement at rotten trunks or stumps or in ash patches and positively to placement near recently felled trees. Crop placement and mulching of crop residues were used less often in simplified crop associations than in traditional intercrops. Nutrient inputs were mainly given to monocrops. Application of purchased inputs concentrated on commercial crops.Most respondents knew the advantages and risks of currently practiced methods, but often lacked information on the use of locally available internal inputs (refuse, kitchen ash, manure). Application of internal inputs was considered too labor demanding. The use of purchased inputs was limited by high prices. Soil fertility was in most cases not regarded as a problem.     

基于VSD模型的区域生态系统脆弱性评价——以广西西江经济带为例

生态系统脆弱性受到自然与人文因素双重影响。以广西西江经济带为例,采用VSD模型,通过暴露度、敏感性和适应能力分解脆弱性,构建包含自然和人为因素25 个指标的评价体系,开展脆弱性评价与分区。结果表明,不脆弱区、一般区、脆弱区、很脆弱区和极脆弱区分别占11.31%、22.63%、27.60%、24.39%和14.07%,东西部地区脆弱性较高,中部地区脆弱性较低;自然因素导致的脆弱区主要分布于东西部山区,人为因素主导的脆弱区分布于中部盆地的城镇及其周边;经济带约53%的建设用地分布于很脆弱区和脆弱区,未来新增建设用地需要重点向不脆弱区和一般区转移。根据分区结果和诱因差异,提出了不同类型区开发与保护的相关建议。     

山东沿海地区百年一遇潮位淹没影响的耕地脆弱性评价

山东沿海七市耕地面积占全省耕地面积的37.91%,农业产值占全省的41.12%。由于经常受风暴潮的影响,农业损失巨大。沿海耕地分布区地势较为低平,潮水灌入农田,使当季农作物损失率为100%,同时又改变土壤性质,影响下一季农作物的生长,而防潮堤标准低且达标率不高,对百年一遇风暴潮抵抗力较弱。因此,对山东沿海地区耕地脆弱性评价有利于防灾减灾。本文利用landsat ETM、数字高程模型和地表覆盖数据,运用GIS系统评价山东沿海地区百年一遇潮位淹没影响的耕地脆弱性。将脆弱程度划分为七级,研究结果如下:极高脆弱性的地区是垦利县、东营区;很高脆弱性的地区有河口区、昌邑县、广饶县与寒亭区;高脆弱性的地区是城阳区、崂山区与寿光市;中脆弱区的地区有莱州市、平度市、垦利县与东营区;低脆弱的地区有岚山区、牟平市、文登市、荣成市、即墨市、胶州市、无棣县、东港区、龙口市、海阳市、河口区、沾化县与黄岛区;很低脆弱的地区有蓬莱市、环翠区、利津、芝罘区、崂山区、乳山市与城阳区;极低脆弱的地区有福山区、莱山区与招远市。其中垦利县、东营区、寒亭区、广饶县、昌邑县与寿光市的脆弱性是由于百年一遇潮位较高,淹没耕地比值大;河口区脆弱性是由于当地淹没耕地比值大。     

The Dynamics of Rural Vulnerability to Global Change: The Case of southern Africa

Research on the agricultural impacts of global change frequently emphasizesthe physical and socioeconomic impacts of climate change, yet globalchanges associated with the internationalization of economic activity mayalso have significant impacts on food systems. Together, climate change andglobalization are exposing farmers to new and unfamiliar conditions.Although some farmers may be in a position to take advantage of thesechanges, many more are facing increased vulnerability, particularly in thedeveloping world. This paper considers the dynamics of agriculturalvulnerability to global change through the example of southern Africa. Wedemonstrate that the combination of global and national economic changesis altering the context under which southern African farmers cope withclimate variability and adapt to long-term change. We find that farmers whoformerly had difficulty adapting to climatic variability may become lessvulnerable to drought-related food shortages as the result of tradeliberalization. At the same time, however, removal of national credit andsubsidies may constrain or limit adaptation strategies of other farmers,leaving them more vulnerable to climate variability and change.     

