160 research outputs found

    Development and diffusion of integrated Striga control practices for small-scale farmers in western Kenya

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    The parasitic weed Striga hermonthica has become one of the most significant constraints to cereal production in western Kenya. In 1995 a collaborative project was initiated to develop control technologies for Kenyan farmers

    Extension and adoption of biofortified crops: Quality protein maize in East Africa

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    Biofortified crops, bred for improved nutritional quality, can alleviate nutritional deficiencies if they are produced and consumed in sufficient quantities. These varieties can be promoted based on their agronomic performance or based on their nutritional qualities. Quality protein maize (QPM) was the first biofortified crop and has been disseminated in Africa using both approaches. To study their effectiveness, a survey of rural households was conducted in the maize-growing areas of East Africa, comparing communities with access to QPM extension activities to control communities. The results show that a third to one half of the farmers in project communities participated in extension activities in all countries except Kenya. In these communities, familiarity with QPM was high (74-80% of farmers), again except for Kenya (19%), but understanding of their nutritional benefits was much lower (47-55%, with 7% in Kenya). In all countries, farmers evaluated QPM varieties as good or better than conventional varieties (CV) for post-harvest characteristics. For agronomic characteristics, however, QPM varieties scored better than CV in Uganda, about the same in Tanzania, but less in Ethiopia. Adoption patterns differed widely between the countries: in the project areas it varied from 70% in Uganda, 30% in Tanzania to none in Kenya. In the control areas, adoption was only observed in Uganda (45% of farmers). Factors that significantly influenced adoption were farmers’ participation in extension activities, farmers’ agronomic and post-harvest evaluation of QPM vs. CM, and their understanding of the nutritional benefits of QPM. Evaluation for agronomic performance was found to be more important than knowledge of nutritional benefits, thus favoring the first approach. A reliable seed supply was, however, found to be a basic condition for adoption.Teaching/Communication/Extension/Profession,

    Potential Markets for Herbicide Resistant Maize Seed for Striga Control in Africa

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    Striga is an obligate parasitic weed attacking cereal crops in Subsaharan Africa. In Western Kenya, it is identified by farmers as their major pest problem in maize. A new technology, consisting of seed coating of herbicide tolerant maize varieties, has prove to be very effective in farmer fields. To bring this technology to the farmer, a sustainable delivery system needs to be developed, preferably through the private sector. To help of the seed companies develop a strategy, the potential market for this technology is hereby calculated, combines different data sources into a Geographic Information System (GIS). Superimposing secondary data, field surveys, agricultural statistics and farmer surveys makes it possible to clearly identify the Striga-prone areas in western Kenya. According to the analysis, the area has 212,000 ha in maize annually, with a population of 5.9 million people and a maize production of 480,000 kg, or 81 kg/person. Population density is high at 359 people/km2. A farmer survey reveals that 70% of farmers in this zone have Striga in their fields. Contingent valuation methods indicate that farmers' would be willing to buy on average 3.67 kg of the new seed each. This translates into a potential demand of 3,400 to 5,200 tons annually. Similar calculations, but based on much less precise data and expert opinion, not farmer surveys, estimate the potential market for herbicide tolerant maize against Striga at 64,600 tons annually, with an estimated value of $129 million.maize, Striga, Africa, weeds, pest control, Crop Production/Industries, Q12,

    Environmental Parameters Associated With Stable Fly (Diptera: Muscidae) Development at Hay Feeding Sites

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    Substrates composed of hay residues, dung, and urine accumulate around winter hay feeding sites in cattle pastures, providing developmental habitats for stable flies. The objective of this study was to relate physiochemical and microbial properties of these substrates to the presence or absence of stable fly larvae. Properties included pH, temperature, moisture, ammonium concentration, electrical conductivity, and numbers of coliform, fecal coliform, Escherichia coli, and Enterococcus bacteria. Each physiochemical sample was classified as a function of belonging to one of the three 2-m concentric zones radiating from the feeder as well as presence or absence of larvae. In total, 538 samples were collected from 13 sites during 2005–2011. Stable fly larvae were most likely to be found in moist, slightly alkaline substrates with high levels of ammonium and low temperature. The probability of larvae being present in a sample was the highest when the moisture content was 347% relative to dry weight and the average pH was 8.4. Larvae were recovered within all zones, with a nonsignificant, but slightly higher, percentage of samples containing larvae taken 2–4m from the center. All methods used to enumerate bacteria, except total coliform, indicated decreasing concentrations in hay bale residue throughout the summer. In addition to the environmental parameters, cumulative degree day 10˚C had a significant effect on the probability of observing stable fly larvae in a sample, indicating that unidentified seasonal effects also influenced immature stable fly populations

    Environmental Parameters Associated With Stable Fly (Diptera: Muscidae) Development at Hay Feeding Sites

    Get PDF
    Substrates composed of hay residues, dung, and urine accumulate around winter hay feeding sites in cattle pastures, providing developmental habitats for stable flies. The objective of this study was to relate physiochemical and microbial properties of these substrates to the presence or absence of stable fly larvae. Properties included pH, temperature, moisture, ammonium concentration, electrical conductivity, and numbers of coliform, fecal coliform, Escherichia coli, and Enterococcus bacteria. Each physiochemical sample was classified as a function of belonging to one of the three 2-m concentric zones radiating from the feeder as well as presence or absence of larvae. In total, 538 samples were collected from 13 sites during 2005–2011. Stable fly larvae were most likely to be found in moist, slightly alkaline substrates with high levels of ammonium and low temperature. The probability of larvae being present in a sample was the highest when the moisture content was 347% relative to dry weight and the average pH was 8.4. Larvae were recovered within all zones, with a nonsignificant, but slightly higher, percentage of samples containing larvae taken 2–4m from the center. All methods used to enumerate bacteria, except total coliform, indicated decreasing concentrations in hay bale residue throughout the summer. In addition to the environmental parameters, cumulative degree day 10˚C had a significant effect on the probability of observing stable fly larvae in a sample, indicating that unidentified seasonal effects also influenced immature stable fly populations

    A Study of Teacher Growth, Supervision, and Evaluation in Alberta: Policy and Perception in a Collective Case Study

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    Teacher effectiveness has long been identified as critical to student success and, more recently, supporting students attaining the skills and dispositions required to be successful in the early 21st century. To do so requires that teachers engage in professional learning characterized as a shift away from conventional models of evaluation and judgment. Accordingly, school and system leaders must create “policies and environments designed to actively support teacher professional growth” (Bakkenes, Vermunt, & Webbels, 2010). This paper reports on the Alberta Teacher Growth, Supervision, and Evaluation (TGSE) Policy (Government of Alberta, 1998) through the eyes of teachers, school leaders, and superintendents. The study sought to answer the following two questions: (1) To what extent, and in what ways, do teachers, principals, and superintendents perceive that ongoing supervision by the principal provides teachers with the guidance and support they need to be successful? and, (2) To what degree, and in what ways, does the TGSE policy provide a foundation to inform future effective policy and implementation of teacher growth, supervision, and evaluation? Results affirm international findings that although a majority of principals consider themselves as instructional leaders, only about one third actually act accordingly (OECD, 2016)
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