Evaluation of crop arrangement and phosphorus rate on performance of maize-common bean intercropping in western Kenya

The effect of phosphorus (P) rate and crop arrangement on the performance of component crops in maize-bean intercropping systems was investigated at two sites; Malanga and Bugeng’i in western Kenya. A split plot design with five crop arrangements in the main plots i.e., one row of maize alternating with one row of beans (conventional), maize and beans planted in the same hole, two rows of maize alternating with two of beans (Mbili), sole maize and sole beans, in a factorial combination with three P rates; 0, 30, and 60 kg ha-1 in the subplots, was used. Bean yields were low (< 1 t ha-1) but they increased with increasing P rate at both sites. Response of maize to P fertilizer was however poor at Malanga mainly due to Striga weed infestation. Yields of beans did not significantly differ among crop arrangements at both sites. At Bungeng’i, there was a significant interaction between P rate and crop arrangement. At this site, the maize yield in the conventional arrangement increased with increasing P rate but for the Mbili arrangement, the grain yield from application of 30 kg P ha-1 was significantly higher than that at 0 kg P ha-1 and similar to that 60 kg P ha-1. Therefore, it is not beneficial to fertilize beyond 30 kg P ha-1 at this site with the Mbili arrangement. Intercropping was beneficial in all crop arrangements (Land equivalent ratio >1) and can therefore be practiced, except for maize and beans planted in the same hole with no P application at Bugeng’i

Estimation Of Reference Crop Evapotranspiration Using Fuzzy State Models

Daily evapotranspiration (ET) rates are needed for irrigation scheduling. Owing to the difficulty of obtaining accurate field measurements, ET rates are commonly estimated from weather parameters. A few empirical or semi–empirical methods have been developed for assessing daily reference crop ET, which is converted to actual crop ET using crop coefficients. The FAO Penman–Monteith method, which is now accepted as the standard method for the computation of daily reference ET, is sophisticated. It requires several input parameters, some of which have no actual measurements but are estimated from measured weather parameters. In this study, we examined the suitability of fuzzy logic for estimating daily reference ET with simpler and fewer parameters. Two fuzzy evapotranspiration models, using two or three input parameters, were developed and applied to estimate grass ET. Independent weather parameters from sites representing arid and humid climates were used to test the models. The fuzzy estimated ET values were compared with direct ET measurements from grass–covered weighing lysimeters, and with ET estimations obtained using the FAO Penman–Monteith and the Hargreaves–Samani equations. The estimated ET values from a fuzzy model using three input parameters (Syx = 0.54 mm, r2 = 0.90) were found to be comparable to ET values estimated with the FAO Penman–Monteith equation (Syx = 0.50 mm, r2 = 0.91) and were more accurate than those obtained by the Hargreaves–Samani equation (Syx = 0.66 mm, r2 = 0.53). These results show that fuzzy evapotranspiration models with simpler and fewer input parameters can yield accurate estimation of ET

Amplification of 1-amino-cyclopropane-1-carboxylic (ACC) deaminase from plant growth promoting rhizobacteria in Striga-infested soil

Experiments were conducted in pots to determine the growth effect of different rhizobacteria on maize under Striga hermonthica infestation. Three bacteria were selected based on their plant growth promoting effects. Whole bacterial cells of the rhizobacteria were used to amplify 1-amino-cyclopropane-1-carboxylic acid (ACC) deaminase gene by polymerase chain reaction (PCR). Each bacterial inoculation increased agronomic characteristics of maize although not always to a statistically significant extent. The extent of growth enhancement differs between the isolates. Enterobacter sakazakii 8MR5 had the ability to stimulate plant growth, however in the PCR study, ACC deaminase was not amplified from this isolate, indicating that not all plant growth-promoting rhizobacteria contain the enzyme ACC deaminase. In contrast, an ACC deaminase specific product was amplified from Pseudomonas sp. 4MKS8 and Klebsiella oxytoca 10MKR7.  This is the first report of ACC deaminase in K. oxytoca. Key words: 1-amino-cyclopropane-1-carboxylic acid, ACC deaminase, PCR, rhizobacteria, Striga hermonthica. (African Journal of Biotechnology: 2003 2(6): 157-160

Optimization Of Fuzzy Evapotranspiration Model Through Neural Training With Input–Output Examples

