School of Agriculture and Biotechnology
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Item Farm Household Typology Based on Soil Quality and Influenced by Socio-Economic Characteristics and Fertility Management Practices in Eastern Kenya(2023) Wawire, Amos; Csorba, Ádám; Zein, Mohammed; Rotich, Brian; Phenson, Justine; Szegi, Tamás; Kovács, Eszter Tormáné; Michéli, ErikaThe smallholder farming systems in Sub-Saharan Africa (SSA) are highly diverse and heterogeneous in terms of biophysical and socio-economic characteristics. This study was conducted in upper Eastern Kenya (UEK) to categorize farm households and determine the influence of socio-economic characteristics (SeC) and soil fertility management practices (SFMP) on soil fertility across farms. Conditioned Latin hypercube sampling (cLHS) was performed to determine 69 soil sampling sites within Meru and Tharaka Nithi counties. From each household (whose field soil sample was obtained), data relating to resource endowment and soil fertility management were collected through a household questionnaire survey. Standard laboratory procedures were used to analyse soil samples. Data reduction was performed using categorical principal component analysis (CATPCA) (for SeC and SFMP) and standard principal component analysis (PCA) (for soil properties). Two-step cluster analysis identified three distinct farm categories or farm types (FT), namely, low fertility farms (FT1), moderately fertile farms (FT2), and fertile farms (FT3). The correlation of clusters against soil properties was significant across pH, soil organic carbon (SOC), cation exchange capacity (CEC), available P, plant available K, and exchangeable bases. FT1 had low SOC, pH, CEC and available P (soil characteristics), low usage of fertilizer and manure (soil fertility management), and smaller household size, lower income, and smaller farm size (socio-economic). FT2 had lower SOC (compared to FT3) and available P. In terms of soil fertility management, FT2 had higher cases of fallowing and composting with moderate fertilizer usage. Households in this category had moderate income, family size, and land size (socio-economic). FT3 had relatively high SOC, pH, CEC, and mineral nutrients. This farm type was characterized by high fertilizer use (soil fertility management) as well as larger household size, higher income, and larger farm size (socio-economic). The results indicate the importance of nutrient management in enhancing soil quality. Delineation and characterization of farms based on the various parameters including resource endowment reveal imbalanced farm resource flows, suggesting a need for locally tailored interventions suited for location-specific conditions to facilitate improved targeting of soil fertility-enhancing technologies and sustainable crop production regimes. While fertilizer is one of the most critical inputs for enhancing agricultural production, it is a major contributor to nitrous oxide emissions from agriculture and can have negative environmental effects on soil biota and water sources. Farmers’ knowledge on the use of fertilizer is thus necessary in developing strategies (such as integrated approach) to promote its efficient use and minimize its detrimental impacts.Item Assessing the contribution of dolichos bean (Lablab purpureus L. (sweet)) to food security in a changing climate in Kenya(2022) Kamotho, Grace N.; Kinyua, Miriam G.; Muasya, Reuben M.Lablab pupureus (L.), is a multipurpose drought tolerant legume which is considered as a minor crop in Kenya, hence, it is underutilized. In Kenya there are few known Lablab genotypes for specific environments. Choice of genotypes to grow is based on colour preference and seed availability, thus low yields are obtained. To assess the status of Lablab production in Kenya, a baseline survey was conducted in Lablab growing localities. A disproportionate stratified sampling was used and a questionnaire was administered to 108 respondents from diverse Lablab growing regions of Kenya. Performance of Lablab genotypes under different environmental conditions was also evaluated. Field trials of forty five (45) accessions of Lablab collected from Rift Valley, Eastern, Coast and Central regions of Kenya were established in three locations with different agro-ecological environments; (Nakuru, Uasin Gishu and Bungoma). The 45 accessions and three environments were factorially combined and replicated three times in a randomized complete block design (RCBD). Results from the survey indicate that most farmers (84.3%) grew Lablab in small acreage of less than 1.0 acre, and only 44.4% of the respondents used the improved Lablab cultivars which were obtained from the Ministry of Agriculture or research stations. Majority (88%) preferred Lablab to common beans and all respondents noted that Lablab fetched