East African Journal of Pure and Applied Sciences

Soil Phosphorous Extraction by Olsen and Double Acid Methods in Acid Soils of Western Kenya

K. J. Maghanga — 2012-10-01

Phosphorous is an essential nutrient in plants required for root establishment. In the soil, it is applied as DAP, TSP or phosphate rocks. In acid soils, aluminium and iron are dominant and tend to “fix” phosphorous, making it unavailable for plant uptake. Phosphorous deficiencies are monitored through soil chemical analysis. There are many methods for the extraction of available forms; however, the choice is dependent on several factors among them soil pH. Forty soil samples were collected from three different acid soils in Western Kenya. The samples were air dried, sieved under 2.0 mm sieve and stored in sample bags for subsequent analysis. Phosphorous extraction was carried out using a basic extractant (Olsen bicarbonate method) and acid extractant (double acid method). The extracts were measured colorimetricaly by the ascorbic acid method at 880 nm wavelength. The methods were compared in terms of extracting efficiency, correlations and soil critical levels. The soils had a pH range of between 4.5 – 6.1; phosphorous, 1.66 – 55.37 mg P/ kg by Olsen method and 3.01 – 158.17 mg P /kg by double acid method. The methods were linearly correlated (r = 0.95), however, double acid extracted more phosphorous than Olsen by a factor of 2.67.

Occurrence of Black Spot Disease of Brassicas Caused by Alternaria Species in Kenya

N.K. Rop — 2012-10-01

Brassicas are important vegetable crops in Kenya for domestic economy. They are cultivated by over 90% of the smallholder farmers each with approximately 1 to 2.5 ha of land. Black spot disease of brassicas caused by Alternaria spp. is one of the major constraints to increased yield in Kenya. There is very little information available on Alternaria spp. affecting brassicas in Kenya. The objective of the present study was to establish the pathogenic Alternaria spp. affecting brassicas in Kenya and to determine the distribution and incidence of the disease in farmer’s fields. This was done by carrying out a field survey in 13 selected districts in Kenya with varying agro-ecological zones. The correlation of environmental variables with incidence and Brassica cultivars was analyzed by Analysis of Variance using SAS Computer package release 6.12 and means separation by least significance difference and student Newman-Keuls test. Out of 89 farms surveyed, 46 (51.7%) had black spot. The farms with cabbage were 52 with 28 (53.8%) having black spot, while farms with kale were 37 with 18 (48.6%) having the disease. The disease incidence on cabbage and kale farms was 30.3% and 8.7%, respectively. Alternaria species identified from black spot infected cabbage and kale were A. brassicicola and A. japonica with the former predominant (64.4%) of cabbage and the later predominant (66.7%) of kale. Both pathogens appeared in 17.8% and 11.1% of infected cabbage and kale farms, respectively. The present findings are useful in the development of Brassica cultivars resistant to Kenyan isolates of Alternaria species. This is the first report implicating A. brassicicola and A. japonica as causal agents of black spot disease of brassicas in Kenya.

Designer Nuclei and Some of their Properties

S. K. Rotich — 2012-10-01

Recently ‘designer’ nuclei with large neutron excess, such as 11Li , have been produced to understand the role played by excess neutrons in studying the properties of new isotopes and to develop new nuclear theory, and to understand how such isotopes can be used to develop new fission and fusion processes for the development of nuclear energy. Using the idea of a nuclear core composed of neutron-proton pairs (np-pairs) surrounded by unpaired neutrons and the Bogoliubov technique, we have calculated the binding energy, binding fraction, specific heat, entropy, and transition temperature of such nuclei, and particularly the isotopes for which the ratio of neutron to proton number is approximately 1.554 or more since this is the ratio for fissile materials.

Evaluation of Predictive CD4 Count and Clinical Reliability in Detecting Cryptococcus Neoformans at Kenyatta National Hospital

Mdodo, R. — 2012-01-01

Cryptococcal meningitis (CM) caused by Cryptococcus neoformans is increasingly becoming a fatal fungal infection, especially among HIV/AIDS patients. This is because the HIV virus targets and destroys CD4 T cells (core cellular immune effector cells) thus causing immunosuppression. The objective of the study was to determine occurrence of CM, CD4T cells counts and assays, in patients either suspected or confirmed to have cryptococcal meningitis. The cross-sectional study design involved 51 HIV patients from KNH, during August-September 2008, sampled using Java and Applets method (2006). Results showed that CD4 T cells count among all the patients suspected to be infected with cryptococcal meningitis ranged from 0-937 cells/µL; majority had CD4 counts of ≤200 cells/µL. Since 43% of HIV patients with cryptococcal meningitis had CD4 counts of ≤143 cells/µL, a CD4 count of 143 cells/µL should be used as the lower limit below which HIV patients should be given prophylactic drugs for the disease, regardless of the prevailing clinical features seen in the affected patients

