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Effects of Tithonia diversifolia on seed germination, growth parameters and the nutrient content of soybean

¹University of Yaoundé 1, Dept. of Biochemistry, Cameroon
²University of Bamenda, Dept. of Biochemistry, Cameroon

Abstract

Conventional farming relies heavily on chemical inputs such as synthetic fertilisers. Yet, their negative impacts on human and environment health have been well documented. Tithonia diversifolia is a plant that could be used as an organic fertiliser due to its high content of nitrogen. This study investigated the effect of T. diversifolia extract at different concentrations and incubation time on the germination of soybean seeds and the effect of T. diversifolia leaves applied in powder form or composted on soybean growth and nutrient content. We employed a split plot design with three replicates made up of four blocks. Each block was amended (main factor) either with T. diversifolia compost (150 g/plant), powder (40 g/plant) or the synthetic fertiliser NPK (10 g/plant) respectively, followed by spraying (second factor) with same fertiliser at 20 g/L, 20 g/L and 2 g/L or water every two weeks after one-time amendment. The control block received no amendment and was sprayed with water. The top of paper method was used to evaluate the effect of T. diversifolia extracts on soybean seed germination at different incubation times. Growth parameters including plant height (cm), number of pods per plants, seed weight per m² (g) and grain yield (t/ha) were recorded. The soybeans were harvested four months after sowing and analysed for crude protein, lipids, and fiber contents using the Kjeldahl, Bourely, and Weende methods respectively. T. diversifolia extract at 1 g/L and three hours incubation time produced the highest percentage seed germination (72%). T. diversifolia compost produced the best growth (P<0.05) in terms of plant height (63.3±3.1), number of pods per pant (83.7±5.1), seed weight per m² (357.7±45.5), grain yield (3.6±0.5) as compared to the others treatments. The highest crude protein content (31.2%) in the soybeans was observed in the T. diversifolia compost treatmentT. diversifolia powder yielded higher lipid (31.4%) and fiber (5.9%) contents as compared to other treatments. Thus, T. diversifolia extract can be used as a bio-stimulant to optimise the germination of seeds like soybean while its leaves whether powdered or composted are a promising organic fertiliser for promoting organic crop production in Africa.

Keywords: Growth parameters, nutrient content, organic fertiliser, soybean, Tithonia diversifolia

Contact Address: Joseph Blaise Dongmo Lekagne, University of Yaoundé 1, Dept. of Biochemistry, Ngoa-Ekele 812, Yaoundé, Cameroon, e-mail: blaiselekagneyahoo.fr