Browsing by Author "Kibe, A.M."

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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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    Production Functions and Their Use in Predicting Chickpea Biomass Yields When Grown under Varying Tillage and Sowing Dates in Naivasha, Kenya
    (Scientific Research Publishing Co., 2007) Kibe, A.M.; Onyari, Charles N.
    The use of production functions as tools for analyzing agronomic relationships and crop growth is gaining importance the world over. Their predictive value in crop adaptation trials for specific agro-ecological sites particularly in semi arid lands is of special interest, but little, if any work is being done with this regard in Kenya. A chickpea (Cicer arietinum L.) cultivar, ICCV 95423 was therefore planted under four tillage systems namely, Conventional (CT), Double Digging (DD), Furrow (FT) and Strip Tillage (ST) and under three sowing dates (two weeks apart) at Naivasha. The aim was to develop evapotranspiration and biomass yield (ET-yield) relationships and determining their potential use in analyzing growth (LAI and DM production) of chickpea. Estimated yields (computed) were produced using the 1st season`s (Jan-May `05) functions and validated with the 2nd season (Jun-Oct ‘05) actual yield data sets. The relationships exhibited very high regression correlation coefficients (R2>0.93) indicating the potential reliability of the functions in predicting chickpea yields. Rate of increase in biomass production per hectare millimeter increase in water use was 17.5kg ha-mm 1. Biomass yields estimated from season II ET data were validated and had a reliability of 0.859 and 0.952 when linear and curvilinear functions were fitted, respectively. The January to June crop produced DM at a higher rate of 685.2 kg ha 1 per unit LAI as compared to 309 kg ha 1 LAI -1 for season II crop. Quadratic functions proved able to account for more variations in DM production than linear functions. They can therefore, be used reliably in analyzing and predicting DM production of chickpea in Naivasha. Chickpea has great agronomic potential for use as a food and forage crop in the dry highlands of Kenya.