Lifestyle Behaviour, Customs, Toilet and Vaginal Hygiene Practices as Contributory Factors in Bacterial Vaginosis: A Case of Nairobi, Kenya

A. C. Auma — 2012-10-01

Bacterial vaginosis (BV) is a poly-microbial syndrome characterized by a shift in vaginal flora from a predominant population of Lactobacilli to their gradual or total replacement with anaerobes. Non pregnant women seeking care at Special Treatment Centre (STC) in Nairobi, Kenya were evaluated for lifestyle behaviours, customs, toilet, vaginal hygiene practices and BV. The prevalence of BV was found to be 28.5%. Vaginal douching (O.R = 1.874, 95% C.I=1.078- 3.328), cleaning anus with water after defecation (O.R = 2.191, 95% C.I=1.056-4.542) and having at least one sexual partner in the previous two months (O.R = 4.588, 95% C.I=1.586- 13.272) had significant positive association with BV while use of sanitary pads and tampons (O.R= 0.499, 95% C.I=0.252-0.989) had significant negative association with BV. There were significant positive independent association between BV and vaginal douching (O.R = 2.086, 95% C.I=1.154-3.772) and having at least one sexual partner in the previous two months (O.R = 5.302, 95% C.I=1.807-15.554) while there was significant negative independent association between BV and those who used sanitary pads and tampons (O.R = 0.428, 95% C.I=0.207-0.885).BV prevalence of 28.5% among these participants warrant a better understanding of the link between toilet and vaginal hygiene and their links with BV.

Growth Performance of African Catfish Clarias gariepinus (Burchell, 1822) Fry in a Green House

Matolla, G.K. — 2012-10-01

Temperature has pervasive controlling effects on the rates of food consumption and metabolism thus affects growth of fish. Water temperature can be increased by use of green houses to enhance fish growth. A study was conducted at Chepkoilel University College fish farm in Eldoret, Kenya to investigate the effect of greenhouse on growth of catfish (Clarias gariepinus) fry. Four day old fry of an initial average length and weight of 6 mm and 0.02 g respectively were held in black circular plastic tanks of 0.7 meters high inside and outside the greenhouse. The tanks were filled with 1.5 m3 of water each. Each tank was stocked with 1000 fry. Dissolved oxygen in tanks that were outside the green house was significantly higher than in those in the green house (p<0.05). While all fry had an initial mean length of 6mm. At the end of the study, mean length inside was 12.19 (±2.9) mm and significantly higher than outside the greenhouse at 9.5 (±1.6) mm (p< 0.05). Initial mean weight was 0.02g (±0.045) and 0.127g (±0.015) inside and outside the greenhouse respectively at the end of the study. Since fry survival was low (37%), regular grading of fry and provision of adequate live feeds to boost survival of fry is recommended for increased catfish fry production in greenhouses.

Effects of Varying Dietary Lipid Levels on Growth Performance and Body Composition of Nile Tilapia

G. K. Matolla — 2012-10-01

A study on growth and body composition of Nile tilapia (Oreochromis niloticus L.) indicates that mean weight, Mean Weight Gain (MWG), Specific Growth Rate (SGR) and Feed Conversion Ratio (FCR) are not affected significantly (p>0.05) by varying dietary lipid levels. However, fat content levels appear to increase significantly in the viscera of fish fed on higher levels (6% lipid diet) at 8.03±2.03% of total body weight (p<0.05). This may be an indication that diets with high lipid levels may contribute to elevated fat deposits in viscera and may contribute to obesity in fish. There were no significant differences among diets in fat contents of the fillets. Dietary lipid levels had no effect on moisture content of both fillets and viscera (p>0.05). Survival of fish fed on 3% lipid diet was significantly high (p<0.05) compared to the other two diets; suggesting some adverse effects may be associated with dietary lipid levels.

