Currently a Professor in Soil Science, Dept of Land Resource Management & Agricultural Technology (LARMAT), served as the Chairman of Dept of Soil Sc and also first Chairman, Dept of LARMAT. A specialist in soil and water management. Has over 150 publications of which 99 are in refereed journals, 42 published book chapters, 18 conference papers in refereed proceedings, 30 proceeding papers, 5 manuals and several soil survey advisory reports. Has supervised 36 MSc and 24 PhD students to completion, 12 of whom are teaching in public universities.



Nguru, WM, Gachene CKK, Onyango CM, Ng’ang’a SK, Girvetz EH.  2021.  Factors constraining the adoption of Soil Organic Carbon Enhancing Technologies among small-scale farmers in Ethiopia.
Nyawade, SO, Gitari HI, Karanja NN, Gachene CKK, Schulte-Geldermann E, Parker ML.  2021.  Yield and evapotranspiration characteristics of potato-legume intercropping simulated using a dual coefficient approach in a tropical highland.
Mugo, N, Nancy N. Karanja, Gachene CN, Klaus Dittert, Harun I. Gitari, E. S-G.  2021.   Response of potato crop to selected nutrients in central and eastern highlands of Kenya. . Cogent Food & Agriculture. . 7(1):1898762...


Mugo, JN, Karanja NN, Gachene CK, Klaus Dittert, Nyawade SO, Schulte-Geldermann E.  2020.  Assessment of soil fertility and potato crop nutrient status in central and eastern highlands of Kenya.
Nyawade, S, Gitari HI, Karanja NN, Gachene CKK, Schulte-Geldermann E, Sharma K, Parker ML.  2020.  Enhancing Climate Resilience of Rain-Fed Potato Through Legume Intercropping and Silicon Application.
Nyawade, SO, Karanja NN, Gachene CKK, Gitari HI, Schulte-Geldermann E, Parker M.  2020.  Optimizing soil nitrogen balance in a potato cropping system through legume intercropping.
Gitari, HI, Nyawade SO, Kamau S, Karanja NN, Gachene CKK, Raza MA, Maitra S, Schulte-Geldermann E.  2020.  Revisiting intercropping indices with respect to potato-legume intercropping systems.
James. N. Mugo, Nancy N. Karanja, Gachene CS, Klaus Dittert, Nyawade SO, Schulte-Geldermann E.  2020.  Assessment of soil fertility and potato crop nutrient status in Central and Eastern Highlands of Kenya.. Nature research.
S.Senda, T, Lance W. Robinson, K.K.Gachene C, Kironchi G, Doyo J.  2020.  An assessment of the implications of alternative scales of communal land tenure formalization in pastoral systems. Land use Policy. 94


Nyawade, SO, Karanja NN, Gachene CKK, Gitari HI, Schulte-Geldermann E, Parker ML.  2019.  Intercropping Optimizes Soil Temperature and Increases Crop Water Productivity and Radiation Use Efficiency of Rainfed Potato.
Nyawade, SO, Karanja NN, Gachene CKK, Gitari HI, Schulte-Geldermann E, Parker ML.  2019.  Short-term dynamics of soil organic matter fractions and microbial activity in smallholder potato-legume intercropping systems.
Gitari, HI, Shadrack N, Kamau S, Karanja NN, Gachene CKK, Schulte-Geldermann E.  2019.  Agronomic assessment of phosphorus efficacy for potato (Solanum tuberosum L) under legume intercrops.
Gitari, HI, Nyawade SO, Kamau S, Gachene CKK, Karanja NN, Schulte-Geldermann E.  2019.  Increasing potato equivalent yield increases returns to investment under potato-legume intercropping systems.
Gitari, HI, Gachene CKK, Karanja NN, Kamau S, Nyawade S, Schulte-Geldermann E.  2019.  Potato-legume intercropping on a sloping terrain and its effects on soil physico-chemical properties.
Gitari, HI, Gachene CKK, Karanja NN, Kamau S, Nyawade S, Schulte-Geldermann E.  2019.  Potato-legume intercropping on a sloping terrain and its effects on soil physico-chemical properties.
Nyawade, SO, Gachene CKK, Karanja NN, Gitari HI, Schulte-Geldermann E, Parker ML.  2019.  Controlling soil erosion in smallholder potato farming systems using legume intercrops.



