The study looked at how using bio-organic fertilizer made from Pleurotus ostreatus residue affects tomato growth. They found that using this fertilizer can improve soil quality by increasing organic matter and nutrient levels. While NPK compound fertilizer gave the highest tomato yield, bio-organic fertilizer led to lower nitrate levels in the fruit and higher levels of sugar, solids, and vitamin C. Overall, using bio-organic fertilizer can boost root growth and improve the quality of tomatoes grown in protected fields.