Human Faecal Matter as a Contaminant of Well Water Sources in Kisii Municipality

C. J. Nyabayo — 2012-10-01

As a result of a rapid growth of urbanization in developing countries, the majority of urban residents in sub-Saharan Africa live often in areas characterized by lack of basic amenities such as water and sewerage disposal facilities. Consequently, the urban population often use pit latrines which are not expensive to construct while at the same time use cheap domestic water source from the nearby hand dug wells. This study sought to assess sanitary practices of urban residents and feacal matter contamination of domestic water sources. A cross- sectional study design was used. The areas studied were; Nyanchwa, Mwembe and Nyamataro estates, targeting people or residential areas of high, middle and low classes. Methods of data collection used in the study were questionnaires, observations, measurements and laboratory water samples testing for faecal coliforms as indicators of faecal contamination. Data analysis was done using multiple regression and Anova. Results revealed significant (P<0.05) faecal coliforms contamination of water in wells with contamination level of 54.9 + 0.6 faecal coliforms colonies/100ml). It was concluded that hand dug well water sources in Kisii municipality was contaminated with human faecal matter due to unsanitary practices near the water source as it was observed in residential areas. The proximity between pit latrines and well water source also had significant influence on faecal coliforms contamination of domestic water sources (P<0.05). Results justified recommendation for public health education on sustainable management of human faecal matter disposal points to keep water borne disease at bay.

Assessment of Amitraz Residue in Milk Samples in Uasin Gishu and Nandi Districts

B. L. Musavi — 2012-10-01

Analysis of amitraz residue in milk samples, in Uasin Gishu and Nandi countiess has been done. The samples were randomly obtained from cows’ farmers using amitraz as a spray and also milk vendors around Eldoret town. Levels of amitraz residue were compared with MRL and ADI levels given as 0.05ppm by WHO, FAO and EPA. GC/MS was used for qualitative analysis. GC/ECD was also used for quantitative analysis. Derivatization of the extractable of amitraz residue from spiked standards and milk samples was done with heptafluorobutyric anhydride, to enhance electron capture for greater sensitivity with ECD. Before spraying amitraz residue was low. After spraying there was a sharp increase, then sharp decrease followed by gradual decreases in concentration of amitraz residue. The average concentration of amitraz residue from milk samples ranged from 0.02 - 0.05 ppm with milk having amitraz residue falling below 0.22ppm. It was found out that 39.58% had an average of amitraz concentration below MRL. About 10.42% of samples had the range of 0.06-022 ppm, which is above the MRL, while about 8.33% had 0.05ppm MRL. The effect of optimising and derivatization gave good extraction conditions, which were 2 hours reflux times, 60 minutes water bath periods and 50oC water bath temperatures. Detection limit using 3x s.d blank method was found to be 0.016 ppm which is below the MRL. The percentage recoveries of amitraz residue were above 80% the accepted value showing how effective extraction was. The butter fat content was found to fall in the range of 2.00 - 5.17% with most milk having butter fat content falling in the range of 2.50- 3.50%. A correlation between butter fat content and amitraz concentration was found to be 0.957 thus positive. The final result had an implication on the usage of amitraz product and its toxicity effect on the consumers. Hence risk mitigation had to be taken in account.

The Effects of Malasses Wastewater on Common Bean Yields in Acid Soils of Kenya

E. K. Bore — 2012-10-01

Muhoroni Agro-Chemicals and Food Company produces approximately 1.2 million litres of wastewater per day that empties into River Nyando. The wastewater discharged is not environmentally friendly and calls for proper treatment and disposal modalities. The study explored disposal of the wastewater by formulation of organic fertilizer and using it to reverse soil acidity. The fertilizer was used to grow common bean crop. Both field and greenhouse experiments were conducted for two seasons at Chepkoilel Campus, Moi University, Eldoret. Soil samples taken during cropping seasons were used to determine changes in soil chemical properties. After harvesting, the grain yields and economic analysis of treatments were done. Important results of the study were that combination of wastewater, biogas effluent, lime produced the highest increase in soil pH of over 1.2 units in both seasons. It also registered the highest increase in overall grain yields by over 250% in both seasons over the control and posted highest net profit of over US$ 416. The soil organic carbon and calcium increased by over 0.3 Cmol/kg while Olsen phosphorus increased by over 10 ppm in treatments with lime. Therefore, the organic fertilizer formulated is suitable in acidic soils.

Development of Slow Release Organic Fertilizer with Superabsorbent and Moisture Preservation Properties from Sugarcane Bagasse

