After the flames then what? exploring the linkages between wildfires and household food security in the northern Savannah of Ghana

ABSTRACT

This study deploys the livelihoods theory in political ecology together with integrated methods including remote sensing, participatory geographic information systems, interviews and focus group discussions to explore the intricate and dynamic linkages between perennial wildfires and household food insecurity among smallholder farmers in the northern savannah zone of Ghana. Our results suggest that wildfires are a major pathway to household food insecurity in two ways, as perceived by the farmers. First, in instances where wildfires destroy the major crops of smallholders, they are unable to find enough food for the lean season which results in transitory food insecurity. Secondly, in the long term, the environmental impacts of wildfires on the soil lead to lower yields and inadequate food to meet household nutritional needs. Farmers then deploy certain strategies such as early-harvesting and switching to early-maturing crops to avoid with the perennial fires and these strategies further reinforce other dimensions of food insecurity such as nutrition insecurity. Because livelihoods strategies such as crop farming, hunting, charcoal production and herding intersect in the northern savannah zone, we recommend policy options that will engage community members in finding common ways of using shared spaces sustainably. Government should also adopt policies that will encourage domestication of certain livelihood strategies such as cattle herding.     

Participatory assessment of soil degradation in the uplands of southwestern Tanzania: Implications for sustainable agriculture and rural livelihoods

Rural household food insecurity and poverty are closely linked to soil degradation in Sub-Saharan Africa. However, causes, degradation processes, coping strategies and need for interventions may vary from one place to another. This study was conducted in Mbinga District, SW Tanzania, to investigate causes and biophysical processes of soil degradation; effects on livelihoods, coping strategies and entry points for interventions. Implications for sustainable production and rural livelihoods are discussed. Participatory Rural Appraisal (PRA), household surveys using a short open-ended questionnaire and biophysical exploration were the research tools used. Soil fertility depletion resulting from continuous cropping and erosion losses is the main form of soil degradation. Maize yield was 57% lower in fertility-depleted farms than in productive farms. Soil pH, Ca²⁺, Mg²⁺ and CEC accounted for 79% of variations in maize yield. Organic soil fertility amelioration was a common strategy used by smallholders. Use of beneficial tree and shrub fallows is the most environmentally, economically and socially promising improvement that can be used to build on the existing strengths of farmers' knowledge and strategies. Subsidy for the right type of fertilizers, infrastructure improvement and education of farmers on proper use of fertilizers should significantly contribute to improved and sustainable production and livelihoods.     

Geographic shifts in the highland cooking banana (Musa spp., group AAA-EA) production in Uganda

Summary

Between 1970 and 1990 Uganda witnessed the decline of the highland cooking banana from traditional growing areas in the central region, coupled with crop expansion in the country's southwest. Apprehension that the factors leading to loss of sustainability in the central region may be replayed in extant production areas has raised concern about the future of the cooking banana in Uganda. Consequently, a multi-disciplinary study was conducted at nine central and six southwestern sites to document shifts in cooking banana production and to elucidate the causes behind these shifts.

Cooking banana production in central Uganda sites fell from 18% of total food crop and 7% of total cash crop production in the 1970s to 4% and 2%, respectively, in the 1990s. Farmers identified reduced labour availability and management, increasing pest pressure and declining soil nutrient status as the major causes of decline. On-farm verification confirmed farmers' observations: weevil levels were the highest yet found in Uganda, while foliar samples indicated deficiencies in magnesium, nitrogen, and potassium. Soil nutrient deficiencies, however, appear to be a direct outcome ofreduced management rather than ‘soil exhaustion’ as postulated by farmers.

In southwestern Uganda, the importance of the cooking banana as a cash crop has quadrupled since 1970. Banana first penetrated the region because of its ease of production and stability of yield. High yields attracted traders and urban market demand drove further crop expansion. With current market incentives, banana management standards have been high. Under current levels of management, it is unlikely that farmers in southwestern Uganda will experience a similar process of decline as that which occurred in the central region. However, concern remains aboqt lack of replenishment of nutrients leaving the farm in the form of fruits sold for market, a nutrient loss which may eventually lead to non-sustainability of the cropping system.     

