On-farm demonstrations were conducted in the semi-arid areas of Ndeiya Location (Kiambu District) in central Kenya to assess the farmers' subjective preference for the technology-specific attributes inherent in tied-ridges moisture conservation praotice, Approximately 83% of Kenya's land surface and its impact on their preference criteria. is classified as the arid and semi-arid lands Three farmers' fields in the focal area of (ASAL) characterized by low and unreliable National Agriculture and Livestock rainfall. Ndeiya location in Kiambu District Extension Proj ect (NALEP) were selected falls under the agro-ecological zone 4 -6 with for the demonstrations. Interviews were annual rainfall ofless than 700 mm (Jaetzold conducted using structured questionnaires and Schmidt, 1983). Like other arid and to capture data on impact of farmers' semi-arid lands of sub-Saharan Africa,subjective preference for technology- rainfall is erratic with long showers or brief specific attributes on the adoption decisions. storms with much of the water lost through Data was also gathered on the impact of runoff. This coupled with high evapothe farm and farmer related socio-economic transpiration rates causes frequent water variables on preference criteria and thus, deficits at critical periods of plant growth, potential adoption behaviour.low crop yields and sometimes crop failures. The results of the study reveal that both Consequently, food production has lagged technology-specific attributes and farm and behind population growth in the area. Yet, farmer related socio-economic variables smallholder farmers in Ndeiya Division have an impact on adoption decisions for depend almost exclusively on agriculture for tied-ridges technology. The tied ridges their livelihood. In spite of the environmental technology had a positive impact on the problems, there is low use of soil and water overall maize biomass yield compared to conservation farming technologies for conventional land preparation practices. rainwater harvesting among the farming Tied-ridges technology also kept the maize community due to lack of technical knowstover green for a relatively longer period how. In order to increase food production and this benefited the smallholder dairy for the increasing population in these areas, production in the mixed farming production more efforts must therefore be aimed at systems that characterize the study area. disseminating the available water harvesting The root zone moisture content in the tied- technologies to farmers. Ridges plots was relatively higher compared This project was implemented to to plots prepared in a conventional way. demonstrate tied-ridges technology as a Tied-ridges technology, when adequately promoted and demonstrated has the potential of increasing productivity in the semi-arid ecosystems of the central Kenya highlands.