Browsing by Author "Onyango, J.W."
Now showing 1 - 7 of 7
- Results Per Page
- Sort Options
Item A comparative Agro-Ecological Assessment of selected irrigation and Drainage Schemes in Western and Central Kenya(Kenya Agricultural Research Institute, 2007) Onyango, J.W.; Radiro, M.O.; Munene, S.; Kenya Agricultural Research InstituteIrrigation and drainage could greatly improve not only agricultural production and diversified cropping patterns but also involve the idle population in highly productive enterprises. Expected financial gains would then go along way in the improvement of the pathetic rural economy dominated by food insecurity and high poverty levels in which the majority of the population find themselves in. A preliminary investigation in these seven districts (i.e. two in Nyanza (Nyando and Bondo), two in Western (Busia and Bungoma), two in Central (Nyeri and Kirinyaga) and one in Eastern (Meru) revealed some reasons why the schemes have not performed to required standards. There are various categories of irrigation and drainage schemes in Kenya. These range between the large-scale centrally-managed to the small-scale individually run categories. Management of the large scale irrigation schemes have undergone through the stages of identification of water source which can be exploited for irrigation purpose and an area to which the irrigation can be applied. These categories of schemes are/were usually financed by already established organisations such as the National Irrigation Board (NIB) who seek assistance from donors. NIB then implements the irrigation/drainage infrastructure, provides inputs and facilitates marketing services.Item Ministry of Agriculture National Agricultural Fertilizer use Project (Phase 1): Final Report Annex III Description of the first priority sites in the various Districts Vol 4 Siaya(Ministry of Agriculture, 1987) Hinga, G.; Nandwa, S.W.; Onyango, J.W.; Muchena, F.N.; Gachene, C.K.K.; Kibe, J.M.; Qureshi, J.N.; Oduor, P.O.S.; Owuor, J.O.; Milikau, R.L.; Wamae, D.K.; Mwangi, B.; Wataka, S.; Ministry of AgricultureThe annual average rainfall of Siaya District increases from 800 mm at the lake shore to 2000 mm near the border of Kakamega District. The contrasts in 66% rainfall reliability, i.e. amounts surpassed in 20 out of 30 years, are even higher, in the first rains from 350 to 900 mm and in the second rains from 50 to 800 mm (see Maps 4.0.1 and 4.0.2). Near Lake Victoria the average annual temperature is about 22.5°C, in the nor~h-eastern part of the District it is 21°C . Humidity of the air is relatively high. For the entire District evaporation is 1800 - 2000 mm per year.Item Ministry of Agriculture National Agricultural Fertilizer use Report (Phase 1): Final Report Annex III Description of the first priority sites in the various Districts Vol 1 Kakamega(Ministry of Agriculture, 1987) Hinga, G.; Nandwa, S.W.; Onyango, J.W.; Muchena, F.N.; Gachene, C.K.K.; Kibe, J.M.; Qureshi, J. N.; Oduor, P.O.S.; Owuor, J.O.; Milikau, R.L.; Wamae, D.K.; Mwangi, B.,; Wataka, S.; Ministry of AgricultureAnnual rainfall in the District is both high, averaging 1200 to 2100 mm, and, apart from the north-eastern parts, reliable. In 20 out of 30 years 500 to 1100 mm are reached or surpassed in the first rains, 450 to 850 mm during the second rains. In the centre of the District rainy seasons cannot easily be distinguished, since there are normally no real dry seasons separating them (see Figure 7.3.5). First rains start at about the middle of February with a second increase in August followed by a third in October/November.Item Ministry of Agriculture National Agricultural Laboratories use recommendation project (phase I), Annex III: Description of the first priority sites in the various Districts Vol 25 Meru district(Ministry of Agriculture, 1987) Hinga, G.; Nandwa, S.W.; Onyango, J.W.; Muchena, F.N.; Gachene, C.K.K.; Kibe, J.M; Qureshi, J.N.; Oduor, P.O.S.; Owuor, J.O.; Milikau, R.L.; Wamae, D.K.; Mwangi, B.; Wataka, S.; Ministry of AgricultureThe Meru District is situated around the eastern slopes of Mt. Kenya. In the south-eastern region, the main agro-ecological zones follow - according to altitude - a similar pattern as in the bordering Embu District. However, the contrast between wet and dry seasons becomes more accentuated . This is reflected in the sequence of sub-zones (see Map 25.3) and in the rainfall diagrams for the various trial sites in Meru (Figutes 25.1.5 , 25.2.5 and 25.3 . 