Bio

Biodata

Prof. Shellemiah Okoth Keya, born 22 Sept 1941 is a Kenyan married with five children, currently Chancellor of Dedan Kimathi Universityof Science and Technology and professor of Land Resources Management and Agricultural Technologies, University of Nairobi.  He attended Wang’apala, Kisii and Kakamega schools and graduated from Makerere University (B.Sc.), Cornell University (M.Sc and Ph.D.).

Publications


2008

Keya, SO.  2008.  FAO/SAA.(2008).

2006

Rodenburg, J; Diagne, OFKPM; SKSOA; S; K;.  2006.  Achievements and impact of NERICA on sustainable rice production in sub - Saharan Africa.. Abstract

In terms of production, rice is the fourth most important cereal (after sorghum, maize and millet) in sub-Saharan Africa (SSA). It occupies 10 percent of the total land under cereal production and accounts for 15 percent of total cereal production (FAOSTAT, 2006). Approximately 20 million farmers in SSA grow rice and about 100 million people depend on it for their livelihoods (Nwanze et al., 2006). Rice is the staple food of a growing number of people in SSA: from 1961 to 2003 consumption increased at a rate of 4.4 percent per year (Kormawa, Keya and Touré, 2004). Among the major cereals cultivated, rice is the most rapidly growing food source in Africa: between 1985 and 2003, the annual increase in rice production was 4 percent, while production growth for maize and sorghum was only about 2.4 and 2.5 percent, respectively (Kormawa, Keya and Touré, 2004). The most widely grown rice species, Oryza sativa, is originally from Asia and was introduced into Africa only about 450 years ago. Another less well-known rice species, O. glaberrima (Steud), is originally from Africa and was domesticated in the Niger River Delta over 3 500 years ago (Viguier, 1939; Carpenter, 1978). As a result of their evolution, domestication and breeding history, both species have distinct and complementary advantages and disadvantages for use in African farming systems. The Asian rice (O. sativa) is characterized by good yields, absence of lodging and grain shattering, and high fertilizer returns – unlike its African counterpart (O. glaberrima). However, in contrast to Asian rice types, landraces of O. glaberrima often have good weed competitiveness and resilience against major African biotic and abiotic stresses (Koffi, 1980; Jones et al., 1997a). Dalton and Guei (2003) concluded that research into genetic enhancement of rice generated approximately US$360 million in 1998, compared with a total investment of just US$5.6 million. This is evidence that rice variety improvement has a potentially enormous impact on the economic development of SSA. Numerous conventional breeding efforts have been made to improve the performance of upland rice (O. sativa) for use in African farming systems. These efforts have had only limited success, partly because the Asian rice, O. sativa, lacks resistance or tolerance to many of the typical African stresses (Jones et al., 1997a).

2002

1993

Keya, SO; Michieka, RW.  1993.  Agricultural sector development.

1992

1990

Karuri, EG;, Okoth MW;, Keya EL.  1990.  Industrial training for Food Science and Technology Students.

1988

MUNGE, PROFMUKUNYAD.  1988.  Kedera, C.J., D.M. Mukunya and S.O. Keya, 1988. Survival of Rhizobium leguminosarum bv. Phaseoli in contact with Captan.. Proceedings of the 1st Symposium of the Crop Science Society of Kenya held on 4-8th July 1988. Nairobi, Kenya. 15 p.. Abstract
n/a

1987

Dommergues, Y, Keya SO, Freire J, Diem Hoang G, Dreyfus B.  1987.  Nitrogen fixation in tropical agriculture and forestry. Abstract

Nitrogen compounds comprise from 40 to 50 percent of the dry matter of protoplasm, the living substance of plant cells. For this reason, nitrogen is required in large quantities by growing plants and is indeed the key to soil fertility. Non-nitrogen-fixing plants, for example cereals, obtain all the nitrogen they need from the soil. In Senegalese conditions this uptake was estimated to be as follows: 79-132 kg N ha/crop for pearl millet; 74-84 kg N ha/crop for rice; 134 kg N hdcrop for sorghum; and 121-139 kg N ha/crop for maize. Nitrogen-fixing plants, essentially legumes, take a part of the nitrogen they require from the atmosphere, the other part being provided by the soil."

Da Silva, EJ, Freire J, Hillali A, Keya S.  1987.  Nuestros amigos los microbios.

1986

Anyango, B;, Keya SO;, Owino F.  1986.  Nodulation Survey of Nitrogen Fixing Tre es in Kenya.
S.O, K, J F, E. J DS.  1986.  MIRCENS: Catalytic tools in agricultural training and development. Abstract

A global network of Microbiological Resources Centres (MIRCENs) , set up by Unesco, includes five centres concerned with biological nitrogen fixation. These centres are Kenya, Brazil, the United States and Senegal-train experts in the methods of Rhizobium inoculation, which when applied to certain leguminous plants can often avert the need to use expensive chemical nitrogen fertilizers in food crop production. The MIRCENs constitute an excellent example of international co-operation in science.

