Journal of Agriculture and Rural Development in the Tropics and Subtropics (JARTS)
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Distribution of Alternaria leaf blight of sunflowers caused by Alternaria alternata in South Africa
Get PDFAlternaria leaf blight (ALB) has been shown in recent years to be one of the major potential disease threats of sunflower capable of causing yield losses in all major production areas. The aim of this study was to determine the causal agent, prevalence and geographical distribution of ALB in the major sunflower production areas of South Africa. Surveys were conducted during 2012/13, 2013/14 and 2014/15 growing seasons at commercial sunflower production fields and at commercial cultivar trials. In the three growing seasons, twenty-nine sunflower commercial production sites were surveyed for ALB disease severity. Furthermore, four cultivars (AGSUN8251, PHB65A25, SY4200 and PAN7049) were surveyed for ALB during cultivar trials in a total of 25 localities during the three growing seasons. The plants were surveyed between 90 to 120 days after planting and leaves showing ALB symptoms were collected. Alternaria alternata was identified as the primary disease-causing organism of ALB in all the fields. Wesselsbron consistently had the lowest ALB disease severity during the 2013/14 and 2014/15 growing seasons, whereas Potchefstroom had the highest disease severity in all three growing seasons. Pearson’s correlation coefficient was greatest for temperature (r=0.6 in 2012/13, r=0.71 in 2013/14 and r=0.84 in 2014/15) and disease severity in all the growing seasons. Information about the distribution of sunflower diseases is important and this survey demonstrated that A. alternata is widespread across sunflower production areas in South Africa and may result in potential yield losses
Bionomics of the sweet potato weevil, Cylas puncticollis (Coleoptera: Brentidae) on four different sweet potato varieties in sub-Saharan Africa
Get PDFSweet potato (Ipomoea batatas (L.) Lam.) is an important staple food crop in sub-Saharan Africa. A limiting production factor is infestation by the sweet potato weevil Cylas puncticollis (Boheman) (Coleoptera: Brentidae). The use of host plant resistance is an essential component of Integrated Pest Management (IPM). Therefore, the bionomic parameters of C. puncticollis were studied under laboratory conditions (30 ± 1 °C and 75 ± 5 % RH) on four sweet potato varieties commonly grown in Ghana (Apumoden, Ligri, Bohye, and Okumkom) to determine their susceptibility to the pest. There were significant varietal differences between some of the parameters. Egg to adult development time was highest on Okumkom while larval survival, emergence rate, intrinsic rate of increase, and the net reproductive rate were lowest on Bohye. The results of this study indicate that Bohye was the least susceptible variety compared to the other varieties tested and can be used in host plant resistance as part of an IPM programme against C. puncticollis in Ghana
Growth performance and digestive tract development of indigenous scavenging chickens under village management
Get PDFThe study was conducted on indigenous scavenging chickens under village management firstly, to evaluate the early development of the digestive tract to 28 days of age and secondly, to determine the growth performance of these chickens up to 20 weeks of age. One hundred and seventeen chicks, 13 chicks per age class (day 1, 4, 7, 10, 14, 17, 21, 24, 28) were randomly purchased from six rural villages in the Vhembe District, Venda, South Africa. The chickens were weighed and sacrificed for measurement of the different parts of its gastrointestinal tract. The liver and pancreas were also weighed. The relative weight of the storage organs and liver peaked at day 4 while that of the small intestine and duodenum peaked at day 10. The relative lengths of the small intestine and jejunum peaked at day 7, duodenum at day 10 and ileum at day 4. Four hundred and forty four (444) chicks from 13 households were recorded at two weekly intervals starting from day old until 20 weeks of age. The mean body weight obtained for males and females were 201.7 and 171.5 g at six weeks of age and 1048.1 and 658.6 g at 20 weeks of age, respectively. The indigenous chickens under village management were characterised by slow digestive tract development, poor growth performance and high mortalities. Further research needs to be conducted to determine the effect of early feed supplementation on the development of the digestive tract and the performance of indigenous chickens under village management
Motivations to consume agroecological food: An analysis of farmers’ markets in Quito, Ecuador
