Influence of Spent Oyster Mushroom Substrates on Growth of Waterleaf (<i>Talinum triangulare</i>) and Microbial Population

Agricultural waste poses a significant environmental pollution problem annually. Repurposing waste, like spent mushroom substrate, can address economic challenges. This study examined microbial populations in spent oyster mushroom substrate and their impact on the growth of water leaf (Talinum triangulare). Microbial analysis of the spent mushroom substrate (SMS) was conducted before and after planting, measuring total microbial counts. Planting substrates comprised three ratios (9:1, 8:2, and 7:3 SMS to soil mix), with a control group using only soil. Six-centimetre water leaf stems were sown in sixteen polythene nursery bags, with each group of three bags containing 2 kg of a planting substrate. Growth parameters were assessed four weeks after planting. Microbial analysis revealed various bacterial species (e.g., Pseudomonas sp., Micrococcus leuteus, Shigella sp., Salmonella sp., Bacillus subtilis, Klebsiella sp., Staphylococcus sp.) and fungal species (e.g., Aspergillus sp., Fusarium sp., Penicillium sp., Alternaria sp., Rhizopus sp.) in SMS. The control group exhibited superior growth compared to SMS-amended soil. The study concluded that while microbes in spent mushroom substrate facilitate organic nutrient decomposition, improving nutrient availability and moisture retention, they adversely affect water leaf growth due to excessive moisture, making it unsuitable for water leaf cultivation