Organic matter decomposition is an important process that assures the recycling of nutrients in agroecosystem soils. This research aimed to assess the presence of decomposition-associated microorganisms on both the organic material and the bag surface, considering them as a buffer between the soil and organic matter. The study of the organic matter decomposition process was conducted using a modified litterbag method, based on tea bags filled with chopped straw, placed in an experimental field exposed to long-term fertilization. Serial dilutions were performed on both the straw material and the surface of the bag that came into contact with the soil and decomposing plant matter. The development of microorganisms increased progressively at 24, 48, and 72 hours, but a maximum CFU (mixed colonies) was recorded in variant 9 for the plant biomass. To this variant intensive soil amendment (5 t/ha) was applied with the addition of phosphorus as a mineral fertilizer, while the other variants ranged from values below 100 to just over 600 colonies. Slightly lower values were recorded in the buffer, where the quantity of fine particles from both soil and straw is lower, which explains the decrease in the number of colonies. The phenomenon of confluence appears in variants 3, 4, and 5, in both the plant biomass and the buffer material in more than half of the plates. This phenomenon led to the unification of microbial colonies, which reduced their visibility and individuality, this process being observed particularly between 48 and 72 hours of incubation. The dynamics of organic matter decomposition are closely associated with the activity of soil microorganisms involved in the transformation and recycling of nutrients. Colony-forming units serve as a useful indicator for evaluating this activity, offering information about the microbial response to various input additions.

organic matter decomposition, long-term fertilization, microbial colonies, CFU, confluence phenomenon

biology

Presentation: poster