5) . For this reason, the cultivation of permanent and annual crops, such as coffee, tea, bananas and cotton, requires in most areas careful water and soil conservation to overcome the drought periods between the seasons. Such conservation measures are also beneficial for the seasonal crops , since the rainy seasons bring rainfall, though very high.Item National Agricultural Laboratories fertilizer use Research Project (Phase I): Final Report Annex III: Description of the First Priority Sites in the Various Districts Vol 26 Machakos District No.26(Ministry of Agriculture, 1987) Hinga, G.; Nandwa, S.W.; Onyango, J.W.; Muchena, F.N.; Gachene, C.K.K.; Qureshi, J.N.; Oduor, P.O.S.; Owuor, J.O.; Milikau, R.L.; Wamae, D.K.; Mwangi, B.,; Wataka, S.; Kibe, J.M.; Ministry of Agriculture; Kibe, J.The centre of Machakos District consists mainly of hills and small plateaus, rising to 1800-2100 m, surrounded by a large plateau, elevated to about 1700 m in the west and sloping down to 700 m in the south-east. This undulating peneplain is broken by isolated mountains such as 01 Donyo Sabuk in the north-west, by the volcanic outflow of the Yatta Plateau in the east, and by a range of volcanic ashes, the Chyulu Hills in the south-westItem A Simple Procedure for Drought Prediction Over the "Water Year" for Agricultural and Hydrological Schedules in West Kenya(1992) Onyango, J.W.; Kenya Agricultural Research Institute, National Agricultural Research Laboratories.Drought is one of most devastating environmental aspects. There is extensive literature on agricultural (Nieuwolt, 1974.1978; Baker. 1977). hydrological (Woodhead, 1968. 1970; Woodhead and Waweru, 1970) and irrigational (pereira, 1957, aspects of drought in East Africa but none has been attributed to solar cycles (Bhalme and Mooley. 1979). Ability to predict the future occurrence of drought would go a long way towards facilitating water management In attempting to define drought, the basic aspects should involve an economic dimension and identification of the water source. It then becomes necessary to define a period of its critical availability for this purpose (Heathcote, 1969) or the prediction becomes of no apparent use.Item Validation of AquaCrop Model for Simulated Climate Change Strategies for Maize Production in a Kenyan Nitisol(East African Agricultural and Forestry Journal, 2023-01-11) Onyango, J.W.; Miriti, J.M.; Esilaba, A.O.; Kenya Agricultural and Livestock Research Organization (KALRO)Climate models predict temperature increases of between 3-4o C in Africa by the end of the 21st Century; roughly 1.5oC higher than the global mean. AQUACROP model was validated to compare climate adaptation measures of irrigation, fertility and planting dates using maize crop. Data was collected in the two seasons of 2012 at Kabete in the Upper Midland agro-zone of Kenya from Climate Analogue Location in East and Southern Africa (CALESA) project. Long-term monthly rainfall, minimum and maximum temperatures data from Kabete Meteorological Station were used to determine trends while additional parameters were used to compute other model parameters. A scenario of 10% decline in rainfall and 3oC temperature increase led to at least 6 and 12% enhanced of biomass and yields respectively. Late planted crop suffered 0.3% reduction in canopy cover (CC), and 7.5% reduced transpiration hence 0.2% biomass. This probably resulted from disuse of initial moisture availability and nitrogen flush usually at rainfall onset. Application of 20 kg/ha of N enhanced transpiration hence biomass and especially grain yields by 24.7%. However, while 40kg/ha of N enhanced canopy cover, this did not lead to increased biomass and/or yields. It is purposeless to irrigate when rains are adequate since this only delays harvest index but does not enhance biomass or yields. Late planting is not recommended since the crop would suffer reduced transpiration, CC and biomass. It is needless to continusly enhance fertility levels beyond 20 kg/ha for maize at Kabete.
