Evaluation of Oyster Mushroom Compost Tea (OMCT) as an Organic Input for the Growth and Yield of Cauliflower Plants

Organic by-products are widely used as sustainable amendments to enhance vegetable productivity while reducing the environmental impact of farming practices. Owing to its high nutritional value, cauliflower (Brassica oleracea L. var. botrytis, cv. El-Soultani) was selected for this study to examine the effects of oyster mushroom compost tea (OMCT), as an organic by-product, on its growth and development. Cauliflower plantlets were cultivated under open-field conditions and sprayed with different dilutions of OMCT three times at 15-day intervals after transplanting. The dilutions included 1 L of OMCT-B mixed with varying amounts of water (50, 100, 150, and 200 L) and the plants sprayed with tap water only served as the control treatment. The results demonstrated that foliar application of OMCT significantly enhanced all evaluated parameters, exhibiting a progressive yet nonlinear concentration response pattern (p < 0.01), with the strongest responses consistently observed at the A3 dilution. Under open-field conditions, treatment 1: 100 dilution (A3) produced the highest average curd weight in both growing seasons. Consequently, total yield increased by 137.03% in the 2023 growing season and by 117.41% in the 2024 growing season compared with the untreated control. These findings indicate that the A3 was the most promising OMCT-B treatment for enhancing cauliflower curd yield and overall productivity under the conditions of the present study. The beneficial effect of OMCT on nutrient availability and nitrogen metabolism may be partly attributed to the organic substances present in OMCT. These substances interact with plant nutrients in complex ways, serving multiple functions.