Currently, due to people’s growing awareness, it is increasingly important to search for alternative preparations to chemical crop protection products and mineral fertilisation, which could be applied in agriculture and horticulture in order to increase the fertility of soil, improve its sanitary condition and yield.
The aim of the study was to assess how an innovative biopreparation made from granules consisting of grain mill waste (oat husks) and molasses, which were inoculated with selected strains of fungi of the Trichoderma genus, affected the microbiological properties of soil, its biodiversity and sanitary condition, as well as the yield and morphological traits of lettuce.
The experiment was conducted under controlled conditions in a greenhouse, on two types of soil with different organic matter content (soil with higher and lower content of nutrients). The assessment of microbiological properties included measurement of the soil biochemical activity, i.e. the activity of dehydrogenases (with the Thalman method) and catalase (with the Johnson and Temple method). The sanitary condition of the soil was assessed by measuring the counts of pathogenic fungi of the Fusarium and Alternaria genera with the serial dilution method. The Komada selective medium with ox bile, chloramphenicol, streptomycin, borax, and PCNB (pentachloronitrobenzene) was used for the Fusarium fungi. The Hong and Pryor medium with 20% lactic acid, botran (dicloran), bayleton (triadimefon), and streptomycin was used for the Alternaria fungi. The metagenomic analysis of the gene encoding 16S rRNA was used to assess the biodiversity of the soil microbiome. The analysis was based on the hypervariable region V3-V4 of the 16S rRNA gene.
The research showed the stimulating effect of the biopreparation made from granulated oat husks inoculated with fungi of the Trichoderma genus (WMT-P) on the phytosanitary properties of the soil. In comparison with the conventional cultivation, the preparation limited the growth of pathogenic fungi of the Fusarium and Alternaria genera on the lettuce plantation. The biopreparation also increased the dehydrogenase activity in the soil, the biological index of fertility (BIF), the yield (fresh weight) of lettuce and the biometric parameters of the root.
The metapopulation analysis of the soil samples showed that the innovative biostimulant increased the soil content of Acidobacteriota and beneficial bacteria of the Gemmatimonadota and Chloroflexi phyla.
Note: The research was financed under the project ‘Development of technology for the production and application of innovative biopreparations promoting plant growth’ as part of the Regional Operational Program - Lubuskie 2020 Priority Axis 1 Economy and innovation for Action 1.1 Research and Innovation (2019-2021), RLPB01.01.00-08-0004/18.