Bio

Prof. Kironchi Bio

He is a Senior lecturer in Soil Science specializing in Ecohydrology and Water Resource Management in the Department of Land Resource Management and Agricultural Technology. He holds a PhD in Soil Science, a Masters in Soil Science, and B.Sc. degree in Range Management from the University of Nairobi, Kenya. He has published widely in his area of specialty.

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Publications


2013

Mulebekea, R, Kironchi G, Tenywa MM.  2013.  Soil moisture dynamics under different tillage practices in cassava–sorghum based cropping systems in eastern Uganda. Abstract

Soil moisture storage in the root zone determines availability of water in crop production, but there is limited attention on water resource management in cassava–sorghum production systems. Soil moisture content was higher under ripping than mouldboard ploughing. Mouldboard ploughed plots had more moisture in the upper (0–10 cm) layer while, the ripped plots accumulated more moisture in the lower (20–40 cm) root zone. Soil surface roughness was stable two months after ploughing. Crop combinations and seasons influenced soil moisture storage over the growing period. The different cropping systems vary in their soil moisture extraction capacities at different growth stages, hence influencing the overall moisture storage and water used in the root zone.

2012

Karuku, GN, Gachene CKK, Karanja N, Cornelis W, Verplancke H.  2012.  Soil hydraulic properties of a nitisol in Kabete, Kenya. AbstractWebsite

Water relations are among the most important physical phenomena that affect the use of soils for agricultural, ecological, environmental, and engineering purposes. To formulate soil-water relationships, soil hydraulic properties are required as essential inputs. The most important hydraulic properties are the soil-water retention curve and the hydraulic conductivity. The objective of this study was to determine the soil hydraulic properties of a Nitisol, at Kabete Campus Field Station. Use of an internal drainage procedure to characterize the hydraulic properties and soil and water retention curves allowed for the establishment of the moisture and matric potential at field capacity and permanent wilting point. The Bt2 (84 -115) and Bt3 (115 - 143 cm) had the highest clay contents of 619 compared to Ap, AB and Bt1 horizons. The PWP was attained at soil moisture contents of 0.223, 0.284, 0277, 0.307 and 0.314 m3m-3 in the Ap, AB, Bt1, Bt2, and Bt3 horizons, respectively. Horizontal saturated hydraulic conductivity (Ksat) was high at 6.0 cm hr-1 in Ap horizon and decreased to 0.4 cm hr-1 in the subsurface horizon (Bt3). Ksat in the vertical direction was higher than horizontal and ranged from 8.3 cm hr-1 in surface layer to 0.6 cm hr-1 in Bt3 horizon, with exception of Bt1 and Bt2 where horizontal Ksat was greater than vertical. The Ap horizon also had the highest crop extractable water. Though the AB and Bt1 had the same water content at low matric suction, the variation was very wide as the SWRC approached saturation point. Bt1 and Bt2 also had similar water contents at suction range of – 7kPa after which Bt1, tended towards Bt3. Bt3 had the narrowest range of crop extractable water and thus was attributed to texture. The Bt3 retained the most amount of water at 0.314 m3m-3concluding that θPWP increased with depth. The total available water capacity between FC and PWP in the profile was 79.2 mm m-1. The study observed that the field capacity, crop available water contents and hydraulic conductivities were influenced positively by soil organic matter. The Van Genuchten parameters of air entry value (α) and pore size distribution (n) indicated that pore size distribution was not even in the AP and AB horizons. The field capacity was attained at higher matric potential at -5kPa for Bt1 while Bt2 and AP, AB, Bt2 and Bt3 was at -10kPa.The functional relationship, K(θ) = aθb that deals with water redistribution as a result of soil hydraulic properties and evaporative demand of the atmosphere was highly correlated to soil moisture content and texture with R2 values > 0.85.

