Effect of phosphorus fortified compost on growth and yield of maize (Zea mays L.) and Lablab (Lablab purpureus L.) intercropped maize in acidic soils of Western Kenya

Phosphorus deficiency majorly constrains maize (Zea mays L.) production in acidic soils of western Kenya. This requires high doses of expensive inorganic P fertilizers to correct. Recommended rock phosphates and manures are lowly adopted because of low solubility and P content respectively. A Randomized Complete Block Design experiment was conducted for two seasons to assess effect of a cheaper alternative P source, Phosphorus fortified Tithonia compost (PCM), on growth and yield of maize and lablab-intercropped maize on two sites with different soil fertility. The experiment was set up on seven farms per site in Kapkerer (low fertility) and Koibem (higher fertility). Three P source treatments of Minjingu rock phosphate (MRP), Phosphorus fortified Tithonia compost and Triple Super Phosphate (TSP) were applied at an equivalent rate of 26 kg P/ha for maize and maize-lablab intercrop. Data on plant height, Leaf Area Index (LAI), aboveground biomass, leaf P concentration and grain yield were collected. PCM treatment significantly (p≤0.05) increased maize height, LAI, aboveground biomass and grain yield compared to TSP in Kapkerer. No significant differences were noted in leaf P concentrations. PCM is a good alternative to expensive inorganic P fertilizers in acidic soils of western Kenya. Key words: Tithonia P-fortified compost, Rock phosphate, intercropping, lablab.