Get PDFThis paper examines the motivations to consume agroecological foods in Quito, Ecuador. Using data from a survey (n = 254) conducted among the customers of farmers’ markets, the results reveal that agroecological consumers are substantially different from the rest of the population in terms of education, income and life style. The perceived healthiness of agroecological food is by far the main motivation to buy at farmers’ markets, with environmental concern as the least important motivation. In terms of who spends the most on agroecological produce, the results of a multilevel regression model indicate that these are single, educated, wealthy individuals who exercise regularly and are part of a social/environmental organisation. These results reflect that agroecological produce is mainly consumed by a segment of wealthy and educated individuals who are not really concerned of the positive effects for the environment that agroecological production involves, so that, additional efforts are needed to make agroecological food accessible to the general population
Genetic variability among wheat (Triticum aestivum L.) germplasm for resistance to spot blotch disease
Get PDFSpot blotch caused by Bipolaris sorokiniana (Sacc.) Shoem. is the most devastating disease limiting wheat productivity in warm and humid environments. One hundred and fifty wheat genotypes were evaluated under field conditions in 2013 and 2014 in six different locations in Zambia. The genotypes showed different levels of resistance to spot blotch. Genotypes 19HRWSN6 (Kenya Heroe), 19HRWSN7 (Prontia Federal) and 19HRWSN15 (BRBT2/METSO) were resistant lines across environments. The genotype plus genotype by environment (GGE) biplot grouped the six environments (E) into three mega-environments (ME) with respect to spot blotch severity. ME I contained Golden Valley Agricultural Research Trust (GART) (E6) only. Mpongwe (E4), Mt. Makulu (E5 and E2) and GART (E3) formed ME II, while ME III contained only Mutanda (E1). Genotypes 16HRWYT5, SB50 and 20HRWSN33 were the most susceptible genotypes in ME I, II and III, respectively. Genotype 19HRWSN7 was the most resistant across test locations. The locations in ME III were highly correlated indicating that they provided similar information on genotypes. This suggests that one location could be chosen among the locations in ME III for screening spot blotch resistance each year if the pattern repeats across years. This could aid in reducing the cost of genotype evaluation and improve efficiency as genotypes would be handled in fewer environments
Impact of agricultural activities on pesticide residues in soil of edible bamboo shoot plantations
Get PDFEdible bamboo shoot is one of the most important vegetables in Asian countries. Intensive agricultural management measures can cause many negative influences, such as soil acidification and excessive pesticide residues. In the present study, more than 300 soil samples were collected from edible bamboo shoot plantations in six areas throughout Zhejiang province, China, to investigate the soil pesticide pollution and its change after different agricultural activities. Thirteen organic chemicals were detected; nine less than that detected during a similar study executed in 2003–2004. All the detected residues were far below the Chinese national environmental standards for agricultural soils. The pesticide residues in bamboo plantations showed a decline over the past decade. Organic materials used for mulching and plantation’s background of being formerly a paddy field are two important factors increasing the pesticide residues. Conversely, lime application to acidified soil and mulching with uncontaminated new mountain soil could decrease the residues significantly. Our results indicated that the current agricultural activities are efficient in reducing pesticide residues in the soil of bamboo shoot plantations and should be further promoted
Typological characterisation of farms in a smallholder food-cash crop production system in Zimbabwe – opportunities for livelihood sustainability
Get PDFThe diversity of smallholder farms in space, resource endowment, production and consumption decisions are often a hindrance to the design, targeting, implementation and scaling out of agricultural development projects. Understanding farm heterogeneity is crucial in targeting interventions that can potentially contribute to improved crop productivity, food security and livelihood sustainability. The study sought to define and understand farm typology in a resettlement smallholder food-cash crop production area in Zimbabwe. Data was collected from five focus group discussions (FGDs), and 102 household interviews. Principal component analysis (PCA), multiple correspondence analysis (MCA) and cluster analysis were used to analyse quantitative and qualitative data variables and aggregate farms into clusters according to production means, socio-economics and demographics. The three identified farm types were (i) resource-endowed, commercial oriented farms, (ii) medium resourced and (iii) resource constrained farms practising subsistence and income oriented production. Labour was cited as a major challenge, with high labour cost relevant for type I farms, while household size has more bearing for type II and III farms. Ownership of tillage implements and operations varied from mechanised on resource endowed farms, to animal drawn on some medium and resource constrained farms. The farms exhibited variable livelihood strategies and all clusters exhibited market participation, albeit to varying extents. Thus strengthening of market links is imperative. Use of multivariate methods allowed for identification of the most discriminating variables for farm delineation and subsequent clustering of farms forms the basis for further exploring variability across farm types for the targeting of management interventions for livelihood sustainability
