NPK Rich Leafy Tree Biomass as Dual-Purpose Substrate: Improving Pleurotus Spp. Nutrients Uptake and Recycling through Spent Mushroom Waste

The use of the NPK (nitrogen, phosphorus, potassium) rich tree based leafy biomass can be used as a sustainable food production option and can valorize the organic waste. This research was conducted to study the mineral dynamics in the cultivation of Pleurotus spp. on paddy straw mixed with different levels (25, 50, 75, and 100 %) of Swietenia macrophylla, Gliricidia sepium, and Sesbania grandiflora leaves. Mineral dynamics at three stages (original substrate, harvested fruiting bodies, and spent mushroom waste (SMW)) were measured. The foliar substrates substantially enriched the substrate medium, and the 75% supplementation fortuitously contributed to maximal nutrient content in fruiting bodies, especially for nitrogen, phosphorus, potassium, calcium, and zinc. Nutrient composition of post-harvest SMW remained high indicating its use as a rich organic soil amendment. These results emphasize the twofold advantage in recycling tree foliage for mushroom production: the enhancement of nutricious yields, with a side contribution to sustainable plant residue upcycling in the framework of a circular bioeconomy.