The Use of Tithonia diversifolia L. as Soil Amendment and Its Effect on the Growth and Yield of Amaranthus cruentus in a Tropical Rain Forest Belt

The effect of the use of Tithonia diversifolia as soil amendments on the growth and yield of Amarantus cruentus was investigated under field conditions at the Teaching and Research Farm of Joseph Ayo Babalola University, Ikeji-Arakeji, Nigeria. Tithonia diversifolia, Pig slurry and Urea were used for soil treatments. Tithonia diversifolia and Pig slurry were applied at the rate of 4,500 kgh-1 while Urea was applied at the rate of 250 kgh-1. The treatments were replicated three times using Complete Randomized Design (CRD). The soil of the experimental site was analyzed before planting and after harvesting of the vegetable. Agronomic data on plant height, stem girth, number of leaves, leaf area, leaf length and width were collected at 19, 22, 25 and 28 days after planting (DAP). Data collected were subjected to analysis of variance (ANOVA) and the means were separated using Duncan multiple range test at 5% probability level. The results showed that plant height, stem diameter, leaf width and leaf area index were significantly influenced by the application of both the organic manures and the urea fertilizer. At 19 days after planting (DAP), the plant height recorded were 14.22 cm, 12.87 cm, 12.53 cm and 10.52 cm for Tithonia diversifolia, pig slurry, urea and the control respectively. From the study, it was evident that organic manures compete favorably with the mineral fertilizer. Tithonia diversifolia performed better in most of the growth parameters taken while the performance of urea does not significantly different from that of pig slurry. The post-harvest pH values of the soil ranged from 6.70 to 6.78, indicating that the soil was slightly acidic. A slight increase in phosphorus content of the soil in the plot where Tithonia diversifolia and urea were applied was observed while a decrease trend was noticed in plots where Pig slurry was applied. The result from this study shows that it is expedient to make amendment to soils in the tropical regions using readily available local resources such as Tithonia diversifolia as organic manures to improve its fertility instead of spending huge amount of money on the purchase of synthetic fertilizer.