Effects of Organic Compost and Trichoderma harzianum Spores on Soil Fertility and Agronomic Performance of Soybean (Glycine max (L.) Merr.)

The food supply has grown steadily over the years, while production has been hampered by the increased use of synthetic fertilizers, leading to pollution and degradation of soil physico-chemical properties. It is imperative to advocate for the promotion of sustainable farming techniques that can enhance crop yields while improving soil fertility, without the excessive utilisation of chemical fertilizers. Hence the interest of this study, which involved the use of organic compost enriched or not with Trichoderma Harzianum spores as an alternative method to assess their effect on the physico-chemical soil and agronomic parameters of the « TGX 1910-14F » soybean variety being tested in a greenhouse growing vase. The study was carried out at the Institute of Research Development (IRD) in Ouagadougou (Burkina Faso), on a completely randomized block trial with four fertilization regimes repeated five times. The trial consisted of comparing soil parameters and soybean yields under four fertilization regimes: T1 (1 l m-3 of Trichoderma harzianum spores); T2 (3 t ha-1 of compost); T3 (3 t ha-1 of compost + 1 l m-3 of Trichoderma harzianum spores), T0 (absolute control with no inputs). 4 kg of fine soil from a lixisol and sieved to 2 mm with a field capacity moisture of 150 ml kg-1 of soil were added to each fertilization regime. The results showed that T2 and T3 fertilization regimes improved the organic status, total N, P and K content, absorbable P and available P of the soils. T3 significantly (P < 0.001) increased plant height (146.80 ± 9.92 cm) and the number of soybean plant leaves (46.20 ± 2.41) compared with treatments T0 and T1. T0 and T1 fertilization regimes significantly increased (P < 0.001) the number and weight of soybean nodules compared with T2 and T3. Total soybean biomass was significantly improved (P < 0.001) under T2 and T3 compared with T1 and T0. Thus, the T2 and T3 fertilization regimes was more effective in improving soil fertility and soybean biomass production. The input of Trichoderma harzianum (T1) and fine soil with no inputs (T0) stimulated nodulation of soybean, while compost combined with Trichoderma harzianum spores (T2 et T3) had an effect on vegetative growth. It may be posited that the latter treatment could serve as an alternative means of improving soil fertility and increasing soybean yields.