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1
Pelster, D. E., M. C. Rufino, T. Rosenstock, J. Mango, G. Saiz, E. Diaz-Pines, G. Baldi, and K. Butterbach-Bahl. "Smallholder African farms in western Kenya have limited greenhouse gas fluxes." Biogeosciences Discussions 12, no. 18 (September 16, 2015): 15301–36. http://dx.doi.org/10.5194/bgd-12-15301-2015.
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Abstract. Few field studies examine greenhouse gas (GHG) emissions from African agricultural systems resulting in high uncertainty for national inventories. We provide here the most comprehensive study in Africa to date, examining annual CO2, CH4 and N2O emissions from 59 plots, across different vegetation types, field types and land classes in western Kenya. The study area consists of a lowland area (approximately 1200 m a.s.l.) rising approximately 600 m to a highland plateau. Cumulative annual fluxes ranged from 2.8 to 15.0 Mg CO2-C ha−1, −6.0 to 2.4 kg CH4-C ha−1 and −0.1 to 1.8 kg N2O-N ha−1. Management intensity of the plots did not result in differences in annual fluxes for the GHGs measured (P = 0.46, 0.67 and 0.14 for CO2, N2O and CH4 respectively). The similar emissions were likely related to low fertilizer input rates (≤ 20 kg ha−1). Grazing plots had the highest CO2 fluxes (P = 0.005); treed plots were a larger CH4 sink than grazing plots (P = 0.05); while N2O emissions were similar across vegetation types (P = 0.59). This case study is likely representative for low fertilizer input, smallholder systems across sub-Saharan Africa, providing critical data for estimating regional or continental GHG inventories. Low crop yields, likely due to low inputs, resulted in high (up to 67 g N2O-N kg−1 aboveground N uptake) yield-scaled emissions. Improving crop production through intensification of agricultural production (i.e. water and nutrient management) may be an important tool to mitigate the impact of African agriculture on climate change.
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Muoni, Tarirai, Eric Koomson, Ingrid Öborn, Carsten Marohn, Christine A. Watson, Göran Bergkvist, Andrew Barnes, Georg Cadisch, and Alan Duncan. "Reducing soil erosion in smallholder farming systems in east Africa through the introduction of different crop types." Experimental Agriculture 56, no. 2 (September 17, 2019): 183–95. http://dx.doi.org/10.1017/s0014479719000280.
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AbstractOn low-input smallholder farms of Kenyan upland landscapes, erosion of nutrient-rich topsoil strongly affects crop yields. Where maize (Zea mays) is intercropped on erosion-prone slopes, intercropping can potentially reduce soil erosion. The objective of this research was to quantify the contribution of crops and crop mixtures of different growth habits to erosion control and their influence on above-ground biomass and earthworm abundance as indicators of soil function in smallholder farming systems under a bimodal rainfall pattern in Western Kenya. The experiment involved five treatments, namely maize (Z. mays)/common bean (Phaseolus vulgaris) intercrop (maize intercrop), maize/common bean intercrop plus Calliandra (Calliandra calothyrsus) hedgerows and Calliandra mulch (Calliandra), sole Lablab (Lablab purpureus), sole Mucuna (Mucuna pruriens) and groundnut (Arachis hypogaea) intercropped with maize (during the short rains). The experiment was conducted over three consecutive cropping seasons and the cropping system had significant effects on soil loss, runoff, water infiltration, earthworm abundance and above-ground biomass and crop grain yield. The Calliandra treatment had the lowest runoff (11.6–17.2 mm ha−1) and soil erosion (31–446 kg ha−1 per season) in all the seasons, followed by the Mucuna treatment. Lablab was affected by disease and showed the highest soil erosion in the last two seasons. Infiltration was highest in Calliandra treatment, and earthworm abundance was higher under Mucuna and Calliandra treatments (229 and 165 earthworms per square metre, respectively) than under other crops. Our results suggest that including sole crops of herbaceous species such as Mucuna, or tree hedgerows with mixtures of maize and grain legumes has the potential to reduce runoff and soil erosion in smallholder farming. Additionally, these species provide a suitable habitat for earthworms which stabilise soil structure and macropores and thus potentially increase infiltration, further reducing soil erosion.
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Oloo, Josephat Okuku, and Paul Omondi. "Strengthening local institutions as avenues for climate change resilience." International Journal of Disaster Resilience in the Built Environment 8, no. 5 (November 13, 2017): 573–88. http://dx.doi.org/10.1108/ijdrbe-12-2013-0047.
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Purpose In Africa, poverty and food insecurity is pervasive due to intertwined factors including, declining crop yields, land degradation and inadequate policy and institutional support. With ever-increasing populations, climate change effects will be intensified, and a major crisis is inevitable unless measures to sustain land resources are urgently taken. This paper aims to argue that vibrant rural institutions are necessary to ensure food security and environmental protection, consequently contributing to climate change resilience. Design/methodology/approach The paper demonstrates the role of institutions by evaluating two types of institutions and their impacts the “status quo” and “hybrid” institutions using case studies from the African Highlands Initiative in Uganda and International Forestry Resources and Institutions in Kenya. It further discusses a model that highlights factors affecting smallholder investment in natural resources management and how these can be used to strengthen local institutions in building their resilience against climate change effects. Findings Weak grassroots institutions characterized by low capacity, failure to exploit collective capital and poor knowledge sharing and access to information, are common barriers to sustainable land management and improved food security. Research limitations/implications Case studies from Uganda and IFRI in Kenya barriers in data collection instruments and language. Practical implications In Africa, poverty and food insecurity is pervasive due to intertwined factors including, declining crop yields, land degradation and inadequate policy and institutional support. With ever increasing populations, climate change effects will be intensified, and a major crisis is inevitable unless measures to sustain land resources are urgently taken. Social implications In Africa, poverty and food insecurity is pervasive due to intertwined factors including, declining crop yields, land degradation and inadequate policy and institutional support. With ever-increasing populations, climate change effects will be intensified, and a major crisis is inevitable unless measures to sustain land resources are urgently taken. Originality/value The paper further discusses a model that highlights factors affecting smallholder investment in natural resources management and how these can be used to strengthen local institutions in building their resilience against climate change effects.
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Langát, Joseph Kimutai. "Effect of Total Solar Radiation and Rainfall on Yield of Different Tea (Camellia sinensis [L.] O. Kuntze) Clones at Two Sites in Kenya." Journal of Agricultural Science 10, no. 6 (May 6, 2018): 40. http://dx.doi.org/10.5539/jas.v10n6p40.
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Tea cultivation is the leading cash crop in Kenya, making significant contribution to the economy. It is the single largest export commodity, accounting for about 26% of the country’s total export earnings. In 2017, the country got US$ 1.23 billion in foreign exchange earnings. However, tea production is affected by weather changes. Majority of research reporting the effects of weather on tea yields in Africa have mostly been carried out at single sites. This study investigated contribution of total solar radiation and rainfall to tea (Camellia sinensis) yields at two sites in Kenya. A split-plot layout study was conducted at two sites differing in altitude and climatic conditions in Kenya: Kangaita (0o30'S, 37o16'E, 2100 m.a.s.l.) and Kipkebe (0o17'S, 35o3'E, 1740 m.a.s.l.). Timbilil (0o22'S, 35o21'E, 2200 m.a.s.l.) was used as a reference site. Four tea clones of commercial and scientific interest in Kenya (AHP SC 31/37, EPK TN14-3, TRFK 301/5 and TRFK 31/8) were studied. Low radiation intensities at Timbilil in 2007 corresponded with low made tea yields at Kangaita (2.1 t ha-1 y-1) and Kipkebe (2.6 t ha-1 y-1) compared to 2008 (4.4 t ha-1 y-1 and 3.2 t ha-1 y-1) and 2009 (3.1 t ha-1 y-1 and 3.0 t ha-1 y-1) respectively when higher total radiation intensities were recorded. Statistical analysis done using two-way ANOVA (P = 0.05) for split plot design showed a strong positive correlation (r = 0.53) between total solar radiation, rainfall and mean made tea yield. Higher radiation and rainfall intensities yielded higher tea outputs.
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Ogega, Janet Kemuma, Beatrice Ang’iyo Were, Abigael Otinga Nekesa, and John Robert Okalebo. "Evaluating the Effectiveness of Different Rhizobia Strains and Their Effect on Crop Yields in Acid Soils of Western Kenya." Turkish Journal of Agriculture - Food Science and Technology 6, no. 2 (March 4, 2018): 195. http://dx.doi.org/10.24925/turjaf.v6i2.195-198.1553.
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Food insecurity in Sub - Saharan Africa (SSA) is on the rise due to soil fertility depletion and in Kenya, Nitrogen (N) is one of the widely deficient nutrients. Biological nitrogen fixation (BNF) can replenish N into the soil system. A study was carried out in acid soils at Koyonzo and Ligala sites of western Kenya to determine the effectiveness of different inoculants after agricultural lime application in enhancing BNF and yields of groundnuts (Arachis hypogea L.) and maize (Zea mays L.) intercrop. Red Valencia groundnut variety was intercropped with Hybrid 513D maize variety. A6w, W1w and V2w indigenous rhizobia strains were tested alongside a commercial rhizobia strain called biofix. Nitrogen treatment was included as a positive control. The results showed that inoculation significantly increased nodule number and weight per plant. There were significant differences among indigenous rhizobia in fixing N. Rhizobia inoculation accounted for 58.91% and 78.95% increase in the amount of N fixed above the control at Koyonzo and Ligala respectively. The strain that fixed the highest amount of N was A6w followed by V2w and W1w at both sites under the dolomitic soil amendment with the values of 14.67, 9.56, 3.53 and 11.37, 8.20 and 1.50 kg N ha-1, respectively at Koyonzo and Ligala sites. Rhizobia inoculation accounted for 80.96% and 47.09% maize yield increase at Koyonzo and Ligala respectively. The best inoculant A6w, gave maize yields of 3.76 and 2.78 t ha-1 at Koyonzo and Ligala, respectively. In conclusion soil amendment with dolomitic lime and inoculating groundnuts with rhizobia strain A6w resulted in increased groundnut and maize yields. This practice can, therefore, be adopted by farmers in western Kenya to improve the productivity of the groundnut maize intercropping systems.
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Okeyo, Jeremiah M., Jay Norton, Saidou Koala, Boaz Waswa, Job Kihara, and Andre Bationo. "Impact of reduced tillage and crop residue management on soil properties and crop yields in a long-term trial in western Kenya." Soil Research 54, no. 6 (2016): 719. http://dx.doi.org/10.1071/sr15074.
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Sustainable farming practices are required to address the persistent problems of land degradation and declining crop productivity in Sub-Saharan Africa. Approaches such as reducing tillage and retaining crop residues as mulch are potential entry points for smallholder farmers to move towards sustainability. In this study, we assessed the impact of reduced tillage (RT) compared with conventional tillage (CT), each combined with crop residue reapplication, on soil quality indicators and crop yields under an 8-year trial in western Kenya. Our results indicate that RT combined with crop residue reapplication enhanced soil physical quality through increased macroaggregate (>2000µm) proportions and mean weight diameter. Similarly, lower respiratory quotient values indicate that soil microbes under RT have better substrate-use efficiency than those under CT. Nevertheless, soil organic carbon (C), potentially mineralisable C, microbial biomass C and mineral nitrogen contents were all higher under CT with crop residue incorporated into the soil. Maize grain yield and aboveground biomass were also higher under CT. Thus, despite RT showing potential to improve soil physical properties, CT performed better. A stepwise approach is proposed towards the practice of conservation agriculture under resource-constrained smallholder farming conditions, starting with increased biomass production to provide crop residue for soil cover, followed by RT approaches.
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Pelster, David, Mariana Rufino, Todd Rosenstock, Joash Mango, Gustavo Saiz, Eugenio Diaz-Pines, German Baldi, and Klaus Butterbach-Bahl. "Smallholder farms in eastern African tropical highlands have low soil greenhouse gas fluxes." Biogeosciences 14, no. 1 (January 12, 2017): 187–202. http://dx.doi.org/10.5194/bg-14-187-2017.
