The Organic Matter and Nitrogen Status of Manure on Smallholder Farms in Central Kenya

REFERENCES

• Alexander, M.A. (1977). Introduction to soil microbiology. John Wiley and Sons, New York, USA.
   Google Scholar
• Beauchamp, E.G. (1986). Availability of nitrogen from three manures to corn in the field. Canadian Journal of Soil Science 66, 713–720.
   Web of Science ®Google Scholar
• Bray, R.H. and Kurtz, L.T. (1945). Determination of total, organic and available forms of phosphorus in soils. Soil Science 59, 39–45.
   Web of Science ®Google Scholar
• Bredero, J. (1977). The role of farmyard manure and green manure in soil fertility restoration in the humid tropics. Abstracts on Tropical Agriculture 3, 9–17.
   Google Scholar
• Cooke, G.W. (1982). Fertilizing for maximum yield. 3rd Ed., Granada, London. 465 pp.
   Google Scholar
• Evans, A.C. and Mitchel, H.W. (1962). Soil fertility studies in Tanganyika I. Improvement to crop and grass production on a leached sandy soil in Bukoba. E. Afr. agric. For. J. 27, 189–196.
   Google Scholar
• FAO. (1977). Organic materials and soil productivity. Food and Agricultural Organisation of the United Nations. Soils Bulletin No. 35, Rome.
   Google Scholar
• Grimes, R.C. and Clarke, R.T. (1962). Continuous arable cropping with the use of manures and fertilisers. E. Afr. agric. For. J. 28, 74–80.
   Google Scholar
• Ikombo, B. (1984). Effects of farmyard manure and fertilisers on maize in semi-arid areas of eastern Kenya. E. Afr. agric. For. J. 44, 266–274.
   Google Scholar
• Ikombo, B., Esilaba, A.O. and Kilewe, A.M. (1994). A diagnostic survey of the farming systems in Kiambu District: Report on diagnostic survey results from Kikuyu, Kiambaa, Gatundu and Thika Divisions. 77 pp.
   Google Scholar
• Im, J.N. 1978. Organic materials and improvement of soil physical characteristics. In: Organic materials and soil productivity in the Near East. Food and Agricultural Organisation of the United Nations. FAO Soils Bulletin No. 45, Rome.
   Google Scholar
• Jameson, J.D. and Kerkham, R.K. (1960). The maintenance of soil fertility in Uganda. Empire J. Expt. Agric. 28, 178–192.
   Google Scholar
• Kilewe, A.M. and Thomas, D.B. (1992). Land degradation in Kenya: A framework for policy and planning. Commonwealth Secretariat, London. 148 pp.
   Google Scholar
• Kwakye, P.K. (1980). The effect of method of dung storage and its nutrient (NPK) content and crop yield in the north east savanna zone of Ghana. FAO Soils Bulletin No 43: 282–288.
   Google Scholar
• Mugambi, S.M. (1979). Manure and fertiliser requirements of potatoes on acid soils. E. Afr. Agric. For. J. 44, 278–284.
   Google Scholar
• Mugwira, L.M. and Murwira, H.K. (1997). Use of cattle manure to improve soil fertility in Zimbabwe: Past and current research and future research needs. Soil Fertility Network for Maize-Based Cropping Systems in Malawi and Zimbabwe (Soil Fert. Net.). Network Research Results Working Paper No. 2. CIMMYT, 33 pp.
   Google Scholar
• Muller-Samann, K.M. and Kotschi, J. (1994). Sustaining growth: Soil fertility management in tropical smallholdings. Margraf Verlag, Germany. 486 pp.
   Google Scholar
• Murwira, K.H., Swift, M.J. and Frost, P.G.H. 1995. Manure as a key resource in sustainable agriculture. In: Livestock and Sustainable Nutrient Cycling in Mixed Farming Systems of Sub-Saharan Africa. Volume II: Technical Papers. Powell, J.M., Fernandez-Rivera, S., Williams, T.O. and Renard, C. (eds.), pp. 131–148. Proceedings of an International Conference held in Addis Ababa, Ethiopia, 22–26 November 1993. ILCA (International Livestock Centre for Africa). Addis Ababa, Ethiopia.
   Google Scholar
• Mwarasomba, L.I., Chui, J.N., Mwangi, D.M., Kimani, S.K., Esilaba, A.O., Wamuongo, J.W., Miriti, J.M. and Odongo, N. (1995). Farmers participation in identification of on-farm research priorities in Kiamathare catchment in Kiambu District. Kenya Agricultural Research Institute. 60 pp.
   Google Scholar
• NARL. (1987). Fertiliser Use Recommendation Project. National Agricultural Research Laboratories, Nairobi. Final Report, annex II.
   Google Scholar
• Okalebo, J.R., Gathua, K. W. and Woomer, P.L. (1993). Laboratory methods of soil and plant analysis: A working manual. KARI-TSBF, Nairobi, Kenya. 88 pp.
   Google Scholar
• Probert, M.E., Okalebo, J.R. and Jones, R.K. (1995). The use of manure on smallholders farms in semi-arid eastern Kenya. Expl. Agric. 31, 371–381.
   Web of Science ®Google Scholar
• Probert, M.E., Okalebo, J.R., Simpson, J.R. and Jones, R.K. (1992). The role of boma manure for improving soil fertility. In: A search for strategies for sustainable dryland cropping in semi-arid eastern Kenya. Australian Centre for International Agricultural Research (ACIAR) Proceedings 41:117–123.
   Google Scholar
• Qureshi, J.N. (1991). The cumulative effects of N-P fertilisers, manure and crop residues on maize and bean yields and some soil chemical properties at Kabete. In: Recent advances in KARI's research programmes. Proceedings of the Second KARI Annual Scientific Conference, Nairobi, Kenya 5–7 September 1990, pp. 160–167.
   Google Scholar
• Scaife, M A. (1971). The long-term effects of fertilisers, farmyard manure and heys at Mwanhala, Western Tanzania. E. Afr. agric. For. J. 37, 8–14.
   Google Scholar
• Smaling, E.M.A. and Braun, A. R. (1996). Soil fertility research in sub-Saharan Africa: New dimensions, new challenges. Commun. Soil Sci. Plant Anal. 27(3 & 4), 365–386.
   Google Scholar
• Simpson, K. (1986). Manures. In: fertilisers and manures, Longman, London.
   Google Scholar
• Tanner, P.D. and Mugwira, L. (1984). Effectiveness of communal area manures as sources of nutrients for young maize plants. Zimbabwe Agricultural Journal 81, 31–35.
   Google Scholar
• Van Fassen, H.G and Van Dijk, H. (1987). Manure as a source of nitrogen and phosphorus in soils. In: Animal manure on grassland and fodder crops: Fertiliser or waste? Van der Meer, H.G., Unwen, R.J., Van Dijk, T.A. and Ennik, G.C. eds) Martinus Nijhoff Publishers, Dordrecht, The Netherlands. Development in Plant and Soil Sciences 30, 27–45
   Google Scholar
• Walkley, A. and Black, I.A. 1934. An examination of the Degtjareff method for determining soil organic matter, and a proposed modification of the chromic acid titration method. Soil Sciences 37. 29–38.
   Google Scholar
• Wapakala, W.W. 1976. Changes in some chemical properties of a red clay soil: Results of long term fertiliser and rotational trials in central Kenya. E. Afr. agric. For. J.42, 201–218.
   Google Scholar