Browsing by Author "Wamuongo, J.W."
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Item Effect of Nitrogen and water stress on the growth, water use efficiency and seed yield of rapeseed (Brassica Napus L.)(1995) Wamuongo, J.W.; Kenya Agricultural Research Institiute, National Agricultural Research Centre, Muguga, Nairobi, KenyaThe effects of water stress and nitrogen application to the growth, yield and water use efficiency of rapeseed were investigated in the greenhouse. The parameters measured included plant height, maximum number of leaves on the main stem, number of primary branches per plant, number of pods per branch, number of seeds per. pod, seed yield per plant and amount of water used. All parameters, except for maximum number of leaves on the main stem, were affected by water stress. Application of N fertiliser when water supply was adequate promoted growth of all plant parts and increased seed yield, while application to water-stressed plants suppressed growth and yield. When N was not applied, there was a more conservative use of available water, leading to less dry matter production than when water was not limiting. Application of N appeared to promote water use with the effect being greater in the nonstressed plants. The water-stressed, non-fertilised plants were the most inefficient in water use, requiring about 3300 g of water to produce 1 g dry matter, while the non-stressed plants, regardless of the N fertiliser applied, were about twice as efficient, requiring about 1600 g of water to produce 1 g dry matter. However, these values are still large compared to those obtained under field conditions.Item Multi-Purpose Trees and Shrubs in Soil And Water Conservation in the Highlands(1996) Odongo, N.; Esilaba, A. O.; Kilewe, A. M.; Wamuongo, J.W.; Miritiu, J. M.Two long-term experiments were set up at the National Agricultural Research Centre, Muguga Kenya, to investigate the potential of several multipurpose trees in enhancing soil productivity and controlling soil erosion in the high and medium potential areas of Kenya. One experiment consisted of Sesbania sesban, Leucaena leucocephala, and Leucaena K28 while the other had Calliandra calothyrsus and Leucaena diversifolia grown in alleys. Maize and beans were the test crops, The trees produced varying amounts of dry matter with Sesbania sesban having the fastest growth rate, Plannings constituted between 34 and 79% of the total tree biomass during the first year which accumulated to between 62 and 83% by the end of second year, Neither the trees nor the pruning s showed positive effects on crop yield. Other aspects (for example analyses of soil physical and chemical properties) that might shed light on the effect of the trees and pruning on soil productivity have not been completed. Research is. However, still needed to establish quantitative measures for improved soil management under varying environments and assess its potential and limitations.Item The Organic Matter and Nitrogen Status of Manure on Smallholder Farms in Central Kenya(2003) Wamuongo, J.W.; Esilaba, A.O.; Miriti, J.M.; Mwangi, J.N.; Kimani, S.K.Mixed arable-livestock farming systems are common m central Kenya and manure from livestock is used as fertiliser in arable fields. However, increasing demographic pressure and intensification of agriculture has resulted in more continuous cultivation of arable lands without the concomitant application of fertilizers. Continuous cultivation of land has resulted in accelerated soil nutrient depletion, declIne in SOIl organic matter content, loss of physical structure and reduced crop productivity (Ikombo et al., 1994; Kilewe and Thomas, 1992).
