Assessing sustainability of low-external-input farm management systems with the nutrient monitoring approach: a case study in Kenya

In the search for Integrated Nutrient Management practices in response to the widely observed soil fertility decline in Sub-Saharan Africa, the potential of low-external-input and organic farming remains to be systematically examined. The nutrient monitoring concept was used to assess the impact of technologies on nutrient flows and economic performance at activity and farm household level in Machakos district, Kenya. The nutrient flows and balances and economic performance indicators of farms practising low-external input agriculture (LEIA) technologies for a number of years were compared with a group of farms practising conventional farm management. Based upon monitoring two farming seasons, it was concluded that both subsistence-oriented farm management systems result in serious N-depletion and that 60–80% of farm income is based upon nutrient mining. No significant differences could be found between the LEIA and conventional farm management group. Only if LEIA farm management reduces nutrient losses through leaching and gaseous losses can a positive impact on nutrient balance be expected. Off-farm income plays a crucial role, especially in the conventional management group, in keeping farm household income levels above the poverty line. High-level compost application treatments in maize are attractive if labour and organic inputs are available. # 2001 Elsevier Science Ltd. All rights reserved.

[1]  E. Smaling,et al.  Do fertilizers play a major role in sustainable agricultural development in West Africa , 1998 .

[2]  John Sherington,et al.  Participatory research methods—Implementation, effectiveness and institutional context , 1997 .

[3]  Francis N. Gichuki,et al.  More People, Less Erosion: Environmental Recovery in Kenya , 1995 .

[4]  A. D. Jager,et al.  Monitoring nutrient flows and economic performance in African farming systems (NUTMON): II. Tool development , 1998 .

[5]  N. Heerink,et al.  Integrated soil improvement and agricultural development in West Africa: why current policy apporaches fail. , 1998 .

[6]  S. Pagiola.  Price policy and returns to soil conservation in semi-arid Kenya , 1996, Environmental and Resource Economics.

[7]  J. Dalsgaard,et al.  A quantitative approach for assessing the productive performance and ecological contributions of smallholder farms , 1997 .

[8]  H. Reuler,et al.  The role of plant nutrients for sustainable food crop production in sub-Saharan Africa. , 1993 .

[9]  Lisa Tang,et al.  Knowledge in action: Local knowledge as a development resource and barriers to its incorporation in natural resource research and development , 1997 .

[10]  Jules Pretty,et al.  Regenerating Agriculture: Policies and Practice for Sustainability and Self-Reliance , 1995 .

[11]  M. Odendo,et al.  Monitoring nutrient flows and economic performance in African farming systems (NUTMON); IV Linking nutrient balances and economic performance in three districts in Kenya' , 1998 .

[12]  E. Smaling,et al.  Restoring and maintaining the productivity of West African soils: key to sustainable development , 1996 .

[13]  E. Smaling,et al.  Classifying, monitoring and improving soil nutrient stocks and flows in African agriculture , 1996 .

[14]  G. Wossink,et al.  The Economics of Agro-Chemicals , 1998 .

[15]  John G. Gibbons.  Knowledge in Action , 2001 .

[16]  A. Dougill.  Sustaining the Soil: Indigenous soil and water conservation in Africa , 1997 .

[17]  K. Shepherd,et al.  Maintenance and improvement of soil productivity in the highlands of Ethiopia, Kenya, Madagascar and Uganda , 1997 .

[18]  Ann Waters-Bayer,et al.  Farming for the future: an introduction to low-external-input and sustainable agriculture. , 1992 .

[19]  E. Smaling,et al.  Soil fertility research in sub‐Saharan Africa: New dimensions, new challenges , 1996 .

[20]  J. Kamp,et al.  Joining farmers' experiments : experiences in participatory technology development , 1991 .