Incorporating natural enemies in an economic threshold for dynamically optimal pest management

The control of pests by their natural enemies represents an important regulating ecosystem service that helps maintain the stability of crop ecosystems. These services, however, are often ignored in pest management decision making. In addition, the use of broad-spectrum insecticides can damage the populations of natural enemies, reducing the cost-effectiveness of insecticide investment if unaccounted for in treatment decisions.The existing literature on modeling of biological control of insect pests has generally focused on simulations of the population dynamics of pest and natural enemy species and the processes underlying pest control. But agriculture is a managed ecosystem where predator–prey relationships are heavily influenced by human managers. In modeling managerial choices, this study develops an intra-seasonal dynamic bioeconomic optimization model for insecticide-based pest management that explicitly takes into account both the biological control effect of natural enemies on pest density and the nontarget mortality effect of insecticides on the level of natural pest control supplied. The model captures predator–prey interactions, linking them to crop growth and yield damage functions, which in turn are evaluated in a dynamic optimization framework. We introduce a new decision rule for judicious insecticide decisions using a natural enemy-adjusted economic threshold. This threshold represents the pest population density at which insecticide control becomes optimal in spite of the opportunity cost of injury to natural enemies of the target pest. Using field data from Michigan, the model is applied to the case of soybean aphid (Aphis glycines, Matsumura), a recent invasive pest of soybean (Glycine max), whose management is of both economic and environmental importance to the North Central region of the United States. As illustrated by the numerical examples, such natural enemy-adjusted threshold is likely to lead to fewer recommendations for insecticide use than naïve models that ignore natural enemies, resulting in less insecticide use, while maintaining profitability for farmers that rely on chemical pest control methods.The bioeconomic model developed in this study can be used to conduct a wide variety of analyses such as identifying dynamically optimal spray strategies and estimating the implied economic value of natural control services. Furthermore, with the incorporation of inter-year carry-over factors, such as overwintering of pests and natural enemies, the current model can contribute to building multi-year models for studying long-term pest management.     

Assessment of land degradation and its impact on crop production in the Dry Zone of Myanmar

Land degradation in terms of soil degradation is a major environmental issue posing threat to sustainable livelihood in the semi-arid region of Central Myanmar. However, the studies on soil degradation status and its impacts in this region are very scanty. The objective of this study was to determine the impact of land degradation on crop production both in terms of area and yield in the Dry Zone of Myanmar. Remote sensing and geographic information system-based modelling was utilized to assess and map soil erosion rates. Household survey was conducted to understand the causes of land degradation and its impacts on crop productivity and livelihoods. It has been found out that the current rate of soil erosion ranged from 0 to 114 t ha^–1 yr^–1, and that the average rate of soil erosion increased from 14.2 to 54.6 t ha^–1 yr^–1 over a period from 2000 to 2012. The major types of land degradation were physical and chemical soil degradation. Farmers identified topographic condition, soil types, improper crop management practices and climatic factors as the main causes of soil erosion. The observed crop yields of monsoon rice, groundnut, sesame and cotton in the highly degraded area were 3–12 times lower compared with the yields of these crops grown in less degraded area. Livelihoods of the farmers in the high-degraded area were affected by crop yield reduction, increased cultivation cost and increased uncultivable land area. The impact of land degradation on crop production was dependent on the severity of degradation. This suggests that advanced conservation measures are immediately required and the supportive policy strategies need to be implemented to educate farmers and to strengthen extension services for sustainable land management in the Dry Zone of Myanmar.     

Traditional agriculture in transition: examining the impacts of agricultural modernization on smallholder farming in Ghana under the new Green Revolution

Following the renewed effort at achieving a new green revolution for Africa, emphasis has been placed on modernizing smallholder agriculture through the deployment of improved inputs especially mechanized technologies. In Ghana, the government has in the last decade emphasized the provision of subsidized mechanized ploughing services to farmers alongside a rapidly growing private sector tractor service market. While mechanized technology adoption rates have increased rapidly, the deployment of these technologies has been without critical analysis of the impacts on production patterns and local agrarian systems. This paper examines the distributional impacts of agriculture mechanization on cropping patterns and farm sizes of smallholder farmers in northern Ghana using Geographic Information Systems (GIS) techniques, and semi-structured interviews with smallholder farmers (n=60). Specifically, comparative analysis of the field sizes and cropping patterns of participant farmers prior to and after the adoption of mechanized technologies was conducted. In-depth interviews were used to contextualize the experiences of smallholder farmers toward understanding how mechanization may be impacting traditional agriculture. Our findings reveal a mechanization paradox in which farm sizes are expanding, while cropping patterns are shifting away from traditional staple crops (pearl millet and sorghum bicolor) to market-oriented crops (maize, rice and groundnuts). This transition we argue, has adverse implications on the cultural dimension of food security, the organization of social life, and climate change adaptation. We recommend a retooling of the current agricultural policy focus to ensure context sensitivity for a more robust battle against food insecurity.     

