Tomasz Ciesielczuk*, Czesława Rosik-Dulewska**, Agnieszka Szewczyk***, Joanna Poluszyńska***
*Uniwersytet Opolski; **Instytut Podstaw Inżynierii Środowiska PAN; ***Instytut Ceramiki i Materiałów Budowlanych

Sustainable fertilization is one of the most important treatments of modern agriculture. Organic agriculture with new demands on agricultural practice, seeks to restrict the use of mineral fertilizers in favor of slow-action organic fertilizers. The fertilizers which are made on the farm are particularly valuable due to their quality and the absence of costs of purchase and transport. From this point of view, the new possibilities of using an organic matter which comes from waste of the food industry or biodegradable wastes from households proves to be interesting. Due to the absence of contamination with other types of waste, it can be used for the production of a fertilizer which could be used even in organic crop production. This paper presents the results of the release dynamics of nitrogen forms from the fertilizer tablets made by covering a mixture made of spent coffee grounds (SCG) with membrane, modified by ash from the low-temperature combustion of biomass. Collagen, polyvinyl acetate, polyvinyl alcohol, shellac, and sodium water glass were used as the test membranes, in order to slowdown of elution of the components from fertilizer. Leaching tests were performed in accordance with PN-EN-13266 norm, for 118 days at 25°C. The obtained results indicate high differences in nitrogen and organic matter leaching speed from fertilizer tablets, depending from the used membrane. A strong inhibition of the emission of components through the membrane of shellac and polyvinyl acetate was observed. Other membranes do not inhibit the release of nutrients in a long time period, but they can be used in agricultural practice as well.

Słowa kluczowe
azot, nawozy, wymywanie, odpady poekstrakcyjne kawy, zrównoważone rolnictwo

Dynamic of Nitrogen Leachate from Slow-action Fertilizers in a Laboratory Experiment

Key words 
nitrogen, fertilizers, leaching, spent coffee grounds, sustainable agriculture

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