Browsing by Author "Mbuvi, J.P."
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Item The Effects of Crop Cover and Residue Management on Runoff and Soil Loss(1988) Kilewe, A.M.; Mbuvi, J.P. ; National Agricultural'Research Centre Muguga, Kenya Agricultural Research Institute, Nairobi, Kenya.The amount of plant cover needed to protect a soil depends on the soil characteristics and the intensity of erosive forces at that time and place. Loose soil on steep slopes needs permanent vegetation to intercept raindrops and to limit the amount and velocity of runoff. Other factors being constant, rainfall erosion from vegetated soil is determined by crop types, planting density, canopy characteristics, growth habits and quality of stand, and the achieved growth stage development by the time rainfall arrives.Item Evaluation of crop cover and residue management C factors for cropping systems and management techniques in the semi-arid region of Kenya(1989) Kilewe, A.M.; Mbuvi, J.P.; Kenya Agricultural Research InstituteThe mean crop cover and residue management C factor for maize with conventional tillage, maize with minimum tillage, maize inter cropped with beans on alternate rows, beans alone, and maize with 3 t ha -1 of maize residue were 0.77, 0.45, 0.44, 0.30, and 0.15 respectively, as measured in two groups of subsequent rainy seasons. The high C factor for maize with conventional tillage was attributed to low planting density for maize and slow ground cover development that provided very minimal soil protection against raindrop impact. Maize was therefore considered extremely prone to soil erosion when grown in mono culture. The high planting density and fast ground cover development achieved by beans alone in the early part of the season resulted in a very low C factor. The cultivation of beans was therefore recommended as a suitable agronomic resource management system in this region either in mono culture or inter crop with erosion prone crops like maize. Mulching at the rate of 3 t ha-1 of maize residue produced the lowest C factor. This was attributed to the effect of maize residue mulch that provided over 50% ground cover right from the beginning of the season when frequency of erosive storms are high. However, due to the scarcity and high demand for crop residue to feed livestock, mulching was not considered a feasible recommendation in cropping systems using artificial fertilizer inputs unless the mulch could be obtained from agroforestry systems using no or very little artificial fertilizer.Item Evaluation of Suitable Rainfall Erosivity Factors for the Semi-Arid Region of Kenya(1989) Kilewe, A.M.; Mbuvi, J.P.; Kenya Agricultural Research InstituteRegression analysis of 28 erosivity factors with soil loss from bare fallow plots was done to ascertain the best erosivity factor for the semi-arid region of Kenya. The El30, defined as the product of the rainstorm's kinetic energy and its maximum 30-minute intensity, emerged as the best erosivity factor having a correlation coefficient of 0.80 and a mean annual cumulative value of 154.9 MJ cm ha-¹ h-1. Al30, 130, and A erosivity factors, defined as the product of the rainstorm's rainfall amount and its maximum 30-minute intensity, the storm's maximum 30-minute intensity, and the storm's total rainfall amount respectively, which are much simpler to compute than El30, were shown to be predictors of sou loss with a decreasing accuracy. They gave correlations with soil loss of 0.79, 0.72. and 0.57 respectively and had simple linear relationships with El30 having correlation coefficient values of 0.99, 0.83, and 0.80 respectively. It was therefore concluded that excellent estimates of El30 and good estimates of soil loss can be made using Ai30. The single parameters 130 and A, although perhaps better than others, must be considered appreciably less accurate in soil loss prediction than their products.Item A preliminary evaluation of the irrigation suitability of the lands in the middle lower Tana Valley(Ministry of Agriculture, 1974) Ministry of Agriculture; Sombroek, W. G.; Mbuvi, J.P.; Kibeb, J.M.At the request of the Land and Farm Management Division of the Ministry of Agriculture and the North Eastern Provincial Crops Officer, site evaluations were carried out on the soil conditions in the Tana valley in the stretch Mbalambala -Garissa-Bura. The field studies were carried out in two legs, 5 and 6 July 