桂林市峰林平原区岩溶水文地球化学特征

峰林平原区往往作为岩溶地下水系统的主要径流、排泄地段且人类活动密集,其水文地球化学特征具有一定的独特性.对典型峰林平原区岩溶水文地球化学特征进行合理分析,不仅能够反应峰林平原区在丰水期的补给模式,而且也能够反应出人类活动对岩溶盆地中水化学组分的影响.通过对桂林市典型峰林平原区的补给区、内排泄区、补给径流区、排泄区岩溶地下水主要出露点和漓江上下游在丰水期与枯水期的野外取样、现场测试,对各化学指标进行空间和时间上的对比分析,结果表明:桂林市峰林平原区水文地球化学性质在丰水期与枯水期均呈现出明显的空间分布规律,且含水层介质岩性对地下水主要离子组分具有强烈的控制作用;丰水期的岩溶水文地球化学信息反应了在峰林平原区内排泄与补给径流区的补给模式以快速流为主,第四系土壤孔隙水垂向补给次之;桂林市峰林平原区人类活动对岩溶水化学性质具有一定的影响,主要为生活污染与农业污染,其重点防护区为内排泄区与补给径流区.     

西北干旱区作物灌溉技术效率及影响因素

水资源短缺是制约西北干旱区可持续发展的硬约束,提高作物灌溉技术效率、压缩农业灌溉用水是缓解水资源供需矛盾的可能途径之一。基于2014年张掖市农户调研数据,采用DEA-Tobit模型,分析了黑河流域中段不同类型灌区作物灌溉技术效率及其影响因素。结果表明：（1）典型灌区主要作物灌溉技术效率均存在改进空间,节水潜力较大。在其他投入保持不变的情况下,如果典型灌区主要作物灌溉技术效率达到目前的最高水平,平原灌区生产同样产量的制种玉米和大田玉米,灌溉用水可分别减少34.47%和38.15%;北部荒漠灌区生产同样产量的棉花、制种西瓜和玉米套小麦,灌溉用水可分别减少48.42%、34.82%和22.99%;沿山灌区生产同样产量的小麦、马铃薯、大麦和大田玉米,灌溉用水可分别减少14.48%、30.75%、25.50%和35.96%。（2）不同灌区之间作物灌溉技术效率的变异系数与作物种植面积占比呈负向关系,同一灌区内部种植相同作物的农户生产管理水平存在明显差异。（3）农地细碎化程度和农户耕地面积扩大会降低作物灌溉技术效率,改善耕地质量能提高北部荒漠灌区作物灌溉技术效率,增加井水灌溉会提高平原灌区大田玉米和沿山灌区作物灌溉技术效率,灌溉次数与多数作物灌溉技术效率呈“倒U型”关系,而农户耕作需求及其对风险态度的影响需结合具体情况进行判断。合理确定种植规模、加快农地空间优化,因地制宜地改善耕地质量,完善水利设施、合理使用井灌、增强河水灌溉放水的灵活性,是提升黑河流域作物灌溉技术效率的主要途径。     

大城市郊区典型区域农户作物种植选择行为及其影响因素对比研究——基于沈阳市苏家屯区238户农户的调查研究

研究从农户作物种植选择行为角度出发,以马斯洛需求层次理论为基础,通过构建社会经济及政策变化对农户种植选择行为影响机理分析框架和理论模型,基于沈阳市苏家屯区238户农户调查数据,采用统计分析法和Logistic回归分析,研究结果表明:工业化、城市化进程的加快促进了大城市郊区非农就业机会的增多和对农产品需求的增加,导致农户作物种植业选择行为出现了明显的"非粮化"和"非农化"趋势,不同区域农户作物选择行为存在明显的差异,在空间上形成近郊区以种植粮食作物为主→远郊区兼种粮食作物和经济作物为主→纯农村区以种植经济作物为主的"反杜能圈"式的种植模式特征。在此研究基础上,从外部环境包括城市扩展、经济结构、市场价格变化、政策制度安排和内部环境包括个人特征、家庭特征、资源禀赋等7类因素13个因子对产生差异的影响机理进行分析,结果显示不同区域、不同因子的作用方向、影响程度与显著性表现均有所不同。根据以上的研究结果,政府应该从鼓励农户发展休闲农业、合理引导农户把握市场和培养新型农民等方面入手,优化农业结构调整,促进农村土地合理利用,提高土地利用效率,实现农村土地资源的持续利用。     

