On everyday basis we are faced with different types of waste, which can be reused by recycling and processing. One of such methods is the processing of biodegradable waste in biogas plants. The final products of this process are biogas which can be used for heating and digestate, which is useful as a fertilizer. In our experiment, samples of digestate produced from food waste, provided by the Company KOTO, were used. We were interested in the effect of the digestate on seed germination, plant growth, and the content of macro and micro elements in the plants. We measured the percentage of germination in seeds of four different plant species (perennial rye-grass (Lolium prenne L. 'CALIBRA'), barley (Hordeum vulgare L.), garden cress (Lepidium sativum L. 'Cressida') and white mustard (Sinapis alba L.)), germinating in Petri dishes on paper soaked in 100%, 50%, 25%, 12,5% and 0% digestate extract. We also monitored the growth speed of sprout roots and shoots. The germination test confirmed the influence of different digestate extract concentration on seed germination. The highest extract concentration showed a negative effect on germination and root growth. To monitor the growth dynamics and the intensity of the leaf chlorophyll coloration intensity at different amounts of added digestate (30% and 15% of added digestate to base substrate and a control), we performed a five week pot experiment with maze (Zea mays). At the end of the experiment we analyzed the content of macro an micro elements in underground and over ground parts of maze plants and the substrates in which they grew. Poorer plant growth was observed in the substrate with the highest amount of added digestate, which we attribute to the lowest concentration of nitrates in these substrates. The content of macro and micro elements in the underground and over ground parts of maze showed strong correlation with the amount of added digestate.
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