PHD-School of Agriculture And Enterprise Development

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This collections contains bibliographic information and abstracts of PHD theses and dissertation in the School of Agriculture and Enterprise Development held in Kenyatta University Library

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An analysis of the efficiency of rural food markets in the Eastern Central highlands of Kenya
(2014) Ngare, Lucy Wangare
Agricultural markets offer opportunities for households to access incomes and food. Efficient food marketing systems assume a competitive structure thus enabling food distribution from surplus to deficit areas. Liberalization of agricultural markets in developing countries, Kenya included in the late 1980‟s and early 1990‟s aimed at achieving a market oriented economy. Earlier studies on agricultural market reforms have reported varied impacts on market efficiency, thus the need to analyze efficiency of rural markets in the eastern central highlands of Kenya so as to inform policy makers. This study analyzes the efficiency of maize and beans markets in the central highlands of Kenya by examining causality, market integration, asymmetric price transmission, structure and performance of the markets. The study used both primary and secondary data. Secondary data consisted of monthly retail prices for maize and beans for a period of fifteen years from nine markets. The results from time series price data analysis was used to determine whether price movements between the maize and beans markets exhibit integration which was used as an indicator of market efficiency. Primary data was from a survey of 252 traders in Mbeere and Tharaka-nithi sub counties who were selected using multistage sampling. These traders were interviewed using a semi-structured questionnaire in august 2009. Information from the survey was used to evaluate the activity of traders and unearth the factors that promote or inhibit efficiency of the markets. Data processing and analysis used the following techniques: Survey data was analysed using SPSS 16 while time series data was analysed using Eviews 7. The results from price analysis showed that there is a long run relationship between the markets in the study area. Causality between markets revealed that Siakago and Ishiara were the central markets for maize and beans respectively. The markets were cointegrated with stronger cointegration relationships observed between markets closer to each other and between markets located in different production potential areas. However, short run price adjustments were found to be very slow for all the markets, ranging between 8 and 39 months for maize and between 2 and 59 months for beans. There are asymmetries in price transmission, with markets far apart recording higher asymmetries. An analysis of the structure and performance of traders showed that the markets are efficient, as evidenced by the low trader concentration levels for retailers and medium concentration for the wholesalers. Although there was no collusive behavior among retailers, some wholesaler reported that they set prices collusively. The study concluded that although the markets are integrated, efficiency was still low. There was a clear indication of lack of improved market infrastructure, market information and credit facilities which may have contributed to low efficiency. A more organized market infrastructure and provision of market information may improve price transmission and encourage efficiency of the supply chain thereby raise rural income and food supply.
Determinants of crop and land management practices and effects on production risks under variable climatic conditions in Eastern Uganda.
(2014-08) Kagorora, Kansiime Monica
This study aimed to establish the effects of various crop and land management practices in reducing production risks under variable rainfall regimes in Eastern Uganda. An approach that integrated both rainfall variability and agricultural production was used, through yield functions. The following specific objectives were addressed based on knowledge and methodological gaps identified in literature review: i) establishing the extent and pattern of variation of annual and seasonal rainfall over a 40-year period, ii) determining factors that influence farmers' decisions to adopt management practices, iii) evaluating the effect of farmer-preferred management practices on the mean and variance of crop production in variable rainfall regimes, and iv) assessing farmers' perceptions of the effectiveness of the various management practices in mitigating against rainfall variability-induced production risks. Data for this study were obtained from 315 households, 9 focus group discussions and 23 key informants drawn from Mbale, Pallisa and Sironko districts. Study results showed an increasing trend in annual and ASON rainfall, and decreasing trend for MAMJ rainfall, with ASON exhibiting higher variations than MAMJ. Farmers employed a number of crop and land management practices strategically in response to perceive seasonal variations in climatic conditions, majorly influenced by their perception of rainfall adequacy. Most of the farmer-preferred management practices showed significant positive mean impacts on yield but had different risk-reducing effects on yield. Changing sowing dates and crop varieties, soil bunds, compost manure, cover crops, crop rotation and intercropping showed significant (p~O.05) risk-reducing effects on yield. Their effects varied across agro-ecological zone, except soil bunds and compost manure whose use consistently exhibited both yield-increasing and risk-reducing effects across all the agro-ecologies. Study results have the following implications: First, the changing scenario in variability of rainfall will affect cropping patterns in the study districts thus requiring introduction of crops or varieties best suited to the patterns such as early maturing crops for MAMJ and more water tolerant crops for ASON. Second, the effectiveness of technologies in reducing production risks is location-specific thus the need to develop and disseminate location specific adaptation approaches, instead of blanket recommendations of similar adaptation measures across locations. Lastly, the need to focus not only on the technical aspects of technologies, but also the social dimensions such as perceptions of smallholder farmers of technology effectiveness, if adoption and retention of management practices is to be increased. Development and research organizations promoting adaptation options should involve farmers in technology evaluation so as to recommend the most feasible options given farmers' situations and local perceptions.
Identification and characterization of Sorghum (sorghum bicolor (l.) Moench) landraces and improvement of on-farm seed production in Eastern Kenya
(2014-08-19) Muui, Catherine W.
