3,692 research outputs found
Agricultural Growth and Economic Development: A View through the Globalization Lens
This paper re-visits the age old proposition that agriculture growth contributes to overall economic development, and asks whether the relationship still holds in an increasingly globalized world. There is overwhelming empirical support for the above proposition, indeed, it is hard to find exceptions, barring a few city states, where sustained economic development has not been preceded by robust agricultural growth. However, there are a large number of countries that have witnessed neither agricultural growth nor economic development. Even in countries where agricultural growth has been significant, dramatic inter-regional differences persist. This paper examines the factors that contribute to or constrain the process of agricultural transformation. Does the process of globalization, and the resultant changes in agrifood systems, offer new opportunities for agriculture led growth, or will it further marginalize excluded countries, regions and groups? The factors that cause exclusion are examined both in terms of globalization forces and in terms of domestic shortcomings in policies and governance. Policy interventions that attempt to reduce the costs of transition to a globalized agricultural system are explored, including safety nets for those left behind.International Development,
International Collaboration in Crop Improvement Research: Current Status and Future Prospects
Investments over the past 35 years have created a system of national and international research centers that has revolutionized the supply of improved cereal varieties to developing country farmers. The newly created scientific ability to exploit genetic resources has been the engine of productivity growth in much of world agriculture. But the success that has been attained in building research institutions has not touched all countries or farmers, nor can it be considered permanent. The financial and political environment of the past decade has halted the expansion of agricultural research capacity and the scarcity of research resources and evolving world intellectual property rights (IPR) regimes complicates the search for stable arrangements for cooperation. This paper examines the current structure and institutional capacity of the international crop breeding systems for rice and wheat. Discussions are presented within the context of a system composed of research functions spanning the basic to applied research spectrum. The model emphasizes that an efficient and stable international system may be comprised of many partner institutions, each with a limited breadth of research activities, particularly when research budgets are fixed or declining. The paper concludes with a review of some of the trends that will influence the future direction of research cooperation.Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,
Confronting the environmental consequences of the Green Revolution in Asia:
Intensive double or triple monocropping of rice has caused degradation of the paddy micro environment and reductions in rice yield growth in many irrigated areas in Asia. Problems include increased pest infestation, mining of soil micronutrients, reductions in nutrient-carrying capacity of the soil, build-up of soil toxicity, and salinity and waterlogging. Emerging sustainability problems in intensive rice agriculture show the need for a greater understanding of the physical, biological and ecological consequences of agricultural intensification and greater research attention to long term management of the agricultural resource base.Green Revolution Asia., Rice Yields Asia., Environmental degradation., Sustainability., Resource management., Agricultural resources.,
Cereal Crop Productivity in Developing Countries: Past Trends and Future Prospects
This paper synthesizes the evidence on cereal crop productivity in developing countries over the past 30 years and looks at future prospects for productivity growth. For more than three decades we have witnessed the phenomenal growth of cereal crop productivity in the developing world. Termed the Green Revolution, the initial phase of this growth resulted from an increase in land productivity and occurred in areas of growing land scarcity and/or areas with high land values. Significant investments in research and infrastructure development, especially irrigation, were the strategic components of this increased productivity. In the post-Green Revolution period, particularly in Asia, productivity growth has been sustained through increased input use and, more recently, through more efficient use of inputs. Lately, however, indicators show a decrease in the growth rate of productivity of two of the three primary cereals, rice and wheat. The first two sections of this paper present trends on cereal crop productivity in developing countries over the last three decades. Supporting evidence includes yield and other partial factor productivity trends and a summary of studies on total factor productivity. The third section speculates on the prospects for future growth.Crop Production/Industries,
Tropical and Subtropical Maize in Asia: Production Systems, Constraints, and Research Priorities