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Abstract. Few field studies examine greenhouse gas (GHG) emissions from African agricultural systems, resulting in high uncertainty for national inventories. This lack of data is particularly noticeable in smallholder farms in sub-Saharan Africa, where low inputs are often correlated with low yields, often resulting in food insecurity as well. We provide the most comprehensive study in Africa to date, examining annual soil CO2, CH4 and N2O emissions from 59 smallholder plots across different vegetation types, field types and land classes in western Kenya. The study area consists of a lowland area (approximately 1200 m a.s.l.) rising approximately 600 m to a highland plateau. Cumulative annual fluxes ranged from 2.8 to 15.0 Mg CO2-C ha−1, −6.0 to 2.4 kg CH4-C ha−1 and −0.1 to 1.8 kg N2O-N ha−1. Management intensity of the plots did not result in differences in annual GHG fluxes measured (P = 0.46, 0.14 and 0.67 for CO2, CH4 and N2O respectively). The similar emissions were likely related to low fertilizer input rates (≤ 20 kg N ha−1). Grazing plots had the highest CO2 fluxes (P = 0.005), treed plots (plantations) were a larger CH4 sink than grazing plots (P = 0.05), while soil N2O emissions were similar across vegetation types (P = 0.59). This study is likely representative for low fertilizer input, smallholder systems across sub-Saharan Africa, providing critical data for estimating regional or continental GHG inventories. Low crop yields, likely due to low fertilization inputs, resulted in high (up to 67 g N2O-N kg−1 aboveground N uptake) yield-scaled emissions. Improvement of crop production through better water and nutrient management might therefore be an important tool in increasing food security in the region while reducing the climate footprint per unit of food produced.
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Nyanumba, Lilian N., Rebecca N. Karanja, and Mary Gikungu. "Diversity and Abundance of Bee Flower Visitors of Beans in Borabu Sub-County, Western Kenya." Journal of Horticulture and Plant Research 13 (July 7, 2021): 24–31. http://dx.doi.org/10.18052/www.scipress.com/jhpr.13.24.
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Globally bees form the main animal pollinators of most crops. Most agricultural crops rely on pollinators, particularly bees for pollination services. Smallholder farmers in Africa commonly use maize/bean intercropping in order to achieve the optimum yields hence providing them with significant food security and economic impacts. Declining of bee colonies due to anthropogenic factors has led to declines in food production in the world. Yet little is known about crop pollination in African countries. In Kenya pollination studies are still scanty, lack harmonisation and only a few crops have been studied. It is against this background that the study was chosen. One administrative sub location was purposively selected. Three plots were selected at equal 1km distance along atransect laid in that sub location. Sampling of 3 plots each of 100m x 100 m was established along transects. Bee sampling was done for 3 months using a sweep net and a bowl trap to collect bees. Diversity was computed using Shannon’s diversity index while abundance was recorded using abundance curves. A total of 992 bee visitors from 2 families and 9 species were collected from the three study farms. High diversity and abundance of bees was recorded. Therefore, farmers, extension workers and other stakeholders should be sensitized and trained on the importance of bee pollination and its contribution to their welfare and on utilization of cost-effective strategies for bee conservation. Key words: Diversity, Abundance, Pollination, Apis, Nyansiongo
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MWENDIA, S. W., I. A. M. YUNUSA, B. M. SINDEL, R. D. B. WHALLEY, and I. W. KARIUKI. "ASSESSMENT OF NAPIER GRASS ACCESSIONS IN LOWLAND AND HIGHLAND TROPICAL ENVIRONMENTS IN EAST AFRICA: PRODUCTIVITY AND FORAGE QUALITY." Experimental Agriculture 53, no. 1 (March 8, 2016): 27–43. http://dx.doi.org/10.1017/s001447971600003x.
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SUMMARYTen accessions of Napier grass (Pennisetum purpureum Schumach.) were evaluated for their dry matter (DM) yield and forage quality in a semi-arid lowland (Katumani) and a relatively wet highland (Muguga) over seven growth cycles from 2011 to 2013 in tropical Kenya. Three biomass yield clusters were identified from the 10 accessions as high-yielding (HYC), medium-yielding (MYC) and low-yielding (LYC) clusters for both sites. Total biomass (shoot and root) yields (t ha−1) over the seven growth cycles were 25.3 for HYC, 22.2 for MYC and 19.6 for LYC at Katumani and 40.0, 41.4 and 29.1 at Muguga. Total biomass yield averaged over the study period was DM 22.4 t ha−1 at Katumani and 36.8 at Muguga. Rainfall productivity was higher at Katumani (28.8 kg ha−1 mm−1) than 20.8 kg ha−1 mm−1 at Muguga. Neutral detergent fibre (NDF) was lower in LYC, which was more leafy than the other clusters and there was little difference in NDF between the two sites.
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MUCHERU-MUNA, MONICAH, DANIEL MUGENDI, PIETER PYPERS, JAYNE MUGWE, JAMES KUNG'U, BERNARD VANLAUWE, and ROEL MERCKX. "ENHANCING MAIZE PRODUCTIVITY AND PROFITABILITY USING ORGANIC INPUTS AND MINERAL FERTILIZER IN CENTRAL KENYA SMALL-HOLD FARMS." Experimental Agriculture 50, no. 2 (September 12, 2013): 250–69. http://dx.doi.org/10.1017/s0014479713000525.
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SUMMARYDeclining land productivity is a major problem facing smallholder farmers today in Sub-Saharan Africa, and as a result increase in maize grain yield has historically staggered behind yield gains that have been achieved elsewhere in the world. This decline primarily results from reduction in soil fertility caused by continuous cultivation without adequate addition of external nutrient inputs. Improved soil fertility management practices, which combine organic and mineral fertilizer inputs, can enable efficient use of inputs applied, and can increase overall system's productivity. The trials were established at two sites with different soil fertility status to determine the effects of various organic sources (Tithonia diversifolia, Mucuna pruriens, Calliandra calothyrsus and cattle manure) and their combinations with mineral fertilizer on maize grain yield, economic return and soil chemical properties. Drought spells were common during the peak water requirement periods, and during all the seasons most (90%) of the rainfall was received before 50% flowering. In good and poor sites, there was a significant (p < 0.001) effect of season on maize grain yield. Tithonia diversifolia recorded the highest (4.2 t ha−1) average maize grain yield in the poor site, while Calliandra calothyrsus gave the highest (4.8 t ha−1) average maize grain yield in the good site. Maize grain yields were lower in treatments with sole fertilizer compared with treatments that included organic fertilizers. The maize grain yields were higher with sole organics compared with treatments integrating organic and inorganic fertilizers. Soil pH increment was statistically significant in the sole manure treatment in good and poor sites (t-test, p = 0.036 and 0.013), respectively. In the poor site, magnesium increased significantly in the sole manure and manure + 30 kg N ha−1 treatments with t-test p = 0.006 and 0.027, respectively. Soil potassium was significant in the sole manure treatment (t-test, p = 0.03). Generally the economic returns were low, with negative net benefits and benefit cost ratio of less than 1. Inorganic fertilizer recorded the highest net benefit and return to labour (p < 0.001 and <0.01, respectively) in the good site. The treatments that had very high maize grain yields did not lead to improved soil fertility, thus there is need for tradeoffs between yield gains and soil fertility management when selecting agricultural production technologies.
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Ochieng, Hannington O., John O. Ojiem, Simon M. Kamwana, Joyce C. Mutai, and James W. Nyongesa. "Multiple-bean varieties as a strategy for minimizing production risk and enhancing yield stability in smallholder systems." Experimental Agriculture 56, no. 1 (March 20, 2019): 37–47. http://dx.doi.org/10.1017/s0014479719000085.
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AbstractCommon bean (Phaseolus vulgaris L.) is perhaps the most important grain legume in sub-Saharan Africa (SSA) smallholder systems for food security and household income. Although a wide choice of varieties is available, smallholder farmers in western Kenya realize yields that are low and variable since they operate in risky production environments. Significant seasonal variations exist in rainfall and severity of pests and diseases. This situation is worsened by the low and declining soil fertility, coupled with low capacity of farmers to purchase production inputs such as fertilizers, fungicides and insecticides, and land scarcity. The objective of this study was to investigate whether growing multiple-bean varieties instead of a single variety can enable farmers enhance yield stability over seasons and ensure food security. Five common bean varieties were evaluated in multiple farms for 11 seasons at Kapkerer in Nandi County, western Kenya. Data were collected on grain yield, days to 50% flowering and major diseases. In addition, daily rainfall was recorded throughout the growing seasons. The five varieties were combined in all possible ways to create 31 single- and multiple-bean production strategies. The strategies were evaluated for grain yield performance and yield stability over seasons to determine the risk of not attaining a particular yield target. Results indicated that cropping multiple-bean varieties can be an effective way for reducing production risks in heterogeneous smallholder systems. Yield stability can be greatly enhanced across diverse environments, leading to improved food security, especially for the resource-poor smallholder farmers operating in risk-prone environments. Although the results show that some of the single-bean variety strategies were high yielding, their yield stability was generally lower than those of multiple strategies. Resource-poor risk averse farmers can greatly increase the probability of exceeding their yield targets by cropping multiple-bean varieties with relatively low yields but high grain yield stability. Trading-off high grain yield for yield stability might be an important strategy for minimizing bean production risks.
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Karienye, David K., and Hellen Kamiri. "Trends of Banana Production among Smallholders’ Farmers Due to Rainfall and Temperature variations in Mount Kenya Region County, Kenya." Budapest International Research in Exact Sciences (BirEx) Journal 2, no. 2 (April 8, 2020): 213–27. http://dx.doi.org/10.33258/birex.v2i2.904.
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Unreliability and unpredictability of rainfall amount and temperature fluctuations have negative impact on agriculture production especially in Africa where coping mechanisms are limited. The future of rainfed agriculture is uncertain more so on banana production among the smallholder’s farmers due to climate variability. This study examined the extent of rainfall and temperature changes on banana production among smallholders’ farmers in Mount. Kenya region of Kenya from 2009 and 2017. The sites were purposively selected to include Imenti south (Meru County) and Mukurweini sub-counties (Nyeri County) where banana production has been practiced since 1990. A sample size of 381 respondents was identified using simple random sampling. Production and climatic (rainfall and Temperature) data were sourced from Horticultural Crop Directorate and Kenya Meteorological Department respectively for the stations adjacent to the study sites for the study period. Results showed decreasing trends on rainfall amounts while temperature increasing trend. Study found that rainfall increase does not necessarily translate to increased production while temperature level of about 18.50C gave the maximum yields. Majority of the respondents (42.8%) in the study region admitted to have changed the land use and type of crops they have been farming during the study period whereas 30% changed from other crops to banana farming. Banana acreage and production in both sub-counties have been increasing during the study period. The County and National government should provide irrigation as a coping mechanism to banana production due to the declining rainfall and increasing temperature in the region. We recommended provision of weather information on the onset of the rainfall period and distribution within the seasons in order to respond to the effects of climate variability.
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Magugu, John W., Song Feng, Qiuqiong Huang, and Gilbert O. Ototo. "Socio-economic factors affecting agro-forestry technology adoption in Nyando, Kenya." Journal of Water and Land Development 39, no. 1 (December 1, 2018): 83–91. http://dx.doi.org/10.2478/jwld-2018-0062.
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AbstractAgro-forestry (AFR) technologies are perceived to improve livelihoods and natural resource sustainability of the rural households. Despite their aggressive promotion by multiple national and international agencies, the adoption of AFR technologies has been minimal in Kenya. This study conducted a survey to examine the socio-economic factors that affect the adoption process in Nyando, Kenya. Results revealed that farmers with bigger farms and higher education were more likely to adopt the new technology. Additionally, farmers were quicker to adopt technology if they had an increase in crop yields and had stayed longer in the study area. Generally, wealthier famers tended to adopt more AFR technology than those with less income. Access to information was the only factor strongly correlated with the rest of the independent variables. The results suggest that, adoption would be more enhanced with a clear focus on extension activities, income enhancing AFR practices and soil amelioration technologies. This study may be replicated in other parts of Kenya and East Africa to improve the level of AFR technology adoption for sustainable rural development.
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Kanampiu, Fred, Dan Makumbi, Edna Mageto, Gospel Omanya, Sammy Waruingi, Peter Musyoka, and Joel Ransom. "Assessment of Management Options onStrigaInfestation and Maize Grain Yield in Kenya." Weed Science 66, no. 4 (April 4, 2018): 516–24. http://dx.doi.org/10.1017/wsc.2018.4.