Sorghum (Sorghum bicolor (L.) Moench) is an under-utilized crop that is tolerant to drought, flooding, saline-alkaline, infertile soils and high temperature. Farmers maintain landraces through preference selection and obtain seed from different sources. Local germplasm provides greater genetic variability and may provide useful traits to broaden the genetic base. Decline in use may erode the genetic base, preventing use of distinctive traits in crop adaptation and improvement which may result in their disappearance. There is also lack of information on on-farm seed production strategies leading to lack of quality seeds, information on use and improved cultural management. The objectives of this research were to identify and determine the key sorghum landraces grown in lower eastern Kenya, establish their diversity, quality levels for seed used by farmers, come up with pre and post harvest handling methods that could be used by farmers to improve on-farm seed quality. A baseline survey was conducted and landraces collected in various agro-ecological zones of lower eastern Kenya. Morphological and molecular characterization, varietal assessment in different ecozones and seed quality tests were done. Two varieties were used to test the effect of location of seed on different panicle sections, storage containers, and seed drying at different times of the day for different duration on seed quality. Results showed that farmers maintain a diversity of landraces unique in adaptation, food quality, grain yield, quality of harvested products and biotic stress resistance. They obtain seed for planting from informal systems of which 36% recorded low viability and 38% low vigor with 85% of seed samples contaminated with either Fusarium sp., Penicillium sp., Rhizorpus sp., Aspergillus niger and Aspergillus flavurs. The landraces recorded low heterozygosity indicating high level of stability in the population. Landraces clustering based on geographical locations was distinct with some overlaps across the locations. Variations were observed for leaf and mid rib colour, panicle compactness, awns and seed colour. A wide range of quantitative characters was observed between the accessions. The lower third part of the panicle recorded the highest seed viability and vigor indicating deterioration had not occurred compared to other panicle parts. The highest seed viability and vigor was realized in seed stored in the gourds and the seed stored for four weeks. Significant differences (P=0.05) were observed in leaf area, leaf, shoot and root length, and in dry matter accumulation among the seeds sampled after one month, two months and three months after storage. The seed viability and vigor decreased with increase in time the seed was sun dried but had no negative effect on seed dried in the seed drier. Farmers maintain a diversity of landraces, and since the region has a high agricultural potential, productivity for better food security could be improved by use of locally available germplasm adapted to this particular environment. Sorghum production may be effectively increased by use of improved production technologies and teaching farmers the importance of the crop to increase the production area. Seeds used by farmers to plant their crop are of poor quality in relation to germination, vigor and pathogen infestations
Evaluation of milk production efficiency Of dairy farms in Embu and Meru counties, Kenya
(2014-09-09) Kimenchu, Mugambi David
Despite Kenya's long dairy farming history spanning about 100 years, favourable climatic conditions and a 3.5 million national herd, milk per capita consumption is low (76.7 kg) and export quantities (milk) to the regional market where its products enjoy preferential access are negligible. These observations raised the question of farm level milk production efficiencies. This study evaluated milk production efficiency of dairy cow farms in Embu and Meru counties of Kenya, using the stochastic frontier approach. Data were randomly collected from 135 dairy farms and were supplemented with information from other dairy industry stakeholders. The sample size was detennined using the Cochran's (1977) formula. Data were analyzed using the SPSS, Frontier 4.1 c and STATA computer softwares, where both descriptive and inferential statistics were derived. Stochastic frontier production and cost functions were estimated using the maximum likelihood estimation technique. The farms were characterized and both technical and cost efficiencies estimated. Each of the efficiencies was then related to milk production cost to establish the cost reduction potential. Results revealed that the number of lactating cows and the amounts of roughages, concentrates, and mineral supplements were the major factors influencing milk output, while the prices of roughages and labour were the major factors associated with the total production costs. The dairy animals received inadequate feeds and mineral supplements. The animals were overstocked and underfed in an average twoacre mixed crop-livestock farm. The mean farm technical and cost efficiencies were 83.7 and 95.6%, respectively, and therefore inefficient. These results implied that milk production could be increased by 16.3% through better use . of available resources given the current state of technology without extra cost, while its cost could be decreased by about 4.4% without decreasing output. The milk production model coefficient was 2.11. It was shown that roughage and labour could substitute for one another to reduce dairy farming costs. Optimization of farm efficiencies and taking advantage of economies of scale through increased production inputs could be part of short-term measures to address the challenges facing smallholder dairy fanning. It was recommended that farmers specialize in either dairy or crop farming. Those choosing dairying, require shifting from the Friesians and Ayrshires to the smaller dairy breeds such as Jerseys, for they require less feed quantities in milk production. The researchers require identifying the least-cost combination ratio for roughages and labour inputs. The policy makers should provide legal guidelines to ensure that sub-division of agricultural land is minimized and further, promote both enterprise specialization and approaches that make the farm inputs such as concentrates and mineral supplements affordable.
Use oMinjingu Phosphate Rock with Tithonia Diversifolia in Maize-Bean Intercrop For Improved Maize Yields in Two Soil Types in Kenya
(Kenyatta University, 2015) Ahmat, Filbert Leone
Phosphorus deficiency and aluminium phytotoxicity are major factors limiting crop production in acid soils. Use of mineral fertilizers, especially by small scale farmers, to alleviate deficiencies of nutrients, such as P, is mainly hindered by their high costs and frequent unavailability. This has made the low input approach using locally available resources such as Tithonia diversifolia and Minjingu Rock Phosphate (MPR) gain a substantial research attention. However, less is known on the response of maize to integrated application of Tithonia and MPR. Therefore, four experiments were conducted to generate this information. Experiment one aimed to examine the relationship between mineral N and available P of surface soils and Tithonia biomass quality (N and P); whereas experiment two was to determine the effect of Tithonia and MPR on soil nutrients, pH and exchangeable AI. The third and forth experiments investigated the influence of the acid synthesized and secreted into the rhizosphere by beans on MPR solubilization and the agronomic responses of maize to Tithonia and MPR application under maize-bean intercrop. In experiment one soil and leafy samples were collected from five areas and analysed for Nand P. The second experiment was an incubation experiment with five treatments while the third experiment was a greenhouse pot experiment with two factors consisting of sole maize and maize-bean intercrop as main factor treatments; and use of different fertilizing input sources plus one combination as sub factor treatments. The fourth was a field trial conducted for two consecutive planting seasons at Kavutiri in Embu County and Muguga in Kiambu County. The experiment was laid in a split plot organized in a Completely Randomized Block Design with two factors: sole maize and maize bean intercrop as the main factor treatments; and sub factor treatments consisting of: Control; T alone (5t1ha dry weight); MPR alone (60 Kg P/ha); TSP alone (60 Kg P/ha); T (5t/ha) combined with MPR (50 Kg P/ha); and T (5t/ha) combined with TSP (50 Kg P/ha). Analysis of Variance (ANOVA) was done using the General Linear Model (GLM) procedure of the Statistical Analyses Software (SAS), version 9.3. Results showed that the concentration levels of mineral Nand available P of the top soils weakly correlated (- .22 ::;r ::;+ .62) with their respective levels in the biomass while in the biomass, N concentration, however, increased with the rising concentration of P (r = +. 95). Integrated application of Tithonia biomass with MPR not only resulted in significant rise, above the control, of available soil N (30.2%), P (182.3%), K (27.6%) and Ca (70.8%) but also in a significant decrease of the concentration of soluble AI; MPR solubilization was further enhanced by 68.7% for MPR applied alone and 223.6% for MPR combined with the biomass under maize-bean intercrop as compared to sole maize. Effects of the applied Tithonia biomass and MPR on agronomic parameters of maize differed under the two cropping systems. In conclusion, this study reveals that integrated use of the low fertilizing inputs (Tithonia biomass and MPR) under maize-bean intercrop improves maize yield on a P-deficient acid soil that is highly saturated with soluble Al more than mineral P fertilizers. Dissemination to farmers of this newly established low input technology by appropriate institutions, such as the ministry of Agriculture, is highly recommended.
Analysis of Household Food Insecurity and the Implication of Measurement Error, Mandera County, Kenya
(Kenyatta University, 2015) Waithaka, Mwenjeri G.