This book examines future technological and policy prospects for the sustainable intensification of rainfed upland maize production in Asia, and derives R&D priorities for specific maize production environments and markets. Village-level and farmer-group surveys were conducted to characterize upland maize production environments and systems in China, India, Indonesia, Nepal, the Philippines, Thailand, and Vietnam. Survey findings, particularly farmer-identified constraints to maize production, complemented with other relevant data, were used in country-level, R&D priority-setting workshops. High on the list of farmer constraints was drought, estimated to affect three production environments that are home to about 48 million rural poor and produce an estimated 16 million tons of maize, and others such as downy mildew, stem borers, soil erosion/landslides, waterlogging, poor agricultural extension/ technology transfer services, and poor access to low-interest credit and markets. Farmers felt that socioeconomic and policy-related constraints impact maize productivity more than technical constraints do. It is important to recognize that technology is not the only key to increasing productivity and bettering the conditions of marginal maize farmers in Asia. There is a growing trend towards commercializing and intensifying maize production that is different from the staple food self-sufficiency paradigm that has been the cornerstone of agricultural policy in most developing countries. Appropriate government policies could help alleviate the adverse consequences of commercialization and promote sustainable intensification of maize production, especially in marginal environments inhabited by resource-poor subsistence farmersMaize, Agricultural development, Farming systems, Production policies, Environmental factors, Cropping systems, Research projects, Project management, Asia, Crop Production/Industries, E10,
Towards Reduced Pesticide Use for Cereal Crops in Asia
Several opportunities are available for dramatically reducing the use of agrochemicals in Asian cereal crop production. The first section of this paper summarizes past trends and future prospects for pesticide use in Asia for the three major cereal crops: rice, wheat, and maize. The second section identifies factors that have contributed to rising farm-level demand for pesticides and factors that could lead to a reduction in their demand. The third section highlights the advances that have been made in generating and disseminating cereal crops with resistance to insects and diseases. It focuses on conventional breeding strategies for host-plant resistance as well as the current and potential contributions of biotechnology. Pesticide productivity, yield variability, and their relation to host-plant resistance are reviewed, along with evidence from trials and farmers' fields. The paper concludes with a discussion of the integrated management approaches that will be necessary for maximizing and sustaining the productivity gains offered by resistant varieties.Crop Production/Industries,
A frictional Cosserat model for the flow of granular materials through a vertical channel
A rigid-plastic Cosserat model has been used to study dense, fully developed
flow of granular materials through a vertical channel. Frictional models based
on the classical continuum do not predict the occurrence of shear layers, at
variance with experimental observations. This feature has been attributed to
the absence of a material length scale in their constitutive equations. The
present model incorporates such a material length scale by treating the
granular material as a Cosserat continuum. Thus localised couple stresses exist
and the stress tensor is asymmetric. The velocity profiles predicted by the
model are in close agreement with available experimental data. The predicted
dependence of the shear layer thickness on the width of the channel is in
reasonable agreement with data. In the limit of the ratio of the particle
diameter to the half-width of the channel being small, the model predicts that
the shear layer thickness scaled by the particle diameter grows.Comment: 17 pages, 12 PostScript figures, uses AmsLaTeX, psfrag and natbib.
Accepted for publication in Acta Mechanic
From hand tillage to animal traction: Causes and effects and the policy implications for sub-Saharan African agriculture
Identifies conditions affecting the transition from hand tillage to animal traction and further transition to tractors. Asseses causes, effects and policy implications for sub-Saharan African agriculture
Computational method to predict thermodynamic, transport, and flow properties for the modified Langley 8-foot high-temperature tunnel
The Langley 8 foot high temperature tunnel (8 ft HTT) is used to test components of hypersonic vehicles for aerothermal loads definition and structural component verification. The test medium of the 8 ft HTT is obtained by burning a mixture of methane and air under high pressure; the combustion products are expanded through an axisymmetric conical contoured nozzle to simulate atmospheric flight at Mach 7. This facility was modified to raise the oxygen content of the test medium to match that of air and to include Mach 4 and Mach 5 capabilities. These modifications will facilitate the testing of hypersonic air breathing propulsion systems for a wide range of flight conditions. A computational method to predict the thermodynamic, transport, and flow properties of the equilibrium chemically reacting oxygen enriched methane-air combustion products was implemented in a computer code. This code calculates the fuel, air, and oxygen mass flow rates and test section flow properties for Mach 7, 5, and 4 nozzle configurations for given combustor and mixer conditions. Salient features of the 8 ft HTT are described, and some of the predicted tunnel operational characteristics are presented in the carpet plots to assist users in preparing test plans
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