Prof. George D. Odhiambo - Academia.edu (original) (raw)

Papers by Prof. George D. Odhiambo

RePEc: Research Papers in Economics, 2006

During participatory rural appraisals, farmers at the Lake Victoria basin of Kenya and Uganda ide... more During participatory rural appraisals, farmers at the Lake Victoria basin of Kenya and Uganda identified Striga, stemborer and declining soil fertility as three major constraints to maize production To reduce food insecurity, several innovative integrated technologies to address these constraints have been developed, including push-pull (maize intercropped with Desmodium and surrounded by napier grass), maize-soybean and maize-crotalaria rotations, and Imazapyrresistant (IR) maize seed coated with the herbicide. To let farmers evaluate the new technologies, 12 demonstration trials, comparing the different technologies, were established in four villages in Siaya and Vihiga districts (Western Kenya) and two villages in Busia (Uganda). These evaluations, where farmers' appreciation and feedback on the technology are captured, are an important step in technology development. During field days at the end of short rainy seasons of 2003 and 2004, 504 farmers individually observed and rated each treatment under the different cropping systems, with and without IR maize, and with and without fertilizer, with a maize continuous monocrop as control. Farmers scored each of the 16 treatments on an ordered scale of five categories: very poor, poor, average, good, and very good. The treatments were scored for each of the criteria farmers has previously determined (including yield, resistance to Striga and stemborer, and improvement of soil fertility). Analysis of the evaluation, using ordinal regression, show significant differences in farmers' preference by year and site. There was, however, little effect of farm and farmer characteristics such as farm size and gender of the observer. Ordinal regression of farmers' scores are not as intuitive and also bit cumbersome to use, but they have a better theoretical foundation than other methods, in particular the use of means. This paper shows how the method can be used, and concludes that, with some effort, it is a convenient way to analyse farmers' ranking of a large number of options.

International Journal of Pest Management, 1993

A field study was conducted at the Regional Research Centre, Mtwapa and at the Msabaha subcentre ... more A field study was conducted at the Regional Research Centre, Mtwapa and at the Msabaha subcentre in Kilifi District of Coast Province, Kenya between 1986 and 1989. The objective of this study was to investigate the effects of four land preparation methods and different weeding regimes on maize (Zea mays) grain yield. Land preparation methods were slashing, hand hoeing, tractor ploughing, and herbicide (paraguat) application. Weeding treatment were: no weeding, hand weeding at 4th leaf, 10th leaf, 16th leaf, 4th and 10th leaf, 4th and 16th leaf, 10th and 16th leaf stages, and weed control using a pre-emergence herbicide (pendimethalin and atrazin-metolachlor mixture). Use of pre-emergence herbicide had the same effect on grain yield as two weedings (at 4th and 10th leaf stages). The yields obtained with chemical weeding were significantly higher than those obtained with one early weeding (at 4th leaf stage). Land preparation methods did not differ significantly in their effect on maize grain yield. Weeding more than once generally gave a yield advantage of about 60-135% over one weeding. There was no significant interaction between land preparation methods and weeding treatments. The possible implications of these findings on maize grain yields in this region are discussed.

Final Technical Report, Apr 20, 2005

Social Science Research Network, 2023

Recent advances in …, 2009

... Authors Nyambati, RO; Okalebo, JR; Othieno, CO; Serem, C.; Imo, M.; Odhiambo, G. Editors Much... more ... Authors Nyambati, RO; Okalebo, JR; Othieno, CO; Serem, C.; Imo, M.; Odhiambo, G. Editors Muchiri, MN;Kamondo, B.;Ochieng, D.;Tuwei, P.;Wanjiku, J. Conference paper; Book chapter Recent advances in forestry research ... ISBN 9966-9660-7-2 Record Number 20103038500. ...