more income per unit quantity than common bean. All respondents utilized Lablab dry beans as food. The crop was also utilized as a livestock feed especially during the dry season when no other crops are in the farms by 51.9% of the respondents while 25% used it in conservation agriculture and for soil erosion control. About 20.4% of farmers used the leaves and green pods as vegetables. The study identified accessions that are suitable for different agro ecological zones. In conclusion, Lablab is a crop that is climate resilient and contributes to food security in communities that grow it. It is recommended that dolichos should be promoted in Kenya as a climate change adaptation measure and for enhancing food security.Item Determination of the effect of fermentation on the rate of plant nutrient release from plant tissues.(2022) KAMOTHO, GRACE N.; MUNGA, ZACHARIA M.The use of fermented plant extracts (FPE) as a top dress in crop production is a natural process that can provide plant nutrients and suppress diseases. However, there is scanty information on the use of plant extracts and the bulky of it is not documented. This study aimed at determining the effectiveness of fermentation in extracting plant nutrients from plant tissues for use as top dress in crop production. Materials from Lantana (Lantana camara, L), stinging nettle (Urtica dioica L) and Tithonia (Tithonia diversifolia, G), common plants that are locally available in most agricultural areas were investigated. A complete randomized design (CRD) was used to set up the experiments in the laboratory. Tender shoots and leaves of these plants were fermented in water and the levels of nitrogen, phosphorous and potassium (NPK) contained were measured at intervals of 1, 5, 10, 15, 20 and 25 days. The concentration of lactic acid bacteria (LAB) yeasts and the pH were also determined at each interval. Standard foliar feeds (Agro-Feed and Power Booster) commonly used by farmers were used as control. The results demonstrated that Lantana and stinging nettle were not significantly different in the percentage of N released. Phosphorous was highest in stinging nettle at 5.26%, Tithonia had 5.12% while Lantana had the lowest at 4.48%. However, potassium was highest in Tithonia at 4.38%, stinging nettle had 3.64%, while Lantana had the lowest at 3.63%. There were also high significant differences in concentration of lactic acid bacteria (LAB), Yeast and pH at p<0.05. The findings of the study showed that nutrients can be extracted from plant materials by fermentation although in less quantities as compared to commercial foliar feeds.Item A community-based evaluation of population growth and agro-pastoralist resilience in Sub-Saharan drylands(2019-02) Burian, Alfred; Karaya, Rebecca; Julia, Wernersson; Egberth, Mikael; Lokorwa, Benjamin; Nyberg, GertAbstract Human population growth is considered together with climate warming as major driver of change in Sub-Saharan Africa. Research on the implications of increased population densities often utilises community knowledge but without incorporating the view of local stakeholders. In this study, we applied a community-centred approach to assess direct and indirect consequences of population growth in drylands of north-western Kenya. Combined social, agricultural and geo-spatial analyses allowed us to identify major system transitions, determine their linkage to population growth and deduce consequences for local livelihoods and community resilience. Community-members reported positive and negative consequences of fourfold population growth since 1974 but evaluated its overall effect as clearly beneficial. This overall positive effect was based on both, positive developments and the successful mitigation of potential system stressors. First, food security was maintained despite high growth rates because a shift from migratory pastoralism to a more labour-intensive agro-pastoralist system helped to increase agricultural productivity. Additionally, land-use changes were linked to land privatisation and improved erosion protection on private land, decoupling population growth from environmental degradation. We detected, however also early warning signs of reduced community resilience as households were unable to fully recover livestock densities after catastrophic events. A population-growth driven reduction in household land-sizes and the decreased monetary value of agricultural production were identified as drivers of this development. The extrapolation of our results to establish a general relationship between population densities, land-use and household resilience in Sub-Saharan drylands suggest that further system transformations will be required to ensure regional food-security.Item ASSESSMENT OF PRODUCTION CONSTRAINTS AND CONTRIBUTION OF AVOCADO TO FOOD SECURITY AND INCOME IN