Mwangi, DM, Miriti JM, Heng LK, Esilaba AO, Gachene CKK.  2012.  Yield and water use efficiencies of maize and cowpea as affected by tillage and cropping systems in semi-arid Eastern Kenya. AbstractWebsite

Soil water conservation through tillage is widely accepted as one of the ways of improving crop yields in rainfed agriculture. Field experiments were conducted between 2007 and 2009 to evaluate the effects of conservation tillage on the yields and crop water use efficiency of maize (Zea mays L.) and cowpea (Vigna unguiculata L.) in eastern Kenya. Experimental treatments were a combination of three tillage practices and four cropping systems. Tillage practices were tied-ridges, subsoiling-ripping and ox-ploughing. The cropping systems were single crop maize, single crop cowpea, intercropped maize–cowpea and single crop maize with manure. The treatments were arranged in split plots with tillage practices as the main plots and cropping systems as the sub-plots in a Randomized Complete Block Design (RCBD). The results showed that tied-ridge tillage had the greatest plant available water content while subsoiling-ripping tillage had the least in all seasons. Averaged across seasons and cropping season, tillage did not have a significant effects on maize grain yield but it did have a significant effect on crop grain and dry matter water use efficiency (WUE). Nevertheless, maize grain yields and WUE values were generally greater under tied-ridge tillage than under subsoiling-ripping and ox-plough tillages. The yields and WUE of cowpea under subsoiling-ripping tillage were less than those of ox-plough tillage. When averaged across the seasons and tillage systems, the cropping system with the manure treatment increased (P ≤ 0.05) maize grain yield, grain WUE and dry matter WUE by 36%, 30%, 26% respectively, compared to treatments without manure. Maize and cowpea when intercropped under ox-plough and ripping tillage systems did not have any yield advantage over the single crop.Highlights ► We studied crop yield and water use efficiencies of maize and cowpea under different tillage practices in semi-arid Kenya. ► Plant available water was highest in tied ridges, followed by ox-ploughing and least in the ripping tillage system. ► Tillage did not have significant effects on maize grain yield and but it had on crop water use efficiency. ► Cowpea yielded less under ripping than ox-ploughing. ► Maize yield was reduced by intercropping but was improved by manure application.

MORAA, DRONYANGOCECILIA, ONWONGA DRRICHARDNDEMO, P PROFMBUVIJOSEPH, GEOFFREY DRKIRONCHI.  2012.  Climate Change and Variability: Farmers. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society Abstract
Aim of the study: This study was conducted to document herbal medicines used in the treatment of Malaria as well as the existing knowledge,attitudes and practices related to malaria recognition, control and treatment in South Coast, Kenya. Methods: Data was collected using semistructured questionnaires and interviews. A focused group discussion held with the community members, one in each of the study villages supplemented the interview and questionnaire survey. Results: The respondents were found to have a good understanding of malaria and could distinguish it from other fever types. They were also aware that malaria was spread by mosquitoes. Malaria prevalence was high, and affected individuals an average of four times a year. Community members avoided. Mosquito bites by using mosquitonets, clearing bushes around their homesteads and burning plant parts. To generate smoke. They prevented and treated malaria by taking decoctions or concoctions of traditional herbal remedies. Forty plant species in thirty-five genera distributed in twenty-four families were used as antimalarials in the study area. Five plant species, namely; Heeria insignis Del. (Anacardiaceae), Rottboelia exaltata L.F (Gramineae), Pentanisia ouranogyne S. Moore (Rubiaceae), Agathisanthenum globosum (A. Rich) Hiern (Rubiaceae), and Grewia trichocarpa Hochst ex A. Rich (Tiliaceae) are documented for the first time in South Coast, Kenya, for the treatment of malaria. Conclusions: The plants documented in the current study are a potential source for new bioactive compounds of therapeutic value in malaria treatment. The results provide data for further pharmacological and toxicological studies and development of commercial antimalarial phytotherapy products.