Measurement of residues of benomyl and mancozeb pesticides in shrub and nonshrub cucumbers sampled from different regions of Mazandaran province (Iran)

Farmers use mancozeb against cucumber pests, such as Perono spoxa, in large amounts without consideration of potential chronic human health hazards resulting from pesticide accumulation in food and fruits. Considering the necessity of food for humans and importance of fruit in daily diet, as well as the determination of pesticide residues in food and fruits as mandated by WHO and FAO, the residues benomyl and mancozeb, the most prominently used pesticides in Iran, were measured. In this study cucumbers from 76 sample regions were used. Data showed that the amounts of benomyl was related to the type of cucumber in the regions, but there was no significant relationship between the amount of mancozeb and type of cucumber.     

Integrating local knowledge with science and technology in management of soil,water and nutrients: implications for management of natural capital for sustainable rural livelihoods

Harnessing local knowledge and practices for sustainable management of soil, water and nutrients is important for sustainable development. This work aims to understand soil productivity in traditional open-ridging practices and integrate scientific ideas and technologies into traditional practices for enhancing management of soil productivity. Participatory assessments, household surveys, field experiments, observations and analyses of outcomes were used. Participatory assessments revealed declining natural soil fertility and maize productivity over time, a concern reiterated by 82.5% of respondents. Evaluation of ridge tillage practices showed that bean yields were significantly (p?<?0.05) higher by 19–35% in traditional open ridges and increased by 23–38% when ties were integrated. Integration of fertilizers resulted in significantly (p?<?0.05) higher subsequent maize yields in tied ridges than in traditional open ridge and flat cultivation practices. Improved integrated tillage practices resulted in increased soil and water conservation, soil fertility and crop tolerance to prolonged no-rainfall spells. National development policies should create enabling environments for smallholder farmers to integrate modern knowledge and technologies with their traditional knowledge and practices in land management for high and sustained quality of natural capital for secure and sustainable livelihoods.     

Towards sustainable land-use in the hills of Central Himalaya,India

SUMMARY

Over-population in relation to poor land productivity and cultivation in less fertile lands is resulting in land degradation and deforestation in UP hills. Growing demand of more food production and increasing need for more cash in hand have forced the hill people to cultivate all kinds of land, resulting in the denudation of land resources and soil erosion. These changes resulted in out migration of the area's human resource. A new management system for the revival of natural resources and the sustainable utilization of the area's human population and livestock has been proposed, involving active local participation in order to change the existing land-use to a system based on the soil fertility scale.     

Examples of sustainable development efforts in Costa Rica

SUMMARY

Efforts towards sustainable development are now being undertaken at all levels and the concept has increasingly entered the consciousness of the average person. For many Costa Ricans however, it is not just an abstract concept but a matter of survival as input costs increase, natural resources diminish and the soil loses fertility or is washed away. This paper reviews three case studies representing different approaches towards achieving sustainable development by different types of organization which are each innovative in preventing further destruction of tropical forest resources.     

Modeling the population dynamics of cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) over a wide area in northern China

The cotton bollworm Helicoverpa armigera (Lepidoptera: Noctuidae) is one of the most serious crop pests in northern China, calling for accurate prediction of pest outbreaks and strategies for pest control. A computer model is developed to simulate the population dynamics of H. armigera over a wide area in northern China. The area considered covers 12 provinces where serious outbreaks of H. armigera have been observed. In this model, pest development is driven by local ambient temperature, and adults migrate long distances between regions and select preferred hosts for oviposition within a region. Six types of host including cotton, wheat, corn, peanut, soybean and a single category composed of all other minor hosts are considered in this model. Survival rates of eggs and larvae are based on life-table data, and simulated as a function of host type, host phenology and temperature. The incidence of diapause depends on temperature and photoperiod experienced during the larval stage. Survival rate of non-diapause pupae is a nonlinear function of rainfall, and overwinter survival rate is a nonlinear function of temperature. Insecticide is applied when population density exceeds the economic threshold on a host crop within a region. Comparisons of model output with light-trap data indicate that our model reflects the pest population dynamics over a wide area, and could potentially be used for testing novel pest control strategies in northern China.     

