Declining soil fertility resulting from continuous cultivation of small holder farms and escalating cost of imported fertilizers and the need to conserve and build natural resource capital and biodiversity, has led to renewed interest in the use of local nutrient resources for soil fertility management in Kenya. The study was conducted at Bukura Agricultural college farm during the short (SRS) and long rain seasons (LRS) of the year 2009 and 2010 respectively. The LRS occurs between March and July and SRS from September/October to December with peaks in April and November, respectively. The experiment aimed at evaluating the effect of combination between two levels of the recommended mineral fertilizers(50% and 100% of research recommended rates) with three types of organic manures on growth, fruit yield and quality of egg plant (Solanum melongena L) var. black beauty. The experimental design was split plot design with three replications, where two levels of mineral fertilizers treatments (50% and 100%) were randomized in main plots while three types of organic manures(FYM, Compost and Tithonia) and control treatments were randomized in the subplots. Topsoil (0-20cm depth) were sampled before transplanting seedlings and analyzed for soil physical properties, PH, N, P, K, OC and CEC. Also the organic manures were also analyzed for their chemical properties i.e. PH, N, P, K, OC and CEC. Results showed significant differences in eggplant growth, fruit yield and quality (p<0.05) between the two main treatments (50%RRR and 100%RRR), the three organic manures and their control. Similarly, there was significant difference between and the interactions between the two inorganic fertilizer levels and the organic manures. Increasing NPK from 50% to 100% of the research recommended rates encouraged the vegetative growth of eggplants as expressed as plant height and fresh weight besides increasing the total yield it enhanced the fruit quality. The plants in the organic manure treated plots were characterized with vigorous vegetative growth, which in turn led to increase in total fruit yields as well as improving fruit quality. The farm yard manure was considered the superior source of manure to obtaining the highest value of the parameters under study as compared to compost and Tithonia diversifolia (tithonia). Soil fertilized with 100% recommended NPK combined with organic manures produced the superior growth of plants and the highest amount of total fruit yields. The promising combination was 100% of recommended NPK combined with farm yard manure produced the best response.
