Maize response to Tithonia diversifolia and rock phosphate application under two maize cropping systems in Kenya

Objective: The experiment was conducted with the aim of investigating maize response to Tithonia diversifolia and Minjingu Rock phosphate (MPR) applied under maize-bean intercrop as compared to the traditional maize monocrop to improve maize grain yields. Methodology: The experiment was conducted in pots in a greenhouse for the duration of 8 weeks.. The trial was laid out in a split plot arrangement with three replicates. The main plots comprised of sole maize crop and maize-bean intercrop whereas the sub plots included the control (no input), Tithonia biomass applied alone, MPR also applied alone, TSP again applied alone and Tithonia biomass co-applied with MPR. Soil samplings were done at 4 and 8 weeks after planting and assessed for .P availability and soil labile P. Data was also taken on maize dry matter yield at 8 weeks. ANOVA was done using SAS (version 9.2) and means separated at 5% probability level using DMRT. Results: Maize-bean intercrop was effective in increasing PR solubilisation, P availability and shoot dry matter production. At the same level of P input from MPR, P availability under maize-bean intercrop increased above the ones under sole maize by 154.8% and 91.4% in the first and second samplings, respectively. The increase is thought to have been partly due to the effect of the rhizosphere acidification by bean (Phaseolus vulgaris) during the process of biologically nitrogen fixation. Implications: This farmers-practices matching and also environmentally-friendly low input approach enables farmers to boost production, cut down the cost of production and consequently increase the profit margin.Keywords: Maize-bean intercrop; Maize shoot dry matter yield; P availability; Rock phosphate solubility