Effect of Manure Placement On Soil Fertility and Maize Productivity in Western Kenya.

Soils in Western Kenya are deep and strongly weathered, which results in a fixation of plant-available phosphorus. This fixation has a negative effect on the profitability of inorganic fertilizers, which are often expensive or not readily available. The objective of this study is to determine if the placement of livestock (cattle) manure fertilizer, in relation to the seed, has an effect on soil fertility, plant uptake of P and the grain yield of maize (Zea mays L.) in the Vihiga District of Western Kenya. The protocol includes three different placement methods of the manure (plus a no-manure control). The first method will spread the manure evenly across the field (broadcast) followed by incorporation into the soil with tillage. The second will concentrate the manure in a row adjacent to the seed furrow. The third application method will place the manure a few inches below the seed furrow. Manure will be applied at 7 Mg ha-1. Soil samples will be taken prior to planting, when the maize is at V8 and post-harvest. Stand counts will be conducted at V4 and at harvest. The above-ground biomass at V8 will be analyzed for nutrient uptake, as will ear leaf samples at R1. Leaf firing, a visual method of determining deficiency, will also be determined at R1. At harvest, yield will be calculated as well as the nutrient content of the grain. Through this information, differences in soil fertility and plant response, if there are any, will be determined using GLM model in SAS. Results from the 2010 long rains season (March through July) will be presented.