THE MOUNT KENYA REGION, KENYA(2023) Kamotho, Grace N.; Asiko, Lydiah A.; Kibanyu, James K.; Kinyua, Phares R.; Karaya, Rebecca N.; Muthee, Patrick M.; Mwathi, Zipporah M.ABSTRACT Avocado (Persea americana Mill.) belongs to the family Lauraceae and it is an important crop to rural communities and economies in Kenya. Currently, avocado is grown in several agro ecological zones mainly by small-scale growers (85%) who grow it for subsistence, local markets and export. About 70% of avocado is grown in Central and Eastern region of Kenya. Central region produces 40%, Eastern 28%, Western 13%, Rift Valley 10%, Nyanza 6%, Coast 2% and Nairobi County 1%. The main production areas are Muranga, Kiambu, Thika, Embu, Meru, Taita Hills and Kitale. The aim of this study was to assess the production constraints and contribution of avocado to food security and income in Mount Kenya region. The study population comprised of smallholder avocado farmers. Purposive sampling was done in selecting highest producing sub-counties of avocado in Nyeri, Muranga and Embu counties. Simple random sampling was used to select 40 smallholder farmers from each of the selected sub counties who participated in the survey. Data was collected using a structured questionnaire and analysed using SPSS computer package. Results indicated several constraints in the production of avocado including pests and diseases, lack of quality planting material, poor soils, lack of technical knowledge by avocado farmers and lack of well-structured marketing system. The study identified a gap in value addition of avocado in Kenya. It was also demonstrated that avocado contributes highly to household income and food security. The crop should therefore be accorded priority by policy makers and more research needs to be encouraged especially in the management of pests and diseases. Capacity building to avocado growers should be routinely carried out so as to avoid the many challenges that emanate from lack of technical knowledge. Intervention in value addition of avocado is an aspect that Kenyan county governments need to engage in by investing in cottage industries on avocado processing.Item Assessment of genetic diversity of Kenyan dolichos bean (Lablab purpureus L. sweet) using simple sequence repeat (SSR) markers.(2016-01) Kamotho, Grace N.; Kinyua, iriam G.; Muasya, Reuben M.; Gichuki, Simon T.; Wanjala, Bramwel W.; Kimani, Esther N.; Kamau, Eliezah N.The level of genetic relatedness or dissimilarity of Lablab genotypes used by growers in different regions in Kenya has not been determined. In this study, ninety six (96) Lablab accessions collected from various parts of Kenya were characterized based on simple sequence repeat (SSR) molecular markers. Ten SSR primers were used and detected a mean of 4.3 alleles per primer. Expected heterozygosity was on average 0.38. The average polymorphic information content (PIC) was 0.63. Analysis of molecular variance (AMOVA) revealed 15% genetic variation among populations and 85% variation within populations. Highest Nei’s genetic distance of 0.998 was found between Western and Mwingi populations while lowest genetic distance of 0.092 was found between Embu and Meru populations. Lablab purpureus populations exhibited a high level of relatedness as revealed by cluster analysis and dendrogram based unweighted pair group method with arithmetic averages (UPGMA)Item Assessment of phenotypic diversity of Kenyan dolichos bean (Lablab purpureus L. sweet) germplasm based on morphological markers(2017) Kamotho, Grace N.; Muasya, Reuben M.; Kinyua, Miriam G.In Kenya, lack of phenotypic diversity assessment of Lablab has hindered its improvement. It is common to find that morphologically similar cultivars do not bear the same name while cultivars bearing the same name may not be identical morphologically. The aim of this study was to clear the ambiguity that exists in differentiating between the various phenotypes of Lablab. The morphological method is the oldest and considered the first step in description and classification of germplasms. Forty five accessions of Lablab collected from farmers’ fields in Rift Valley, Eastern, Coast and Central regions of Kenya were planted at Kenya Agricultural and Livestock Research Organization, Njoro farm. A descriptor from Asian Vegetable Research Development Center was used as a guide. Results on means separation showed a high level of variability in quantitative traits and a low level of variability in qualitative traits. Eigen vectors derived from principal component analysis indicated that seed yield per plant, number of pods per plant, plant height and days to 90% mature pods contributed highly to total diversity in Lablab. In conclusion, Lablab germplasm grown in Kenya is morphologically diverse in quantitative traits where different genotypes are distinctly