Surveying farmers' agroforestry plots: experiences in evaluating alley-cropping and tree border technologies in Western Kenya

Evaluation of existing on-farm agroforestry plots should provide useful supplementary information for the design of improved agroforestry systems, in both research and development projects. Such evaluation has been little used, however, largely due to the methodological difficulties of surveying highly variable on-farm plots, and difficulties in identifying key variables for measurement. This paper describes a set of methods and tools used in evaluating plots of alley-cropping and tree borders around crop fields established by farmers working with the CARE Agroforestry Extension Project in western Kenya. Details of survey design, sampling, and implementation are discussed, and suggestions made for carrying out agroforestry surveys in other projects. A condensed version of the questionnaire is appended.     

Building opportunities for small-farm agroforestry to supply domestic wood markets in developing countries

Agroforestry Systems - The fastest-growing demand for wood products is in domestic markets of developing countries. These markets could offer significant economic opportunities for hundreds of...     

Evaluating agroforestry interventions in extension projects

Because of the relative dearth of scientific information in agroforestry, monitoring and evaluation of agroforestry technologies in development projects plays an important role in the development and improvement of technical extension recommendations. To identify appropriate methodologies, ICRAF conducted in 1988–89 a review of agroforestry technology monitoring and evaluation in 166 projects worldwide, of which 108 responded. Almost 80% of these were involved in technology evaluation. Many extension projects were conducting research to test technologies on-farm or on research plots. Technology evaluation by projects focused on the biological of trees, often with inadequate consideration of the technology context. Few projects seemed to use farmer assessment in evaluation. Recommendations are made for an effective evaluation process and selection of appropriate methods and variables to be assessed by projects. Methods should be selected according to the availability of resources and should favour collaborative or collegial interaction between farmers and project staff.     

Ecological speciation in South Atlantic island finches

Examples of sympatric speciation in nature are rare and hotly debated. We describe the parallel speciation of finches on two small islands in the Tristan da Cunha archipelago in the South Atlantic Ocean. Nesospiza buntings are a classic example of a simple adaptive radiation, with two species on each island: an abundant small-billed dietary generalist and a scarce large-billed specialist. Their morphological diversity closely matches the available spectrum of seed sizes, and genetic evidence suggests that they evolved independently on each island. Speciation is complete on the smaller island, where there is a single habitat with strongly bimodal seed size abundance, but is incomplete on the larger island, where a greater diversity of habitats has resulted in three lineages. Our study suggests that the buntings have undergone parallel ecological speciation.     

Farmer costs and benefits from agroforestry and farm forestry projects in Central America and the Caribbean: implications for policy

This paper presents results of an evaluation of the benefits provided by agroforestry and farm forestry projects in Central America and the Caribbean, and the policy implications. Tree planting provided financial benefits to farmers, as well as social, economic and environmental benefits. These justify policy interventions to explicitly recognize the potential of on-farm tree-planting efforts and provide a policy environment favorable to such efforts. New or revised policies are needed, particularly in a period of declining public budgets, to limit external incentives to in-kind inputs, rather than financial subsidies; promote market development for tree products; adopt low-cost, community-based extension strategies; focus research support; and reduce regulatory disincentives.     

Evaluation of a canine C6 ELISA Lyme disease test for the determination of the infection status of cats naturally exposed to Borrelia burgdorferi

The efficacy of a commercially available in-office kit (SNAP 3Dx, IDEXX Laboratories) for detection of antibodies directed against an invariable region (IR6) of the B. burgdorferi surface protein VlsE (Vmp-like sequence, Expressed), a surface antigen of the spirochete recognized during active infection has been evaluated in dogs. The present study was conducted to determine whether this in-office test could be useful for detection of antibodies to B. burgdorferi in cats. Cats owned by clients of a veterinary hospital located in an area hyperendemic for Lyme disease were included in the study. When possible, cats with an outdoor lifestyle, bite wounds, or current tick infestation were recruited for the study to help ensure that animals with a likelihood of exposure to natural infection by B. burgdorferi would be included in the test group. Of the 24 cats tested, 17 samples were positive for antibodies to B. burgdorferi by the C6 ELISA kit. For all 17 of these samples, a duplicate sample tested by immunofluorescent assay (IFA) was in agreement with the ELISA. Five samples were negative by both assays. Two samples that were negative by the C6 ELISA test had low IFA titers (1:100). One of these two discrepant samples was negative and one was positive for antibodies to B. burgdorferi by the Western blot test. It was concluded that the C6 ELISA test performed with good agreement with the IFA and Western blot tests for detection of antibody to B. burgdorferi in the majority of cats tested. The test offers the advantages of producing a result rapidly (approximately 8 minutes), and it requires only two drops of serum, plasma, or whole blood.     