常宁市林业有害生物发生现状和防控对策

结合常宁市林业有害生物普查工作,在实地调查全市林业有害生物发生种类和发生现状的基础上,通过分析常宁市林业有害生物发生特点和成灾原因,结合林业工作实际,提出了常宁市林业有害生物防控对策．参7．     

Host plant resistance to insects: an eco-friendly approach for pest management and environment conservation

Host plant resistance (HPR) to insects is an effective, economical, and environment friendly method of pest control. The most attractive feature of HPR is that farmers virtually do not need any skill in application techniques, and there is no cash investment by the resource poor farmers. Considerable progress has been made in identification and development of crop cultivars with resistance to the major pests in different crops. There is a need to transfer resistance genes into high-yielding cultivars with adaptation to different agro-ecosystems. Resistance to insects should form one of the criteria to release varieties and hybrids for cultivation by the farmers. Genes from the wild relatives of crops, and novel genes, such as those from Bacillus thuringiensis can also be deployed in different crops to make HPR an effective weapon to minimize the losses due to insect pests. HPR will not only cause a major reduction in pesticide use and slowdown the rate of development of resistance to insecticides in insect populations, but also lead to increased activity of beneficial organisms and reduction in pesticide residues in food and food products.     

农户参与三氯杀螨醇替代技术培训积极性的影响因素分析

病虫害综合防治（1PM）技术旨在结合生物、农学及物理防治方法,合理使用化学农药,降低农业生产成本,保护农业劳动者健康和生态环境.以联合国开发计划署（UNDP）、环境保护部对外合作中心和全国农业技术推广中心联合启动实施的“中国含滴滴涕三氯杀螨醇生产控制及IPM技术替代全额示范项目”为例,系统分析影响农户参与IPM培训积极性的主要因素.结果表明,农户种植规模对农户参与IPM培训的积极性影响显著,学员性别和年龄不是影响其参加培训积极性的显著因素;学员参加培训的次数越多,其对IPM技术的采纳率越高.农民田间学校应更多地吸收老人和妇女参加三氯杀螨醇替代技术及IPM培训     

Sustainability aspects of vegetable production in the peri-urban environment of Bogotá, Colombia

Although the peri-urban region around Bogotá, Colombia contains a diversified horticulture sector, local vegetable production suffers from a critical lack of research and availability of un-biased, scientifically validated information on crop management. In this study, we identify current trends and deficiencies in fertilisation and pest management for local vegetable production. We relate pesticide type with target pests, evaluate temporal patterns in pesticide and fertiliser use for a key crop (i.e. spinach) and conduct basic nutrient budget accounting. Personal interviews with vegetable growers were combined with a detailed follow-up of management activities and soil nutrient profiles on pilot farms in two different peri-urban municipalities. Most (84%) vegetable growers relied on personal experience, and indicated a lack of unbiased information on fertiliser effectiveness and pesticide action spectra. The majority of farmers used pesticide mixtures on a calendar basis and commonly applied products below recommended doses. Soil nutrient accounts indicate insufficient fertilisation and a progressive depletion of key nutrients. Extraction rates for the principal vegetable crops exceeded by 33.6%, 20.5% and 93.0% soil nutrient availability of N, P and K, respectively. Organic products are included in local fertilisation schemes, with chicken manure as the principal source, at an average application rate of 6 t ha^?1. Our findings could help policymakers and local institutions set a research and extension agenda to promote sustainable peri-urban vegetable production and help secure peri-urban livelihoods while ensuring healthy and safe horticultural production.     

Computer simulation applied to the biological control of the insect Aphis gossypii for the parasitoid Lysiphlebus testaceipes

In integrated pest management (IPM), biological control is one of the possible options for the prevention or remediation of an unacceptable pest activity or damage. The success of forecast models in IPM depends, among other factors, on the knowledge of temperature effect over pests and its natural enemies. In this work, we simulated the effects of parasitism of Lysiphlebus testaceipes (Cresson, 1880) (Hymenoptera: Aphidiidae) on Aphis gossypii (Glover, 1877) (Hemiptera: Aphididae), a pest that is associated to crops of great economic importance in several parts of the world. We made use of experimental data relative to the host and its parasitoid at different temperatures. Age structure was incorporated into the dynamics through the Penna model. The results obtained showed that simulation, as a forecast model, can be a useful tool for biological control programs.     