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AbstractThe parasitic purple witchweed [Striga hermonthica(Del.) Benth.] is a serious constraint to maize production in sub-Saharan Africa, especially in poor soils. VariousStrigaspp. control measures have been developed, but these have not been assessed in an integrated system. This study was conducted to evaluate a set of promising technologies forS. hermonthicamanagement in western Kenya. We evaluated three maize genotypes either intercropped with peanut (Arachis hypogaeaL.), soybean [Glycine max(L.) Merr.], or silverleaf desmodium [Desmodium uncinatum(Jacq.) DC] or as a sole crop at two locations under artificialS. hermonthicainfestation and at three locations under naturalS. hermonthicainfestation between 2011 and 2013. Combined ANOVA showed significant (P<0.05) cropping system and cropping system by environment interactions for most traits measured. Grain yield was highest for maize grown in soybean rotation (3,672 kg ha−1) under artificial infestation and inD. uncinatumand peanut cropping systems (3,203 kg ha−1and 3,193 kg ha−1) under natural infestation. Grain yield was highest for theStrigaspp.-resistant hybrid under both methods of infestation. A lower number of emergedS. hermonthicaplants per square meter were recorded at 10 and 12 wk after planting on maize grown underD. uncinatumin the artificialS. hermonthicainfestation. A combination of herbicide-resistant maize varieties intercropped with legumes was a more effective method forS. hermonthicacontrol than individual-component technologies. Herbicide-resistant andStrigaspp.-resistant maize integrated with legumes would help reduce theStrigaspp. seedbank in the soil. Farmers should be encouraged to adopt an integrated approach to controlStrigaspp. for better maize yields.
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Myeni, Lindumusa, Mokhele Edmond Moeletsi, Isaiah Nyagumbo, Salome Modiselle, Lebohang Mokoena, and Ikalafeng Ben Kgakatsi. "Improving the Food and Nutritional Security of Smallholder Farmers in South Africa: Evidence from the InnovAfrica Project." Sustainability 13, no. 17 (September 3, 2021): 9902. http://dx.doi.org/10.3390/su13179902.
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This article highlights evidence and lessons learned from the InnovAfrica project conducted by the Agricultural Research Council in collaboration with other international organizations between 2017 and 2021. This project aimed to test and upscale best-bet Sustainable Agricultural Intensification (SAI) practices through Multi-Actor Platforms (MAPs) and improved dissemination strategies across six African countries (viz. Ethiopia, Kenya, Malawi, Rwanda, South Africa and Tanzania). The goal of the project was to improve the food and nutritional security of smallholder farmers in Africa. The article briefly discusses some of the key challenges that smallholder agriculture is facing, results from the agricultural interventions brought in by the InnovAfrica project, evidence-based actions and policy recommendations to improve the sustainable agricultural productivity of smallholder farmers in the South African case study. The study showed that SAI practices increased crop yields and build climate-resilient farming communities. It is recommended that the promotion of SAI practices should be supported by enabling institutions and conducive policies that will enhance access to inputs, market linkages, improved access to credit and good agricultural lands, the establishment of functional farmer groups and participatory learning models. These recommendations can be used by the government and other agencies to develop effective interventions to improve food and nutrition security.
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Field, C. R. "Utilization of marginal and arid rangelands for livestock and wildlife in Africa." BSAP Occasional Publication 21 (1998): 77–86. http://dx.doi.org/10.1017/s0263967x00032080.
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AbstractThe main uses to which marginal and arid rangelands are put involve livestock production, tourism based on wildlife and ethno-tourism, and agriculture, i.e. crop production. There is minimal dry land forestry, sometimes as agro-forestry. The emphasis placed on these three main uses varies according to the ecological potential (i.e. climate, topography and soils) and accessibility to the areas.Taking the Kenyan example, approximately 20% of the land is arid and used almost exclusively for livestock production while ethno-tourism runs a poor second in dry seasons because of inaccessibility. Current technology in Africa precludes extensive irrigation. Peak production of livestock is in the late wet season and early dry with marketing mostly in dry seasons. Over 50% of the land is semi-arid where all three uses are practised. Livestock production is still the most important and agriculture the least important, because rainfall is unreliable and erratic, wildlife populations are larger and so tourism is more important (e.g. Amboseli, Isiolo, Samburu). Agriculture occurs particularly in wet years and wet seasons.Although land is only very locally suited to agriculture, permanent water sources, rivers and springs may enable year round settlement. Farmers of non-pastoral backgrounds (and even some pastoralists) wish to follow their traditions and attempt cultivation. This is occasionally successful in above average years of rainfall (two years in five) on good soils but fails in dry years when it also deprives livestock of essential traditional dry season grazing reserves.Marginal areas occupy perhaps 12% of the land but are in high demand for all three use categories. Pastures are ideal for fattening livestock bred in more arid areas and they have a rapid turn-over. Wildlife populations are often at their highest in these areas, e.g. Laikipia, Mara and Nairobi park. Areas are relatively accessible on tarmac roads for year round viewing of wildlife. Agricultural resettlement has spilled over from higher potential lands where human populations are exceeding the carrying capacity.Increasing food requirements have led to a greater demand for efficient land use and to diversification into new areas, e.g. eco-tourism, ostrich farming or the intensification of traditional uses such as camel rearing.Lailipia District, situated mostly in marginal and semi-arid land is used as a case study. Here, successful conservation measures on mostly private land, which was formerly used by Maasai for subsistence pastoralism, has led to the largest population of wildlife in Kenya outside parks and reserves. At the same time land is used in part for crop production especially in the higher potential areas, but also wherever land is available for co-operative arable farmers to purchase. Livestock production remains however, the most widespread form of land use. The main seasonal variation in use is with crop production in the rains and game viewing in the dry seasons but extremes are less than in the lower rainfall areas.Recent preliminary analysis of the economics of various forms of land use in Laikipia indicate that in those limited areas where agriculture is reliable (e.g. irrigated areas near rivers) returns may be as high as US$ 132 to 166 per ha per annum. Wildlife tourism which prevails in less well watered areas may yield US$ 4 to 5 per ha, while conventional livestock rearing yields from US$ 0.2 to 1.4 per ha per annum. Game cropping is the least well developed and the least productive but is accepted as a necessity by the Kenya Wildlife Service, particularly with regard to zebra which compete with livestock for resources. It yields only US$ 0.2 to 0.4 per ha per annum.Wildlife and livestock occur together, except where there has been considerable outlay on electric fencing. Predators, especially lions and hyenas, are incompatible with livestock and together with certain wildlife which may act as disease vectors (e.g. buffalo) reduce income by US$ 0.5 per ha per annum. By contrast, the addition of camels, which are eco-friendly milk and meat producers, with no reduction of conventional stock, may increase livestock yields by US$ 0-4 per ha per annum.Combined wildlife tourism, cropping and livestock, including camels, may yield US$ 4.7 to 6.4 per ha per annum, which although still less than 5% of agricultural yield, is the best that may be achieved at present on a sustainable basis. Crop production is highly dependent on rainfall which becomes less predictable the more arid the land. It may not be sustainable in the long term in its present form.Current returns on investment are low for all forms of land use. Constraints to increasing returns are outlined. Research agendas need to be tailored to provide answers which could help minimize them. In particular, we need to refine our knowledge concerning the economics of the different options, both conventional and non-conventional.
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KIHARA, J., A. BATIONO, B. WASWA, J. M. KIMETU, B. VANLAUWE, J. OKEYO, J. MUKALAMA, and C. MARTIUS. "EFFECT OF REDUCED TILLAGE AND MINERAL FERTILIZER APPLICATION ON MAIZE AND SOYBEAN PRODUCTIVITY." Experimental Agriculture 48, no. 2 (October 11, 2011): 159–75. http://dx.doi.org/10.1017/s0014479711000895.
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SUMMARYReduced tillage is said to be one of the potential ways to reverse land degradation and ultimately increase the productivity of degrading soils of Africa. We hypothesised that crop yield following a modest application of 2 t ha−1 of crop residue in a reduced tillage system is similar to the yield obtained from a conventional tillage system, and that incorporation of legumes in a cropping system leads to greater economic benefits as opposed to a cropping system involving continuous maize. Three cropping systems (continuous maize monocropping, legume/maize intercropping and rotation) under different tillage and residue management systems were tested in sub-humid western Kenya over 10 seasons. While soybean performed equally well in both tillage systems throughout, maize yield was lower in reduced than conventional tillage during the first five seasons but no significant differences were observed after season 6. Likewise, with crop residue application, yields in conventional and reduced tillage systems are comparable after season 6. Nitrogen and phosphorus increased yield by up to 100% compared with control. Gross margins were not significantly different among the cropping systems being only 6 to 39% more in the legume–cereal systems relative to similar treatments in continuous cereal monocropping system. After 10 seasons of reduced tillage production, the economic benefits for our cropping systems are still not attractive for a switch from the conventional to reduced tillage.
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Mongare, P. O., J. R. Okalebo, C. O. Othieno, J. O. Ochuodho, R. Njoroge, and A. N. Otinga. "Effect of Cropping System and Nitrogen on Maize and Soy Bean Yields in Western Kenya." Sustainable Agriculture Research 9, no. 3 (May 14, 2020): 39. http://dx.doi.org/10.5539/sar.v9n3p39.
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Inherent low soil fertility in the highly weathered and degraded soils largely accounts for low and unsustainable crop yields in most African countries (Okalebo et al., 2006; Sanchez et. al., 1997). Productivity of maize and soybeans in Kenya, particularly in the western region is generally low. The high costs of inorganic fertilizers and the possibility of decreasing soil productivity in due to soil mining and environmental pollution demands a reassement of their use, vis-a-vis, other alternative technologies. The objective of this study was to assess the effect of selected cropping systems, N fertilizer and manure on maize and soy bean crop yields in western Kenya (Bungoma, Vihiga, and Teso). The experiment was a split plot design arranged and laid down in a randomized complete block design (RCBD) with three replications. Cropping systems (mono cropping, MBILI and conventional) were the main factor while fertility interventions (FYM and CAN) were the treatments. The cropping systems consisted of conventional (Maize and soy beans were planted as intercrop in 37.5 cm alternating rows), MBILI (Managing Beneficial Interactions in Legume Intercrops), maize and soybean monocrop. Five fertilizer treatments were used: calcium ammonium nitrate and farm yard manure, both applied at the rate of 30 kg N ha-1 and 75 kg N ha-1, respectively, and absolute control that had no added treatment. Field experiments were planted during two cropping seasons of short rains season (August to December 2011) and one long rains season (April to August 2012) Generally, maize yields were found to be significantly higher in both the mono cropping system (mean yield: 2.00 t/ha) and MBILI system (mean yield: 1.77 t/ha) compared to conventional farming (mean yield: 1.27 t/ha). Soybean yields were found, overall, to be significantly higher in the mono cropping system (mean: 1.00t/ha) compared to both MBILI (mean: 0.75 t ha-1) and conventional system (mean: 0.59 t ha-1). For both maize and soy bean grain, application of CAN75N and planting with FYM75N were found to significantly increase yields, compared to either top dressing with CAN30N or planting with FYM30N. CAN generally produced higher yields with monocrop system whereas MBILI system did better when FYM is used, suggesting that an optimal system could consist of MBILI with organic fertilizers. The mean Land Equivalent Ratio (LER) values were always greater than 1.0 for intercropping and I.0 for mono cropping system. Manure was found to produce similar yields as those in fertilizer applications. This study recommends MBILI system and organic manure as a beneficial way of growing maize and soy beans
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Linguya, Kimaru, Onyango Moraa, Kimenju Wangai, and Kilalo Chao. "Potential of intercropping for management of some arthropod and nematode pests of leafy vegetables in Kenya." Journal of Agricultural Sciences, Belgrade 60, no. 3 (2015): 301–14. http://dx.doi.org/10.2298/jas1503301l.