Journal of Experimental Agriculture International, 2020

This study investigated the effects of applying different combinations of two contrasting plant r... more This study investigated the effects of applying different combinations of two contrasting plant residues, Calliandra calothyrsus (Calliandra) and maize stover, with urea on Striga infestation and maize yield in western Kenya. A randomized complete block design (RCBD) with 12 treatments replicated four times was used. The following plant residue: urea combinations was used so as to supply a total of 75 kg ha-1 in each treatment combination; 75:0, 60:15, 45:30, 30:45, 15:60, and 0:75 for five seasons (2007-2009). A control treatment where no nutrient inputs were applied was included. Calliandra applied at 45 kg N ha-1 plus urea (30 kg N ha-1) and maize stover applied 15 kg N ha-1 plus urea (60 kg N ha-1) had consistently lower Striga infestation compared other treatments. Negative linear relationship between maize yield and Striga population were observed in the first three seasons i.e. 2007 LR, 2007 SR and 2008 LR. Overall mean maize grain yields over the five seasons were highest (3...

Chapter 1-Introduction Methodology The Binomial probit model Chapter 2-Socioeconomic characterist... more Chapter 1-Introduction Methodology The Binomial probit model Chapter 2-Socioeconomic characteristics of the households Demographic and socioeconomic characteristics of households Chapter 3-Household farm resources and productivity Land allocation to crops/cropping systems Intensification of maize farming systems Chapter 4-Striga and Striga control technologies Striga control technologies Awareness of Striga control technologies Current use status of Striga control technologies Sources of information on modern Striga control technologies Farmer perceptions on maize yields under different Striga control technologies Average years since adoption of the various Striga control technologies Perception on effectiveness of Striga control technologies Knowledge of management practices for modern Striga control technologies Reasons for non-adoption of modern Striga control technologies Training on IR maize technology Chapter 5-Perceptions on IR maize productivity and farm management practices Chapter 6-Vulnerability context Food security situation in western Kenya Food shortage in western Kenya Morbidity and mortality Anthropometric measurements on vulnerable groups v Chapter 7-Institutional issues Awareness on government activities in the villages Awareness of Non-Governmental Organisations' activities in the villages Chapter 8-Conclusions and recommendations References Appendix 1

Phosphorus is known to affect growth and formation of nodules although its role in the process is... more Phosphorus is known to affect growth and formation of nodules although its role in the process is less understood. Several workers have, however, related phosphorus nutrition with rhizabial activities in leguminous plants. In other studies, it has been shown that nodules are stronger sinks for phosphorus-compared roots, shoots and even young mature leaves. We initiated this study to determine the effect of phosphorus on selected desmodium species growth and nodulation parameters in a pot experiment. A 2 by 8 factorial experiment was laid in a complete randomized design (CRD) at KARICYMMIT Research Station located in western Kenya. Pots were each filled with 7.5 kg 2 mm sieved dry soil. The treatments consisted of two desmodium species (D. intortum and D. uncinatum) and 8 levels of phosphorus applied at 0, 10.3, 20.6, 30.9, 41.2, 51.5, 61.8 and 72.1 mg P kg -1 soil. The experiment was replicated 3 times. Plants were top dressed with urea (at 85.5 mg N pot -1 ) at 21 days after emerge...

African Journal of Agricultural Research, 2020

African Journal of Agricultural Research, 2019

Avocado (Persia americana) a very important crop worldwide nutritionally and economically. In Ken... more Avocado (Persia americana) a very important crop worldwide nutritionally and economically. In Kenya avocado does not thrive well in soils with high salinity, flooded or waterlogged areas. Survey was conducted around Lake Victoria Basin in Kenya to establish socioeconomic factors and flooding that affects its production. A sample of 400 households was interviewed using structured questionnaire, focus group discussions and key informants. Data were collected and analysed using Statistical Package for Social Scientists. Objectives were to find how flood, human capital and other socioeconomic factors such as gender, age, farmer education affects avocado production in areas with saline soils and floods among other factors namely Busia, Muhoroni, Nyando and Rachuonyo counties in Kenya. Results indicated that the major impediments were water logging (76.2%), flooding (73.0%), soil fertility (62.5%) and soil salinity (42.9%), to agricultural development and affect the crop production. Farmers had limited access to information on avocado production and marketing 31.3%, and sourced information from fellow farmers. Majority of farmers owned indigenous or non-certified avocado trees; low fruits market prices also discouraged its production. Therefore, farmers should be sensitized on the impacts of climate change on agriculture, encourage majority of them to take samples of their plots for soil analysis. 65.5% expressed soil fertility problems in their farms yet 95.5% of them had not taken their plots for soil analysis. Increasing of human capital, farmer education, and extension services may contribute to farmer's abilities to adopt new technologies for increased avocado production in these areas and may positively contribute to improved livelihood through nutrition, income generation of the stakeholders. Farmers should be encouraged to plant certified avocado seedlings tolerant to water logging and salinity.

