Effect of compost amendments from Tridax procumbens L. and cow dung on the microbial activity and agronomic traits of tomato plants infested with Ralstonia solanacearum

Incorporation of compost amendments into the soil is a promising strategy for the control of some soil-borne plant diseases. The aim of this study was to evaluate the effect of compost amendments from Tridax procumbens L. and cow dung on the microbial activity and agronomic traits of tomato plants infested with Ralstonia solanacearum. Tridax procumbens L. and cow dung were composted for 20 days using five different proportions. Physicochemical properties and microbial load of the composts were determined using the standard methods. Isolates were identified based on morphological, colonial and biochemical characterisations. Different compost concentrations were added to sterile soil with and without Ralstonia solanacearum after which tomato nurseries were transplanted. Agronomic parameters such as plant height, number of leaves, stem girth and leave area were determined after two and four weeks of transplanting. Cow dung only (CD) had the highest Total Bacterial Count (TBC) and Total Fungal Count (TFC) of 265.67 x 10(4) CFU/g and 92.3 x 10(3) CFU/g respectively while T. procumbens only (TP) had the least TBC (46.3 x 10(4) CFU/g) and TFC (13.33 x 10(3) CFU/g) . Bacillus species, Pseudomonas species, Aspergillus species and Penicillium sp. were predominant throughout the duration of composting. Highest pH (7.3) was recorded by Cow dung + T. procumbens (C:T)(1:1) while TP had the least pH (6.2). Highest temperature (41.9 degrees C) was recorded by C:T(1:2) while TP recorded the least 29.8 degrees C. After four weeks, the compost amendments improved the plant height, number of leaves, stem girth, and leaf area in the un-infested and diseased tomato plants. This study showed that compost from T. procumbens and cow dung can be used to improve the growth of tomato and also suppress bacterial wilt of tomato.