Ombega, NJ, S. M. Mureithi, O. K. Koech, Karuma AN, Gachene CKK.  2017.  Effect of rangeland rehabilitation on the herbaceous species composition and diversity in Suswa catchment, Narok County, Kenya. Ecological Processes.



Mureithi, SM, Verdoodt A, Njoka JT, Gachene CKK, Gachene CKK, Warinwa F, Ranst EV.  2014.  Impact of Community Conservation Management on Herbaceous Layer and Soil Nutrients in a Kenyan Semi‐Arid Savannah. Land Degradation and Development.
Mureithi, SM, Verdoodt A, Njoka JT, Gachene CKK, Ranst EV.  2014.  Benefits Derived from Rehabilitating a Degraded Semi‐Arid Rangeland in Communal Enclosures, Kenya. Land Degradation and Development.


Eunice, G, Gachene CKK, Jesse TN, Omondi SM.  2013.  Nitrogen Fixation by Natural Populations of Acacia Senegal in the Drylands of Kenya Using 15N Natural Abundance. Abstract

Nitrogen (N) fixation was estimated for three Acacia senegal (L.) (A. senegal) Willd. varieties (A. senegal var. senegal, kerensis, and leiorhachis) growing naturally in different sites in the dryland areas of Kenya. The quantities of N2 fixed were estimated by the 15N natural abundance method, using leaves as the sampling material. Balanites aegyptiaca (B. aegyptiaca) was selected as the reference species growing in the same area. Soil samples were also collected under A. senegal trees for nodule assessment. Leaf 15N natural abundance values (δ15N) were significantly different between A. senegal and B. aegyptiaca. These values averaged 6.35, 4.67, and 3.03% for A. senegal var. kerensis, leiorhachis, and senegal, respectively, and were lower than those of the adjacent reference species. There were also significant differences in the amount of N2 fixed (%Ndfa) among the varieties. A. senegal var. senegal showed the highest levels of N2 fixation with a mean of 36% while A. senegal var. kerensis and leiorhachis had equal estimates of 25%. However, no nodules were observed in the collected soil samples. Leaf N values were significantly different among the varieties with a mean of 2.73, 2.46, and 4.03% for A. senegal var. kerensis, leiorhachis, and senegal, respectively. This study shows that the three varieties of A. senegal are able to fix N2 in their natural ecosystems and the differences could probably be due to soil properties and nutrient availability under the different environments. The species can hence be utilized as plantations in agriculture and land rehabilitation programs.


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

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.


Githae, EW;, Gachene CKK;, Njoka JT;, Odee DW;, Omondi SF.  2011.  Genefic Diversity of Gum Arabic-producing Acacia senegal Variefies in Kenya using Inter-Simple Sequence Repeat (ISSR) and Chloroplast Simple Sequence. Abstract

Acacia senegal is a drought-tolerant, multi-purpose tree species, highly valued for gum arabic production and increasingly being used in agro-forestry in Sub-Saharan Africa. Despite its long history of use, there has not been exhaustive genetic evaluation of the extant genetic resource base of A. senegal in Kenya for genetic improvement of the species. Inter-simple sequence repeat (ISSR) and chloroplast microsatellite (cpSSR) markers were used to study genetic diversity among seven Kenyan populations of A. senegal embracing three putative varieties: kerensis, leiorhachis and senegal. The two marker types detected similar levels of Nei’s gene diversity (HISSR = 0.211, HcpSSR = 0.212) among the A. senegal populations. Acacia senegal var. kerensis exhibited the highest diversity using ISSR markers (HISSR = 0.248), followed by varieties leiorhachis (HISSR = 0.218) and senegal (HISSR = 0.151). Analysis of molecular variance (AMOVA) detected significant genetic variations within and among populations (P < 0.001 and P < 0.01 for ISSR and cpSSR, respectively). Based on the unweighted pair group method with arithmetic mean (UPGMA) dendrogram of the seven populations, two regions were differentiated (north and south). Both markers demonstrated their potential for delineating population structure at local and regional levels, and infra-specific relations within the species, hence their potential as tools for conservation, improvement programmes and sustainable use of the species. This study provides baseline genetic information for the domestication of A. senegal varieties in Kenya.