The objective of this study was to analyze food insecurity, underlining the significance of accurate measurement to formulate the required policies for addressing food deprivation. The need for accurate measurement of food requirement is essential to generate adequate information to support decision making especially in areas vulnerable to food shortages and famine. Using random sampling techniques and employing Fisher’s formula, a total of 323 households were selected for the study. Informed by demand theory as articulated by Engel’s law of inverse relationship between total household income and the expenditure on food, plus adding a quadratic term in the equation, the study sought to estimate the magnitude of food insecurity in Mandera County. The cost of basic needs (CBN) method was employed to provide preliminary estimate for the households’ food expenditure level. In order to deal with the problem of measurement error econometric models including ordinary least squares and using instrumental variable in generalized method of moment (IV-GMM) techniques were applied to quantitatively analyze data on quadratic Engel curve. The study established that Mandera County experiences food deprivation of significant magnitude. The study has revealed that, observed household expenditure is not a perfect measure of the actual food insecurity situation. This is because microeconomic data are contaminated by measurement error which reduces reliability of parameters and if not addressed will result to erroneous conclusion in economic analysis. The results show negative and significant quadratic coefficients for both OLS and IV-GMM. Accordingly the results shows that for the estimator that corrects for measurement error 81% of the households are food insecure as opposed to 64%. In this study it is observed that measurement error reduces parameter reliability by 32% which leads to underestimation of food insecurity by about 17%. Among the recommendations resulting from the study include; first it is easy to underestimate the proportion of food insecure households if they are incorrectly estimated and therefore superior statistical and sampling techniques should form the basis of quantifying food insecurity to facilitate decision making process. Secondly, the study supports for policy formulation that is guided by economic limitations not only as a gauge to measure food insecurity but also to guide intervention and evaluating policies aimed at alleviating it. Lastly, to increase food availability and reduce food insecurity, sound data-based analysis anchored on statistical theory that provides inferential basis for guiding policy and program interventions in of paramount importance.
Seed Quality of Soybean (Glycine Max [L.] Merrill) Genotypes under Varying Storage and Priming Methods, Mother Plant Nutrient Profiles and Agro-Ecologies in Kenya
(Kenyatta University, 2015-10) Chirchir, Grace Jepleting
world. The demand for soybeans in Kenya is high yet production is negligible due to various challenges, one of which is lack of a well-organized soybean seed system. Soybean seed has been known to deteriorate rapidly in the tropics but the rates vary with the environment, initial quality of the seed and genotype. The broad objective of the research was to enhance soybean seed longevity and vigor through manipulation of storage and priming methods, mother plant nutrition and agro-ecology. A socio-economic survey was conducted to evaluate soybean enterprise, seed handling and quality in Meru South - Tharaka Nithi County. A seed storage trial was done to assess the effect of agro-ecology, genotype, seed dressing and storage materials on soybean seed longevity and vigor. Soybean genotypes tested Gazelle and TGx 1740-2F(SB19) were dressed with wood ash and Apron star® and stored in sealed plastic cans and synthetic gunny bags in farmers stores at Kirege (UM II) and Igambatuntu (LM IV) in Meru South. Monitoring of seed quality during 8 months of storage was done by moisture content, germination, electrical conductivity and accelerated ageing tests at Genetic Resource Research Institute Laboratory, Muguga. The effects of osmo and hydro-priming seed invigoration techniques on soybean seed quality and storability of primed seed was assessed. The influence of mother plant nutrition, genotype and agro-ecology on soybean productivity and seed quality was carried out at Muguga (LH3) and Nkoroi in (UM4) during the short rains of October-November 2013; and seed quality analyzed using accelerated ageing and electrical conductivity tests. Soybean farmers survey revealed that soybean was grown mostly by older (>40yrs -79%), small scale (0.9Ha) mixed farmers on small parcels (0.05ha) and producing low yields of about 283 kg ha-1 . Soybean was newly introduced (<4yrs - 89%) crop, grown mainly in the short rains (84%) as a pure crop (77%), with main varieties being Gazelle (82%) and TGx 1740-2F (14%). Due to lack of assured markets, the crop was mainly grown for own use (74%) mostly as composite flours. Due to lack of a certified seed, farmers relied on farm-saved-seed, stored in synthetic gunny bags (89%) for 1-8 months, with viability ranging from 0% in the warmer LM4 to 100% in the cooler UM2. The seed storage study showed that hermetic storage in sealed plastic Jeri cans, seed dressing with wood ash and storage in cooler agro-ecologies (UM2) was found to be effective and low cost seed storage method for enhancing soybean seed viability and vigor. Soybean genotype SB19 had higher viability, longevity and vigor than Gazelle. Priming enhanced seed vigor by reducing seed leachates, but reduced germination. The 24 h priming duration and PEG -1.0 Mpa was the most beneficial treatment for SB19 but not for Gazelle. Primed seed retained high vigor after 8 months of post priming storage than non-primed seed. The manipulation of mother plant nutrition genotype and agro-ecology revealed that soybean grown in cooler LH3 had greater longevity and vigor, but with lower yields than seed grown in the warmer LM4; and TGx1740-2F resisted field weathering than Gazelle. Nitrogen and Phosphorus fertilization had no effect on soybean productivity, but N25 and N25+ P60 enhanced seed longevity, but these effects varied with site and genotype. The study recommends establishment of source of quality seed, streamlining marketing and promoting utilization of soybean to enhance production of the crop. Seed dressing with ash and storage in hermetically sealed plastic cans in the cooler highlands is recommended for better seed quality. In addition seed should be produced with good nutrition, in the cooler highlands for enhanced longevity. Priming is recommended for enhancing vigor of SB19.
Analysis of Vertical and Horizontal Integration as Determinants of Market Channel Choice among Smallholder Dairy Farmers in Lower Central Kenya
(Kenyatta University, 2015-11) Mutura, James K.
Dairy farming is a significant economic activity in Kenya as it accounts for four percent of the country’s Gross Domestic Product (GDP) and fourteen percent of total value of agricultural output. Market-oriented smallholder dairy farms in the country tend to be concentrated close to urban centres because the effects of market forces over-ride many production factors. Urbanization creates competition for alternative land uses thus leading to land fragmentation which has a potential negative impact on dairy farming especially in Lower Central Kenya. The resultant diminishing land sizes implies that peri-urban smallholder dairy farmers have to intensify milk production by adopting cost minimizing strategies, value addition and marketing through integration. Integration leads to high gross margins, better choice of market channel and improved market participation thus encouraging commercialization of dairy smallholder farming. Multistage sampling technique was used in collecting data from 288 farmers in Kiambu County in 2012. Data management was carried out using SPSS version 20 while econometric analysis were carried out using STATA version 12. Descriptive statistics were used to characterize households while multinomial logit regression (MNL) was used to estimate the probability of households using different marketing channels. Logit regression model was used to determine the likelihood of a household to integrate vertically or horizontally in its dairy enterprise. Mean difference was used to distinguish integrated and non-integrated smallholder dairy farmers. Fixed investment cost, storage type, milk cost share, percentage of milk sold and dairy enterprise turnover explain a household likelihood to vertically integrate in its dairy sector. An increase in total fixed investments, turnover and volume of output increases the probability of household integrating horizontally. The gender of the household head, age, distance from markets, land parcel sizes, milk output and level of education have a significant relationship with horizontal integration. Level of education, training, milk output, and access to information and transaction costs significantly influences the choice of marketing channel. It is recommended that programmes relating to information on milk marketing be made accessible to farmers. There is need to profile farmers on the basis of production and education level and encourage them to use specific marketing channel. Policy makers should identify strategies for disseminating information. It is recommended that farmers should establish and strengthen existing associations and integrate vertically and horizontally on the basis of their spatial location and milk output.
