Benefits of Rhizobial Inoculation and Phosphorus Application on Growth of Lucerne (Medicago-sativa) in Kenya

Field experiments were conducted to study the effects of Phosphates on growth components of Lucerne during the long and short rain seasons of 2016-2017 at Kenyatta University farm in Kiambu County in Kenya. The experiments were laid out in split-plot arrangement in a Randomized Complete Block Design (RCBD) with four replicates. The treatment factors were: (i) Main plot factor – Lucerne, (ii) Sub-plot factor – inoculation and no inoculation and (iii) Sub-sub plot factor - different phosphorus forms, no phosphate, RP and TSP totalling to twelve treatment combinations which were replicated three times. Rows of 50cm apart were made, leaving 25 cm on the edge. The maximum number of branches (18) was recorded on plants under the TSP treatment, followed by RP (15) whereas the plants in the control had the lowest number of branches (11). Inoculation significantly reduced the number of nodules in Lucerne probably due to the high population of indigenous rhizobia already present in the soil which might have led to negative competition.