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African leafy vegetables (ALVs) play an important role as income and food security crops in many households in Kenya. However, their potential in alleviating poverty and ensuring household food and nutrition security has not been fully exploited. The objectives of this study were to identify some arthropod and nematode pests that infest ALVs and to evaluate the effectiveness of intercropping of susceptible and resistant plants for the management purposes. Three vegetable types: African nightshade, sunn hemp and spider plant were used in determining the efficacy of an intercrop of susceptible and non-susceptible types in reducing arthropod and nematode pest effect. The treatments in the field experiment consisted of different intercrop designs and a sole crop design as control while data was taken based on five different variables. Crops in the field were infested with arthropod pests and eight different species were enumerated. The same row and hill intercropping designs were the most effective in reducing the effect of arthropod and nematode pests compared to the control plots. Spider plant and African nightshade intercrops recorded the least arthropod pest damage, higher fresh and dry shoot yields and differed significantly (P?0.05) to African nightshade planted as a sole crop. A similar trend was observed when the experiment was repeated with a sunn hemp and African nightshade intercrop. It is concluded from this study that intercropping of different crops can be integrated with other methods to provide an easily adaptable technology to apply for effective management of arthropod and nematode pests with low external inputs.
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Mutundi, Alfred N., James W. Muthomi, Florence M. Olubayo, Philip K. Leley, and Felista M. Nzuve. "Effect of Farm Saved Maize (Zea mays L.) Seed on Intensity of Foliage Diseases." Journal of Agricultural Science 11, no. 8 (June 15, 2019): 45. http://dx.doi.org/10.5539/jas.v11n8p45.
Full textAbstract:
Majority of farmers in Africa recycle farm saved seed from the previous seasons. Such seed is usually contaminated with disease causing pathogens, has low vigor and result in low yields. This study was, therefore, conducted to determine the effect of recycling maize seeds on incidence of foliage diseases. Maize seeds were collected during 2016 short rain season from farmers, local market and Agrovet shops in Busia County of western Kenya. The seeds were subjected to field evaluation during 2017 long rain season at two sites in Busia and Kakamega Counties. Data was collected on emergence, off types, lodging, ear aspect and abnormalities, incidence and severity of diseases and yield. Seeds from local market had significantly higher emergence of up to 66% while the farm saved seeds and local market resulted in the highest percentage of off-types of up to 18%. Crop from farm saved seed and seeds from the local market showed high susceptibility to stalk lodging, ear abnormalities and high levels of diseases. Diseases detected include northern leaf blight, gray leaf spot, rust, brown spot, downy mildew, and ear rots. The study showed that though informal seeds had high plant establishment, they have high level of off types, are susceptible to lodging, diseases and low yields. Therefore, farmer should be encouraged to use certified or improved seeds to enhance crop productivity.
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Burgess, Paul J., and M. K. V. Carr. "Responses of Young Tea (Camellia Sinensis) Clones to Drought and Temperature. I. Yield and Yield Distribution." Experimental Agriculture 32, no. 3 (July 1996): 357–72. http://dx.doi.org/10.1017/s0014479700026296.
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SUMMARYThe yield response to drought and temperature of six contrasting tea clones was studied in a line-source irrigation experiment in Southern Tanzania. The selected clones, all commercially and/or scientifically important in eastern Africa, embrace a range of morphological and physiological types. The bushes were planted in August 1988 and differential drought treatments were imposed for 16 and 13 weeks towards the end of the dry seasons in 1990 and 1991, respectively. The resulting soil water deficits were successfully simulated using a water balance model. Under well-watered conditions Clone S15/10 (from Kenya) gave the highest yield of dry tea, reaching 5600 kg ha−l in the fourth year after planting (1991/92) compared with 3640–4420 kg ha−1 for the other five clones. During the cool season Clone SFS150 (from Malawi) yielded more than Clones 1, 207, 6/8 and K35. Although annual yields decreased curvi-linearly as the maximum soil water deficit increased, single values for the drought sensitivity of each clone could be derived by using stress time as an index of drought. On this basis Clones S15/10 and 207 were identified as being the most sensitive to drought; Clones SFS150 and 1 were drought resistant. The reasons for these differences in yield responses and the importance of determining drought sensitivity over an appropriate time period are discussed.
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Mohtasin, Fahmid. "A Case Study on Disaster Insurance in Kenya." Research in Agriculture Livestock and Fisheries 8, no. 1 (May 1, 2021): 57–64. http://dx.doi.org/10.3329/ralf.v8i1.53268.
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This study aims to provide a comprehensive outlook on the active disaster insurance scene in the East African country, Kenya. It begins with a geographic and economic analysis of the country followed by its historical challenges with natural disasters, namely droughts. The study is both qualitative and quantitative in nature and mostly deals with secondary sources of data. Establishing the current status of the country, the discussion brings into light the three insurance programs that have gained prominence there in the last decade: Kenyan Livestock Insurance Program (KLIP), Area Yield Index Insurance (AYII), and Kilimo Salama or Safe Agriculture. These programs use state of the art remote sensing technology to determine the availability of pasture, crop yields, etc. through standardized vegetation indices. Once the indices reach a predetermined minimum threshold, they trigger the payout mechanisms of the respective programs, economically uplifting the vulnerable communities involved and avoiding potential disaster. The programs are partially subsidized by the government which allows ease of adoption for local communities and helps stabilize the economy by keeping the agriculture and livestock sectors in balance. The study also acknowledges the limitations faced by the programs in order to provide a more realistic depiction and aims to encourage the piloting of similar programs in other developing nations like Bangladesh.
Res. Agric., Livest. Fish.8(1): 57-64, April 2021
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Batchelor, William D., L. M. Suresh, Xiaoxing Zhen, Yoseph Beyene, Mwaura Wilson, Gideon Kruseman, and Boddupalli Prasanna. "Simulation of Maize Lethal Necrosis (MLN) Damage Using the CERES-Maize Model." Agronomy 10, no. 5 (May 15, 2020): 710. http://dx.doi.org/10.3390/agronomy10050710.
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Maize lethal necrosis (MLN), maize streak virus (MSV), grey leaf spot (GLS) and turcicum leaf blight (TLB) are among the major diseases affecting maize grain yields in sub-Saharan Africa. Crop models allow researchers to estimate the impact of pest damage on yield under different management and environments. The CERES-Maize model distributed with DSSAT v4.7 has the capability to simulate the impact of major diseases on maize crop growth and yield. The purpose of this study was to develop and test a method to simulate the impact of MLN on maize growth and yield. A field experiment consisting of 17 maize hybrids with different levels of MLN tolerance was planted under MLN virus-inoculated and non-inoculated conditions in 2016 and 2018 at the MLN Screening Facility in Naivasha, Kenya. Time series disease progress scores were recorded and translated into daily damage, including leaf necrosis and death, as inputs in the crop model. The model genetic coefficients were calibrated for each hybrid using the 2016 non-inoculated treatment and evaluated using the 2016 and 2018 inoculated treatments. Overall, the model performed well in simulating the impact of MLN damage on maize grain yield. The model gave an R2 of 0.97 for simulated vs. observed yield for the calibration dataset and an R2 of 0.92 for the evaluation dataset. The simulation techniques developed in this study can be potentially used for other major diseases of maize. The key to simulating other diseases is to develop the appropriate relationship between disease severity scores, percent leaf chlorosis and dead leaf area.
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Mahuku, George, Benham E. Lockhart, Bramwel Wanjala, Mark W. Jones, Janet Njeri Kimunye, Lucy R. Stewart, Bryan J. Cassone, et al. "Maize Lethal Necrosis (MLN), an Emerging Threat to Maize-Based Food Security in Sub-Saharan Africa." Phytopathology® 105, no. 7 (July 2015): 956–65. http://dx.doi.org/10.1094/phyto-12-14-0367-fi.
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In sub-Saharan Africa, maize is a staple food and key determinant of food security for smallholder farming communities. Pest and disease outbreaks are key constraints to maize productivity. In September 2011, a serious disease outbreak, later diagnosed as maize lethal necrosis (MLN), was reported on maize in Kenya. The disease has since been confirmed in Rwanda and the Democratic Republic of Congo, and similar symptoms have been reported in Tanzania, Uganda, South Sudan, and Ethiopia. In 2012, yield losses of up to 90% resulted in an estimated grain loss of 126,000 metric tons valued at $52 million in Kenya alone. In eastern Africa, MLN was found to result from coinfection of maize with Maize chlorotic mottle virus (MCMV) and Sugarcane mosaic virus (SCMV), although MCMV alone appears to cause significant crop losses. We summarize here the results of collaborative research undertaken to understand the biology and epidemiology of MLN in East Africa and to develop disease management strategies, including identification of MLN-tolerant maize germplasm. We discuss recent progress, identify major issues requiring further research, and discuss the possible next steps for effective management of MLN.
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HARY, I. "The impact of controlled breeding on milk production in pastoral goats in northern Kenya: an application of polynomial growth curve fitting." Journal of Agricultural Science 140, no. 3 (May 2003): 357–71. http://dx.doi.org/10.1017/s0021859603002995.
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The paper investigates the effect of controlled seasonal breeding on milk production in a herd of Small East African (SEA) goats. Polynomial growth curve models were fitted to both daily and cumulative milk yield data obtained from an experiment conducted over a period of 4 years (1984–88) under simulated pastoral herd management in Isiolo District, northern Kenya. The experimental treatment consisted of six different mating seasons per year, which were replicated three times over the course of the experiment.Milk yields in the first 2 weeks of lactation were negatively affected (<400 g/day) when kidding took place between June and September, whereas maximum initial yields of about 450 to 550 g/day were achieved at the onset and during the long rainy season. Multiple peaks in milk yield curves were observed when a rainy season occurred after about the first half of the lactation period. In terms of total amount of milk produced until 28 weeks of lactation, the production system could benefit from the introduction of a restricted breeding management allowing does to be bred in the period from June to November, with total milk yields being estimated at approximately 60 kg of milk. Maximum milk production until weaning can be expected to be achieved by does mated between October and January (between 46 and 48 kg of milk). The present experiment has revealed that mating just prior to or during the long rainy season leads to low milk yields until weaning and significantly increases the incidence of early kid deaths.It is concluded that evaluating milk production in goat herds exposed to strong seasonal changes in forage supply is perhaps best carried out in terms of cumulative milk yields, instead of average daily yields, which are subject to large fluctuations. Furthermore, under these conditions fitting polynomial growth curves to longitudinal milk yield data using the general linear mixed model appears to be more appropriate than the estimation of non-linear algebraic lactation curves.
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Murithi, H. M., J. S. Haudenshield, F. Beed, G. Mahuku, M. H. A. J. Joosten, and G. L. Hartman. "Virulence Diversity of Phakopsora pachyrhizi Isolates From East Africa Compared to a Geographically Diverse Collection." Plant Disease 101, no. 7 (July 2017): 1194–200. http://dx.doi.org/10.1094/pdis-10-16-1470-re.
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Soybean rust, caused by the biotrophic pathogen Phakopsora pachyrhizi, is a highly destructive disease causing substantial yield losses in many soybean producing regions throughout the world. Knowledge about P. pachyrhizi virulence is needed to guide development and deployment of soybean germplasm with durable resistance against all pathogen populations. To assess the virulence diversity of P. pachyrhizi, 25 isolates from eight countries, including 17 isolates from Africa, were characterized on 11 soybean genotypes serving as differentials. All the isolates induced tan lesions with abundant sporulation on genotypes without any known resistance genes and on soybean genotypes with resistance genes Rpp4 and Rpp5b. The most durable gene was Rpp2, where 96% of the isolates induced reddish brown lesions with little or no sporulation. Of the African isolates tested, the South African isolate was the most virulent, whereas those from Kenya, Malawi, and some of the isolates from Tanzania had the lowest virulence. An Argentinian isolate was virulent on most host differentials, including two cultivars carrying multiple resistance genes. Ten distinct pathotypes were identified, four of which comprised the African isolates representing considerable P. pachyrhizi virulence. Soybean genotypes carrying Rpp1b, Rpp2, Rpp3, and Rpp5 resistance genes and cultivars Hyuuga and UG5 were observed to be resistant against most of the African isolates and therefore may be useful for soybean-breeding programs in Africa or elsewhere.
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Kangai Munene, Ann, Felister Nzuve, Jane Ambuko, and Damaris Odeny. "Heritability Analysis and Phenotypic Characterization of Spider Plant (Cleome gynandra L.) for Yield." Advances in Agriculture 2018 (July 31, 2018): 1–11. http://dx.doi.org/10.1155/2018/8568424.