1973Item A preliminary evaluation of the soil conditions on the East Bank of lower Tana (Bura East area) for large scale irrigation development. MOA-NAL-Kenya Soil Survey NO.P21 1975 HM(Ministry of Agriculture, 1975) Sombroek, W.G.; Mbuvi, J.P.; Leyder, B.A.; Ministry of Agriculture; Kenya Soil SurveyIn the request of the Tana River Development Authority, a site evaluation was carried out to determine the irrigation potential of the East bank of the Lower Tana River (Bura-East area’). The request was made in view of the proposal to start a major irrigation scheme in the area, as a complementary to the Bura (West) scheme of 14,000 ha, which is already in an advanced stage of planning.Item A Preliminary Evaluation of the Soils around Nyangoma Mission Bondo Division No.19 1974 HM(Ministry of Agriculture, 1974) Weg, R.F.; Mbuvi, J.P.At the request of Dr. Joan Camphell consultant to the UNEP Bureau of Programme Division III. Settlement, Nairobi, a site evaluation of the soil conditions around the Nyangoma Mission in Bondo Division. Siaya District. Nyanza was carried out on '29th and 30th October, 1974. The request was made in relation to the feasibility of conducting a pilot project in eco-development in the above mentioned area (Harrison, 1974).Item A Preliminary Evaluation of the Soils of North Western Machakos District (Parts of Matungulu and Mbiuni Locations), 1974(Ministry of Agriculture, 1974) Mbuvi, J.P.; Braun, H.M.H.; Weg, R.F.; Ministry of AgricultureAt the request of the Medical Research Centre, Nairobi, a site evaluation was carried out in the N. W. part of' Machakos District. . At present the M.R.C. is carrying out a longitudinal study and morbidity and mortality of' a number of' childhood diseases in this area. The study aims at the collection of demographic and medical data among two population groups of' 5,000 each in different ecological settings, (Vogel et 0.1, 1974). There is no proper soil data for this area, though it is covered by the land System Atlas of' Western Kenya", scale 1:1.000.000 which is based on photo interpretation with a minimum of' field observations. The D.O.S. report on the soils of' Nairobi-Thika-Yatta Machakos area (Scott, 1963) also covers this part (scale 1:100.000). This-is also mainly a photo interpretation map wit~ few field observations. These two documents are on a reconnaissance scale, and do not give sufficient data for the urea under consideration.Item A Preliminary Evaluation of the Soils of North-Western Machakos District (Parts of Matungulu and Mbiuni Locations)(Kenya Agriculture Research Institute, 1974) Mbuvi, J.P.; Van de Weg, R. F.; Braun, H.M.H.; Ministry of AgricultureAt the request of the Medical Research Centre, Nairobi, a site evaluation was carried out in the N.W. part of Machakos District. At present the M.R.C. is carrying out a longitudinal study on morbidity and mortality of a number of childhood diseases in this area. The study aims at the collection 01' demographic and medical data among two population groups of 5,000 each in different ecological settings, (Vogel et al, 1974). There is no proper soil data for this area, though it is Covered by the "lend System Atlas of Western Kenya", scale 1:1.000.000 which is based on photo interpretation with a minimum of field observations~ The,D,O.S. report on the soils of Nairobi-Thika-Yatta-Machakos area (Scott, 1963) also covers this part (scale 1:100.000). This -is also mainly a photo interpretation map with few field observations. These two documents are on a reconnaissance scale, and do not give sufficient data for the area under considerationItem A Preliminary Report on the Suitability of the area of Busia District for Sugar Cane Development, 1975(Ministry of Agriculture, 1975) Mbuvi, J.P.; Ministry of AgricultureBusia is one of the districts in the Western Province of Kenya bordering Uganda and stretching southwards to L. Victoria (see fig. 1). It covers an area of 1629 sq. km. and a population of 174.2 thousand (1969 census). The majority of the inhabitants are Luhyas and Teso. Communication in the district as revealed in fig. J is mainly by road. The only tarmac roads are those from Kisumu to Busia and from Bungoma to Tororo. The railway to Tororo in Uganda passes through the northern part of the district through Kalaba. The road from Mumias to Busia through Nambale is impassable during the rainy season because of unstable surface. In order to direct