Micro-Dosing of Inorganic Inputs on Maize Production on an Acid Soil in Kenya: An Agronomic and Economic Evaluation

Abstract

Aims: The study determined the effect of micro-dosing of lime, P and N fertilizers on maize grain yield and economic benefits. Study Design: The experiment was a 2 x 2 x 3 split-split plot laid out in randomized complete block design with N (0 and 37.5 kg N ha-1) in the main plot, P (0 and 13 kg P ha-1) in the sub-plot and lime (0, 0.77 and 1.55 tons lime ha-1) in sub-sub plot. 37.5 kg N and 13 kg P ha-1 are 50% of the recommended fertilizer rates for maize production in Kenya while 0.77 and 1.55 tons lime ha-1 are 25 and 50% of the actual requirement. Place and Duration of Study: The study was carried on nutrient deficient acid soil on a small holder farmer (SHF) field in Busia County, Kenya during the years 2008 and 2009. Methodology: Lime was applied once during the long rain in the year 2008 while P and N fertilizers each cropping season. Results: Grain yield increased by 148 and 40% due to 50% of both the recommended N and P fertilizers, respectively and 5-17% due to 25-50% of the lime requirement. Majority (57-75%) of the production costs were due to inorganic inputs. Only combined application of 50% of both the recommended N and P fertilizers produced economically viable returns throughout the cropping period. Combination of 50 and 25% of the recommended P and lime, respectively and 50 and 25% of the recommended N and lime, respectively produced economically viable returns only during the second and third cropping seasons. A combination of 50% of both the recommended P and lime produced economically viable returns during the third cropping season only. Conclusion: Small holder farmers producing crops on Kenya’s acid soils deficient in N and P such as in Busia County can realize economically viable returns by micro-dosing of N, P fertilizers and lime.