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Soil acidity is one property associated with decline of most crop productivity. Alfisols and Ultisols are some of the acidic soils predominant in western Kenya. An experiment was conducted in both soils to find out the effect of farmyard manure (FYM) and inorganic fertilizers on maize yield on farmers' fields during wet and dry seasons of 2006. The experiment, laid out in a randomized complete block design (RCBD), had five replications in each soil type. The treatments were: farmer's practice, N (60 kg ha ). During wet season, all treatments in Alfisols gave nearly double grain yield compared to Ultisols. In both soils, during the same season, except for optimal fertilizer, FYM was not significantly (P≤0.05) different from other inorganic fertilizer treatments on plant population, height, cob number, stover, grain yield and 100-seed weight. FYM had a 108% and 103% grain yield advantage over farmer's treatment in Alfisols and Ultisols, respectively. During dry season, plant population, number of cobs and grain yield were higher in Ultisols compared to Alfisols. In each soil type, FYM plus 30 kg N ha -1 provided maize grain yield equivalent to that of N, NP and NPK treatments. FYM had a 4% grain yield advantage over optimal and NPK treatments on Ultisols during dry season. We conclude that larger amount of fertilizers or liming is needed on Ultisols to enhance their productivity to the level of Alfisols and that due to the fact that smallholder farmers are not likely to afford large amount of fertilizer and liming, use of FYM is their best bet for maize production on both Alfisols and Ultisols as there is no significant yield advantage from N, NP or NPK over FYM. Ultisols appear to be more responsive to FYM during dry season probably due to prevailing higher temperatures and relatively dry soil which enhances faster mineralization of organic matter to available plant nutrients. Addition of N fertilizer failed to increase yield in Ultisols, probably due to decline in soil pH and consequently inefficient utilization of applied resources.

During participatory rural appraisals, farmers at the Lake Victoria basin of Kenya and Uganda identified Striga, stemborer and declining soil fertility as three major constraints to maize production To reduce food insecurity, several innovative integrated technologies to address these constraints have been developed, including push-pull (maize intercropped with Desmodium and surrounded by napier grass), maize-soybean and maize-crotalaria rotations, and Imazapyr- each of the criteria farmers has previously determined (including yield, resistance to Striga and stemborer, and improvement of soil fertility). Analysis of the evaluation, using ordinal regression, show significant differences in farmers' preference by year and site. There was, however, little effect of farm and farmer characteristics such as farm size and gender of the observer. Ordinal regression of farmers' scores are not as intuitive and also bit cumbersome to use, but they have a better theoretical foundation than other methods, in particular the use of means. This paper shows how the method can be used, and concludes that, with some effort, it is a convenient way to analyse farmers' ranking of a large number of options.