Assessment of the Structure and Performance of the Milk Value Chain in Western Kenya
(Kenyatta University, 2015-11) Omondi, Simon Peter Wanjala
Western Kenya Counties of Busia, Bungoma, Kakamega and Vihiga experience persistent milk deficit and low commercialization on smallholder farms. Information and knowledge on sources and points of inefficiency along the dairy value chain that contribute to low milk production and hence persistent milk deficit are scanty. The main objective of this study was to assess the structure and performance of the milk value chain in the region to determine market opportunities, variables influencing milk production, sources of inefficiencies and an upgrading strategy. An explanatory research design was used to collect both quantitative and qualitative data from 385 consumers and seven institutions in the four Counties and;400 dairy farmers, six focus groups and twelve key informants in Butula and Butere Sub Counties using a stratified proportional random sampling technique. End market tool kit and' descriptive statistics; Household Commercialization Index, Pearson's correlation and multiple linear regression were used to analyse data on markets, farm assessment and upgrading strategy respectively. The findings on markets revealed that the region's milk deficit was about 177 million litres per year with demand estimated to be 392 million litres per year against an annual production of 215 million litres. Quality and price were found to be the most important attributes significantly influencing choice of milk supplier (p
Molecular characterization and non-chemical management of root-knot nematodes (meloidogyne spp.) on African nightshades in selected parts of Kenya
(Kenyatta University, 2016-04) Nchore, Shem Bonuke
Root-knot nematodes (RKN) (Meloidogyne spp.) cause up to 80 % yield losses in infected vegetables. A study was carried out to; assess the influence of farmers’ knowledge and awareness on RKN damage on African nightshades (AFNS); assess the incidence and severity of RKN on AFNS; characterize the RKN species infecting AFNS; screen the AFNS for response to RKN and determine the efficacy of solarizing soils amended with selected organic materials against RKN. A root-knot nematode survey was carried out in selected farms in Lower midlands 1 (LM1), Upper midlands 1 (UM1), UM2, UM3 and UM4 located in Nandi, Bungoma, Kakamega and Uasin Gishu Counties during the April to July 2014 growing season. The survey revealed that 53.6 % of the AFNS farmers were not aware of RKN. Majority (66.7 %) of the farmers planted AFNS using organic manure while 33.3 % used inorganic fertilizers. Farmers controlled RKN through the use of pesticides, crop rotation, woodash and uprooting diseased crops. Two hundred and fifty soil and root samples were taken from depths of 20 cm from ten different points per farm to determine the disease incidence and severity. Incidence and severity of 94.13 % and 2.63 respectively was reported. Galling index ranging from 1.3 to 4.43 was reported. Molecular characterization identified M. incognita, M. arenaria, M. hapla, M. javanica and M. lopezi from the surveyed areas. The response of AFNS to RKN varied from resistant to susceptible. Solanum eldoretiunum and S. scabrum were resistant, while S. sarrarachoides was tolerant in the greenhouse and field conditions. Solanum americanum and S. nigrum line IP03 were resistant in the greenhouse, but were tolerant to RKN in both field experiments, while S. nigrum landrace from Kakamega and S. opacum were resistant in the greenhouse and field test at Kenyatta University but were tolerant to RKN at Chepterwai. Both S. nigrum from Simlaw Seed Company and S. villosum line BG03 were susceptible in the field test at Chepterwai though they were tolerant in the field test at Kenyatta University. In addition, resistant and tolerant AFNS had lower RKN damage and reproduction compared to susceptible AFNS. Solarized soils amended with Cattle manure (Cm), Tithonia diversifolia (Td) and pymarc (Pm) reduced RKN population and damage significantly compared with non-solarized and non-amended controls. Solarization improved efficacy of Cm, Td and Pm against RKN reproduction and damage on S. villosum. Reproduction was lower on Cm, Pm and Td amended soils while galling index ranged from 0.7 to 2.2 in solarized soils compared to 1.4 – 5.0 in non-solarized soils. Sensitization of farmers on RKN damage and application of organic amendments to reduce disease incidence and severity is proposed. The dominant RKN identified threatens AFNS production in the surveyed regions. Farmers should grow tolerant AFNS on heavily infested soils to reduce RKN population and reproduction. The tolerant AFNS could also be used in breeding programs for the management of RKN. Solarizing soils amended with organic materials is an ideal integrated pest management strategy for combating RKN infecting AFNS.
Economics of biological control of cereal stemborers in Eastern Africa: a case study of maize and sorghum production in Kenya
(Kenyatta University, 2018-01) Midingoyi, Soul-Kifouly Gnonna
The International Centre of Insect Physiology and Ecology (icipe), undertook a biological control (BC) programme for control of stemborers from 1993 to 2008, to reduce cereal yield losses due to stemborer attack in East and Southern Africa. The programme released four biological control agents—Cotesia flavipes, Cotesia sesamiae, Telenomus isis and Xanthopimpla stemmator—to control the economically important stemborer pests Busseola fusca, Chilo partellus and Sesamia calamistis. The purpose of this research was to assess the ex-post economic impact of the BC program among smallholder farmers in Kenya. Specifically, the study sought to: i) determine the productivity-effects of BC at farm level, ii) assess the impact of BC on food security and poverty and iii) estimate the global welfare-effect from the BC. Primary data was obtained from biological and household surveys. The household survey was conducted to collect socio-economic data on 600 households randomly sampled across maize agro-ecological zones of Kenya. Secondary data included time-series evolution of maize and sorghum production, yield, cropped area, market prices, price-elasticity of supply and demand and GIS information of the release locations. Methodologically, econometrics-based damage control function framework was adopted to address the first objective, the counterfactual framework using continuous treatment regression analysis for the second objective and economic surplus model analysis to address the third objective. Findings from productivity analysis show a reduction of insecticide use with the BC, thus demonstrating the potential environmental hazard-reducing effect of BC. Additionally, results show that BC has a positive impact on productivity and the derived marginal physical product show that 1% increase in BC level is associated with at least 12 kilograms per hectare increase in yield. The dose response functions (DRF) and the Marginal Treatment Effect (MTE) from the continuous treatment models provide evidence that BC has had a positive and increasing impact on poverty outcomes and food security components exept dietary diversity. For poverty, on average one percent increase in BC intensity is associated with a US$ 1.15 increase of household expenditures and a 0.5% reduction in poor households. With regards to food security, a one percent increase in BC level increased food expenditures by US$ 1.24 and calorie intake by 6.94 Kcal, and reduced the number of food-insecure households by 0.16%. Findings from the global welfare-effect show that BC intervention has contributed to an aggregate monetary surplus of US$ 0.74 billion to the Kenyan economy over 20 years period (1993 to 2013), with 76.71% ($US 568.06 million) from maize and the remaining 23.29% ($US 172.45 million) from sorghum. The net present value was estimated at US$ 142 million for both crops. The attractive internal rate of return (IRR) of 113% as well as the estimated benefit–cost ratio (BCR) of 276:1, illustrate the efficiency of investment in the BC research and intervention. The estimated number of people that could be lifted out of poverty was on average 57,400 persons (consumers and producers) per year, representing an annual average reduction of poor populations of 0.35%. These findings underscore the need for increased investment in BC research to sustain cereal production, and developing BC can be seen as an additional environmentally-friendly tool in the fight against food insecurity and poverty in Kenya. Policy implications are two-folds: boosting the effectiveness of the BC in regions with low level of control through augmentative and conservative BC, and up-scaling the BC strategy to regions with serious stemborers invasion.