Future needs in potato post-harvest technology in developing countries

The reduction of post-harvest food losses, which are particularly high in perishable crops in developing countries, is important not only from an obligation to avoid waste, but also because the cost of preventing food losses in general is considered to be less than producing a similar additional amount of food of the same quality. In perishable vegetatively propagated crops like the potato, appropriate post-harvest technology is not only required to reduce food losses, but also to maintain the perishable planting material from one growing season to the next.Extensive knowledge on basic post-harvest technologies and principles exists for potatoes. The future emphasis in tropical developing countries should be in their low-cost application to specific local problems. In attempting to use known technologies to solve these problems, lessons should be learnt from many past failures where attempts concentrated on the direct transfer of technologies which were successfully used in one location to a similar problem in another location. Basic technologies and principles are universal but their application is location-specific and requires a good understanding of the socio-economic as well as technical needs of each location. The best use of limited resources in the transfer and application of known technologies could be achieved through the use of interdisciplinary research teams which involve their final client — farmer, merchant or consumer — in their efforts at an early stage, rather than relying on traditional disciplinary research and extension approaches.As an alternative to trying to copy the development path of countries which use high-input technologies, the authors suggest that developing countries, in an effort to reduce post-harvest potato losses and to make potatoes available to an increasing number of their peoples by the year 2000, should investigate alternative low-cost application of basic principles.     

中国县域单元生态脆弱性时空变化研究

以中国2853个县(市、旗、区)为研究单元,以1980、1990、2000和2010年全国1 km格网土地利用数据和中国县级行政单元社会经济统计数据为基础,通过VSD模型,构建了基于自然和人为共同作用下的生态系统影响力指数和社会经济适应力指数,用以综合表达生态脆弱性空间分异,在此基础上对中国县域单元的生态脆弱性进行定量评价.结果表明:中国县域生态系统影响力指数持续降低,2000年之前呈现由"东北到西南"逐渐降低的趋势,2000年之后,基本呈现"中东部及新疆北部高、西南低"的格局.适应力指数空间分布差异十分明显,表现出东南沿海高于中部,中部又高于西部的格局.从生态系统脆弱性空间分布格局来看,东南部比西部地区更脆弱,从时间变化来看,中国生态脆弱度整体好转,局部恶化;从数量变化来看,1983个县域单元处于高度脆弱区和极度脆弱区,仅有327个县域单元于处于轻度和微度脆弱区.处于极度脆弱区和高度脆弱区的县域单元未来要合理规划土地利用,加强土地利用管理,调整用地布局并严格控制城镇规模扩张;对于轻度和微度脆弱区则应坚持以生态建设和环境保护为主,禁止污染型产业发展,有序引导人口转移,发展生态旅游业和高技术产业.     

滇池北岸入湖河流水质变化趋势分析

文章采用WPI水污染指数法评价滇池北岸各片区河道的水质,并分析其变化趋势,同时采用pearson相关分析方法研究旱季和雨季各片区河道WPI指数变化趋势的相关度。结果表明:1988-2001年滇池北岸河道水质污染主要为减轻的趋势;2001-2007年随着昆明市的大规模扩张,其加重趋势非常明显;2007-2009年,随着河道水环境综合整治工程的大规模开展,又主要表现为减轻趋势,且旱季水质污染减轻的趋势比雨季明显,在纳入统计的5个片区河道中,旱季有4个片区河道水质好转,雨季有3个片区河道水质好转。这是由于2007-2009年间开展的河道水环境综合整治工程主要针对点源污染控制。此外,由于面源污染特征在5个片区中的4个片区都非常相似,雨季各片区河道WPI指数变化趋势的相关度比旱季高。     

