Effectiveness of Compost Produced from Spent Substrate of Deep Root Mushroom (Xerula radicata) on the Growth and Yield of Maize (Zea mays L.)

Spent mushroom substrate from Xerula radicata cultivation is an underutilized organic resource that requires appropriate management. This study evaluated three initial C:N ratios (25:1, 30:1, and 35:1) and three Trichoderma-CTU inoculation rates (0.1%, 0.5%, and 1.0%) in terms of composting performance, followed by an evaluation of maize seed germination, soil properties, plant growth, and yield. The initial C:N ratio influenced several composting characteristics, with treatments at a C:N ratio of 35:1 reaching the thermophilic phase earlier and showing higher particle uniformity than the lower C:N ratio treatments. The resulting composts had final C:N ratios within the range of 13.89–20.57, low heavy-metal concentrations, and favorable microbiological characteristics. Compost application significantly affected several germination and seedling-growth parameters, increased soil pH, and enhanced soil microbial populations following maize cultivation. Although several compost treatments showed favorable numerical trends in maize growth and yield, these responses were not consistently significantly different among treatments. Overall, the findings support the potential of Xerula radicata spent substrate as a raw material for compost production and provide an initial evaluation of its agronomic performance under pot-scale maize cultivation.