2011

Mpairwe, D, Zziwa E, Isabirye B, Mugerwa. S.  2011.  Soil degradation following land use and cover change in the rangelands of Uganda. Website

2010

Njiru, EN;, Kironchi, G; Mbuvi NJP; S, Kironchi G;, Mbuvi JP;, Nguluu S.  2010.  Analysis of climate data and the associated risks to maize production in Semi-Arid Eastern Kenya.
Kironchi, G;, Bagine RK;, Maranga EK.  2010.  Integrated natural resource management. Website

2006

GEOFFREY, DRKIRONCHI.  2006.  Strengthening Agricultural and Environmental Capacities through Distance Education and Locally Relevant Research: Proceedings of the Pan Commonwealth Forum of Distance Education, Ocho Rios, Jamaica, 2006.. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society Abstract
Aim of the study: This study was conducted to document herbal medicines used in the treatment of Malaria as well as the existing knowledge,attitudes and practices related to malaria recognition, control and treatment in South Coast, Kenya. Methods: Data was collected using semistructured questionnaires and interviews. A focused group discussion held with the community members, one in each of the study villages supplemented the interview and questionnaire survey. Results: The respondents were found to have a good understanding of malaria and could distinguish it from other fever types. They were also aware that malaria was spread by mosquitoes. Malaria prevalence was high, and affected individuals an average of four times a year. Community members avoided. Mosquito bites by using mosquitonets, clearing bushes around their homesteads and burning plant parts. To generate smoke. They prevented and treated malaria by taking decoctions or concoctions of traditional herbal remedies. Forty plant species in thirty-five genera distributed in twenty-four families were used as antimalarials in the study area. Five plant species, namely; Heeria insignis Del. (Anacardiaceae), Rottboelia exaltata L.F (Gramineae), Pentanisia ouranogyne S. Moore (Rubiaceae), Agathisanthenum globosum (A. Rich) Hiern (Rubiaceae), and Grewia trichocarpa Hochst ex A. Rich (Tiliaceae) are documented for the first time in South Coast, Kenya, for the treatment of malaria. Conclusions: The plants documented in the current study are a potential source for new bioactive compounds of therapeutic value in malaria treatment. The results provide data for further pharmacological and toxicological studies and development of commercial antimalarial phytotherapy products.

2005

Mugendi, D;, Kironchi G;, Gicheru PT;, Gachene CKK;, Macharia PN;, Mburu M;, Mureithi, J; Maina F, Maina F.  2005.  Modelling soil organic matter dynamics in the Kabete long-term experiment in Kenya. Abstract

In order to meet the challenges of increasing food production, many agricultural production technologies are being developed and recommended for use by the small- scale fanners who are also the main agricultural producers in sub-Saharan Africa. Whereas some ofthe technologies seem promising in the short-term, their long-term effects on soil productive properties are largely unknown. Soil organic carbon which is closely related to soil productivity has been used to measure the impact caused by the application of external inputs to soils since it is known to respond to such changes. However changes in soil organic carbon caused by the applied inputs are slow, often taking several decades to emerge. Therefore simulation models have been used to predict the likely long¬tenn changes in soil organic carbon, hence soil productivity, as a result to continuous application of external inputs to soils. The work reported here evaluates the applicability of ROTH C-26.3, the current version of the Rothamsted carbon model, to simulate the turnover of soil organic matter in soil under tropical conditions using soil organic carbon concentrations from the Kabete long-term trial measured 22 yrs after the start of the experiments. Measured and Long-term field experiments offer the best modeIled soil organic carbon were closely practical means of monitoring and correlated showing the applicability of the understanding the changes caused by model to simulate soil organic matter different agricultural systems, since these turnover in the tropical soil. The results show changes are slow, often taking many years that even the continuous application of to appear (Powlson et al., 1987; Poulton, inorganic fertilizer alone failed to stop the 1996). The Kabete long-term experiment in decline in soil C. When crop residues were Kenya has now run for long enough to yield returned, decline was slowed. However the useful information on the effects of inorganic only treatments able to stop the decline involved large additions of animal manure. The model predicts a lengthy and difficult amelioration process for degraded soils that have received no organic inputs particularly in the smallholder farms where only small amounts of organic resources are available to restore soil organic matter back to agronomically viable levels. Howeverthe use of Farmyard manure alone or in combination with inorganic fertilizer wi111ead to higher equilibrium C concentrations than the initial amount of soil organic C at the start of the trials.