Land use and climate change adaptation strategies in Kenya

Climate variability and change mitigation and adaptation policies need to prioritize land users needs at local level because it is at this level that impact is felt most. In order to address the challenge of socio-economic and unique regional geographical setting, a customized methodological framework was developed for application in assessment of climate change vulnerability perception and adaptation options around the East African region. Indicators of climate change and variability most appropriate for the region were derived from focused discussions involving key informants in various sectors of the economy drawn from three East African countries. Using these indicators, a structured questionnaire was developed from which surveys and interviews were done on selected sample of target population of farming communities in the Mt. Kenya region. The key highlights of the questionnaire were vulnerability and adaptation. Data obtained from respondents was standardized and subjected to multivariate and ANOVA analysis. Based on principle component analysis (PCA), two main vulnerability categories were identified namely the social and the bio-physical vulnerability indicators. Analysis of variance using Kruskal-Wallis test showed significant statistical variation (P ≤ 0.05) in the perceived vulnerability across the spatial distribution of the 198 respondents. Three insights were distinguished and were discernible by agro-ecological zones. Different vulnerability profiles and adaptive capacity profiles were generated demonstrating the need for prioritizing adaptation and mitigation efforts at local level. There was a high correlation between the bio-physical and social factor/livelihood variables that were assessed.     

Adaptation to climate change in Ethiopia and South Africa: options and constraints

Climate change is expected to adversely affect agricultural production in Africa. Because agricultural production remains the main source of income for most rural communities in the region, adaptation of the agricultural sector is imperative to protect the livelihoods of the poor and to ensure food security. A better understanding of farmers’ perceptions of climate change, ongoing adaptation measures, and the decision-making process is important to inform policies aimed at promoting successful adaptation strategies for the agricultural sector. Using data from a survey of 1800 farm households in South Africa and Ethiopia, this study presents the adaptation strategies used by farmers in both countries and analyzes the factors influencing the decision to adapt. We find that the most common adaptation strategies include: use of different crops or crop varieties, planting trees, soil conservation, changing planting dates, and irrigation. However, despite having perceived changes in temperature and rainfall, a large percentage of farmers did not make any adjustments to their farming practices. The main barriers to adaptation cited by farmers were lack of access to credit in South Africa and lack of access to land, information, and credit in Ethiopia. A probit model is used to examine the factors influencing farmers’ decision to adapt to perceived climate changes. Factors influencing farmers’ decision to adapt include wealth, and access to extension, credit, and climate information in Ethiopia; and wealth, government farm support, and access to fertile land and credit in South Africa. Using a pooled dataset, an analysis of the factors affecting the decision to adapt to perceived climate change across both countries reveals that farmers were more likely to adapt if they had access to extension, credit, and land. Food aid, extension services, and information on climate change were found to facilitate adaptation among the poorest farmers. We conclude that policy-makers must create an enabling environment to support adaptation by increasing access to information, credit and markets, and make a particular effort to reach small-scale subsistence farmers, with limited resources to confront climate change.     

滇池河流降雨径流资源利用的技术途径

根据城市污水土地处理慢速渗滤等工艺的去除率BOD₅和COD_Cr分别为84.3%和82.5%,TP、KN和NH_3-N分别为94.9%、85.8%和89.4%,SS也高达58.4%。保证这类生态工程终年稳定运行的核心问题是:处理出水水质稳定和处理水量的稳定。影响稳定的主要因素有作物非用水季节(收获和栽种)的水量调节系统、雨季稳定运行和高去除率的处理工艺、适应慢速土地处理的气候和土壤等环境条件以及水量平衡调节与管理的有效保证。集水区域内实行分区管理的截流和改善下垫面排水调控能力的水利工程,配合使用灌溉型慢速土地处理(SR)或植物生长淹没床(VSB)湿地资源化利用与处理系统等生态工程处理工艺,是实现降雨径流资源化利用的主要技术保证。