An amount of over 1 800 thousand tonnes of spent mushrooms substrate is generated every year in Poland. This waste is characterized by a high content of organic matter, macro- and micronutrients. For this reason, spent mushroom substrate should be used in agriculture primarily to improve the balance of organic matter and to enrich the soil with available forms of nutrients. The aim of this study was to develop a technology of producing a new granulated organo-mineral fertilizer from spent mushroom substrate and assess its quality for possible use in horticultural production. Granulated organo-mineral fertilizers were produced from composted spent mushroom substrate, and two fertilizers were produced from compost made from fresh spent mushroom substrate mixed with sewage sludge. Prior to granulation, different amounts of mineral fertilizers were added to the compost. The evaluation of the fertilization value of the granulated organo-mineral fertilizers was conducted on the basis of a microplot experiment established on sandy soil at the Experimental Station of the Warsaw University of Life Sciences. The tested plant was white cabbage (Brassica oleracea L. var. capitata L.). Organo-mineral fertilization effects a significant increase of soil pH, organic carbon content and total nitrogen content in soil, in addition to which it increased the soil content of phosphorus, potassium and magnesium. The tested fertilization regime significantly affected the yield of cabbage, which increased by 90 to 103% relative to the control. Nitrogen use efficiency (NUE) for the tested organo-mineral fertilizers ranged from 15.9 to 33.0%, and agronomic efficiency (AE) varied from 1.6 to 51.1 kg DW kg-1 N.

24.3.2019