SEEDLING EMERGENCE AND GROWTH RESPONSE OF SPINACH TO SOIL AMENDED WITH DIFFERENT SPENT OYSTER MUSHROOM SUBSTRATES

Soil health is one of the most important factors that influence plant productivity. Incorporation of soil into plant residues that are high in organic matter has been reported to improve soil’s physical and chemical properties which enhance plant growth and development. Therefore, the objective of this study was to investigate the effect of soils amended with different spent oyster mushroom substrates on seedling emergence and growth of spinach (Spinacia oleracea). The respective soil samples were amended with different Spent Mushroom Substrates (SMS) at ratio 60:40 (soil/substrate). Treatments were: T1= U. panicoides + soil, T2= Z. mays + soil, T3= D. stramonium + soil, T4= Substrate mix [60% soil: U. panicoides (13.33%), Z. mays (13.33%) and D. stramonium (13.33%)] and T5= un-amended soil (100%). The respective treatments were filled into 25cm diameter pots and arranged in a Complete Randomized Design (CRD) in a temperature-controlled glasshouse. In each respective pot, three S. oleracea seeds were planted at a depth of 2cm and watered 3 times a week. S. oleracea growth response was determined by assessing the following variables: emergence rate, plant height, number of leaves/plant and chlorophyll content over a period of 12 weeks. Total dry biomass was assessed at harvest by oven drying the plants at 60ºC for 72 hrs. On the first assessment, seedlings raised in Z. mays SMS had significantly higher emergence percentage than seedlings raised in D. stramonium, Substrate mix, U. panicoides SMS (p<0.05). Seedlings raised in Z. mays SMS attained 100% emergence 7 days after planting (DAP), and un-amended soils had 91.75% 9 DAP. Seedlings raised in Z. mays and D. stramonium SMS had significantly higher plant height than seedlings raised in U. panicoides SMS and un-amended soils (p<0.05). Seedlings raised in Z. mays SMS attained 26.27cm height compared to U. panicoides SMS and un-amended soils which attained 12.67cm and 14cm height, respectively. Findings of this study revealed that Z. mays and D. stramonium SMS amended soils have inherent properties that positively influenced the seedling emergence, establishment, and growth of S. oleracea. This would, therefore, have influence on the leaves which are the main agronomic yield of the crop.