Effect of co-application of Trichoderma spp. with organic composts on plant growth enhancement, soil enzymes and fungal community in soil.

The application of Trichoderma spp. has the potential to reduce not only mineral fertilizer use in agriculture but also improve soil health through increased soil biological activity. Trichoderma spp. have shown potential as bio-control agents and plant growth promoting ability, but little attention has been paid to the effect of Trichoderma spp. inoculation on nutrient availability and the soil microbiome. In this study, we evaluated the effect of Trichoderma spp. inoculation on nitrogen mineralization and quantified soil enzymatic activities along with plant growth promotion potential. The influence of Trichoderma spp. and organic amendments on the soil fungal community was also investigated. For this purpose, pots and incubation experiment was carried out, and seven treatments were set as follows; poultry compost (PC), poultry compost + RW309 (PCT), cattle compost (CC), cattle compost + RW309 (CCT), rapeseed oil cake (OC), inorganic fertilizer (N) and only soil (S) were set as control. We evaluated that Trichoderma sp. RW309 produced indole-3-acetic acid, which suggested that it could contribute to plant growth enhancement during early plant growth. Inoculation of RW309 with organic materials stimulated nitrogen mineralization and increased soil phosphatase activity. Furthermore, RW309 altered the fungal community in rhizosphere soil. However, cattle compost was a more suitable culture medium for RW309 than poultry compost in terms of nitrogen mineralization, soil enzyme activity, and growth of RW309. In conclusion, Trichoderma sp. RW309 could be considered for use as a bioorganic fertilizer in combination with organic compost to minimize the use of mineral fertilizers.