Differential reproductive success within the Krummhörn population (Germany, 18th and 19th centuries)

Summary On the basis of a family reconstitution study (Krummhörn, Germany, 18^th und 19^th centuries) it is shown how in one marriage cohort (1720–1750), family land ownership correlates with systematic fitness differentials. Farmers have a greater long-term fitness, on the average, than members of non-peasant population, and farmers possessing better than average wealth achieve a greater long-term fitness than farmers with medium-sized or small landholdings. The proximate causes herefore are to be found in both the varying patterns of marital fertility and in the differences in the marital and migration habits of the children from the various social groups. That is why the number of live births or even the number of surviving children is not the best estimate of a person's genetic contribution to the next generation of the local population. This can be shown by using a new algorithm for the assessment of long-term fitness differentials.     

Assessing the capacity of three Bolivian food systems to provide farm-based agroecosystem services

ABSTRACT

Food system activities have modified 40% of the Earth’s terrestrial surface. These activities affect the sustainability of food systems – and their ability to provide agroecosystem services. Here, we compare three food systems in Bolivia. One is agro-industrial (soybean), one is indigenous to a Guarani community (maize and beans), and one is an agroecological, horticulture-based food system. We use the Agroecosystem Service Capacity (ASC) approach, which is based on a list of 23 agroecosystem services that allow the ASC index of farm-based agroecosystems to be estimated. Our findings show that agroecological (ASC = 2.57) and indigenous (ASC = 2.43) farm-based agroecosystems have a higher capacity to provide farm-based agroecosystem services than the agro-industrial (ASC = 0.82). This capacity differs because farmers in the agroecological and indigenous farm-based agroecosystems achieve a higher structural diversity and know how to use more agroecosystem services. These results could promote more sustainable food systems by fostering agricultural landscapes that provide a diversity of farm-based agroecosystem services.     

Ecologically based management of rodents in the real world: applied to a mixed agroecosystem in Vietnam.

Rodents cause significant damage to lowland irrigated rice crops in the Red River Delta of Vietnam. A four-year study was conducted in 1999-2002 to examine the effectiveness of applying rodent control practices using the principles of ecologically based pest management. Four 100-150 ha study sites adjacent to villages were selected and farmers on two treated sites were asked to follow a set of rodent management practices, while farmers on the untreated sites were asked not to change their typical practices. Farmers on the treated sites were encouraged to use trap-barrier systems (TBS's; 0.065-ha early planted crop surrounded by a plastic fence with multiple capture traps; one TBS for every 10-15 ha), to work together over large areas by destroying burrows in refuge habitats soon after planting (before the rats reestablish in the fields and before the onset of breeding), synchronizing planting and harvesting of the their rice crops, cleaning up weeds and piles of straw, and keeping bund (embankment) size small (<30 cm) to prevent burrowing. A 75% reduction in the use of rodenticides and plastic barrier fences (without traps or an early crop) was achieved on treated sites. The abundance of rodents was low after implementation of the management practices across all sites. There was no evidence for an effect of treatment on the abundance of rodents captured each month using live-capture traps, and no difference in damage between treatments or in yields obtained from the rice crops. Therefore, ecologically based rodent management was equally effective as typical practices for rodent management. Farmers on the treated sites spent considerably less money applying rodent control practices, which was reflected in the comparative increase in the partial benefit:cost of applying ecologically based rodent management from 3:1 on treated sites and untreated sites prior to the implementation of treatments to 17:1 on treated sites in the final year of the project.     

花椒农林复合生态系统的简化对某些相关因子的影响

对单一种植和复合种植两种模式的花椒林地(即有草模式和无草模式)进行了相关生态因子的对比调查,以评价现存花椒林单一模式的合理性．结果表明,在单一种植模式下,花椒林的高度、地径和冠幅虽显著优于复合模式,但是病虫害严重;两种模式中土壤含水率均是随土层厚度的增加而增大,但是变幅有较大差异：复合模式的变幅较稳定,为7．59%～23．79％;而单一模式的变化较剧烈,为4．73％～49．72％,复合模式的土壤含水率显著高于单一模式．复合模式的昆虫种类、多样性、丰富度和均匀度也明显高于单一模式,其中单一模式中的肉食性和寄生性昆虫种类低于复合模式,而植食性蚜虫数量则高于复合模式,暗示单一模式中天敌的栖境和资源以及特定的食草昆虫与有益菌缺少．讨论认为,杂草在花椒林生态系统中起着重要的生态作用,现存的单一种植模式虽然对花椒的生长和产量有利,但却是以牺牲农林系统的可持续发展以及生物多样性为代价的．表3参9。