Browsing by Author "Ouma, John"

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    Effect of tillage method and sowing time on phenology, yield and yield components of chickpea (Cicer arietinum L.) under semi-arid conditions in Kenya
    (2010) Onyari, Charles N.; Ouma, John; Kibe, A.M.
    Objective: To determine the phenology, dry matter yield, grain yield and yield components of chickpea under four tillage methods and three sowing times within a semi-arid area of Kenya. Methodology and results: Field experiments were carried out at the National Animal Husbandry Research Centre, Naivasha, Kenya, between 2005 and 2007. Four tillage methods (Conventional, Strip, Furrow tillage, and double digging) and three sowing times (at onset, one week, two weeks after onset of rains) were evaluated. The experiment was a Randomized Complete Block Design replicated thrice in a split plot treatment design with tillage methods as main plots and sowing times allocated to the subplots. Days to 50% flowering and physiological maturity was 61 and 120 respectively irrespective of tillage method or sowing time in both seasons. Shoot biomass varied from 3242.1 to 4231.3 kg ha-1 in Season 1 and 3035.8 to 4556.1 kg ha-1 in Season 2 under tillage treatments, but, no significant differences in season 1 among sowing times. In season 2, the crop sown 2 weeks after onset of rains had significantly lower biomass yield. Plants in strip tilled plots had 36% more pods than other tillage methods in season I but not in 2. Sowing time had no significant effect on number of pods in season 1 but in season 2; the crop sown 2 weeks after the onset of rains had fewer pods. Grain yield was not influenced by tillage method or sowing times in season 1, but in season 2, strip tillage and sowing at the onset of rains yielded significantly higher grain yield than the other respective treatments. Mean grain yield were 1604kg /ha and 1895.95 kg/ha for season 1 and 2 respectively. Conclusion and application: Tillage methods and sowing times independently influenced growth, biomass development, yield components and grain yield in Kabuli chickpea, Var ICCV 95423 under semi-arid conditions in Kenya. The results were season -dependent. Sowing within two weeks after the onset of rains did not significantly lower biomass and grain yield. Strip tillage was superior to conventional tillage in the parameters measured. The time to 50% flowering and 50% maturity were not affected by tillage methods and sowing times. These results indicate that there is good potential for chickpea production (1.4 to 2.5 tonnes/ha) in this area which could be exploited to diversify grain legume production in Kenya.
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    Investigation of The Effect Of Initial Metal Ion Concentration on Chromium (Iii) Adsorption onto Thebanana Leaf Petiole as the Biosorbent
    (University of Embu, 2019) Ouma, John
    There is a tremendous increasing demand for portable water due to the rising human population and urbanization and industrialization and climate change. There is no doubt that water in this county and largely the country is a scarce resource. This calls for better technologies to be developed to curb this. They include sea water desalination, scavenging distant waters through construction of dams and supplying it by piping systems, exploration of deeper ground waters and treatment the contaminated waters. Due to the huge usage of waters by the large human populace, recycling and reusing the water rather than losing, it to the sewer systems would be more economical. This would make more water available for domestic and agricultural use. This will be done by employing technologies, which could improve on the quality of water for such applications. Some of the conventional methods for wastewater treatment include chemical precipitation, reverse osmosis, ion exchange, membrane filtration and biosorption. Most of these methods of wastewater treatment are expensive and partially remove heavy metals’ ions. The latest research has been on developing low-cost technologies for grey water treatment. This brings in handy the use of adsorbents in removing the heavy metal pollutants from wastewaters and in particular, bio-sorbents to replace the commercial adsorbents. This study investigates the potential of the banana leaf petiole as a low-cost adsorbent for chromium (III) contaminated wastewater. This study will investigate the effect of contact time on chromium (III) adsorption onto the banana leaf petiole and the effect of initial metal ion concentration on chromium (III) adsorption onto the adsorbent. The biological and physicochemical parameters of the chromium (III) contaminated water to be considered for decontamination are Bio-Chemical Oxygen Demand, pH, Total Dissolved Solids, Temperature and both the initial and final concentrations of chromium (III) ions. The results will be subjected to the standard methods for examining pure water and wastewater. The results will then be subjected to the analysis of variance and mean values. Q Test, T Test, and F Test will be done for further analysis. The obtained experimental data will be fitted to the Langmuir isotherm. Atomic Absorption Spectroscopy will then be used to determine the absorbance of the samples. The results of this project will be used to determine the viability of using the banana petiole biomass as an adsorbent. They also will be used to provide an alternative to the available adsorbent.
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    Urinary soluble egg antigen levels in Schistosoma haematobium infection in relation to sex and age of Kenyan schoolchildren following praziquantel treatment
    (2009-08) Kihara, Jimmy H.; Njagi, Eliud N.; Kenya, Eucharia U.; Mwanje, Marium T.; Odek, Adel E.; van Dam, Govert; Kahama, Anthony I.; Ouma, John
    Schistosoma haematobium soluble egg antigen (SEA) secreted in urine can be assayed to determine egg tissue load and hence morbidity in infected individuals. A cohort of 158 infected children aged 4-18 years was followed-up for 33 days pre and post treatment with a single dose of praziquantel. There was a significant difference in the prevalence of S. haematobium between males and females (P < 0.05). There were also significant differences in egg counts between age group < or = 5 years compared with 6-8 years, 9-11 years and 12-14 years, and age group > or = 15 years compared with 6-8 years, 9-11 years and 12-14 years (P < 0.05). Comparison of SEA among age groups indicated a significant difference between age group < or = 5 years compared with 9-11 years, 12-14 years and > or = 15 years, and age group > or = 15 years compared with 9-11 years and 12-14 years (P < 0.05). There was a statistically significant correlation between levels of SEA and egg output (r2=0.961, P=0.010). These results are useful in the development of a SEA-based dipstick assay for field diagnosis of urinary schistosomiasis.