S. W. Ndambuki — 2012-10-01

Efficient assimilation of nutrients in farm lands and improvement of soil water retention capabilities can be achieved through the application of controlled release fertilizers. The ideal fertilizer should be able to provide essential nutrients and preferably with reasonable water holding capacity, be environment friendly and affordable. In addition, utilization of raw materials available in nature and their application to derive other useful products without any adverse impact on the environment has long been a desired goal. A controlled release organic fertilizer with superabsorbent and moisture preservation properties was prepared from sugarcane baggase (SCB), a lignocellulosic waste of sugarcane industry, as the source of the organic material and N, N’-methylene-bis-acrylamide (NNMBA) as crosslinker. The influence of SCB, crosslinker, reaction time, reaction temperature and acrylic acid neutralization on water absorbency was investigated. Macro and micro nutrient properties of the fertilizer and SCB were studied using Kjeldahl, flame photometry, Olsen method (colorimetry) and AAS, while characterization was done using FTIR. The nutrient release and moisture retention behaviour of the fertilizer treated, and untreated soil were also investigated. Water absorbency of fertilizer and SCB was found to be 2.12 g and 0.53g per gram sample respectively, when allowed to swell in tap water for one hour at room temperature. The results of nutrient analysis showed that the fertilizer contained 2.06% N, 2.51 ppm P and 9.94 ppm K while SCB contained 0.88% N, 0.91 ppm P and 5.42 ppm K. Although similar properties of the fertilizer were found in raw SCB, experimental results revealed that the fertilizer product possessed superior properties such as controlled release, superabsorbent and moisture preservation capabilities, which justified that it could be used as a bio-fertilizer for agricultural and horticultural applications, especially in areas that experience low rainfall patterns.

The Biological Properties of the Genus Eriocephalus L. (Asteraceae)

E. W. Njenga — 2012-10-01

The genus Eriocephalus belonging to the family Asteraceae is economically important with some of its members used as traditional herbal remedies, perfumes and in cosmetics. Most of the uses of members of the genus as traditional herbal remedies have not been validated and therefore this study seeks to determine their biological properties. The biological activities of some of the species were studied to determine the scientific rationale for the use of members of the genus in traditional herbal remedies. Antimicrobial, anti-inflammatory, antioxidant activities and qualitative screening for inhibition of acetyl cholinesterase of oils and leaf extracts were investigated. Aerial parts were hydro distilled to obtain essential oils and leaves were soaked in acetone, filtered and dried for further use. The essential oils were active against the gram +ve bacteria Bacillus cereus with a minimum inhibitory concentration of 0.2-16mg/ml and the yeast Cryptococcus neoformans 0.5-16mg/ml. The oils showed anti-inflammatory properties with IC50 of 30.2-98.9μg/ml but did not show antioxidant properties. The essential oils showed inhibitory properties against acetlylcholinesterase. The leaf extracts had antioxidant activity with IC50 of 21.8-58.8 μg/ml. The biological activity of the oils indicates that most of the traditional uses are influenced by their presence. The in vitro results provide a scientific basis for use of the members of the genus in traditional herbal remedies.

Activity of Extractives from Albizia anthelmintica Brongu and Teclea trichocarpa Engl. as Biorational Alternatives to Control the Maize Weevil (Sitophilus zeamais)

Mwangi, S.K.E — 2012-01-01

Organic solvent extractives and isolated compounds of two Kenyan plants Albizia anthelmintica and Teclea trichocarpa were evaluated for insecticidal activity against maize weevil, Sitophilus zeamais Motchulsky, and for brine shrimp lethality. Hexane extract of the leaves of Teclea trichocarpa displayed mild brine shrimp toxicity (LD50 =153.2 g/ml), while the other extracts showed no significant toxicity (LD50 240 g/ml). Both hexane and dichloromethane extracts of leaves of Teclea trichocarpa showed the highest mean percentage adulticidal activity at almost all doses. Threeacridone alkaloids melicopicine 1, normelicopicine 2, arborinine 3 and the furoquinoline, skimmianine 4 were isolated from Teclea trichocarpa and had previously been reported from the other Teclea species were noted to have low mortality of between 10% and 22% at 0.1% w/w of the compounds against Sitophylus zeamais. The other metabolites were the two terpenoids, βsitosterol 5 which showed higher activity (12.5±2.5) than -amyrin 6. The results are discussed with regard to the use of the two plants as suitable and sustainable alternatives to synthetic insecticide in maize grain storage.

Ordinary Hybrid Finite Difference Methods for Solving Burgers’ Equation.

A. Koross — 2012-10-01

Burgers’ equation appears as a model in turbulence and gas dynamics. We construct hybrid finite difference schemes from ordinary finite difference methods for solving this equation. Among the hybrid methods developed are the Crank-Nicholson-Du Fort and Frankel and Crank-Nicholson- Lax-Friendrich’s and Du Fort and Frankel. We determine that the Du Fort and Frankel discretization have an improvement effect on other finite difference schemes whereas the Lax- Friedrich’s method reduces their efficacy. We note that the Du Fort and Frankel method increases the number of grid points involved by one. The increase of the grid points is responsible for the improved accuracy of the Crank-Nicholson and the Hybrid Crank-Nicholson-Lax-Friedrich’s, methods. The hybrid Crank-Nicholson-Lax-Friedrich’s,-Du Fort and Frankel scheme is the most accurate.