dissimilar.Item Assessing the efficacy of wild basil (Ocimum americanum L. (Walp)) in the management of cowpea weevil (Callosobruchus maculatus)(2022-02-28) Mwandikwa, Jacob M.; Kamotho, G. N.Cowpea (Vigna unguiculata (L.) Walp) belongs to the family Fabaceae and is one of the pulses that suffer postharvest losses greatly. The major insect that attacks stored cowpea seed in Kenya is the cowpea weevil (Callosobruchus maculatus). The insect can damage 100% of stored cowpea seeds causing weight loss of up to 60%. Although insecticides are widely available, they have high potential risks to users and also pollute the environment. In drier areas of Kenya where the pest is common, small-scale farmers use botanicals with varying levels of success. This study sought to assess the effectiveness of a locally available botanical, Ocimum americanum, in the management of the cowpea weevil. Different plant parts of O. americanum, the leaves, flowers and whole mature young plants were dried and ground into powder. From each plant part, 0.5, 1.0, 2.0, 4.0 and 8.0 g were used to determine their effectiveness against the weevil in stored cowpea seed. Two controls were used, that is, no protectant and Actellic super dust. For each treatment, 10 g of cowpea seeds were placed in plastic vials containing ten pairs (male and female) cowpea weevil adults. The experiments were laid out in a completely randomized design at the Kenya Agricultural and Livestock Research Organization (KALRO), Nairobi, Entomology Laboratory. Lowest post-harvest weight loss (3.0 g) of cowpea seed and highest mortality (92.5%) of cowpea weevil was recorded when 8 g of leaf powder were used. Since wild basil is a common weed in drier parts of Kenya such as Mbeere, Tharaka-Nithi, Kitui, Makueni and Mwingi, it can be utilized in these areas as a cheap control bioinsecticide for cowpea weevil.Item Investigation of noradrenergic receptor system in anti-nociception using formalin test in the naked mole rat (Heterocephalus glaber).(Elsevier Ltd., 2023-10-23) Mwobobia, R. M.; Kanui, T. I.; Abelson, K. S. P.The naked mole rat (NMR) is a rodent that has gained importance as a biomedical research model for various conditions like hypoxic brain injury, cancer and nociception. This study was designed to investigate possible involvement of the noadrenergic receptor system in antinoception in the NMR, using the alpha-2 adrenergic receptor specific ligands clonidine (agonist) and yohimbine (antagonist) in the formalin test. Formalin test followed 30 min after intraperitoneal administration of ligands or control. A total of 96 naked mole rats were used. A significant reduction in nociceptive behaviours was demonstrated after administration of clonidine in the doses 1,3,10 and 30 μg/kg (n = 8 per group). Doses of clonidine above 30 μg/kg caused loss of motor and proprietion skills exhibited by prostration and failure to turn over when placed on their backs. The antinociception by 3 μg/kg clonidine was reversed by administration of 30 μg/kg of yohimbine. The present study demonstrates that the noradrenergic receptor system is present and involved in formalin test-related antinociceptive mechanisms in the NMR, similar to other mammals. Given the increasing importance of the NMR as a model for pain and nociception, the species may prove useful as an animal model for noradrenergic mechanisms in pain modulation.Item The effects of clonidine and yohimbine in the tail flick and hot plate tests in the naked mole rat (Heterocephalus glaber).(Springer Nature, 2021-05-17) Mwobobia, R. M.; Kanui, T. I.; Abelson, K. S. P.Objective: The naked mole rat (NMR) (Heterocephalus glaber) is increasingly considered an important biomedical research model for various conditions like hypoxic brain injury, cancer and nociception. This study was designed to investigate the effects of clonidine and yohimbine, an alpha-2 (α2) adrenoceptor agonist and antagonist respectively in the tail flick and hot plate tests. Results: A significant difference in tail flick latency was noted between saline control and 30 µg/kg clonidine, which was reduced after administration of 30 µg/kg yohimbine. A significant difference in hot plate latency was also noted between saline control and 30 µg/kg clodinine during the periods 30, 45, 60, 75 and 90 min after administration, and between saline control and 10 µg/kg clonidine during 30 min after administration. The hot plate latency by 30 µg/ kg clonidine was also reduced by 30 µg/kg yohimbine during 30 min after administration. Since the tail-flick and hot plate tests mediate the effects at spinal and supraspinal levels respectively, the present study indicates the presence and involvement of noradrenergic receptors in thermal antinociception at spinal and supraspinal levels of the NMR, similar to what has been found in other mammals.