Population dynamics and management of vectors of viruses causing maize lethal necrosis disease in Bomet County Kenya
(Kenyatta University, 2018-04) Namikoye, Everlyne Samita
Maize production in Kenya is under threat due to infection by maize lethal necrosis disease (MLND). The disease is known to cause intensive complete yield loss. It is caused by a synergistic infection of maize by maize chlorotic mottle virus and sugarcane mosaic virus which are mainly vectored by corn thrips (Frankliniella williamsi, Hood) and corn leaf aphids (Rhopalosiphum maidis, Fitch) respectively. This study was carried out with the aim of investigating the following aspects; farmer‘s knowledge and practices on vectors of MLND causing viruses, movement and dispersal of the two vectors in a maize farm and various management strategies through sticky roll trapping, varietal tolerance, action threshold levels, polycropping systems and biocontrol strategies towards the control of the disease and vectors. Field trials were carried out in Bomet County for two seasons from November 2014 to September 2016 using a randomized complete block design. Data was collected by counting vectors, scoring for MLND severity and disease incidence. Presence of MCMV, SCMV virus was also carried out using ELISA tests. Data was analyzed using Genstat version 17 to get mean and significant means were there after separated using LSD. Survey results indicated majority of respondents in Bomet as being youths aged between 21 to 30 years while 58% of the farmers had attained education up to upper primary level. Only 23% were high school graduates. Majority of the farmers were aware of MLND but only 3% knew about the vectors of MLND.The use of vertically positioned blue sticky traps were more attractive to corn thrips compared to the yellow ones (P = 0.023). Similarly, blue sticky rolls trapped more corn thrips and prevented maize from MCMV infection (P<0.001) while the yellow sticky rolls trapped more corn leaf aphids and prevented maize from SCMV infection (P<0.001). Sampling of maize along the rows gave the best prediction for the vector infestations (P<0.001) while the upper plant region proved most effective for vector sampling.The most appropriate time for vector sampling was from 8.30 am to 10. 30 am as well as from 3.30 pm to 5.30 pm. The monthly spray regime had the highest net returns as compared to all the other spray regimes. More over, maize from the entire thunder sprayed plots tested MLND negative compared to the control that received no spray (P<.001). Results showed variety Pannar as the most resistant to MLND (P<.001) as well as landraces MLR1 and MLR 15 (P = 0.002). The companion crops used in the polycropping system showed coriander harboring significantly more corn leaf aphids compared with other companions (P = 0.04). Furthermore, maize planted with coriander tested negative for SCMV and hence MLND negative. Findings from this study provide scouting and monitoring strategies for both vectors as well as various successful management and control methods for the disease and its vectors. Adoption of techniques such as sampling patterns, sampling time, scouting methods, use of sticky cards and sticky rolls will give an indication of the vector status in the field as well as offer control mitigation measures. Varietal resistance coupled with action thresholds of the vectors and the use of companion crops was able to result into minimal disease spread and reduced chances of MLND occurance. This information can be used to formulate a management strategy for the vectors of MLND causing viruses as well as develop a national vector and disease monitoring plan for both the vectors and the disease. This will culminate into improved maize production and food security.
Assessment of efficiency of agro food marketing systems: a case of macadamia nuts value chain in the Central Kenya highlands
(Kenyatta University, 2018-07) Murioga, Wilfred Muchiri
ABSTRACT The macadamia industry in Kenya has been faced with numerous operational and marketing challenges forcing the government to impose export ban of raw nuts since 2008 to date. The then Ministry of Agriculture appointed a task force in 2011 to specifically look into challenges that have been facing the macadamia industry including import ban of Kenya’s kernel by USA. Export of macadamia nuts from Kenya has also dropped from 2nd to 5th position in sales volume in the world from 1990s to dare. These problems point to efficiecy challenge. It was upon this background that this study was carried out. The main purpose was to examine and assess the intervening multi-factor market variables that affect the the efficiency of this value chain by concentrating on Central Kenya Highlands. The study sought to assess the efficiency of agrifood marketing systems in five purposively selected counties in the Central Kenya Highlands, focusing on quality control systems, information flow, pricing systems, gross margins, promotion and advertising, as well as market organizational structures and conduct. To achieve this, the study relied on the world economic triangle model and social marketing theory. The world economic triangle model was used in providing information on global markets and global value chain, while social marketing theory was used in providing the strategic orientation of macadamia marketing to increase efficiency. The study developed a conceptual framework which linked the research objectives with five market channel players in order to develop efficiency in the macadamia marketing system in the central Kenya highlands. Multistage sampling procedure was carried out and five sets of questionnaires were used to obtain primary data for analysis. There were 292 market traders taken from 32 stratified market centers in Embu, Kiambu, Kirinyaga, Murang’a and Nyeri counties. Each set of questionnaires was tailored to elicit particular information from the market traders who were 162 farmers, 28 middlemen, 7 processors, 30 distributors and 65 retailers. Data from the field was cleaned, coded and saved for processing using Statistical Packages for Social sciences SPSS version20 and STATA version 12 for descriptive statistics. Both descriptive and inferential statistics were used alongside statistical models such as regression, multiple regressions, integration, co-integration and price transmission, in determining macadamia marketing efficiency. Findings from the study showed that lack of proper organizational structures and conduct, poor pricing systems, lack of centralized authority for quality control standardization and certification of macadamia for exports are some factors that lower the market efficiency. The existing macadamia marketing system was inefficient, which required a total marketing system overhaul and a new marketing strategy in development of macadamia industry. This included adoption of alternative new technology to reverse the current downward market trend of macadamia industry in Kenya, where it has moved from second to fifth position in sales volume in the world in last few years. This study recommends proper organizational structures on quality control, better pricing policies, promotions and advertising as well as auction board to be set, to improve efficiency of macadamia marketing systems in Kenya.
