Fruits and vegetables are important commodities in global agriculture. However, in sub-Saharan Africa, production is sub-optimal in terms of yield, quality and environmental health practices due to several constraints such as insect pests which reduce yields through direct damage, or indirectly as disease vectors often promoting microbial diseases. Pest control still relies mainly on chemicals with their associated risks of resistance selection and toxicity to humans and environment. Several alternatives including biopesticides, semiochemical and nets are being explored in pest management. Insect nets applied on tomatoes, cabbages, beans and leafy vegetables protect them from flies, butterflies, moths, albeit to a lesser extent, whiteflies, aphids and thrips reducing their outbreaks as compared to open cultivation. As a result, pest control is limited and yield quantity and quality are improved. Insect nets are safe and cost effective for a period of 3-5 years if well maintained, and they may be re-used and recycled. Insect nets applied on cabbages in Benin yielded 3-fold more profit than current practice. However, insect nets are not effective against all pests inclusion of insect attractants or repellents may enhance efficacy of netting technology. The use of insect nets offers a cost-effective insect pest management option to among smallholder vegetable growers. The full benefit will be achieved with intensified extension efforts to make this technology better known.
Contract farming is seen by its proponents as a tool for creating new market opportunities as well as for providing credit and training, leading to increased incomes of smallholder farmers. Critics, however, argue that contract farming encourages unequal bargaining relationships with agribusiness firms and is likely to pass risks to farmers, thus favouring large scale farmers at the expense of smallholders. Another school of thought contends that the effect of contract farming on the livelihoods of smallholder farmers is context specific and depends on the enterprise in question. Yet, there is a dearth of empirical evidence from such studies in Sub-Saharan Africa. We use data collected in 2012 from 100 smallholder avocado farmers in Kandara district in Kenya, obtained using multistage sampling technique, to examine the effect of contract farming on household income. Because of lack of pre-treatment data and the possibility of selection bias due to observable characteristics, we use propensity score matching technique to construct controls for the treatment group. The results indicate that contract farming has a positive and significant effect on avocado income. However, further analysis reveals that contract farming does not have any significant effect on the total household income of smallholder avocado farmers. Instead, support services such as interlinked credit and provision of information should be taken into consideration in contract farming because of their potential benefits for smallholders.
Production of cowpea [Vigna unguiculata (L.) Walp.] leaves as vegetables is the primary goal of many producers. Little is known about how leaf harvesting practices affect N2 fixation and leaf and grain yields. Better information would help optimize overall production of leaves and grain. The objective of this study was to establish an optimal time from crop emergence when harvesting of leaves can be initiated and a frequency of leaf harvesting that would give good vegetable leaf yield without compromising grain yield and N2 fixation. Two cowpea cultivars, Kathoka and Ex-Luanda were used. Leaf harvesting initiation (LHI) was at 2, 4, or 5 wk after emergence (WAE). Leaf harvesting frequency was at 7- or 14-d intervals. Kathoka produced higher total leaf weight than Ex-Luanda, while Ex-Luanda produced more grain yield and nodule weight than Kathoka. Initiating leaf harvesting at 2 WAE gave higher leaf yield but lower grain yield and nodule weight. Initiating leaf harvesting at 5 WAE gave very low leaf yields but high grain yield, as might be expected. Optimum LHI was at 4 WAE and provided adequate leaf yield with acceptable grain yield and nodule weight. Weekly leaf harvesting gave higher leaf yield but lower grain yield and nodule weight than biweekly leaf harvesting. Control plants had the highest grain yield and nodule weight. These data show that producers could potentially optimize production of leaf and grain according to their goals.
Continuous coverage of vegetables with nets under different climate conditions in Benin and Kenya proved effective in prot ecting vegetable nurseries and main fields against key lepidopteran and dipteran pests. However, netting did not effectively protect the vegetables against small insects such as aphids and whiteflies, although a visual barrier could delay outbreaks. Hence, opening the nets during the day could be an alternative option to conserve the natu ral enemies for small insects. Moreover, the efficacy of the visual barrier may be complemented by a repellent compound impregnated in the net. The small-holder growers adopting the nets in Benin and Kenya have reduced the number of pesticid e applications required by 70-100%. They have also increased the yield in quality and quantity of production due to microclimate modification. Cost-benefit anal yses of the technology showed that with insect proof nets profitability rates of up to three times could be achieved when compared to the farmers' practices observed in the real environment. Hence, this technology could be a promising way to develop an agro-ecological approach for sustainable management of key horticultural crop pests. (Resume d'auteur)
Abstract This study focused on mapping agripreneurship curriculum and lecturers’ competencies in 8 African Higher Education Institutions (HEIs), participating in the Strengthening Agri-Entrepreneurship and Community Engagement Training in East, West and North Africa (AgriENGAGE) joint Project. A sample of 194 lecturers from East, West, and North Africa participated in the study. The study employed a mixed method approach with concurrent nested research design methodology to collect information. Among the main results found in this study, the key aspects that were implemented in curricula were; business plan development (µ = 3.57), business opportunities identification (µ = 3.56), and communicating with value chain actors (= 3.51). Concerning the forms of entrepreneurship taught, most institutions focused on subsistence agripreneurship (µ = 3.23) with growth-oriented agripreneurship (µ = 2.50) and innovative-oriented agripreneurship (µ = 2.50) having the lowest rating. Regarding teaching methods within the provision of entrepreneurship education, most of the institutions were using traditional teaching methodologies with the common ones being formal lectures, field trips, in-class group discussions, and group project-based learning. Most lecturers had low teaching competencies concerning instructional quality and a moderate/average level of entrepreneurial competencies. The study recommends that universities should implement more professional development and pedagogical training over and above the subject competency to improve lecturers’ entrepreneurial competency.