World Development, 2008

This paper assessed the relative economic efficiency and output supply and input demand responses... more This paper assessed the relative economic efficiency and output supply and input demand responses of women farmers in western Kenya. The results showed that women are as technically and allocatively efficient as men. However, neither men nor women have absolute allocative efficiency. Women farmers are equally responsive to price incentives in terms of output supply and input demand. While education and extension contact have significant effects on overall maize supply and input demand, only extension contact has significant effects among women farmers. The paper discusses a number of significant results and concludes with implications for policy.

African Crop Science Journal, 2010

Common bean (Phaseolus vulgaris L.) is an important food and cash crop particularly in Eastern, S... more Common bean (Phaseolus vulgaris L.) is an important food and cash crop particularly in Eastern, Southern and Great lake region. The efficacy of water based crude plant extracts of Neem (Azadirachta indica), Mexican marigold (Tagetes minuta), Tobacco (Nicotiana tobacum) and Peri-winkle (Vinca rosea) in controlling soil-borne fungi (Fusarium oxysporum Schl. f. sp. phaseoli) of common bean (Phaseolus vulgaris L.) was studied in the western province of Kenya. Thirty farms were used in the study carried out in August-September 2005 and March-June 2006. Broth microdilution method was used to determine minimum inhibitory concentration (MIC). All crude plant extracts controlled Fusarium yellows with varying efficacy. Neem extract was the most effective, while peri-winkle was the least. Wilt incidence was not affected by dosage regime. Neem is inhibitory to Fusarium growth at lower dosage than tobacco, Mexican marigold and peri-winkle with MIC ranging between 2.5 and 10.0 mg ml-1 .

Agricultural Systems, 2010

Striga hermonthica (del) Benth is threatening rural livelihoods in western Kenya where maize is t... more Striga hermonthica (del) Benth is threatening rural livelihoods in western Kenya where maize is the major food and cash crop. Vulnerability analysis was conducted on a sample of 802 households in eight districts of Nyanza and Western provinces. Farmers perceived Striga as the major cause of poverty and food insecurity. Both household income and child nutrition indicators showed alarming conditions for the majority of households. The coping strategies and informal safety nets were not capable of addressing the vulnerability issue successfully. A logistic regression model of determinants of poverty was estimated to examine the determinants and correlates of poverty. Results revealed certain characteristics of households that were more likely to be poor: poor access to land and farm assets; high dependency ratio; headed by older farmer with low education attainment; no off-farm work, no cash crops; depend on credit; Striga has been on the farm for long, high perceived yield loss to Str...

A study of intercropping systems in the upper midland agroecological zone (AEZ) of western Kenya ... more A study of intercropping systems in the upper midland agroecological zone (AEZ) of western Kenya sought to evaluate yield patterns of different maize+artemisia spacing regimes as potential practices for enhancing biodiversity, through identification of the most beneficial system component. The experiment was carried out between 2009 and 2010 in two consecutive seasons. 8 treatments were laid out in a Randomized Complete Block Design (RCBD) design with 3 replications. The productivity of these systems was evaluated using Replacement Value of Intercropping (RVI), Cost-Benefit analysis (CBA) and Dominance Analysis (DA). The treatments had a significant effect on RVI (P 0.05), but there was a positive correlation between artemisinin and the chlorophyll content of artemisia (r 2 =0.7) in SR. CBA showed artemisia monocrops to be economically more advantageous than other treatments. Maize+artemisia intercrops exhibited a 60% to 70% more biological and economical yield advantage than maize ...