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Knowledge on phenotypic diversity among existing spider plant accessions is a milestone in the improvement of spider plant, which is a highly nutritious indigenous vegetable in Kenya. A study involving agronomic and morphological characterization of 49 spider plant accessions assembled from East and South Africa was carried out at the University of Nairobi Field Station for two seasons in a randomized complete block design with three replications. Phenotypic data was collected on growth habit, flower, petiole, leaf and stem colour, petiole, leaf and stem hairiness, number of leaves per plant, plant height, number of primary branches, leaf length and width, single leaf area, and chlorophyll content according to FAO descriptors with modifications. Data was analyzed using both DARwin software V6 and Genstat Version 14. We observed significant differences among the traits implying great genetic variability among the evaluated spider plant accessions. The high genetic variation was further validated using the Unweighted Pair Group Method with Arithmetic mean (UPGMA) clustering method with stem and flower colour as key traits. The 49-spider plant accessions were clustered into 2 major groups, each consisting of Kenyan and South African accessions. Stepwise regression revealed that plant height had the most influence on yield in terms of number of leaves per plant. We also observed high heritability for several traits including days to flowering (91%), number of leaves per plant (99%), plant height (99%), number of primary branches (94%), chlorophyll content (94%), and single leaf area (87%). Our results reveal the high genetic variation between different spider plant accessions, especially from different regions of Africa that could be further exploited to improve productivity in the plant. The high heritability of most of the yield related traits is promising for improving yield in the crop through direct selection.
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DeLay, Nathan D., S. M. Thumbi, Julia Vanderford, Elkanah Otiang, Linus Ochieng, M. Kariuki Njenga, Guy H. Palmer, and Thomas L. Marsh. "Linking calving intervals to milk production and household nutrition in Kenya." Food Security 12, no. 2 (January 15, 2020): 309–25. http://dx.doi.org/10.1007/s12571-019-01006-w.
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AbstractMaternal and child under-nutrition resulting in childhood stunting remains prevalent in east Africa, leading to increased disease risk, limiting cognitive development, and impeding human capital accumulation that constrains individuals, communities, and nations from reaching their full potential. In a western Kenyan population with a high prevalence of childhood stunting, frequency of milk consumption has been shown to increase monthly height gain in children, indicating the potential to improve health through livestock productivity. However, calving rates remain low, constraining the availability of milk to the household. Here we model average herd-level calving intervals and its relation to milk yield and nutrition in the context of an agricultural household production model, applying a dynamic panel econometric approach to household level data. We provide evidence that targeted on-farm specialization leads to significantly higher calving rates and shorter calving intervals, which in turn predictably increase milk production. Importantly, we show that the positive link between calving and household milk nutrition is present across households that primarily consume milk produced on-farm (“producer-consumers”) and those that predominantly purchase milk (“milk buyers”), indicating that efforts to improve herd fertility in western Kenya could improve food security on a community scale.
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Ngure, Mary, SO Wandiga, DO Olago, and SO Oriaso. "Scaling up crop diversification among farming communities for food security under climate change: A case study of the Kenyan pelis programme." African Journal of Food, Agriculture, Nutrition and Development 20, no. 07 (December 18, 2020): 17025–44. http://dx.doi.org/10.18697/ajfand.95.19590.
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Climate change poses significant risks to food security globally with predictions of 10-20 % decline in rain-fed crop yields by 2050. Sub-Saharan Africa remains highly susceptible to food shortage since over 95 % of the region’s total cropland is rain-fed. Kenya’s over reliance on rain-fed agriculture predisposes the country to climate-induced food insecurity. Murang’a County in Kenya is experiencing climate change challenges manifested in prolonged droughts and floods. The consequences,are failed cropping seasons, soil erosion, landslides, altered crop suitability and a resurgence of human, livestock, crop pests,and diseases,culminating into food insecurity. This study was conducted with Kimandi-Wanyaga community in the Gatanga Sub-County in Murang’a County, Kenya. Residents are smallholder subsistence rain-fed farmers. The study explored the potential of up-scaling crop diversification under the Plantation Establishment and Livelihood Improvement Scheme (PELIS) for food security vis-à-vis climate change. The community’s climate change coping strategies were explored to account for the need to up-scale crop diversification under PELIS. A mixed methods research design was applied whereby a systematic sampling method was used to select 281 household-heads. Three key informants were purposively selected and primary data were collected through a household survey, in-depth key stakeholder interviews, focus group discussions and on-farm trials. Quantitative data were analysed using descriptive and inferential statistics while qualitative data were analysed using thematic and content analysis. The study established that 92.9 % of the community perceived climate change and its impacts. They had adopted a combination of coping strategies most of which,were found to be informed by short-term survival and hence,considered inadequate for long-term adaptation. The PELIS approach had been piloted in Murang’a County and was found to be a promising strategy for crop diversification and food security among forest-adjacent communities. However, only 11 % of the studied community participated in the scheme. Therefore, the study endeavoured to work with the community to promote cultivation of traditional vegetables under PELIS for crop diversification and food security in the face of climate change.The PELIS beneficiaries who adopted cultivation of Black nightshade, Amaranths and Cowpeas managed to produce enough for household consumption and sale of surplus for income. The PELIS,therefore, possesses the co-benefits of climate change adaptation through crop diversification for food security and climate change mitigation through afforestation for carbon sequestration.
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Birithia, R., S. Subramanian, H. R. Pappu, P. Sseruwagi, J. W. Muthomi, and R. D. Narla. "First Report of Iris yellow spot virus Infecting Onion in Kenya and Uganda." Plant Disease 95, no. 9 (September 2011): 1195. http://dx.doi.org/10.1094/pdis-01-11-0057.
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Onion (Allium cepa L.) is one of the key vegetables produced by small-holder farmers for the domestic markets in Sub-Saharan Africa. Biotic factors, including infestation by thrips pests such as Thrips tabaci Lindeman, can inflict as much as 60% yield loss. Iris yellow spot virus (IYSV; family Bunyaviridae, genus Tospovirus) transmitted by T. tabaci is an economically important viral pathogen of bulb and seed onion crops in many onion-growing areas of the world (2,4). In Africa, IYSV has been reported in Reunion (1) and South Africa (3). In September 2009, symptoms suspected to be caused by IYSV were observed on onions and leeks cultivated in Nairobi, Kenya. Symptoms consisted of spindle-shaped, straw-colored, irregular chlorotic lesions with occasional green islands on the leaves. The presence of the virus was confirmed with IYSV-specific Agdia Flash kits (Agdia Inc., Elkart, IN). Subsequently, surveys were undertaken in small-holder farms in onion production areas of Makueni (January 2010) and Mwea (August 2010) in Kenya and Kasese (January 2010) and Rwimi (January 2010) in Uganda. The incidence of disease in these locations ranged between 27 and 72%. Onion leaves showing symptoms of IYSV infection collected from both locations tested positive for the virus by double-antibody sandwich-ELISA with IYSV-specific antiserum (Agdia Inc). IYSV infection was confirmed by reverse transcription-PCR with primers IYSV-465c: 5′-AGCAAAGTGAGAGGACCACC-3′ and IYSV-239f: 5′-TGAGCCCCAATCAAGACG3′ (3) as forward and reverse primers, respectively. Amplicons of approximately 240 bp were obtained from all symptomatic test samples but not from healthy and water controls. The amplicons were cloned and sequenced from each of the sampled regions. Consensus sequence for each isolate was derived from at least three clones. The IYSV-Kenya isolate (GenBank Accession No. HQ711616) had the highest nucleotide sequence identity of 97% with the corresponding region of IYSV isolates from Sri Lanka (GenBank Accession No. GU901211), followed by the isolates from India (GenBank Accession Nos. EU310287 and EU310290). The IYSV-Uganda isolate (GenBank Accession No. HQ711615) showed the highest nucleotide sequence identity of 95% with the corresponding region of IYSV isolates from Sri Lanka (GenBank Accession No. GU901211) and India (95% with GenBank Accession Nos. EU310274 and EU310297). To our knowledge, this is the first report of IYSV infecting onion in Kenya and Uganda. Further surveys and monitoring of IYSV incidence and distribution in the region, along with its impact on the yield, are under investigation. References: (1) L. J. du Toit et al. Plant Dis. 91:1203, 2007. (2) D. H. Gent et al. Plant Dis. 88:446, 2004. (3) H. R. Pappu et al. Plant Dis 92:588, 2008. (4) H. R. Pappu et al. Virus Res. 141:219, 2009.
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Human, Maria Petronella, Irene Barnes, Maryke Craven, and Bridget Genevieve Crampton. "Lack of Population Structure and Mixed Reproduction Modes in Exserohilum turcicum from South Africa." Phytopathology® 106, no. 11 (November 2016): 1386–92. http://dx.doi.org/10.1094/phyto-12-15-0311-r.
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Exserohilum turcicum is the causal agent of northern corn leaf blight, a destructive foliar disease of maize that results in yield losses worldwide. In South Africa, typical yield losses range from 15 to 30%. Previous studies found high haplotypic diversity with evidence for sexual recombination in E. turcicum populations from tropical climates such as Kenya. However, the population genetic structure and method of reproduction of E. turcicum in South Africa is unknown and, therefore, was investigated. Twelve polymorphic microsatellite markers were screened on 258 E. turcicum isolates from maize collected during 2012 and 2013 from three maize fields in South Africa. A multiplex polymerase chain reaction assay amplifying both mating type idiomorphs was applied to investigate the distribution of mating types. No distinct genetic clusters were observed. Shared haplotypes were identified between isolates separated by distances of up to 762 km, which provided evidence of migration. High haplotypic diversity indicated that sexual reproduction is occurring among E. turcicum isolates, although mating type ratios and linkage disequilibrium analyses did not support the hypothesis of random mating. The population genetic structure of E. turcicum in South Africa is likely due to the direct movement and spread of isolates undergoing a mixed reproductive lifecycle.
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BIDINGER, F. R., A. G. BHASKER RAJ, NEGUSSE ABRAHA, ADAM MOHAMED ALI, A. B. OBILANA, and R. B. JONES. "TOPCROSS HYBRIDS AS AN ENTRY INTO COMMERCIAL SEED PRODUCTION OF PEARL MILLET IN EASTERN AFRICA." Experimental Agriculture 41, no. 3 (July 2005): 335–56. http://dx.doi.org/10.1017/s001447970500267x.
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Pearl millet topcross hybrids (inbred male-sterile seed parent × open-pollinated variety restorer) based on locally adapted varieties and publicly available seed parents provide an ideal entry point into the commercial hybrid seed business, which can stimulate commercial investment by prospective seed producers. To demonstrate this potential, fifteen topcross hybrids made with the widely adapted variety ICMV 221 were evaluated in Eritrea, Sudan and Kenya for overall field performance, and in India for mechanisms of expression of heterosis and for terminal drought tolerance. Across all evaluation environments, the mean yield heterosis was 8%, with a range of −1% to +19%; six hybrids had a statistically significant, positive across-environment yield heterosis (ranging from +11% to +19%). Significant grain yield heterosis in rainy season environments was a consequence of heterosis in both biomass and harvest index, but not necessarily in any specific yield component. Positive grain yield heterosis under terminal drought stress, a common occurrence in millet-growing environments, was related to positive heterosis for grain size. These results are discussed in terms of their support for topcross hybrids as an entry point for prospective millet seed producers, and a scheme presented for the rapid creation, evaluation and marketing of locally adapted topcross hybrids.
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Kunguni, Josephine Sarah, Damaris A. Odeny, Otto G. Dangasuk, Lexa G. Matasyoh, and Chrispus O. A. Oduori. "Response of Elite Kenyan Finger Millet (Eleusine coracana, L. Gaertn) Genotypes to Ethrel Application." International Letters of Natural Sciences 48 (November 2015): 43–52. http://dx.doi.org/10.18052/www.scipress.com/ilns.48.43.
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Finger millet is a staple food crop of many communities in Africa. The crop is highly nutritious and has incredible grain storage quality. Limited research investment in finger millet in the past has resulted in poor yields and there are currently no commercial hybrids. We investigated the response of different finger millet genotypes (Okhale-1, Gulu-E, KACCIMMI-72, IE 2872, IE 4115 and U-15) to the application of a plant growth regulator hormone (Ethrel). Six elite Kenyan finger millet varieties with contrasting agronomic traits were crossed in a 6 x 6 diallel pattern. To enhance male sterility across female parents, we subjected the plants to Ethrel at concentrations of 1,500ppm, 1,750ppm and 2,000ppm against a 0ppm check. Dwarfing of sprayed plants that resulted in less lodging and ultimately higher yields were observed among plants sprayed with Ethrel at different concentrations. Ethrel application at 2,000ppm had the most dwarfing effect on plants while spraying plants with 1,500ppm of Ethrel resulted in increased grain weight. Although our results demonstrate overall positive effect of Ethrel on finger millet production, the optimum concentrations for more efficient hybridization will still need to be determined.