Cowpea [ Vigna unguiculata (L.) Walp.] is a vital component of traditional cropping systems in the subtropics and tropics, grown both for high‐protein grain and nutritious fresh leaves. The objectives of this study were to determine the effects of (i) cropping regime and (ii) leaf harvesting initiation time and frequency on yield and yield components of dual‐purpose cowpea. Studies were conducted at the Kenya National Dry land Research Center–Katumani over four seasons. Cowpea cultivar ‘K80’ was grown as a monocrop or intercropped with maize. Leaf harvesting was initiated at 2, 3, or 4 wk after emergence (WAE) and thereafter done at 7‐ or 14‐d intervals. Control plants remained intact with no leaf harvesting. The number of lateral stems per plant, pods per plant, seeds per pod, unit seed weight, and vegetable and grain yields were monitored throughout each season, and plant productivity was found to be lower in intercropped than in monocropped cowpea. Leaf harvesting reduced all yield components. Initiating leaf harvesting at 3 and 4 WAE resulted in the highest leaf and grain yields, respectively. Harvesting leaves at a 7‐d interval was associated with higher leaf yield, while a 14‐d interval led to higher grain yield. Overall, yields were highest under treatments with no leaf harvest and lowest when leaf harvesting was initiated 2 WAE. Results of this study can help dual‐purpose cowpea growers optimize yields according to their production goals.
French bean [ Phaseolus vulgaris (L.)] is among the leading export vegetable in Africa, mostly produced by small-scale farmers. Unfavorable environmental conditions and heavy infestations by insect pests are among the major constraints limiting production of the crop. Most French bean producers grow their crop in open fields outdoors subject to harsh environmental conditions and repeatedly spray insecticides in a bid to realize high yield. This has led to rejection of some of the produce at the export market as a result of stringent limits on maximum residue levels. Two trials were conducted at the Horticulture Research and Teaching Field, Egerton University, Kenya, to evaluate the potential of using agricultural nets (herein referred to as agronets) to improve the microclimate, reduce pest infestation, and increase the yield and quality of French bean. A randomized complete block design with five replications was used. French bean seeds were direct-seeded, sprayed with an alpha-cypermethrin-based insecticide (control), covered with a treated agronet (0.9 mm × 0.7 mm average pore size made of 100 denier yarn knitted into a mesh impregnated with alpha-cypermethrin), or covered with an untreated-agronet (0.9 mm × 0.7 mm average pore size made of 100 denier yarn knitted into a mesh not impregnated with insecticide). Alpha-cypermethrin and agronets were manufactured by Tagros Chemicals (India) and A to Z Textile Mills (Tanzania), respectively. Covering French bean with the agronets modified the microclimate of the growing crop with air temperature increased by ≈10%, relative humidity by 4%, and soil moisture by 20%, whereas photosynthetic active radiation ( PAR ) and daily light integral (DLI) were decreased by ≈1% and 11.5%, respectively. Populations of silverleaf whitefly [ Bemisia tabaci (Gennadius)] and black bean aphids [ Aphis fabae (Scopoli)] were reduced under agronet covers as contrasted with control plots. Furthermore, populations of both pests were reduced on French bean grown under impregnated agronets compared with untreated agronets, but only on three of the five sampling dates [30, 44, and 72 days after planting (DAP)] for silver leaf whitefly or at only one of the five sampling dates (30 DAP) for black bean aphid. Covering French bean with agronets advanced seedling emergence by 2 days and increased seedling emergence over 90% compared with control plots. French bean plants covered with both agronet treatments had faster development, better pod yield, and quality compared with the uncovered plants. These findings demonstrate the potential of agronets in improving French bean performance while minimizing the number of insecticide sprays within the crop cycle, which could lead to less rejection of produce in the export market and improved environmental quality.
High seed cost accompanied by poor germination and seedling performance renders cabbage nursery and field production enterprises unsustainable to many small-scale growers in tropical and sub-tropical countries. In most nurseries, adverse ecological conditions and pest damage are among the major factors responsible for poor seedling performance. The objective of this study was to test the potential use of eco-friendly net (EFN) covers as a low cost technology for sustainable cabbage seedling production. The study was a two-season experiment conducted using a randomized complete block design with five replications and two treatments. Treatments were: the standard open field transplant production (control) and transplant production under 0.4 mm mesh polyethylene net covering. EFN covering increased both temperature and relative humidity, enhanced seedling growth and reduced insect pest damage. Seed germination and seedling emergence were under the net covering earlier. Higher seed germination and seedling survival were recorded under the EFN treatment, indicating a potential for reducing the seed requirement per unit area of cabbage production. Seedlings grown under the nets had higher stomatal conductance and leaf chlorophyll content; furthermore, they grew taller, with more leaves within a shorter period of time compared to the control seedlings. The use of EFN in cabbage nurseries offers a sustainable technology for enhancing seedling performance by reducing pest infestation, thereby lowering production cost and improving the grower’s income.
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