In a previous study, we demonstrated that fuzzy evapotranspiration (ET) models can achieve accurate estimation of daily ET comparable to the FAO Penman–Monteith equation, and showed the advantages of the fuzzy approach over other methods. The estimation accuracy of the fuzzy models, however, depended on the shape of the membership functions and the control rules built by trial–and–error methods. This paper shows how the trial and error drawback is eliminated with the application of a fuzzy–neural system, which combines the advantages of fuzzy logic (FL) and artificial neural networks (ANN). The strategy consisted of fusing the FL and ANN on a conceptual and structural basis. The neural component provided supervised learning capabilities for optimizing the membership functions and extracting fuzzy rules from a set of input–output examples selected to cover the data hyperspace of the sites evaluated. The model input parameters were solar irradiance, relative humidity, wind speed, and air temperature difference. The optimized model was applied to estimate reference ET using independent climatic data from the sites, and the estimates were compared with direct ET measurements from grass–covered lysimeters and estimations with the FAO Penman–Monteith equation. The model–estimated ET vs. lysimeter–measured ET gave a coefficient of determination (r2) value of 0.88 and a standard error of the estimate (Syx) of 0.48 mm d–1. For the same set of independent data, the FAO Penman–Monteith–estimated ET vs. lysimeter–measured ET gave an r2 value of 0.85 and an Syx value of 0.56 mm d–1. These results show that the optimized fuzzy–neural–model is reasonably accurate, and is comparable to the FAO Penman–Monteith equation. This approach can provide an easy and efficient means of tuning fuzzy ET models

Differences In \u3ci\u3eUrochloa\u3c/i\u3e Hybrids and Cultivars Biomass Production in Several Sites in Western Kenya

Forage production is at the core of improved livestock productivity, especially in sub Saharan Africa. The genetic potential of existing animals remains underutilized due to limited forage quality and quantity. Albeit wide range of forage germplasm that exists, little data is available for identifying suitable genotypes, matched to specific environments and production systems. Due to the spatial and temporal diverse environments in which livestock production happens, multi-locational screening of forage production and characterizing genotype by environment interaction is key. We selected seven Urochloa (Syn. Brachiaria) genotypes comprising three hybrids and four cultivars and established them in on-farm trials in western Kenya for dry matter evaluation and nutritional quality. We selected eight sites covering four administrative counties (Siaya, Kakamega, Busia, Bungoma), and each county hosting two replicated trials, with each trial replicated 3 times. We observed dry matter yield differences across the counties in the order Bungoma \u3e Busia \u3e Kakamega \u3e Siaya. Similarly, the genotypes returned varied performance across the sites. Hybrids did well in one of the county, a mix of hybrids and cultivars in two counties and cultivars in the last county. Amongst sites, variation was least in Busia, and more pronounced in Bungoma. Continued assessments in subsequent cuts are underway. These will feed into context-specific recommendations about suitable forages for sustainable intensification in the face of global warming

Evaluation of Polyethylene-Based Long Lasting Treated Bed Net Netprotect on Anopheles

We studied the effect on malaria incidence, mosquito abundance, net efficacy, net use rate, chemical analysis, and holes of a long lasting insecticide treated bed net (Netprotect) in western Kenya, 2007–2010. Nets were hung in 150 households 6 months before they were hung in a second, 2 km away. Indoor resting densities were monitored by pyrethrum spray catch and malaria cases by passive detection using clinical manifestations and rapid diagnostic test. The probability of finding An. arabiensis in the control area was 2.6 times higher than that in intervention area during the first 6 months. Human blood feeding index of Anopheles funestus declined 17%. After bed nets were hung in the second area, malaria incidence declined 25% down to the level in the first area. Incidence remained at this low level for 2 years. 90% of collected nets were efficacious after 3-year use. Deltamethrin dosage declined from 1.9 to 0.5 g/kg over 3 years. Attrition rate after 3 years was 21%. WHO hole index changed from 333 to 114 to 381 over the three years. This index summarizes the numbers of holes in size categories and multiplies with the mean hole area per category. It is very sensitive to the impact of big holes in a few nets

Sorghum Landraces Production Practices in Nyanza, Coast and Eastern Regions, Kenya