Combined Effects of Tillage, Mulching and Nitrogen Fertilizer Application on Maize Yields and Soil Properties in Tharaka-Nithi County, Kenya
(Kenyatta University, 2018-09) Abdi, Zeila Dubow
High dependence on rain-fed agriculture, low and erratic rainfall, inadequate water and soil conservation techniques and declining soil fertility expose resource-poor farmers to low agricultural productivity in tropical regions. A study was conducted in 2012 at Kirege Primary School in Tharaka Nithi County to evaluate the effects of soil tillage, soil surface management and nitrogen fertilisation on rain-fed maize yields and properties of Humic Nitisols. Eight treatment combinations (T1M0N1, T1M0N0, T1M1N1, T1M1N0, T0M0N1, T0M0N0, T0M1N1 and T0M1N0) were laid out in randomised complete block design and replicated thrice. Data on grain and stover yields, mineral N, soil water content and soil organic carbon content were collected over six cropping seasons. Physical fractions of soil organic matter were evaluated down to 0-80 cm depths. T1M1N1 and T1M0N1 treatment combinations significantly had the highest maize yields in three out of six seasons (SR2013, LR2014 and SR2014), ranging from a low of 1.9 Mg ha-1 in SR2013 to a high of 4.9 Mg ha-1 in LR2015. T1M1N1 combination was superior for stover yields in four out of six seasons, ranging from a low of 2.7 Mg ha-1 in SR2013 to a high of 7.9 Mg ha-1 in LR2015. T0M0N1 combination had highest water use efficiency for biomass production (WUEB), with the highest water use efficiencies noted in LR2014 at 13.3 kg ha-1 mm-1 and short rains 2014 at 9.6 kg ha-1 mm-1 .Significantly higher WUEGY of 9.6 kg ha-1 mm-1 were recorded in T0M0N1 in short rains 2014 and 3.4 kg ha-1 mm-1 in T1M0N1 in long rains 2015. Generally, the NO3-N concentrations in all treatments decreased with increase in soil depth from 0-20 and 20-40, after which the concentrations increased from 40-60 and 60- 80 cm depths. There were significant differences in the amount and distribution of soil nitrate-N at the depths of 60-80 cm at 10 WAP, with higher net N mineralisation in minimum tillage treatments than in conventional tillage treatments. The highest soil water content in the study conserved in the minimum tillage with mulch retained at 0 kg of N fertiliser while minimum tillage treatments had higher crop evapotranspiration. Overall, soil carbon content decreased with increase in soil depth. In all the three class size aggregates, the highest increases in soil carbon were noted in the 0-20 cm depths, with the highest overall increases in both soil meso-aggregates and macro-aggregates between 2012 and 2015 observed in T1M1N1 combination. There was enhanced soil carbon in the 0-20 cm depth in all the three aggregate fractions in treatments with conventional tillage combinations, with increases of 3.5 t C ha-1 in micro-aggregates, 2.2 t C ha-1 in meso-aggregates and 3.7 t C ha-1 in macro-aggregates. While more rains fall during the SR seasons, the LR seasons were found to be more important, with higher grain and stover yields in SR than LR. Retention of mulch on-farm was found to be crucial for soil water conservation at soil depths below 50 cm and enhancing mineralisation of nitrogen, showing a clear potential for seasonal water buffering. This underscores the possibility of adapting to erratic climate regimes. This research has confirmed the importance of conventional tillage practices in ensuring better maize yields for farmers and promoting soil C content in smallholder maize-based farming systems conducted in Humic Nitisols and that in the long-term the formation of stable micro-aggregates in smallholder farms can be useful carbon sinks.
Performance of Amaranth Accessions against Moisture Stress and Key Insect Pests and Their Indigenous Parasitoids in Arusha, Tanzania
(Kenyatta University, 2019) Othim, Stephen Tarmogin Omburo
Amaranths are African indigenous vegetables (AIVs) that have recently gained importance as a food source in Africa owing to the high nutritional value of their leaves and grains. Production of this crop is, however, limited by arthropod pests especially the lepidopteran leaf-webbers, leaf-worms and stem weevils. The use of insecticides for their management is uneconomical and also present health and environmental concerns. Host plant resistance (HPR) to insects is an effective, economical and environmentally friendly alternative that is poorly understood and unexploited among AIVs. The aim of this study was to assess Amaranthus accessions for resistance to leaf-webbers and stem weevils, their tolerance to water stress conditions and the performance of indigenous parasitoids on selected accessions. Field and laboratory experiments were conducted at the World Vegetable Centre (WorldVeg) in Arusha Tanzania with 36 accessions and lines of amaranth. Accessions VI036227, RVI00027, VI054569, VI033487, VI044432, VI048076, VI049639, VI049530 and VI049698 had high levels of pest resistance with significantly lower infestations (≤ 11.11±2.14%) and damage (≤ 68.06±3.90%) by leaf-webbers and leaf-worms. The accession VI036227 was found to be highly resistant against Spoladea recurvalis, exhibiting exemplary antibiosis by causing 100% larval mortality despite not being deterrent for oviposition. The accessions VI048076, VI056563 and VI047555-B demonstrated moderate resistance against the pest for specific parameters including low oviposition, moderate early stage larval mortality and reduced adult longevity. The relative growth rate (RGR) of accessions VI033479, VI049698 and VI056563 were not significantly affected by the three soil water levels (40%, 60% and 90% water holding capacity (WHC)). Apanteles hemara performed well on all the other moderately resistant accessions except VI056563 that recorded lower parasitism rates compared to the susceptible accession. The longevity of the parasitoid was significantly extended on the resistant accessions compared to the susceptible one. The functional response curve exhibited by A. hemara corresponded to type II functional response with an asymptote at the density of 30 larvae. Apanteles hemara parasitism was significantly higher in 1-2-day-old compared to 3-4-day-old larvae (P=0.04). Thus, accessions VI036227 and VI049698 were identified to be highly resistant to leaf-webbers in addition to 24 moderately resistant ones while VI047517-B, VI036227 and VI056563 had low levels of resistance against stem weevils. Accessions VI033479, VI049698 and VI056563 were also tolerant to moisture stress. The identified pest resistant and water stress-tolerant amaranth accessions from this study are recommended for multiplication and release to farmers to alleviate the effects of pests and drought. These can also be used in breeding programs to improve locally cultivated varieties. The identified parasitoids can also be reared and released into farmer fields to synergize host plant resistance.
Fingerprinting and Relating Juvenile Characters of Rice to Yield and Yield Components in Kiambu and Kirinyaga Counties
(Kenyatta University, 2019-02) Henga, Sylvia A.