Multi-functional landscapes from the grassroots? The role of rural producer movements

Around the world, agricultural landscapes are increasingly seen as “multi-functional” spaces, expected to deliver food supplies while improving rural livelihoods and protecting and restoring healthy ecosystems. To support this array of functions and benefits, governments and civil society in many regions are now promoting integrated farm- and landscape-scale management strategies, in lieu of fragmented management strategies. While rural producers are fundamental to achieving multi-functional landscapes, they are frequently viewed as targets of, or barriers to, landscape-oriented initiatives, rather than as leading agents of change. In reality, however, rural producers in many areas have embraced elements of multi-functional land management. In this paper, we explore the role and recent evolution of producer movements in influencing multi-functional farm and landscape management. We explore these roles through six case studies, including a land reform movement in Brazil, indigenous territorial development in Bolivia, conservation agriculture associations in Canada, environmental cooperatives in the Netherlands, indigenous and biocultural heritage associations in Peru, and Landcare groups in the Philippines. These experiences suggest that producer movements are playing pivotal roles in supporting landscape multi-functionality, not only through agroecological farming practices but also through off-farm efforts to conserve ecosystems and support multi-stakeholder landscape planning. On the other hand, interests of producer movements are not always fully aligned with multi-functional landscape management approaches. The contribution of producer movements to multi-functional landscapes depends on these movements including farm and landscape stewardship in their values and goals, and having the political support and capacity to engage meaningfully in multi-stakeholder processes.     

Demethylation of Dimethylarsinic Acid and Arsenobetaine in Different Organic Soils

Methylation and demethylation of arsenic may change substantially the toxicity and mobility of arsenic in soils. Little is known about demethylation of organic arsenic species in organic soils. We incubated dimethylarsinic acid (DMA) and arsenobetaine (AsB) in soils and aqueous soil extracts from a forest floor and fen, in order to investigate demethylation processes. Incubations were conducted at 5°C in the dark under oxic or anoxic conditions. Arsenobetaine demethylated rapidly in all soil extracts with half-lives of 3.6–12 days, estimated from first order kinetic. Demethylation of DMA was relatively slow with half-lives of 187 and 46 days in the forest floor extracts and oxic fen extracts, respectively. In comparison, DMA was stable for 100 days in anoxic fen extracts. The apparent half-lives were much shorter in soils for DMA (1.3–12.6 days) and AsB (0.5–1.9 days) than in soil extracts, suggesting also irreversible AsB and DMA adsorption to soils beside demethylation. An unknown arsenic species and DMA were detected as metabolites of AsB demethylation. The results indicate rapid demethylation of AsB probably via the pathway AsB → Dimethylarsenoylacetate → DMA, followed up by slow demethylation of DMA → monomethylarsonic acid → inorganic As species.     

The role of nitrogen oxides in oxidant production as predicted by the Regional Acid Deposition Model (RADM)

Regional oxidant distributions produced under various atmospheric conditions and emission scenarios are investigated using the Regional Acid Deposition Model (RADM). RADM is a complex, evolving three-dimensional Eulerian model that describes the chemistry, transport and deposition of tropospheric trace species including SO₂, sulfate, NO _x and volatile organic compounds as well as O₃, other major oxidants and acids. The model calculates the short-term temporal evolution of atmospheric trace gas concentrations and their deposition on the regional scale. This study is focused on oxidant production in the eastern United States and southeastern Canada. The influence of atmospheric conditions is explored by comparing three characteristic winter, summer and spring/fall cases. Base-case 1985 emissions of SO _x , NO _x , volatile organic compounds (VOCs), NH₃ and CO are specified using the comprehensive pollutant emissions inventory developed as part of the National Acid Precipitation Assessment Program (NAPAP). The perturbed case, which represents projected anthropogenic emission changes for 2010, indicates changes in daily total 80 km grid average NO _x emissions ranging from increases of 75% to decreases of 45% and VOC emission changes ranging from increases of 65% to decreases of 20%. The largest NO _x emission changes occur in the northeast, and the largest VOC changes occur in the Gulf Coast area. Ground level grid average midday O₃ concentrations for the 1985 emission cases are highest (on the order of 70 to 100 ppb) in the New York City and Houston metropolitan areas for the summer and spring cases; the summer case also indicates relatively high grid average O₃ concentrations of greater than 80 ppb in the southeast. Winter case values are much lower than summer O₃ values throughout the region, with highs of 40 to 50 ppb occurring in the southeast and the Great Lakes area. Changes in NO _x and other emissions under the complex 2010 emissions scenario for the summer case result in maximum O₃ concentration reductions of 10% in the Houston area and increases in O₃ of a few percent in some rural areas of the southeast. This study underscores the need for more comprehensive assessment of the complex relationships among regional emission changes, oxidant production and atmospheric conditions.