Ash from Jerusalem artichoke and biopreparations enhance the growth and physiological activity of sorghum and limit environmental pollution by decreasing artificial fertilization needs

An increase in plant productivity and the limitation of environmental pollution through the use of natural fertilizers are becoming the most important issues in contemporary sustainable agriculture. Therefore, the purpose of the research was to demonstrate the effect of Jerusalem artichoke ash, used alone or together with biopreparations and biogas plant waste, on the growth and physiological activity of sorghum and to show their applicability as an alternative to chemical fertilization. The sorghum plants, cultivated in Central and North Poland, were fertilized with the YaraMila Complex, a chemical fertilizer (0, 150, 300 kg ha-1) and each concentration was supplemented with Jerusalem artichoke ash (0-4 t ha-1), applied separately or together with Apol-Humus (10 L ha-1), biogas plant waste (30 m3 ha-1) and Stymjod (5 L ha-1). Within each YaraMila Complex addition, the all ash doses (preferably 2-4 t ha-1), biopreparations and biogas plant waste significantly enhanced plant growth, biomass yield, chlorophyll content, gas exchange (net photosynthesis, transpiration, stomatal conductance, intercellular CO2 concentration), enzyme activity (acid and alkaline phosphorylase, RNase, dehydrogenase) and slightly enhanced the content of the measured elements in plants and their energy properties. The ash applied together with a lower than recommended amount of YaraMila Complex (0 or 150 kg ha-1) increased plant development slightly more than twice the dose of YaraMila Complex used alone (150 or 300 kg ha-1, respectively). This demonstrates that the studied ash can serve as a natural fertilizer and may halve the recommended chemical fertilizer doses.