EFFECT OF PHOSPHATE FERTILIZER APPLICATION METHODS AND NITROGEN SOURCES ON MAIZE IN WESTERN KENYA: AN AGRONOMIC AND ECONOMIC EVALUATION

Abstract

Simultaneous deficiencies of nitrogen (N) and phosphorus (P) which limit crop production in western Kenya can be overcome through a combined application of organic and inorganic fertilizers. An experiment was conducted with maize (Zea mays) for two seasons to compare two methods of applying inorganic P fertilizer (broadcast versus spot) in a factorial combination with three N sources, i.e. farmyard manure (FYM), Tithonia diversifolia green manure (tithonia) and urea. Net financial benefits of the tested practices were computed using partial budgeting. Maize yield was not significantly affected by the P fertilizer application method in the first season, but the broadcast method was generally superior to spot application in the second season. The three N sources produced maize yields that were comparable in both seasons. FYM integrated with P fertilizer applied using the broadcast method, however, had the highest cumulative net benefit and was therefore the most economically attractive input combination.