Kironchi, G;, Gicheru PT;, Gachene CKK;, Macharia PN;, Mburu M;, Mureithi JG;, Maina F.  2005.  Kironchi,. Abstract

Effect of liming and application of phosphatic fertilizer on growth and root nodulation of common bean in an old tea land was investigated. A field trial was conducted where tea had been uprooted after 70 years of monoculture under high inorganic fertilizer input. Lime was applied at 0, 4, 8 and 12 tonnes ha-1 and triple superphosphate at 0, 5, 10 and 15 g per planting hole. The treatments were combined in a factorial design and investigated for effects on the soil pH, nodule formation, and some plant growth parameters. Lime application raised the soil pH and also significantly (P= 0.05) increased dry matter production and nodule quantity. Phosphorus also increased dry matter production and nodule quantity significantly (P = 0.05). These observations are discussed in regard to ways of enabling bean crop grow on old tea lands

GEOFFREY, DRKIRONCHI.  2005.  Mugendi, D.N., G.Kironchi, and P.T. Gicheru. 2005 (Eds). Capacity building for land resource management to meet the challenges of food security in Africa. Proceedings of the 21st Conference of the Soil Science Society of East Africa.. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society Abstract
Aim of the study: This study was conducted to document herbal medicines used in the treatment of Malaria as well as the existing knowledge,attitudes and practices related to malaria recognition, control and treatment in South Coast, Kenya. Methods: Data was collected using semistructured questionnaires and interviews. A focused group discussion held with the community members, one in each of the study villages supplemented the interview and questionnaire survey. Results: The respondents were found to have a good understanding of malaria and could distinguish it from other fever types. They were also aware that malaria was spread by mosquitoes. Malaria prevalence was high, and affected individuals an average of four times a year. Community members avoided. Mosquito bites by using mosquitonets, clearing bushes around their homesteads and burning plant parts. To generate smoke. They prevented and treated malaria by taking decoctions or concoctions of traditional herbal remedies. Forty plant species in thirty-five genera distributed in twenty-four families were used as antimalarials in the study area. Five plant species, namely; Heeria insignis Del. (Anacardiaceae), Rottboelia exaltata L.F (Gramineae), Pentanisia ouranogyne S. Moore (Rubiaceae), Agathisanthenum globosum (A. Rich) Hiern (Rubiaceae), and Grewia trichocarpa Hochst ex A. Rich (Tiliaceae) are documented for the first time in South Coast, Kenya, for the treatment of malaria. Conclusions: The plants documented in the current study are a potential source for new bioactive compounds of therapeutic value in malaria treatment. The results provide data for further pharmacological and toxicological studies and development of commercial antimalarial phytotherapy products.

2003

Shivonje, FM;, Okwach GM;, Kironchi G.  2003.  Soil crust formation as affected by slope gradient on clay soils of semi-arid Machakos District, Kenya. Abstract

Surface crusts formed by impact of raindrop restrict water infiltration into soil. The decrease in infiltration not only leads to an mcrease in surface flow and accelerated erosion, but also to reduced available water to plants. Upon drying the surface crust may impede plant emergence and growth, thereby reducing yield. This study was carried out with the aim of assessing the effect of slope gradient on crust properties with a view of developing elationships between crust formation and slope gradient when soil is subjected to natural rainfall. A surface of the top horizon (Ap) of a chromic Luvisol was exposed to rainfall at four slope gradients (1 %, 10%,20% and 30%) for two rain seasons. Crust thickness, crust strength and crust conductance were measured under various cumulative rainfall amounts. Thick and strong crusts were observed at the soil surface after the first rainfall event. Crust thickness and strength were significantly different (PO .05) between slope gradients, with crust formation being more pronounced at lower slop gradients (1% and 10 %) compared to higheI slope gradients (20% and 30%). Both crust thickness and strength followed a similar trend; as cumulative rainfall increased, they showed a slight increase after 2-3 storms, followed by a gradual decline as rainfall increased. Crust conductance was reduced by between 60% and 80% after the first ramfall event, and increased thereafter as the surface crust continued to decay with rainfall increase. Crust conductance was more strongly correlated to crust thickness (r