Rice is increasing as an important food and cash crop in Kenya and is third to maize and wheat in terms of consumption. Consumption has continually outstripped production resulting in massive importation. The main problem affecting productivity involves lack of proper information on best storage time, use of poor quality seed, varietal admixtures which has contributed to low yields. There is need to characterize genotypes. Microsatellit are useful in various plant genetic studies and plant characrerization. Accelerated aging is considered an excellent option as a vigor test due to shortest time of acquisition and efficient results. In the proposed study, seed quality experiments including germination, dormancy, purity, were carried out in the laboratory using eight rice varieties in a Completely Randomized Design. Accelerated ageing tests at 0,24,48 and 72hrs(45oC and 98%RH) were carried out JKUAT post-harvest laboratory using eight rice varieties‟ in four replications of100 seeds each. Data was collected on dates to plumule and radical emergence and height. Five varieties were used to produce seeds which were stored for 1,2,3,4,5 and 6 months respectively. The seedlings were transplanted into fields in a Randomized Complete Block Design using 5*6 factorial arrangement. The study also determined the relationship between juvenile characters and adult characters of rice in Kiambu and Kirinyaga counties. All the data were analyzed using GENSTAT statistical package. ANOVA and LSD at 5% significant level. Seed quality results showed that There was significant variation in both coleorrhiza and coleoptile formation among rice varieties (p<0.001), treatments (p<0.001) and interaction between rice varieties and treatment ((p<0.001). The difference between all treatments was significant with 72 hours treatment having the highest number of days to coleorhiza and coleoptile formation. Results showed that the effect of genotype on coleorhiza and colleoptille formation was significant (p<0.001). Genotype B317 had the earliest colleoptile formation 8.75days, coleorhiza formation (9.81), B317 also had the highest germination percentages at 7(33.69), 14 (52.44) and at 21 days after sowing (56.62). Mzungu had the latest number of days to coleorhizae (12.44), coleoptiles (11.18) and lowest germination percentages at 14(27.52) and 21days (31.31). The genotype had significant effect on germination index, seed length and seedling vigor index. In Mwea, there was a significant effect of storage time on germination, with 4 months giving the highest seedling vigor index (673.6), height at 1 month after transplanting (73.3cm), height at maturity (72.3cm) and 3 months giving the highest days to flowering(58.87) .The interaction between storage time and genotype on was significant, with genotype B217 stored for 3 months leading in height at one month after transplanting (87.7), height at maturity(91.8cm) .in Kiambu.The interaction between storage time and genotype was significant with 5months of storage having the highest seedling vigor index (759.5), 1000grain weight (69) and yield (15.5kg/ha). Analysis of molecular variance results indicated that the five polymorphic markers used in this study showed a total of 11 alleles across the loci of the 18 rice genotypes studied. Juvenile characters such as seedling vigor and height at transplanting had a positive and significant correlation to 1000grain weight.Genotypes TXD and B217 were identified by the 5 markers. TXD (Saro 5) was the best fit for fingerprinting as it was identified by only 1 marker. These results could be used in preparing rice seed certification procedures, in gene bank management and other seed storage ventures
Soil Moisture Conservation, Cropping Systems and Soil Fertility Effects on Soil and Maize Performance in Machakos County, Kenya
(Kenyatta University, 2019-05) Mwende, Ngie
The main causes of food insecurity in semi–arid parts of Kenya are low soil fertility, low and unreliable rainfall. These two causes are the main challenges facing small-scale farmers in food production especially in semi-arid areas of the country. To overcome these challenges, soil and water management technologies especially those in soil and water conservation need to be embraced. The aim of the study was to determine the effect of tied ridges, fertilizers and cropping systems on soil properties (moisture, pH and organic carbon), growth and yield parameters of maize; and to identify the most cost effective water and soil management technology. This study was carried out in four seasons at Katumani in Machakos County. The experiment was a 2 x 4 x 2 factorial, laid out in a randomized complete block design (RCBD). The treatments were: tied ridging, flat bed planting, farm yard manure 0 t/ha, farm yard manure 5 t/ha, nitrogen fertilizer 20 kg/ha, farm yard manure 5 t/ha + nitrogen fertilizer 20 kg/ha, maize mono crop and maize cowpea intercrop. Data collected included soil moisture content, soil pH, total organic carbon, growth parameters and maize yield. The results showed that, treatments with flat bed planting in maize mono crop significantly increased soil moisture content at 0–20cm depth as compared to tied ridging in maize cowpeas intercrop during short rains 2015. Application of farm yard manure at 5 t/ha increased soil moisture content at 2 and 4 weeks after planting. The soil moisture content ranged from 6.30% to 23.80%. During the short rains 2015, maize mono crop significantly increased vegetative growth in comparison to maize cowpeas intercrop. Treatment with flat bed and 20 kg N/ha in maize mono crop had the highest mean for vegetative growth. However, during the long rains 2016, treatment with tied ridging and 20 kg N/ha in maize mono crop registered the highest mean for vegetative growth. During the short rains 2015, treatments with maize mono crop significantly increased grain yield with a range of 1.35 t/ha 3.59 t/ha. Flat bed planting with farm yard manure 5 t/ha in maize cowpea intercrop significantly increased the grain yield by 165.93%. The harvest index during the short rains 2015 ranged between 0.35 and 0.48. Treatments with maize mono crop significantly increased gross benefit, net profit, gross margin and cost benefit ratio during short rains 2015 and long rains 2016. Application of farm yard manure 5 t/ha + 20 kg N/ha had the highest variable cost. The cost benefit ratio was positive during the short rains 2015 with a range of 1.47–2.98. The yield differences among the four seasons could have been as a result of variations/distribution in rainfall amount, soil moisture content and soil fertility as induced by the treatments. Flat bed planting increased the yields during the short rains 2015 when the amount of rainfall was high whereas tied ridging resulted in improved yields during short rains 2014, long rains 2015 and 2016 when rainfall amount was low. For the farmers to maximize yields and profits in the study area, adoption of flat bed planting with farm yard manure 5 t/ha and maize cowpeas intercrop during the seasons of high rainfall could be appropriate treatment combination according to the findings of this study. However, during seasons with low rainfall, tied ridging with 20 kg N/ha and maize mono crop could be recommended for adoption. Also, variations in seasonal rainfall should be considered when integrating different soil and water management practices because the effectiveness of different technologies vary with the seasons. Farmers in Machakos County may have to consider use of supplementary irrigation during the dry spells to increase soil moisture.
Characterization, Water Stress and Nutrient Management of Yellow Passion Fruits (Passiflora Edulis, Var F. Flavicarpa. Deg) in Kiambu and Embu Counties, Kenya
(Kenyatta University, 2019-06) Mwirigi, Peter
Passion fruit has gained significant importance as a horticultural crop of choice among farmers in Kenya. The yellow passion has been recently commercialized in Embu County due to its adaptation to the hot arid conditions and potential for high yields. Currently, the production levels of the fruit are low due to poor agronomic practices, declining soil fertility levels and changing climate leading to reduced rainfall. To further understand these challenges, there is need for careful investigation of plant-soil-water relations which requires careful in-depth analysis of the soil’s nutrients of any area. This is because each nutrient has a specific role to play in the development of the plant and deficiency symptoms will manifest specific to each nutrient. Further, to establish and manage nutritional and water stress related disorders, their causes requires knowledge of the symptoms. The primary objective of this study was to carry out socioeconomic survey of passion fruit farmers and determine the correct water and nutrient management of yellow passion fruit in Embu County. The study also carried out morphological characterization of the cultivated populations to identify hybrids with favorable characteristics such as drought tolerance. The study involved a mixture of field survey, on-farm experiments with selected farmers and controlled experiments at Kenyatta University research farm. Results of the survey established that majority of the farmers grow passion on small acreages of less than 2 acres and have a common source of planting materials. Further, major agronomic practices including fertilizer and water application were also not correctly followed. The results on morphological characterization indicate the presence of two main groups of cultivars. Further, for fertilizer application, the study established that the treatments 100g DAP+20kg Manure+50g CAN and 20kgManure+50gNitrabor had the best impact on flowering (p≤0.05) and fruit development while results on determination of water uptake established the treatment of 10 liters of water per day giving the longest primary vine and highest number of secondary vines (p≤0.05). In conclusion, field survey and on-farm experimental results indicate the need for increased availing of new knowledge to farmers in the management of the crop while results from controlled experiments at the university farm indicate a need for correct application of fertilizers and efficient monitoring of irrigation regimes. All these factors will lead to improved quality and quantity in yield of yellow passion fruit. The study recommends provision of updated agronomic management practices to yellow passion farmers in Embu County, the use of either 100gDAP+10kgManure+50gNitrabor, 100gDAP+20kgManure+50gNitrabor or 50gDAP+10kgManure+50gNitrabor and the application of 10 liters of water per day per plant for optimum yield of passion fruits. Future studies on nutrient partitioning and water use efficiency can also be conducted to have a clear understanding of the nutrient and water relations in yellow passion fruit.