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Wolday, A., T. Fetch, D. P. Hodson, W. Cao, and S. Briere. "First Report of Puccinia graminis f. sp. tritici Races with Virulence to Wheat Stem Rust Resistance Genes Sr31 and Sr24 in Eritrea." Plant Disease 95, no. 12 (December 2011): 1591. http://dx.doi.org/10.1094/pdis-07-11-0582.
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Wheat stem rust, caused by Puccinia graminis f. sp. tritici, has historically been a major limiting factor in wheat production. Identification of isolate Ug99 in Uganda in 1999 highlighted the vulnerability of a large proportion of the global wheat crop and raised international concerns. Since initial detection, seven races have been identified in the Ug99 lineage and occurrence has been confirmed in nine countries (4). During rust surveys of Eritrea undertaken in October 2010, stem rust was found to be widespread throughout the highland wheat-growing areas. Presence of P. graminis f. sp. tritici was recorded in 95% of the 92 cereal fields surveyed, with high disease severity (>40%) recorded at 50 sites. Collected stem rust samples were analyzed for race identity in a level 3 biocontainment laboratory in Canada. Nine collections yielded viable spores for infection studies. Virulence analysis with 20 differentials in the letter-code nomenclature system (1) identified two races from repeated experiments; TTKST (four confirmed isolates) and PTKST (five confirmed isolates). Both races belong to the Ug99 lineage and both exhibit combined Sr31 and Sr24 virulence. TTKST and PTKST differ only in their virulence or avirulence to Sr21, respectively. This first confirmation of TTKST and PTKST in Eritrea is important because it represents further geographical spread of Ug99-related races. Since first detection of a Sr24 variant of Ug99 (race TTKST) in Kenya in 2006 (1), these variants have become the predominant P. graminis f. sp. tritici pathotypes in most of eastern Africa. Race TTKST caused epidemics in Kenya in 2007, and race PTKST was first detected in Ethiopia the same year (T. Fetch, unpublished data). Recent detection of race PTKST in three additional southern Africa countries (South Africa, Zimbabwe, and Mozambique [2,3]) indicates on-going range expansion within the African continent. Sr24-virulent variants of Ug99 are a cause for concern since a high frequency of cultivars from South America, Australia, the United States, and the CIMMYT are known to possess the Sr24 resistance gene. On the basis of observed occurrence and postulated migration routes of the original Ug99 (race TTKSK), the confirmed presence of TTKST and PTKST in Eritrea increases the possibility for range expansion out of Africa by crossing the Red Sea and into the Arabian Peninsula. Future spread of TTKST and PTKST to western Asia is considered highly likely. References: (1) Y. Jin et al. Plant Dis. 92:923, 2008. (2) F. Mukoyi et al. Plant Dis. 95:1188, 2011. (3) Z. A. Pretorius et al. Plant Dis. 94:784, 2010. (4) R. P. Singh et al. Annu. Rev. Phytopathol. 49:465, 2011.
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Cheruiyot, Duncan, Charles A. O. Midega, Jimmy O. Pittchar, John A. Pickett, and Zeyaur R. Khan. "Farmers’ Perception and Evaluation of Brachiaria Grass (Brachiaria spp.) Genotypes for Smallholder Cereal-Livestock Production in East Africa." Agriculture 10, no. 7 (July 4, 2020): 268. http://dx.doi.org/10.3390/agriculture10070268.
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Brachiaria (Urochloa) is a genus, common name brachiaria, of forage grasses that is increasingly transforming integrated crop-livestock production systems in East Africa. A study was undertaken to (i) assess smallholder farmers’ perception on benefits of brachiaria in cereal-livestock production, (ii) identify brachiaria production constraints, and (iii) identify farmer preferred brachiaria genotypes. A multi-stage sampling technique was adopted for sample selection. Data were collected through semi-structured individual questionnaire and focus group discussions (FGDs). The study areas included Bondo, Siaya, Homabay and Mbita sub-counties in Western Kenya and the Lake zone of Tanzania. A total of 223 farmers participated in individual response questionnaires while 80 farmers participated in the FGDs. The respondents considered brachiaria mainly important in management of cereal pests (70.4% of respondents) and as an important fodder (60.8%). The major production constraint perceived by both male and female respondents is attacks by arthropods pests (49.2% and 63%, respectively). Spider smites had been observed on own farms by 50.8% of men and 63.1% of women, while sorghum shoot flies had been observed by 58.1% of men and 67.9% of women. These pests were rated as a moderate to severe problem. Xaraes was the most preferred genotype, followed by Mulato II and Piata. These genotypes are important in developing new crop pest management strategies, such as push-pull, and for relatively rapid improvements in crop management and yield increases, particularly in developing countries.
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Birithia, R., S. Subramanian, J. Villinger, J. W. Muthomi, R. D. Narla, and H. R. Pappu. "First Report of Tomato yellow ring virus (Tospovirus, Bunyaviridae) Infecting Tomato in Kenya." Plant Disease 96, no. 9 (September 2012): 1384. http://dx.doi.org/10.1094/pdis-05-12-0462-pdn.
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Tomato (Lycoperscion esculentum) is one of the most popular vegetables and a major source of nutrition and income for smallholders in Africa. Thrips-transmitted tospoviruses are among the economically important pathogens of tomatoes that cause significant crop losses worldwide (3). In surveys for Tomato spotted wilt virus (TSWV) in the major tomato production areas of Kenya between March 2010 and January 2012, tomato fruits with chlorotic ring spots on fruits with stem and leaf necrosis were observed frequently. The symptoms were more evident in the dry seasons and disease incidence ranged from 28 to 42%. The pathogen did not react with antiserum specific to TSWV (Agdia Biofords, Ervy, France) in double-antibody sandwich (DAS)-ELISA. Furthermore, the pathogen did not react with antiserum specific to Capsicum chlorosis virus (CaCV), Chrysanthemum stem necrosis virus (CSNV), Groundnut ring spot virus (GRSV), Impatiens necrotic spot virus (INSV), Iris yellow spot virus (IYSV), and Watermelon silver mottle virus (WSMoV) (Agdia Biofords and DSMZ, Germany) in DAS-ELISA, but reacted positively to antiserum specific to Tomato yellow fruit ring virus (TYFRV) (DSMZ, AS0526). The nucleocapsid (N) gene specific primers (TFfor: 5′-ACTCATTAAAATGCATCGTTCT-3′ and TFrev: 5′-CTAAGTAAACACCATGGCTACC-3′ as forward and reverse primers, respectively) were designed by choosing six conserved regions of the N gene sequences of known TYFRV and Tomato yellow ring virus (TYRV) sequences available from GenBank. Using these primers, TYRV infection of tomatoes collected from Loitokitok, Kenya (2.73°S, 37.51°E) was confirmed by reverse transcription (RT)-PCR. PCR products of approximately 912-bp were obtained from six out of 11 symptomatic tomato samples tested, but not from healthy and water controls. Amplicons were gel-purified using QuickClean II Gel Extraction Kit (GenScript, UK) and sequenced using TFfor and TFrev primers. A consensus sequence was generated using Geneious Pro 5.5.6 Software (Biomatters Ltd., Auckland, NZ). The BLAST revealed that the N-gene sequence of the Kenyan tomato isolate (GenBank Accession No. JQ955615) had sequence identity with the Cineraria isolate (98.5%) (Accession No. DQ788693.1) and the Anemone isolate (98.1%) (Accession No. DQ788694.1) of TYRV (4) from Fars Province, Iran; an Alstroemeria isolate (98.4%) (Accession No. HQ154130.1) and two tomato isolates (98.3%) (Accession Nos. HQ154131.1 and AY686718.1) of TYRV from northern Khorasan Province, Iran, and a tomato isolate (98.1%) (Accession No. AJ493270.1) of TYFRV from Varamin, Iran. The Kenyan tomato isolate differed from a TYFRV potato isolate (87.5%) from Iran (Accession No. EU126931.1) (1), a TYRV potato isolate (87.5%) from Iran (Accession No. JF836812.1); a soybean isolate of TYRV (87.4%) from Iran (Accession No. DQ462163.1) (2), and showed significant divergence from that of Polygonum ringspot virus from Italy (81%) (Accession No. EF445397.1). To our knowledge, this is the first report of TYRV infecting tomatoes in Kenya. Further surveys and monitoring of TYRV incidence and distribution in the region, vector competence of thrips species, and impact on the crop yield are in progress. References: (1) A. R. Golnaraghi et al. Plant Dis. 92:1280, 2008. (2) A. Hassani-Mehraban et al. Arch. Virol. 152:85, 2007. (3) H. R. Pappu et al. Virus Res. 141:219, 2009. (4) R. Rasoulpour and K. Izadpanah, Austral. Plant Pathol. 36:285, 2007.
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Mudereri, B. T., E. M. Abdel-Rahman, T. Dube, T. Landmann, S. Niassy, H. E. Z. Tonnang, and Z. R. Khan. "POTENTIAL OF RESAMPLED MULTISPECTRAL DATA FOR DETECTING DESMODIUM-BRACHIARIA INTERCROPPED WITH MAIZE IN A ‘PUSH-PULL’ SYSTEM." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B3-2020 (August 21, 2020): 1017–22. http://dx.doi.org/10.5194/isprs-archives-xliii-b3-2020-1017-2020.
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Abstract. Poor crop yields remain one of the main causes of chronic food insecurity in Africa. This is largely caused by insect pests, weeds, unfavourable climatic conditions and degraded soils. Weed and pest control, based on the climate-adapted ‘push-pull’ system, has become an important target for sustainable intensification of food production adopted by many small-holder farmers. However, essential baseline information using remotely sensed data is missing, specifically for the ‘push-pull’ companion crops. In this study, we investigated the spectral uniqueness of two of the most commonly used ‘companion’ crops (i.e. greenleaf Desmodium (Desmodium intortum) and Brachiaria (Brachiaria cv Mulato) with co-occurring soil, green maize, and maize stover. We used FieldSpec® Handheld 2™ analytical spectral device to collect in situ hyperspectral data in the visible and near-infrared region of the electromagnetic spectrum. Random forest was then used to discriminate among the different companion crops, green maize, maize stover and the background soil. Experimental ‘push-pull’ plots at the International Centre of Insect Physiology and Ecology (icipe) in Kenya were used as test sites. The in-situ hyperspectral reflectance data were resampled to the spectral waveband configurations of four multispectral sensors (i.e. Landsat-8, Quickbird, Sentinel-2, and WorldView-2) using spectral response functions. The performance of the four sensors to detect the ‘push-pull’ companion crops, maize and soil was compared. We were able to positively discriminate the two companion crops from the three potential background endmembers i.e. soil, green maize, and maize stover. Sentinel-2 and WorldView-2 outperformed (> 98% overall accuracy) Landsat-8 and Quickbird (96% overall accuracy), because of their added advantage of the strategically located red-edge bands. Our results demonstrated the unique potential of the relatively new multispectral sensors’ and machine learning algorithms as a tool to accurately discern companion crops from co-occurring maize in ‘push-pull’ plots.
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Ngelenzi, Munywoki James, Ogweno Joshua Otieno, and Saidi Mwanarusi. "Improving Water Use Efficiency and Insect Pest Exclusion on French Bean (Phaseolus vulgaris L.) Using Different Coloured Agronet Covers." Journal of Agricultural Science 11, no. 3 (February 15, 2019): 159. http://dx.doi.org/10.5539/jas.v11n3p159.