Dietary protein and energy requirements of Venda village chickens
Get PDFThe objective of this study was to determine the dietary protein and apparent metabolisable energy (AME) requirements of local chickens. Freshly laid eggs of scavenging chickens collected in rural villages were hatched and randomly distributed to 27 floor pens, 10 chicks per pen. Chicks were fed 9 experimental diets that were combinations of three CP levels (140, 170 and 190 g kg−1 DM) and three AME levels (11.0, 11.7 and 12 MJ kg−1) during the starter phase (0–6 weeks) and combinations of three CP levels (120, 150 and 180 g kg−1 DM) and three ME levels (11.3, 12.0 and 12.4 MJ kg−1) during the grower phase (7–17) weeks. Significant differences within means on CP × AME interaction effect were observed in all parameters measured, except feed intake during starter period and dressing percentage (%) and breast yield of 17 weeks old chickens. The results of the present study indicated that during the starter and grower phases, unsexed chickens would require dietary combinations of 170 g CP kg−1 and 11.0 AME MJ kg−1 and 150 g CP kg−1 and 12 AME MJ kg−1 in their diets to optimise weight gain and FCR, and 150 g CP kg−1 and 11.3 MJ kg−1 to optimise ash content of muscles, protein content of the breast and fat content of the leg muscle. Supplementation of 27 g CP kg−1 feed to grower scavenging chickens would be enough to improve chicken production in the rural villages
The role of trust and networks in developing Nicaraguan farmers’ agribusiness capacities
Get PDFThe main focus of most programmes in developing countries carried out by NGOs is to develop small-scale farmers’ capacities. One approach hereby is to use multi-stakeholder innovation systems, such as the ‘Nicaraguan Learning Alliance’ (NLA). However, tools for the evaluation of multi-stakeholder innovation systems are rare. This paper reports on the implementation of a conceptual framework to carry out an impact evaluation of multi-stakeholder innovation systems using the NLA as the object of study. The assessment focused on the business relationship constructs of trust and capacity development. Survey interviews, in-depth interviews and focus group discussions collected data from agribusiness stakeholders linked with the NLA and from a control group of stakeholders involved with other networks. The quantitative data were analysed through factor and regression analyses. Results from the quantitative analyses were triangulated with qualitative data. The analysis shows that the NLA has been successful in developing smallholder farmers’ capacities as a result of trust developed through its dedicated project managers. Nonetheless, the NLA has not been more successful at developing agribusiness capacities among Nicaraguan farmers than other networks with the same goals. Results from this study point to the need for facilitating more interactions between the different networks of farmers’ cooperatives and organisations with other stakeholders already active within the Nicaraguan agrifood innovation system
Intensification of rain-fed groundnut production in North Kordofan State, Sudan
Get PDFThe main objective of this study was to evaluate intensification pathways for groundnut production in the marginal rain-fed environment of North Kordofan State, Sudan. The effect of intensification on yields was assessed in three different experiments. In the first experiment, the treatments were organised according to increasing level of intensification from the traditional production package to the improved production package (the ladder experiment). The complete improved package in the ladder approach consisted of increased density, new variety, seed priming, microdosing (0.6 g NPK per pocket) and mulching. Three levels of mulching and two levels of intensification constituted the second experiment (mulching experiment), while the third was an on-farm experiment involving 20 farmers testing two levels of intensification (on-farm experiment). The average yield increases were 75, 61, and 32 %, from the ladder, mulch and on-farm experiments, respectively. Results from the ladder experiment showed that farmers’ gross margin increased by 83 % compared to traditional practices. Resource limited farmers can increase yield by 18 % and gain 25 % additional cash incomes by only adopting increased plant density. As farmers differ in their wealth status, they can choose low-cost, low-risk components of the technological package whereas farmers with more access to resources can achieve high cash incomes by adopting the complete improved production package. There was no clear effect of mulching on yields in these experiments