Quantifying Greenhouse Gas Emissions and Carbon Stocks in Maize-Soybean Cropping Systems in Siaya County, Kenya
(Kenyatta University, 2020-11) Karanja, Anne Njeri
As climate change continues to threaten ecosystems’ functions, agriculture remains one of the major source of greenhouse gas (GHG) emissions that are responsible for global warming. The major GHG in agriculture are; carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4). Unfortunately, agriculture is also one of the most affected sectors by climate change. There is therefore need to reduce emissions by adopting agricultural practices with mitigation potential. This is by enhancing soil carbon sequestration to offset emissions, or reducing emissions while safeguarding crop yields. However, little is still known about GHG quantities and intensities that major cropping systems in Kenya emmit. Site specific studies on GHG emissions to establish interventions for mitigation of climate change and enhanced crop production is therefore of essence. The objective of this study was to examine the effect of reduced tillage, crop residue retention and use of controlled release urea (CRU) in maize-soybean cropping systems on GHG emissions, soil N mineralization, organic carbon stocks and yields. Field measurements were carried out in a 13 year old researcher-managed trial in Siaya county, Kenya between March 2016 and January 2017. Four treatment combinations: ZT M-S NU (reduced tilage+maize soybean rotation+normal urea), ZT M-S CRU (reduced tillage+maize soybean rotation+controlled release urea), ZT M/S (reduced tillage+maize soybean intercrop without urea), CT M-S NU (Conventional tillage+maize soybean rotation+normal urea) were tested. The treatments were laid out in a randomized complete block design. DAYCENT model was used to simulate soil carbon, N2O emissions and maize yields. Results showed that daily fluxes of N2O ranged between -0.5-26 g ha-1 d-1 and -2-10 g ha-1 d-1 in the long and short rainy seasons respectively. Cumulatively, N2O emissions were between 0.2 - 0.7 kg ha-1 and 0.2 - 0.4 kg ha-1 in the long and short rainy seasons respectively. In the long rainy season, ZT M-S CRU had significantly higher N2O fluxes than the other treatments (P=0.05). In the short rainy season there were no significant effects of treatment on N2O emissions. In the long rainy season, CO2 daily fluxes were between 9 to 42 kg ha-1 while the cumulative emissions ranged between 2.5 to 2.8 t ha -1. In the short rainy season daily CO2 fluxes ranged between 6 to 30 kg ha-1 while cumulative emissions were 1.8- 2.5 t ha -1. There was no significant effect of treatment on CO2 emissions. Methane emissions were largely negative, and did not differ significantly among treatments. Yield was significantly low for ZT M/S but N2O emission intensities were not significantly different among treatments. DAYCENT simulated soil carbon and maize yield within the same ranges observed by measurement. N2O emissions by DAYCENT were higher during the peak of the seasons, but were comparable with observed measurements later in the seasons. Even though the long rainy season had higher N2O and CO2 emissions, the difference was not significant. These results indicate that emissions in the study area were low.These results further indicate that the current soil management practices in Siaya County influence GHG emissions, and the higher emissions observed with ZT M-S CRU in the long rainy season calls for further investigations of the effect of CRU on N2O emissions. The lower emission intensity shown by ZT M/S despite having lower yield points to the need of evaluating cropping systems for climate change mitigation and adaptation. These results indicated that DAYCENT model can be used to simulate soil carbon and yield but not N2O emissions in the study area.
Impact of Improved Sorghum Varieties on Poverty Reduction among Rural Farming Households in Tharaka Nithi County, Kenya
(Kenyatta University, 2021) Mwangi, Backson Mutonya; Ibrahim Macharia Ndegwa; Eric Kiprotich Bett
Poverty alleviation and attainment of food security are among the major concerns facing majority of households in arid and semi-arid land areas of Kenya. The Government of Kenya in partnership with other sector stakeholders have invested heavily in the development and promotion of suitable high yielding improved sorghum varieties that are less susceptible to climate change, pests and diseases. Over the years, sorghum demand has outstripped supply. The deficit supply gap keeps expanding and this trend is unexpected since farmers have been assured of a market and price through forward delivery contracts. The interventions are intended to reduce poverty among adopting households. However, the impact of the interventions is not clear and has not been empirically established. In response, this study formulated three specific objectives where the first aimed to assess the determinants of adoption, intensity of use and speed of uptake of improved sorghum varieties. The second and third attempted to evaluate the profit efficiency and estimate the impact of improved sorghum varieties on poverty reduction respectively. Cross-sectional research design was used and primary data were collected from a sample size of 452 households using a structured questionnaire. Further, focus group discussions and key informant interviews were also conducted. Data were analyzed using Double Hurdle and Duration Analysis models for the first objective. To answer the second objective, Cobb-Douglas Stochastic Profit Frontier was used. Furthermore, 3 models namely; Propensity Score Matching, Inverse Probability Weighted Regression Adjustment and Endogenous Switching Regression models were used to answer the third objective related to impact of improved sorghum varieties on poverty reduction. Findings generated by Double Hurdle and Duration Analysis models indicated that determinants of the three adoption decisions are not necessarily the same. While many variable coefficients depicted expected a priori, distance to the nearest agricultural offices and intensity of use of improved sorghum varieties depicted unexpected positive a priori indicating possible use of home saved seeds. Further, access to agricultural credit returned unexpected negative a priori for both intensity of use and speed of adopting improved sorghum varieties’ decisions. On the other hand, results generated by Cobb-Douglas Stochastic Profit Frontier showed a wide range of profit efficiency from 0.12 to 0.96 for the worst and best sorghum farmer, respectively, with a mean of 0.17. Average treatment effects results generated by the 3 impact models indicated a positive significant difference in daily consumption expenditure per adult equivalent of between USD 0.09 to 0.21. Further, counterfactual results generated by Endogenous Switching Regression model showed that, non-adopters would have increased their consumption expenditure per adult equivalent by on average USD 0.96 daily had they decided to adopt. Therefore, adoption-stimulating policies that target to raise resource endowment of households, improve access to extension service and rural infrastructure need to be implemented. Further, this study advocates for incentive-based policies aimed at widening agro-dealer networks mainly directed to County Government to consider reducing certifications such as trade permits. Additionally, policies targeting to reduce credit providers’ cost of doing business and increase their lending appetite such as use of technology, business champions and guarantee schemes should be developed.

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