Evaluation of the quality and effectiveness of some commercial microbial products in enhancing the growth and yield of soybean and maize
Field studies consisting of five treatments each for soybean and maize were conducted to assess the quality and effectiveness of some commercial products on soybean (Eco-Rhiz-Soya and Eco-T) as well as maize (Enrich and Eco-T). The treatments were arranged in a Randomised Complete Block Design with three replications. The quality of the commercial products was tested in the laboratory based on microbial density, pH and moisture content. The study showed that, although the products had microbial density lower than that labeled on them, the colony forming units (CFU’s) determined met the Kenyan standards of biofertilizer specifications. The application of Eco-Rhiz-Soya + Eco-T significantly increased (P<0.05) soybean nodulation by 69% and 67% over the control at Kpongu and Akukayili respectively. Furthermore, shoot biomass yield increased by 45% and 58% respectively at Kpongu and Akukayili. Grain yield of soybean was increased by Eco-Rhiz-Soya + Eco-T by 19% and 43% over the control at Kpongu and Akukayili respectively. Moreover, soybean shoot N was significantly increased (P<0.05) by Eco-Rhiz-Soya + Eco-T at both sites of the study whereas shoot P uptake was only significantly increased at Akukayili. The soybean inoculation treatments had no significant effect on grain P uptake while grain N was significantly increased at Akukayili only. With respect to maize, the treatments had no significant effect (P>0.05) on grain yield shoot biomass, shoot and grain N and P at both sites of the study. The products used for the maize experiments need to be evaluated further to assess their efficacy before concrete conclusions can be made on their effectiveness and subsequent recommendation for use by smallholder farmers.
A thesis submitted to the Department of Crop and Soil Sciences, Faculty of Agriculture, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirements for the degree of Master of Science in Soil Science, 2014