attention to possible sites for sugar cane development a prior examination of several factors including climate, natural water resources, accessability, centrality of the site and soil quality were considered. Only the Sio and Walatsi rivers are conveniently situated to facilitate a sugar cane development which may command a large area of land within Busia District. Moreover, the rainfall (see the data in brackets in fig. 1) in the area bordering these two rivers seems to be the best for the District. The area indicated in fig. 2 was therefore selected for field study.Item SOILS OF THE KINDARUMA AREA (Quarter Degree Sheet 136)(Kenya Agricultural Research Institute, 1975) van de Weg, R.F.; Mbuvi, J.P.; Kenya Agricultural Research Institute; Kenya Agricultural Research InstituteThe present soil survey is the first in a series of "reconnaissance soil surveys", with a multi-purpose land evaluation. A programme of systematic inventory of the soil and land resources of the country was initiated by the Kenya Soil Survey in 1972, after strengthening with manpower and funds from the Netherlands Directorate for Development Co-operation through the "Kenya Soil Survey Project", of the then Soil Survey Unit of the National Agricultural Laboratories in Nairobi. This long-term programme envisages the mapping of the so-called "high potential" areas and most of the "medium potential" areas of the country at scale 1:100,000, and of the "low potential" areas at scale 1:250,000 (see Fig. 1). Reconnaissance soil maps and the associated multi-purpose land evaluation form the logical basis for the selection, by planning officers at both National, Provincial and District level, of areas to be developed for one or another specific type of land use. Once such areas and their preferred land use are identified, then these parts of the survey area may be covered by more detailed soil surveys, accompanied with a land evaluation in more quantitative terms, for that particular land use. At the chosen scale, the reconnaissance soil survey can however also be used as a first basis for location and extension of trials on soil fertilizing, and the programming of soil conservation and soil management in general. It can also be taken as starting point for the estimation of actual and potential human carrying capacity in the area, on the notion of sustained preservation of its soil and land resources. The comprehensive character of the land evaluation on the basis of reconnaissance soil surveys implies that not only the soils themselves are studied and mapped, but also the topography, the climate conditions, the vegetative cover, the present land use, and the soil erosion incidence and hazards. Concurrently and in association with agro-economists and the potential users, an identification and characterization is provided of the relevant land utilization types, ie. the physically possible and socially (and economically) promising forms of land use. It is shown in this report that land resources in the Kindaruma area are limited. There is little scope for opening up new land for agriculture. One of the most limiting factors in this respect is climate, the scarce and unreliable rainfall is a major constraint for most of the land use alternatives. The development of the land potentialities will have mainly to come from improvement of the existing types of land use, to be obtained by a gradual improvement of land use techniques, measures of soil conservation and grazing control. Being the first of the series, the report gives an ample description and discussion of the methods employed. Part of these methods are liable to be improved upon as more experience with this type of survey and land evaluation is being gathered, and the needs of the users of the map and data become better known. Suggestions to this effect are therefore whole heartedly invited.Item Some Preliminary Notes On the Soil Of Katumani Kampi Ya mawe Embu And Murinduko Agricultural Research Stations(Ministry Of Agriculture, 1975) ; Van de Weg, R.F. ; Mbuvi, J.P.Visits were paid to Katumani, Embu and Murinduko Stations with the aim of comparing the soils of these research stations in the Eastern Province with those of Kindaruma area (sheet 136+) and to assess how far the trial results from the stations are applicable to aforementioned surveyed area. During the visits several pits and augerholes were described and sampled for analysis.