Macharia, PN;, Gachene CKK;, Mureithi JG;, Kinyamario JI;, Ekaya WN;, Thuranira EG.  2011.  The effect of introduced forage legumes on improvement of soil fertility in natural pastures of semi-arid rangelands of Kajiado District, Kenya. Abstract

A two phase study was carried out from 2002 to 2005 in the semi-arid rangelands of Kajiado District, Kenya to determine the effect of introduced forage legumes on soil fertility improvement of natural pastures. During legume evaluation phase, Neonotonia wightii (Glycine), Macroptilium atropurpureum (Siratro), Lablab purpureus cv. Rongai (Dolichos), Mucuna pruriens (Velvet bean) and Stylosanthes scabra var. Seca (Stylo) were screened for adaptability and growth performance under the semi-arid conditions for two years. Results of soil analysis showed there were significant increases in soil pH (4.92 to 5.36), organic carbon (1.17 to 2.57%) , nitrogen (0.17 to 0.22%) and potassium (1.23 to 1.68 me%) probably due to the large amounts of organic residues produced by the legumes (particularly Glycine, Siratro and Stylo which are perennials). The calcium content decreased significantly from 7.97 to 4.50 me% (which was attributed to plant uptake) while the decrease of phosphorus was not significant. During the second phase of study for 1½ years Glycine, Siratro and Stylo were integrated into natural pastures. The results showed that only the soil pH significantly increased from 5.23 to 5.31 while all the other nutrients decreased results, which were attributed to production of less organic residues by the legumes compared to the residues produced during the legume evaluation phase. The study concluded that Glycine, Siratro and Stylo were capable of improving the soil fertility of semi-arid natural pastures only if the respective dry matter production was 10.31, 7.81 and 3.52 tha-1, amounts which were able to produce large amounts of organic residues.

Zziwa, E, Kironchi G;, Gachene CK, Mugerwa S;, Mpairwe D.  2011.  Production systems, land cover change and soil factors affecting pastur e production in semi1arid Nakasongola. Abstract

The current pace of rangeland degradation imparted by appalling land use and management systems is greatly limiting the potential of the soil resource to support pasture production in semi - arid rangeland s of Uganda. Our objectives were to determine the effects of land cover change and production systems on pasture biomass yield and to identify the critical soil factors affecting pasture production in Nakasongola. The area was stratified into three product ion systems and three land cover types from which six pasture and soil samples were collected following a Modified - Whittaker sampling method. Pasture biomass was significantly high (p < 0.0001) under herbaceous cover (2019 kg/ha) compared to woody (1302 kg /ha) and bare which had no pasture biomass. The settled production system had a significantly (p = 0.013) high pasture biomass (1266 kg/ha) compared to non settled (1102 kg/ha) and semi settled systems (953 kg/ha). Biomass yield was more associated with hi gh levels of organic matter (r = 0.91), calcium (r = 0.91), magnesium (0.83), nitrogen (r = 0.77) and base saturation (r = 0.88). It can be concluded that maintaining native vegetation cover of the rangelands and increasing levels of limiting nutrients are the major strategies for increasing pasture production in semi - arid rangelands of Nakasongola

Eunice, GW, Charles K K, Jesse T N.  2011.  Soil physicochemical properties under Acacia senegal varieties in the dryland areas of Kenya. Abstract

Acacia senegal is a multipurpose drought-tolerant tree or shrub legume and is commonly used in agroforestry systems in sub-Saharan Africa for gum arabic production and soil fertility improvement. Despite its wide distribution in Kenya, there has not been exhaustive evaluation on the effects of the extant varieties (kerensis, leiorhachis and senegal) on soil properties under their canopies for sustainable utilization of the species. Three sites in the drylands of Kenya representing the three varieties were selected for assessment. Soil samples were collected under tree canopies at a depth of 0 to 25 cm and were compared with the soils from the open canopies. There were significant differences in soil physicochemical properties among the three varieties (P<0.05 and P< 0.01). Soil nutrients under the canopies were higher than in the open canopies mainly due to effects of litter accumulation. The three varieties have beneficial effects on soil nutrient status in their natural ecosystems and would most likely improve crop productivity in agroforestry systems as well as enhance herbage productivity in the rangelands. The varieties growing under different soil types may have an effect on their gum Arabic production and quality. Key words: Acacia senegal varieties, soil nutrients accumulation, sustainable utilization.

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