Farmers must prioritize soil enhancement methods to preserve soil health and sustainability as the world population grows, whereas arable lands deplete and degrade owing to poor land management and agricultural policy. Biochar and compost are essential for replacing nutrients and organic matter, improving soil quality. In 2019, an experiment was carried out at Jordan University of Science and Technology. Various soil amendments, including biochar and compost, both with and without the combination of poultry manure, were employed. The experimental design followed a completely randomized layout, with seven distinct treatments: T1–soil (control), T2–biochar (3%) (BC), T3–compost (3%) (Comp), T4–poultry manure (3%) (PM 3% (38.2 ton/ha)), T5–Biochar (3%)+poultry manure (60 ton/ha) (BC+PM 60 ton/ha), T6–compost (3%)+poultry manure (60 ton/ha) (Comp + PM 60 ton/ha), and T7–poultry manure (60 ton/ha) (PM 60 ton/ha). The assessment encompassed the examination of various physicochemical characteristics of the soil, including bulk density, porosity, water holding capacity, pH, and EC. Morphological and physiological measurements comprised height and length of plant shoots and roots, number of leaves, fresh and dry weight of shoots and roots, leaf relative water content, and chlorophyll content. Additionally, the chemical composition, encompassing crude fibers, crude fats, antioxidant activities, total phenols, flavonoid content, and minerals were evaluated. Physicochemical results revealed that (BC+PM 60 ton/ha) excelled in water holding capacity and porosity, whereas PM 60 ton/ha exhibited the optimal soil pH. In terms of morphological results, (Comp+PM 60 ton/ha) and (PM 3% (38.2 ton/ha)) demonstrated superiority in plant height, shoot fresh and dry weight. The application of (BC) outperformed in root fresh and dry weight and leaf relative water content, while (Comp) exhibited the highest root length. Poultry manure applications scored higher values in chlorophyll content, with (BC+PM 60 ton/ha) recording the highest among them. Chemical analysis revealed that crude fibers were highest with the application of (PM 3% (38.2 ton/ha)), while (control) recorded the highest antioxidant activities, total phenols, and total flavonoids. In terms of mineral content in shoots, (Comp+PM 60 ton/ha) demonstrated the highest nitrogen content. Phosphorus, potassium, magnesium, and calcium were most abundant in (BC+PM 60 ton/ha). Moreover, PM (60 ton/ha) exhibited the highest sodium content. Notably, the (BC+PM 60 ton/ha) application excelled in physiochemical soil properties, excluding soil pH and EC, while also demonstrating superior mineral content in lettuce plants, except for sodium.