2002

GEOFFREY, DRKIRONCHI.  2002.  Gebremichael, M., G. Kironchi, D.M. Nyariki and E.K. Biamah, E.K. 2002. Soil and water conservation. p. 83-93. In: Managing Dryland Resource in Eastern and Southern Africa, International Institute of Rural Reconstruction (IIRR), Nairobi, Kenya.. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society Abstract
This book provides an overview of selected problems and issues in dryland agriculture in eartern and southern Africa, and the various attempts by individuals, communities and development organizations to overcome these problems. It provides specific examples of technologies and approaches, as well as selected experiences of individual farmers, organizations and communities

2001

Kironchi, G, Nyariki DM;, Ogara WO;.  2001.  Food Security In Rural Development. Website
GEOFFREY, DRKIRONCHI.  2001.  Ogara, W.O., D.M. Nyariki and G. Kironchi. 2001 (Eds). Food Security in Rural Development. Proceedings of the Seminar of Berlin Alumni Network, November 22-24, 2000, Nairobi, Kenya. ISBN 3-823613472. pp. 119. www.ban.fu-berlin.de. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society Abstract
This book provides an overview of selected problems and issues in dryland agriculture in eartern and southern Africa, and the various attempts by individuals, communities and development organizations to overcome these problems. It provides specific examples of technologies and approaches, as well as selected experiences of individual farmers, organizations and communities

2000

GEOFFREY, DRKIRONCHI.  2000.  Kironchi, G., H.P. Liniger and J.P. Mbuvi. 2000. Degradation of soil physical properties of overgrazed rangelands in Laikipia District. p. 5-10. In: Gichuki. F.N., D.N. Mungai C.K. Gachene and D.B. Thomas (eds). Land and Water Management in Kenya. English. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society Abstract
Infiltration rate, bulk density, saturated hydraulic conductivity, organic carbon content, particle size distribution and water content, for bush cover, grass cover and bare ground sites within four representative soil types of the overgrazed Mukogodo rangelands were assessed. All properties, except particle size distribution, differed significantly among soil cover types consistently, but rarely among soil types. Surface soil properties differed more often than those of the sub-surface layers. The infiltration rates of grass and bush cover sites were three to four times higher than bare ground. Consistently, bare-ground surface soils retained significantly less water than vegetated sites and also held the least amount of plant-available water. The results indicate that depletion of soil cover due to overgrazing has adversely affected the soil physical properties important for soil water intake, storage and availability to plants

1999

GEOFFREY, DRKIRONCHI.  1999.  Kironchi, G., J.P. Mbuvi, and F.N. Gichuki. 1999. Hydraulic properties of andosols following deforestation in the northern slopes of Mt. Kenya. East Africa Agricultural and Forestry Journal, Volume 65(2): 115-124.. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society Abstract
Deterioration in soil hydraulic properties due to deforestation adversely affects the hydrology of catchments, especially those on mountain slopes. The effects of clearing natural forest (NF) for potato cultivation (PC) and livestock grazing (GL) on the hydraulic properties of an andosol (after 5 to 8 years) were investigated in the northern slopes of Mount Kenya. The two farming activities have resulted in deleterious changes in soil water flow and storage. Results obtained showed that steady infiltration rates were 65.7, 9.7 and 13.4 cm h-1 in NF, PC and GL, respectively. Sorpitivity decreased by 15% in PC and 22% in GL, while topsoil saturated hydraulic conductivity decreased by 62% in PC and 76% in GL compared to NF. Both PC and GL topsoil had higher volumetric water content at soil matric potentials (<-25cm) than NF. Cultivation and grazing in the area have led to compacted topsoil with lower (11%) total porosity and decreased plant available water holding capacity by 16 in PC and 19% in GL