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French bean (Phaseolus vulgaris L.) is important in the socio-economic farming systems of East and Central Africa. It is a crop with great potential for addressing food insecurity, income generation and poverty alleviation in the region. Enhanced French bean productivity is hindered by a number of biotic and abiotic constraints as the crop is predominantly grown in open fields. The crop is mostly grown under irrigation and cannot withstand prolonged dry spells. Farmers rely heavily on insecticides to control insect pests. This increases the risk of rejection of their produce due to stringent maximum residue levels (MRLs) in export markets. This study was undertaken in the Horticulture Research and Teaching Field, Egerton University, Kenya to determine the potential of coloured net covers in improving French bean water use efficiency and insect pest exclusion. The experiment was set in a Randomized Complete Block Design (RCBD) with six treatments replicated four times. French bean ‘Source’ was grown under different coloured nets (white, blue, yellow, grey, and tricolour) and control (open field). Variables measured included; pest population, fresh pod yield, total plant biomass, leaf relative water content (LRWC) and water use efficiency for plant growth (WUE DW). Covering French bean with different coloured net covers reduced the numbers of silverleaf whitefly and black bean aphids. Coloured net covers enhanced crop performance marked by higher fresh pod yield and total plant biomass as well as improved LRWC and WUE DW of the crop. Results of this study present the potential of coloured net covers to be used as part of integrated French bean management programme(s) to reduce insect pest population and pesticide application while enhancing water use efficiency and crop performance under tropical field conditions.
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Mutisya, Daniel L., Canute PM Khamala, Jacob JO Konyango, Clement K. Kamau, and Lawrence K. Matolo. "Timed Strategy for Control of Bollworm for Sustainable Sorghum Crop Yield under Varied Regimes of Rainfall, Temperature and Soil Fertility." Sustainable Agriculture Research 5, no. 4 (October 10, 2016): 71. http://dx.doi.org/10.5539/sar.v5n4p71.
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<p class="sar-body"><span lang="EN-US">Various environmental factors influence yield of sorghum grain, <em>Sorghum bicolor</em> (L) in Sub-Sahara Africa. Various production conditions of rainfall amount, temperature regimes, soil fertility levels and bollworm <em>Helicoverpa armigera</em> density at specific sorghum grain stage were evaluated for effect to sorghum grain yield. High rainfall amount, high temperature and soil fertility levels were positively correlated to sorghum grain yield at three test sites at Ithookwe, Katumani and Kampi of eastern Kenya. The warmest Kampi site achieved the highest seed viability on germination test at 43, 87 and 99% for grain stage of light-green, cream-dough and hard dough, respectively. High <em>H. armigera</em> density was inversely correlated to grain yield. Comparatively, yield loss of < 10% was observed when grain was at early soft dough and > 35% as the grain ripened to early hard dough stage. Thus initial <em>H. armigera</em> damage occurred at late soft dough stage and increased exponentially as the grain ripened to early hard dough stage. The right time to spray against <em>H. armigera</em> was determined as at soft dough stage of sorghum grain to prevent economic damage of the crop. Thus fertility level, rainfall amount and time of bollworm pest attack were deemed worth considerations towards sustainable yield of sorghum. </span></p>
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DIXIT, P. N., P. J. M. COOPER, J. DIMES, and K. P. RAO. "ADDING VALUE TO FIELD-BASED AGRONOMIC RESEARCH THROUGH CLIMATE RISK ASSESSMENT: A CASE STUDY OF MAIZE PRODUCTION IN KITALE, KENYA." Experimental Agriculture 47, no. 2 (March 25, 2011): 317–38. http://dx.doi.org/10.1017/s0014479710000773.
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SUMMARYIn sub-Saharan Africa (SSA), rainfed agriculture is the dominant source of food production. Over the past 50 years much agronomic crop research has been undertaken, and the results of such work are used in formulating recommendations for farmers. However, since rainfall is highly variable across seasons the outcomes of such research will depend upon the rainfall characteristics of the seasons during which the work was undertaken. A major constraint that is faced by such research is the length of time for which studies could be continued, typically ranging between three and five years. This begs the question as to what extent the research was able to ‘sample’ the natural longer-term season-to-season rainfall variability. Without knowledge of the full implications of weather variability on the performance of innovations being recommended, farmers cannot be properly advised about the possible weather-induced risks that they may face over time. To overcome this constraint, crop growth simulation models such as the Agricultural Production Systems Simulator (APSIM) can be used as an integral part of field-based agronomic studies. When driven by long-term daily weather data (30+ years), such models can provide weather-induced risk estimates for a wide range of crop, soil and water management innovations for the major rainfed crops of SSA. Where access to long-term weather data is not possible, weather generators such as MarkSim can be used. This study demonstrates the value of such tools in climate risk analyses and assesses the value of the outputs in the context of a high potential maize production area in Kenya. MarkSim generated weather data is shown to provide a satisfactory approximation of recorded weather data at hand, and the output of 50 years of APSIM simulations demonstrate maize yield responses to plant population, weed control and nitrogen (N) fertilizer use that correspond well with results reported in the literature. Weather-induced risk is shown to have important effects on the rates of return ($ per $ invested) to N-fertilizer use which, across seasons and rates of N-application, ranged from 1.1 to 6.2. Similarly, rates of return to weed control and to planting at contrasting populations were also affected by seasonal variations in weather, but were always so high as to not constitute a risk for small-scale farmers. An analysis investigating the relative importance of temperature, radiation and water availability in contributing to weather-induced risk at different maize growth stages corresponded well with crop physiological studies reported in the literature.
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J., Sitta, Nzuve F. M., Olubayo F. M., Mutinda C., Muiru W. M., Miano D. W., Muthomi J. W., and Leley P. K. "Response of Assorted Maize Germplasm to the Maize Lethal Necrosis Disease in Kenya." Journal of Plant Studies 6, no. 2 (July 16, 2017): 65. http://dx.doi.org/10.5539/jps.v6n2p65.
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Maize (Zea mays L.) is the most widely grown staple food crop in Sub Saharan Africa (SSA) and occupies more than 33 million hectares each year. The recent outbreak and rapid spread of the Maize Lethal Necrosis (MLN) disease has emerged as a great challenge to maize production, threatening food security for the majority of households in the Eastern Africa region with yield loss estimated to be 50-90%. The disease is a result of synergistic interaction between two viruses, Sugarcane mosaic virus (SCMV) and Maize chlorotic mottle virus (MCMV). The objective of this study was to identify maize genotypes with resistance to MLN. In season one, 73 maize genotypes comprising 25 inbred lines from research institutes, 30 lines from the International Maize and Wheat Improvement Centre (CIMMYT) and 18 farmer varieties were screened for resistance to MLN. In season 2, only 48 genotypes were screened after some of the inbred lines showed complete susceptibility to MLN. These genotypes were grown in three replications in a completely randomized design in polythene bags in the greenhouse at the University of Nairobi. The plants were artificially inoculated using a mixture of SCMV and MCMV. .Weekly MLN disease severity scores using a scale of 1 to 5 (1 = highly resistant and 5 = highly susceptible) and % MLN incidence were recorded and eventually converted into Area under Disease Progress Curve (AUDPC) to give an indication of the disease intensity over time. The plants were allowed to grow to flowering stage to observe the effect of the MLN on the maize productivity. Analysis of Variance revealed wide genetic variation among the genotypes ranging from resistant to highly susceptible. In season 1, three farmer varieties namely MLR2, MLR11 and MLR13 showed resistance to MLN with a mean severity score of 2. In season 2, MLN12, MLN17, MLN18, MLN19, and MLR4 showed low MLN severity ranging from 2-3. The genotypes MLR6, MLR9, MLR16 and MLR18 showed MLN severity of 3 and early maturity traits. This study also validated the presence of MLN resistance among some CIMMYT lines depicted to show resistance in previous studies. These resistant genotypes could serve as donors in the introgression of the resistance into the adapted Kenyan maize backgrounds. This will go a long way in ensuring sustainable maize productivity while improving the livelihoods of the small-scale farmers who form the bulk of the major maize producers in Kenya.
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Wangithi, Charity M., Beatrice W. Muriithi, and Raphael Belmin. "Adoption and Dis-Adoption of Sustainable Agriculture: A Case of Farmers’ Innovations and Integrated Fruit Fly Management in Kenya." Agriculture 11, no. 4 (April 9, 2021): 338. http://dx.doi.org/10.3390/agriculture11040338.
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The invasive fruit fly Bactrocera dorsalis poses a major threat to the production and trade of mango in sub-Saharan Africa. Farmers devise different innovations to manage the pest in an attempt to minimize yield loss and production costs while maximizing revenues. Using survey data obtained from Embu County, Kenya, we analyzed farmers’ knowledge and perception as regards the invasive fruit fly, their innovations for the management of the pest, and the determinants of their adoption and dis-adoption decisions of recently developed and promoted integrated pest management (IPM) technologies for suppression of the pest. The results show that farmers consider fruit flies as a major threat to mango production (99%) and primarily depend on pesticides (90%) for the management of the pest. Some farmers (35%) however use indigenous methods to manage the pest. Though farmers possess good knowledge of different IPM strategies, uptake is relatively low. The regression estimates show that continued use of IPM is positively associated with the gender and education of the household head, size of a mango orchard, knowledge on mango pests, training, contact with an extension officer, and use of at least one non-pesticide practice for fruit fly management, while IPM dis-adoption was negatively correlated with the size of the mango orchard, practice score and use of indigenous innovations for fruit fly management. We recommend enhancing farmer′s knowledge through increased access to training programs and extension services for enhanced adoption of sustainable management practices for B. dorsalis.
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Stenfert Kroese, Jaqueline, John N. Quinton, Suzanne R. Jacobs, Lutz Breuer, and Mariana C. Rufino. "Particulate macronutrient exports from tropical African montane catchments point to the impoverishment of agricultural soils." SOIL 7, no. 1 (March 15, 2021): 53–70. http://dx.doi.org/10.5194/soil-7-53-2021.
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Abstract. Agricultural catchments in the tropics often generate high concentrations of suspended sediments following the conversion of natural ecosystems. The eroded fine particles are generally enriched with carbon (TC) and nutrients (TN and TP) originating from the topsoil of agricultural land. Sediment-associated TC, TN and TP are an important loss to the terrestrial ecosystem and tightly connected to an increase in riverine particulate TC and nutrient export. Soil nutrient depletion can limit crop growth and yields, whereas an excess of nutrients in streams can cause eutrophication in freshwater systems. Streams in East Africa, with widespread land conversion from forests to agriculture, are expected to receive high loads of sediment-associated TC, TN and TP. In this study, we assess the effect of land use on particulate TC, TN and TP concentrations. Suspended sediments (time-integrated, manual-event-based and automatic-event-based sediment samples) were analysed for TC, TN and TP concentrations collected at the outlet of a natural montane forest (35.9), a tea-tree plantation (33.3) and a smallholder agriculture (27.2 km2) catchment in western Kenya during a wet sampling period in 2018 and a drier sampling period in 2019. Particulate TC, TN and TP concentrations were up to 3-fold higher (p<0.05) in the natural forest catchment compared to fertilized agricultural catchments. However, because of higher sediment loads from the smallholder agriculture catchment, the total sediment-associated loads of TC, TN and TP were higher compared to the natural forest and tea-tree plantation catchment. The higher C:N ratios in the natural forest suggest that the particulate nutrients are of organic origin due to tighter nutrient cycles, whereas lower ratios in both agricultural catchments suggest a mixture of mineral and organic sediment sources. The findings of this study imply that with the loss of natural forest, the inherent soil fertility is progressively lost under the current low fertilization rates and soil management strategies.
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Gogo, Elisha Otieno, Mwanarusi Saidi, Jacob Mugwa Ochieng, Thibaud Martin, Vance Baird, and Mathieu Ngouajio. "Microclimate Modification and Insect Pest Exclusion Using Agronet Improve Pod Yield and Quality of French Bean." HortScience 49, no. 10 (October 2014): 1298–304. http://dx.doi.org/10.21273/hortsci.49.10.1298.
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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.
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Saponari, M., G. De Bac, J. Breithaupt, G. Loconsole, R. K. Yokomi, and L. Catalano. "First Report of ‘Candidatus Liberibacter asiaticus’ Associated with Huanglongbing in Sweet Orange in Ethiopia." Plant Disease 94, no. 4 (April 2010): 482. http://dx.doi.org/10.1094/pdis-94-4-0482a.