Ssali, H, Keya SO.  1986.  The effects of phosphorus and nitrogen fertilizer level on nodulation, growth and dinitrogen fixation of three bean cultivars.. Abstract

Application of P (150 kg P/ha) increased nodulation, dry matter yield, P uptake, tissue N yield, dinitrogen fixation and seed yield of the three bean cultivars (Rose Coco, Canadian Wonder and Mwezi moja) at both N levels (10 and 100 kg N/ha). A high dose of N severely reduced nodulation only where P was not applied but severely reduced dinitrogen fixation at both P levels. Where P was applied cultivars fixed comparable quantities of dinitrogen. At no P + 10 kg N/ha cultivar Rose Coco nodulated well early in the growth stages and fixed substantial dinitrogen

1985

Yamoah, CF;, Mulongoy K;, Agboola AA;, Ssali H;, Keya SO.  1985.  Decomposition and nitrogen contribution by prunings of selected legumes in alley cropping.
Anyango, B;, Keya SO;, Widdowson D;, Wangaruro S;, Mugane C;, Karani FN.  1985.  Current Status of Legume Inoculant Production in Kenya..
Keya, SO, Ssali H.  1985.  Nitrogen level and cultivar effects on nodulation, dinitrogen fixation and yield of grain legumes: I. Cowpea cultivars. Abstract

N fixation was studied by the 15N method in Vigna unguiculata cv. ERI-2, Vita 4 and Machakos 74 grown in a field which had been fallow for 3 years and given 20 or 100 kg N/ha. The higher N rate reduced nodulation in all cv., with effects differing somewhat between cv., and increased DM and N yield/plant and uptake of non-fertilizer soil N, with least and greatest effect in cv. ERI-2 and Machakos 74, resp. The amount of N fixed was 50.5, 73.7 and 60.7 kg/ha at the low N rate and was 69.7, 74.5 and 100% lower at the high N rate in the 3 cv., resp.

MUNGE, PROFMUKUNYAD.  1985.  Mutitu, E.W., D.M. Mukunya and S.O. Keya, 1985, Biological control of Fusarium yellow on beans caused by Fusarium oxysporum Schl. F.sp phaseolus Kendrick and Snyder using organic amendments. ACTA HORT. 218:267 . Proceedings of the 1st Symposium of the Crop Science Society of Kenya held on 4-8th July 1988. Nairobi, Kenya. 15 p.. Abstract
n/a

1984

Ssali, H;, Keya SO.  1984.  Biological nitrogen fixation in Africa.
Keya, SO, Ssali H.  1984.  Phosphorus and cultivar effects on nodulation, growth, dinitrogen fixation and yield of cowpea (Vigna unguiculata).. Abstract

In field experiments at Katumani in 1982, cowpea cv. Katumani 80 and Vita 4 were grown in chromic luvisol soils and treated with 15N-labelled ammonium sulphate at 20 kg N/ha, with or without 70 kg P/ha. Differences in nodule DW, DM yield, P uptake and tissue N yield were detected between cv. at maturity, but P rate had no effect. Av. seed yields of Katumani 80 and Vita 4 were 1.16 and 1.05 t/ha, resp., and were unaffected by P rate.

1982

Keya, SO;, Scali H;, Balasundaram YR.  1982.  Potentials and constriants for inoculation of grain legumes in Kenya.
Keya, SO;, Balasundaram VR;, Ssali H;, Mugane C.  1982.  Multilocational field responses of Phaseolus vulgaris to inoculation in eastern Africa.
S.O, K, N. K M, M. A A.  1982.  Population dynamics of soil microorganisms in relation to proximity of termite mounds in Kenya. Abstract

Microbial populations estimated in termite-affected soils show that bacteria and actinomycetes are most abundant during the wet season. The highest density of bacteria recorded was 106 and, of actinomycetes, 105g dry soil. In contrast, fungi, which dominate only during dry periods, numbered 104 and declined to 102 cells/g dry soil during the wet period. Fungi, actinomycetes, bacteria and Protozoa were higher in 'dead' than in 'live' mounds. Counts of denitrifiers, ammonifiers, cellulose decomposers, nitrifiers and Protozoa were in the order of 103/g dry soil. The evolution of CO, was also related to microbial activities. This is the first time such information has been recorded for Kenyan soils. The study provides evidence that 'live' termite mounds differ from 'dead' ones in respect of the microorganisms associated with them.

N., PROFKARANJANANCYK.  1982.  Arshad, M.A., Mureria, N.K., Keya, S.O. 1982. Effect of termite activity on soil microflora. Pedobiologia 24, 161-167.. Poster presented at the 8th Congress of the African Association for Biological Nitrogen Fixation (AABNF), 23-27 November, 1998. Abstract
n/a

1981

1980

Balasundaram, VR;, Keya SO.  1980.  Microbial Flora of Some Kenyan Soils..

1979

UoN Websites Search