1998

1997

GEOFFREY, DRKIRONCHI.  1997.  Mbuvi, J.P., G. Kironchi and P.M. Mainga. 1997. Effect of topography and climate on soils of the northwestern slopes of Mount Kenya. ITC Journal, 1997 (2): 154-159.. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society
GEOFFREY, DRKIRONCHI.  1997.  Matuva, D, G. Kironchi and L. MacOpiyo. 1997. Environmental impact assessment for swamps drainage in Laikipia District. Technical Report. ASAL Programme, Laikipia District. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society

1996

GEOFFREY, DRKIRONCHI.  1996.  Kironchi, G. and J.P. Mbuvi. 1996. Effect of deforestation on soil fertility on the northwestern slopes of Mount Kenya. ITC Journal, 1996 (3/4): 260-263.. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society

1995

GEOFFREY, DRKIRONCHI.  1995.  Kironchi, G., S.M. Kinyali and J.P. Mbuvi. 1995. Environmental influence on water characteristics of soils in two semi-arid catchments in Laikipia District, Kenya. African Crop Science Journal, 3 (4): 417-424.. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society Abstract
Physical and chemical properties of soil surface crusts formed on overgrazed bare ground, in Mukogodo catchment in Kenya were investigated. These were compared with those of underlying soils and of adjacent grass and bush covered topsoils. Crusting effects on infiltration, hydraulic conductivity and water content were also investigated. The crusts were moderately strong to strong with a thickness of 1-5 mm. Crusts had higher amounts of sand, silt and clay than the underlying layer, while their total N was lower and organic C content higher than the underlying layer. On average, the contents of Ca, Mg and Na were higher in the crusts than in the underlying layers. Similarly, soil pH, EC and ESP were higher in the crusts than in the underlying layer. Cation exchange capacity and K were slightly higher in the underlying layer than in the crusts. Infiltration, hydraulic conductivity and soil water content in both the rainy and dry seasons in bare ground were significantly lower than those of the bush and grass covered topsoils. Bare ground surface soil bulk density was higher compared to vegetated topsoils and subsurface layers
GEOFFREY, DRKIRONCHI.  1995.  Mbuvi, J.P, S.N. Wanjogu and G. Kironchi. 1995. Characteristics of soil crusts and their influence on some soil properties in Mukogodo catchment, Kenya. African Crop Science Journal, 3 (4): 425-431.. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society Abstract
Physical and chemical properties of soil surface crusts formed on overgrazed bare ground, in Mukogodo catchment in Kenya were investigated. These were compared with those of underlying soils and of adjacent grass and bush covered topsoils. Crusting effects on infiltration, hydraulic conductivity and water content were also investigated. The crusts were moderately strong to strong with a thickness of 1-5 mm. Crusts had higher amounts of sand, silt and clay than the underlying layer, while their total N was lower and organic C content higher than the underlying layer. On average, the contents of Ca, Mg and Na were higher in the crusts than in the underlying layers. Similarly, soil pH, EC and ESP were higher in the crusts than in the underlying layer. Cation exchange capacity and K were slightly higher in the underlying layer than in the crusts. Infiltration, hydraulic conductivity and soil water content in both the rainy and dry seasons in bare ground were significantly lower than those of the bush and grass covered topsoils. Bare ground surface soil bulk density was higher compared to vegetated topsoils and subsurface layers