Sorghum Sorghum bicolar L. is an important cereal crop grown in the semi-arid areas. It is rank as the fifth key cereal crop worldwide. The ability of sorghum to adapt to drought, salinity, infertile soils, and high temperatures makes it a critical crop in the dry regions. However, farmers grow many landraces some of which do not perform well since the majority cannot afford nitrogenous fertilizers to boost their harvest. Therefore, a baseline survey was conducted in Eastern, Nyanza and Coastal regions to assess the production systems for sorghum. Structured questionnaires were used to gather information from a total of 76 randomly selected farmers in the study regions. Data on socio-economic characteristics, sorghum varieties, use of farm inputs, and source of seeds, farming systems, traits preference, farm sizes, yields and constraints in production of the crop was collected. Parameters studied were analyzed using Statistical Programmes for Social Sciences (SPSS) (IBM SPSS Statistics 20). Results showed that majority of respondents in Eastern (99%), 80% in Nyanza and all respondents in the coastal region cultivated landraces. Most of the respondents had farm sizes between 0.5-5acres. A larger proportion of respondents in the three regions reported low harvests from their farms, recording below 5 bags every season. Most of the farmers across the three regions intercrop sorghum with other crops with all respondents in Eastern, 80% in Coast and 68% in Nyanza. Some farmers plant sorghum without fertilizers, others used either inorganic or organic fertilizers while the rest use both organic and inorganic. The traits desired by farmers in the region included high yields, early maturity, resistance to pest and diseases, sweetness and tolerance to drought. Farmers cited pests and diseases, weeds such as striga, and drought as the key constraints to sorghum production in the regions. Key words: drought, landraces, sorghum, tolerance, traits DOI: 10.7176/JESD/10-10-16 Publication date:May 31st 201

Intermittent Preventive Treatment in Infants for the Prevention of Malaria in Rural Western Kenya: A Randomized, Double-Blind Placebo-Controlled Trial

Background Intermittent preventive treatment in infants (IPTi) with sulphadoxine-pyrimethamine (SP) for the prevention of malaria has shown promising results in six trials. However, resistance to SP is rising and alternative drug combinations need to be evaluated to better understand the role of treatment versus prophylactic effects. Methods Between March 2004 and March 2008, in an area of western Kenya with year round malaria transmission with high seasonal intensity and high usage of insecticide-treated nets, we conducted a randomized, double-blind placebo-controlled trial with SP plus 3 days of artesunate (SP-AS3), 3 days of amodiaquine-artesunate (AQ3-AS3), or 3 days of short-acting chlorproguanil-dapsone (CD3) administered at routine expanded programme of immunization visits (10 weeks, 14 weeks and 9 months). Principal Findings 1,365 subjects were included in the analysis. The incidence of first or only episode of clinical malaria during the first year of life (primary endpoint) was 0.98 episodes/person-year in the placebo group, 0.74 in the SP-AS3 group, 0.76 in the AQ3-AS3 group, and 0.82 in the CD3 group. The protective efficacy (PE) and 95% confidence intervals against the primary endpoint were: 25.7% (6.3, 41.1); 25.9% (6.8, 41.0); and 16.3% (−5.2, 33.5) in the SP-AS3, AQ3-AS3, and CD3 groups, respectively. The PEs for moderate-to-severe anaemia were: 27.5% (−6.9, 50.8); 23.1% (−11.9, 47.2); and 11.4% (−28.6, 39.0). The duration of the protective effect remained significant for up to 5 to 8 weeks for SP-AS3 and AQ3-AS3. There was no evidence for a sustained beneficial or rebound effect in the second year of life. All regimens were well tolerated. Conclusions These results support the view that IPTi with long-acting regimens provide protection against clinical malaria for up to 8 weeks even in the presence of high ITN coverage, and that the prophylactic rather than the treatment effect of IPTi appears central to its protective efficacy

Webuye Health and Demographic Surveillance Systems Baseline Survey of Soil-Transmitted Helminths and Intestinal Protozoa among Children up to Five Years

Background. The intestinal parasitic infections (IPIs) are globally endemic, and they constitute the greatest cause of illness and disease worldwide. Transmission of IPIs occurs as a result of inadequate sanitation, inaccessibility to potable water, and poor living conditions. Objectives. To determine a baseline prevalence of IPIs among children of five years and below at Webuye Health and Demographic Surveillance (HDSS) area in western Kenya. Methods. Cross-sectional survey was used to collect data. Direct saline and formal-ether-sedimentation techniques were used to process the specimens. Descriptive and inferential statistics such as Chi-square statistics were used to analyze the data. Results. A prevalence of 52.3% (417/797) was obtained with the male child slightly more infected than the female (53.5% versus 51%), but this was not significant ( 2 = 0.482, > 0.05). Giardia lamblia and Entamoeba histolytica were the most common pathogenic IPIs with a prevalence of 26.1% (208/797) and 11.2% (89/797), respectively. Soil-transmitted helminths (STHs) were less common with a prevalence of 4.8% (38/797), 3.8% (30/797), and 0.13% (1/797) for Ascaris lumbricoides, hookworms, and Trichuris trichiura, respectively. Conclusions. Giardia lamblia and E. histolytica were the most prevalent pathogenic intestinal protozoa, while STHs were less common. Community-based health promotion techniques are recommended for controlling these parasites