Application of Phytotoxkit in the quick assessment of ashes suitability as fertilizers in sorghum crops

The aim of the research was to check the suitability of the Phytotoxkit test for quick assessment of usefulness of ashes from the combustion of sorghum and Jerusalem artichoke biomass as fertilizers in the cultivation of energy crops. Seeds of Sorghum bicolor L. were placed in the Phytotoxkit-plates, filled with Alonet Substrate KS (Latvia) and containing 0-100% of ash from burnt sorghum and Jerusalem artichoke plants. Based on daily measurements under greenhouse conditions, dynamics of seed germination, growth speed of shoots and roots, their fresh and dry biomass, index of chlorophyll content and parameters of gas exchange were evaluated. The results indicated that the modified Phytotoxkit biotest could be useful for quick assessment of ashes usefulness as fertilizers, it can be performed under greenhouse conditions regardless of the growing season and may be an alternative to laborious and long-term field trials. Biotest showed that the studied ashes, used in the proper dosages, improved seed germination, plant growth and biomass yield. These events were associated with increased index of chlorophyll content in leaves, net photosynthesis, stomatal conductivity, transpiration and proportionally decreased concentration of intercellular CO2. This indicate, that the studied ashes can be used as fertilizers in sorghum crops.