Combined application of microbial consortium and humic substances to improve the growth performance of blueberry seedlings

Abstract

A field experiment was carried out to assess the effectiveness of microbial consortium (bacteria and fungi) and humic substances separately, as well as the effect of the combined application of them on the growth of blueberry (Vaccinium corymbosum L.) seedlings and the physicochemical and biological properties of a volcanic ash-derived soil. One year after seedlings were planted, the treatment consisting of the combined application of microbial consortium and humic substances was the most effective, recording a 50% increase in shoot dry weight and a 43% increase in root dry weight compared to the control plants. Similarly, the microbial inoculant treatment also showed increased shoot and root dry weights, with values 32% and 31% higher than the control plants. The combined application of microbial consortium and humic substances improved nitrogen and potassium uptake compared to the unamended soil. Regarding soil properties, the soil nitrate content was higher when applying the humic substances alone, while changes were also observed in the rhizobacterial community composition. This suggests that the use of humic substances substantially modifies the bacteriological characteristics, but not the mycological characteristics of the rhizosphere. The combined treatment had positive effects on both plant performance and nutrients uptake in a volcanic ash-derived soil.