12658 1 archive 5608 disk0/00/01/26/58 2008-09-22 2009-08-20 14:38:17 2009-08-20 14:38:17 conference_item show 0 en int-conf-owc-2008-research-02-1 int-conf-owc-2008-research June, 16-20, 2008 16th IFOAM Organic World Congress Modena, Italy never 0 TRUE paper Bett Eric Msc Freyer Bernhard Prof. Leonhartsberger Philipp Msc unpub countries_africa Soil fertility, Kenya highlands, smallholders, legumes, organic farming Soil fertility degradation still remains the single most important constraint to food production in the Kenyan Highlands. It is estimated that 64% of the population resides in the highlands, with population densities in some areas of over 1000 persons/km2. Use of inorganic fertilisers on smallholdings in the Kenya Highlands has been steadily declining since the 1960s, when heavy promotion and subsidization of fertilisers coincided with the release of improved maize varieties and the creation of co-operatives such as the Kenya Grain Growers Co-operative Union. Currently, their use continues to be constrained by their high cost, the low purchasing power of smallholders, and limited access to credit facilities. Farm sizes are getting smaller, and this promotes continuous cropping with limited scope for crop rotation and inadequate soil fertility replenishment. Soil fertility improvement can be achieved through organic farming techniques such as biomass transfer, re-activation of the ‘N bulge’, and phosphorus scavenging. Legume intercropping with maize – Kenya’s staple food – as well as the implementation of short rain legume fallows are known to enhance maize yields in most cases. 2007 published De Jager, A., Kariuki, I.,,Matiri, F. M.,Odendo, M. and Wanyama, J.M., 1998: Linking Economic Performance and Nutrient Balances in Different Farming Systems in Kenya: A Synthesis Towards an Integrated Analysis of Economic and Ecological Sustainability. Agriculture, Ecosystems, and Environment, Vol. 71, No. 2, pp. 81-92. Gachene, C.K.K., Palm C.A. and Mureithi, J.G., 1999. Legume cover crops for soil fertility improvement in the East African region. Report of an AHI Workshop on 18-19 February 1999 in Nairobi, Kenya. Kiama, J. and Mureithi, J.G. 2001. Revival of Matanya LRNP site in Laikipia District, Legume Research Network Project Newsletter, No. 5, KARI, Kenya. Lelei, J. N. J., 2004. Impact of soil amendments on maize performance and soil nutrient status in legume-maize intercropping and rotation systems in Central Rift Valley Province of Kenya. Mburu, M.W.K, Mureithi, J.G. and Gachene, C.K.K,., 2003. Effects of Mucuna Planting Density and Time on Water and Light Use in a Maize – Legume Intercrop System. Legume Research Network Project Newsletter, No. 10, KARI. Onwonga, R, and Freyer, B. 2006. Impact of Traditional Farming Practices on Nutrient Balances in Smallholder Farming Systems of Nakuru District, Kenya. Proceedings of the Tropentag conference October 11 - 13, Bonn, Germany Rao, M.R., Mathuva, M.N., 2000. Legumes for improving maize yields and income in semi-arid Kenya. Agric. Ecosy. Environ. 78, 123-137. Schlecht, E., Buerkert, A., Tielkes, E., and Bationo, A., 2006. A critical analysis of challenges and opportunities for soil fertility restoration in Sudano- Sahelian West Africa- Nutrient Cycling in Agroecosystems. Smaling, E. M. A.,Nandwa, S. M. and B. H. Janssen. 1997. “Soil Fertility in Africa is at Stake.” In Buresh, R. J.,Sanchez, P. A. and F. Calhoun (eds.). Replenishing Soil Fertility in Africa. Madison, Wisconsin: Soil Science Society of America. public 8568 1 12658 1 rtf en public

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