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Huanglongbing (HLB) is a serious disease of citrus worldwide. Three different ‘Candidatus Liberibacter’ species are associated with HLB: ‘Ca. Liberibacter asiaticus’, ‘Ca. L. africanus’, and ‘Ca. L. americanus’ (1). ‘Ca. L. africanus’ and its vector, Trioza erytreae, are both heat sensitive, and when present, occur in citrus when temperatures remain below 30 to 32°C. In Africa, ‘Ca. L. africanus’ and T. erytreae have been reported in South Africa, Zimbabwe, Malawi, Burundi, Kenya, Somalia, Ethiopia, Cameroon, and Madagascar (1). Inspection of citrus trees in orchards and budwood sources in nurseries located in the warmer citrus-growing areas of Tigray and North Wollo in northern Ethiopia revealed nearly 100 trees with symptoms of leaf yellowing with a blotchy mottle pattern, dead branches, and decreased fruit quality and yield. Two symptomatic sweet orange budwood trees and three symptomatic orchard plants were sampled in April 2009, along with three healthy-looking sweet orange plants. DNA was extracted from 200 mg of desiccated leaf midribs using the CTAB method (4) and subjected to conventional PCR using the primer pairs A2/J5 (2) and OI2/23S1 (3) that amplify the ribosomal protein gene in the rplKAJL-rpoBC operon and the 16S/23S ribosomal intergenic regions, respectively, of ‘Ca. L. africanus’ and ‘Ca. L. asiaticus’. Positive PCR reactions were obtained for all five symptomatic samples with both primer pairs. PCR amplicons of 703 bp (A2/J5) and 892 bp (OI2/23S) recovered from two of these samples were purified, cloned, and sequenced. BLAST analysis revealed that the nucleotide sequences we obtained for the ribosomal protein (GenBank Accessions Nos. GQ890155 and GQ890156) shared 100% identity with each other and 99% identity with sequences of ‘Ca. L. asiaticus’ from Brazil (DQ471904), Indonesia (AB480161), China (DQ157277), and Florida (CP001677). Similarly, the 16S/23S ribosomal intergenic sequences (GU296538 and GU296539) shared 100% identity with each other and 99% identity with homologous ‘Ca. L. asiaticus’ sequences from Brazil (DQ471903), Indonesia (AB480102), China (DQ778016), and Florida (CP001677) and contained two tRNA genes as occurs in ‘Ca. L. asiaticus’ but not in ‘Ca. L. africanus’ (3). To our knowledge, this is the first report of ‘Ca. L. asiaticus’ in Africa. The presence of ‘Ca. L. asiaticus’ is a threat for warmer citrus-growing areas of Africa that are less favorable for ‘Ca. L. africanus’ and T. erytreae. In areas where ‘Ca. L. asiaticus’ was confirmed, symptomatic trees must be promptly eradicated and surveys to determine spread of the disease and its vectors are necessary. References: (1) J. M. Bove. J. Plant Pathol. 88:7, 2006. (2) A. Hocquellet et al. Mol. Cell. Probes 13:373, 1999. (3) S. Jagoueix et al. Int. J. Syst. Bacteriol. 47:224, 1997. (4) M. G. Murray and W. F Thompson. Nucleic Acids Res. 8:4321, 1980.
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Gogo, Elisha O., Mwanarusi Saidi, Francis M. Itulya, Thibaud Martin, and Mathieu Ngouajio. "Microclimate Modification Using Eco-friendly Nets for High-quality Tomato Transplant Production by Small-scale Farmers in East Africa." HortTechnology 22, no. 3 (June 2012): 292–98. http://dx.doi.org/10.21273/horttech.22.3.292.
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Unfavorable environmental conditions, pests, and viral diseases are among the major factors that contribute to poor growth and quality of tomato (Solanum lycopersicum) seedlings in tropical areas. Improving crop microclimate and excluding insects that transmit viruses may improve transplant quality and yield in production fields. This study was carried out in two seasons at the Horticulture Research and Teaching Field of Egerton University in Njoro, Kenya, to investigate the effects of agricultural nets herein called eco-friendly nets (EFNs) on germination and performance of tomato seedlings. Tomato seeds were either raised in the open or under a permanent fine mesh net (0.4-mm pore diameter). Eco-friendly net covers modified the microclimate resulting in significantly higher day temperatures and relative humidity, compared with the open treatment. Nets increased temperature and relative humidity by 14.8% and 10.4%, respectively. Starting seeds under a net advanced seedling emergence by 2 days and resulted in higher emergence percentage, thicker stem diameter, more leaves, and faster growth leading to early maturity of seedlings and readiness for transplanting. Netting improved root development by increasing root quantity and length. Stomatal conductance (gS) and estimates of chlorophyll content were higher in seedlings under net covering compared with those in the noncovered control treatment. Insect pests and diseases were also reduced under net covering. The use of the net in the production of tomato transplants presented a 36.5% reduction in the cost of seeds, through improved emergence and reduced pest damage. All other factors held constant, healthy and quality transplants obtained under a net covering also translate into better field performance; hence, increasing economic returns for commercial transplants growers, as well as for tomato farmers. Results of this study suggest that EFNs can be customized not only for their effective improvement on growth and quality of tomato transplants but also for their pest and disease management in the nursery alone or as a component of integrated pest and disease management.
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Chitambo, Oliver, Solveig Haukeland, Komi K. M. Fiaboe, and Florian M. W. Grundler. "African Nightshade and African Spinach Decrease Root-Knot Nematode and Potato Cyst Nematode Soil Infestation in Kenya." Plant Disease 103, no. 7 (July 2019): 1621–30. http://dx.doi.org/10.1094/pdis-07-18-1193-re.
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Plant-parasitic nematodes, particularly root-knot nematodes (RKN: Meloidogyne spp.) and cyst nematodes (CN: Globodera and Heterodera spp.) cause severe yield reduction in most cultivated crops and are of high economic importance. African nightshade (Solanum spp.) and African spinach (Amaranthus spp.) are important African indigenous vegetables (AIV) and are rich sources of nutrition and income. However, their host status to plant-parasitic nematodes remains largely speculative. Therefore, a survey was conducted which revealed that S. villosum exhibited high root galling, whereas on S. scabrum, A. cruentus, and A. dubius root galling was rare or very low. Additionally, soil collected from the rhizosphere of S. villosum and S. scabrum contained few cysts of potato cyst nematodes (PCN), and no developing PCN females were observed on the roots of growing plants. Therefore, we studied the dynamics of RKN and PCN on A. dubius, A. cruentus, S. scabrum, and S. villosum over 2 years in a field experiment. The effects of AIV crop species on RKN and PCN soil infestation were evaluated using susceptible S. lycopersicum or S. tuberosum. After first, second, and third cultivation of A. dubius, A. cruentus, and S. scabrum, RKN infestation of the soil decreased by more than 85%, whereas S. scabrum and S. villosum decreased PCN densities by more than 80%. When cropping susceptible crops, after three seasons of successive cultivation of these AIV, galling index and number of developing PCN females measured on susceptible crops decreased by more than 75%. Wilting and RKN-PCN coinfection incidences also decreased significantly. Here, we present data that support the development of a novel cropping system including African spinach and African nightshade, which reveals a high potential to manage RKN and PCN in an environmentally friendly, effective, and productive way.
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Sánchez, Pedro A. "Tripling crop yields in tropical Africa." Nature Geoscience 3, no. 5 (May 2010): 299–300. http://dx.doi.org/10.1038/ngeo853.
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Mbanzibwa, D. R., F. Tairo, C. Gwandu, A. Kullaya, and J. P. T. Valkonen. "First Report of Sweetpotato symptomless virus 1 and Sweetpotato virus A in Sweetpotatoes in Tanzania." Plant Disease 95, no. 2 (February 2011): 224. http://dx.doi.org/10.1094/pdis-10-10-0707.
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Sweetpotato (Ipomea batatas L.) is grown widely from tropical to temperate regions and is an important food security crop in tropical countries. In Africa, sweetpotato is infected by RNA viruses of many taxa (4), but DNA viruses, such as the genus Begomovirus (family Geminiviridae), infecting sweetpotatoes in the Americas have been reported only in Kenya (3). A caulimo-like DNA virus (family Caulimoviridae) has been detected in sweetpotatoes in Uganda (1). Recently, two novel badnaviruses (genus Badnavirus, family Caulimoviridae) and a new mastrevirus (genus Mastrevirus, family Geminiviridae) were discovered in a local sweetpotato cultivar maintained in a germplasm collection in Peru (2) but were not reported elsewhere. This study examined the possible existence of these novel viruses in landrace sweetpotato varieties grown in Tanzania. Nine landrace sweetpotato varieties and one introduced cultivar (NIS 91 from the International Potato Centre, Peru) were sampled from six regions of Tanzania. DNA was extracted (2) and amplified by PCR using primers (MastvKF: 5′-GACAGACCCCTAGGGTGA-3′; MastvsR 5′-ACTGCATATAGTACATGCCACA-3′) designed in this study to amplify partial, putative movement and coat protein gene sequences of Sweetpotato symptomless virus 1 (SPSMV-1) (GenBank Accession No. FJ560945) (2). Products of the expected size were detected in seven samples (varieties Ex-London, Ex-Lyawaya, Gairo, Hombolo, Kagole white, Mbeya, and Shangazi) representing four regions surveyed (Dodoma, Mbeya, Morogoro, and Kagera). PCR products from five samples were sequenced (396 nt; GenBank Accession Nos. HQ316938 to HQ316942) and found to be identical to each other and the isolate described originally in Peru (2). Amplification with primers (BadnaBKF: 5′-CAAATTAGGAGGCAGATAAATG-3′; BadnaBsR: 5′-GGTCTTCTTATGTTCCACCTT-3′) designed in this study according to the sequence of Sweetpotato virus B (SPBV-B) (GenBank Accession No.FJ560944) resulted in products of the expected size in three samples (varieties Ex-Lyawaya, Gairo, and Hombolo collected in Mbeya, Morogoro, and Dodoma, respectively) that were positive also for SPSMV-1. Sequences of the products (787 nt; HQ316935 to HQ316937) were nearly identical (99.4%). They were 96.8 to 96.9% similar to a region (nts 830-1616) of Sweetpotato virus A (SPBV-A; FJ560943) (2), whereas they were only 83.2 to 83.6 % similar to the corresponding region (1,486 to 2,272 nt) of SPBV-B (FJ560944) (2). No virus was detected in cv. NIS 91. All plants sampled exhibited mild mottling or mosaic symptoms, but a contribution to the symptoms by other untested viruses cannot be excluded because few of the large number of sweetpotato viruses have been studied in Africa (4). To our knowledge, this is the first report of SPSMV-1 and SPBV-A outside South America and in sweetpotatoes grown in the field. The results show that the two viruses are distributed widely in local sweetpotato varieties in Tanzania, which suggests that they may be found in other sweetpotato-growing areas where they have not been studied. While the yield losses caused by SPSMV-1 and SPBV-A remains to be studied, the data from this study are of practical importance in terms of regional and international exchange of sweetpotato germplasm. References: (1) V. Aritua et al. Plant Pathol. 56:324, 2007. (2) J. F. Kreuze et al. Virology 388:1, 2009. (3) T. Paprotka et al. Virus Res. 149:224, 2010. (4) F. Tairo et al. Mol. Plant Pathol. 6:199, 2005.
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Karuma, Anne, Peter Mtakwa, Nyambilila Amuri, Charles K. Gachene, and Patrick Gicheru. "Enhancing Soil Water Content for Increased Food Production in Semi-Arid Areas of Kenya Results From an On-Farm Trial in Mwala District, Kenya." Journal of Agricultural Science 6, no. 4 (March 15, 2014): 125. http://dx.doi.org/10.5539/jas.v6n4p125.
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Soil water conservation through tillage is one of the appropriate ways of addressing soil moisture deficit in rainfed agriculture. This study evaluated the effects of tillage practices on soil moisture conservation and crop yields in Mwala District, Eastern Kenya during the long rains (LR) and short rains (SR) of 2012/13. Six tillage systems: Disc plough (MB), Disc plough and harrowing (MBH), Ox-ploughing (OX), Subsoiling – ripping (SR), Hand hoe and Tied Ridges (HTR) and Hand hoe only (H) and, three cropping systems namely, sole maize, sole bean and maize - bean intercrop, were investigated in a split-plot design with four replicates. Data on soil water content was monitored at different weeks after planting and the crop yields at end of each growing season. A three-season average shows that soil water content and crop yields were higher in conventional tillage methods compared to the conservation tillage methods. Long term tillage experiments are thus required at different locations, under various environmental and soil conditions to validate the study findings.