1994

GEOFFREY, DRKIRONCHI.  1994.  Mbuvi, J.P and G. Kironchi. 1994. Reconnaissance soil survey of the Upper Ewaso Ng'iro Basin. Laikipia-Mt. Kenya Papers, Baseline Data Series, B-8.. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society Abstract
Physical and chemical properties of soil surface crusts formed on overgrazed bare ground, in Mukogodo catchment in Kenya were investigated. These were compared with those of underlying soils and of adjacent grass and bush covered topsoils. Crusting effects on infiltration, hydraulic conductivity and water content were also investigated. The crusts were moderately strong to strong with a thickness of 1-5 mm. Crusts had higher amounts of sand, silt and clay than the underlying layer, while their total N was lower and organic C content higher than the underlying layer. On average, the contents of Ca, Mg and Na were higher in the crusts than in the underlying layers. Similarly, soil pH, EC and ESP were higher in the crusts than in the underlying layer. Cation exchange capacity and K were slightly higher in the underlying layer than in the crusts. Infiltration, hydraulic conductivity and soil water content in both the rainy and dry seasons in bare ground were significantly lower than those of the bush and grass covered topsoils. Bare ground surface soil bulk density was higher compared to vegetated topsoils and subsurface layers

1993

Liniger, H;, Mbuvi JP;, Kironchi G.  1993.  The need to protect Mt. Kenya area soils with permanent cover..
Kironchi, G, Ondieki C, Liniger HP.  1993.  Soil cover for improved productivity: attractive water and soil conservation for the drylands in Kenya.. Abstract

The importance of soil cover and topsoil management for soil and water conservation was studied in catchment and test plot studies and infiltration trials in the west and north of Mount Kenya. The short-term improvement of productivity through specific biological and management measures is discussed along with aspects of long-term sustainable development for implementation programmes. Results show that permanent grass cover (50%) reduced catchment runoff rates to less than one third and erosion rates to less than one in thirty of that from an overgrazed area with a cover of less than 10%. Infiltration on different soil types increased 3-12 times under permanent cover compared to that under overgrazed land. Monitoring of cropland productivity under different conservation measures illustrated the potential of mulching/minimum tillage and agroforestry systems to double yields with no additional input, compared to local practices

GEOFFREY, DRKIRONCHI.  1993.  Kironchi, G., S.M. Kinyali and J.P. Mbuvi. 1993. Validity of Philip equation for infiltration into soils of Sirima and Mukogodo catchments in Laikipia District. East Africa Agricultural and Forestry Journal, 58(4): 155-160.. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society Abstract
The capability of the two-parameter Phiip equation to describe infiltration of water into soils of the semi-arid Sirima and Mukogodo catchments in Laikipia District was investigated. Field measurements of infiltration during dry and wet seasons were taken using a double cylinder infiltrometer on plots under four landuse/vegetation cover treatments within different soil types surveyed at detail level. The four treatments were: (i) tree/bush, (ii) open grass, (iii) bare ground, and (iv) cultivation. The infiltration rates predicted by the Philip equation after 180 minutes in the dry and the wet seasons for Mukogodo and the wet season for Sirima agreed with observed infiltration rates. However, the fit of the equation was inadequate in the early stages of infiltration in both areas and seasons. Equation parameters obtained by best fit of observed data significantly differed between the landuse /vegetation cover treatments and soil types within each area. Only Sirima soils yielded significantly different parameters in-between seasons

1992

GEOFFREY, DRKIRONCHI.  1992.  Kironchi, G., S.M. Kinyali and J.P. Mbuvi. 1992. Effect of soils, vegetation and land use on infiltration in a tropical semi-arid catchment. East Africa Agricultural and Forestry Journal, 57(3): 177-185.. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society Abstract
The capability of the two-parameter Phiip equation to describe infiltration of water into soils of the semi-arid Sirima and Mukogodo catchments in Laikipia District was investigated. Field measurements of infiltration during dry and wet seasons were taken using a double cylinder infiltrometer on plots under four landuse/vegetation cover treatments within different soil types surveyed at detail level. The four treatments were: (i) tree/bush, (ii) open grass, (iii) bare ground, and (iv) cultivation. The infiltration rates predicted by the Philip equation after 180 minutes in the dry and the wet seasons for Mukogodo and the wet season for Sirima agreed with observed infiltration rates. However, the fit of the equation was inadequate in the early stages of infiltration in both areas and seasons. Equation parameters obtained by best fit of observed data significantly differed between the landuse /vegetation cover treatments and soil types within each area. Only Sirima soils yielded significantly different parameters in-between seasons

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