Experimental and numerical research of granular manure fertilizer application by centrifugal fertilizer spreading

. Conventional, intensive farming depletes the soils. In order to preserve yields, mineral fertilizing rates are being raised, which even more is damaging the soil and the environment. One of the ways to contribute to the implementation of the principles of sustainable agriculture is organic fertilizers. Granular manure, meat-and-bone meal, RPK, and other fertilizers are currently widely used. Different fertilizer spreaders can be used to spread the fertilizer: direct spreading, centrifugal, precision. In this work, experimental field fertilizer spreading studies were performed using organic granular cylindrical manure fertilizers with an average diameter of 4.79 mm, length 7.86 mm, and density 1390 kg m -3 . The study was performed using a mounted two-disc centrifugal fertilizer spreader. Two spreading disc blades of different lengths were used to spread the organic fertilizer. Two different fertilizer spreading methods were used in the study: one directional and gradual. When using the fertilizer, the uniformity of spreading was assessed over the entire working width of the spreader according to standardized methodologies. A significant difference was not found between the two driving modes. A typical gradually decreasing trend of the fertilizer weight distribution from the centre of the spreader was obtained. The results showed that as the spread rate of the fertilizer was higher, the distribution was more uniform. Complementing and expanding the possibilities of the experimental research, studies of the dispersion of analogous granules under analogous conditions by the modelling DEM software were performed. The mean of the numerical values was obtained 10% lower than the experimental one. This discrepancy may have been due to the granule properties, environmental parameters, and other factors that were not enough evaluated in the software.