No abstract

Lignocellulosic residues are used to produce mushrooms, but they generate large amounts of spent mushroom substrate (SMS). The objective of this study was to evaluate they effect of SMS of Pleurotus ostreatus, combined with organic fertilization, on biomass production and essential oil yield of basil (Ocimum basilicum L.) plants. The fertilizer was formulated using combinations of organic compounds: SMS, organic compost (OC), and earthworm humus (EH). The treatments were applied using 35 g of the formulations, corresponding to an application of 20 Mg ha-1. The treatments used were: 100% OC; 100% EH; 100% SMS; 75% SMS + 25% OC (C1); 75% SMS + 25% EH (C2); 50% SMS + 50% OC (C3); 50% SMS + 50% EH (C4); 50% SMS + 25% OC + 25% EH (C5), and a control with no fertilizer application (CT). Plants grown with the soil fertilizers containing SMS, single or combined with OC and EH, presented higher average plant height (55.6 to 62.2 cm) and leaf area per plant (696.5 to 836.4 cm2). The treatment C3 resulted in plants with higher mean dry weight (10.9 g plant-1), and C2 resulted in the highest oil yield (5.0 kg ha-1), representing a gain of 324.8% in oil yield when compared to the control. Thus, SMS increases biomass production and essential oil yield of basil plants.