The sports field consists of three layers (sub-base, base (substrate) and grass). The base is  responsible for the radicular development of the grass, directly influencing the characteristics that provide quality, water drainage and lawn durability and allows athlete performance. The construction of sports field base generally follows USGA (United States Golf Association) recommendations for golf course greens. Sand is the main component based on its high capacity for drainage. This study aimed to define the best composition of the base for sports fields covered with Bermuda grass. The following treatments were evaluated: T1: sand; T2: sand (80%) + peat (20%); T3: sand (90%) + clay soil (10%); T4: sand (70%) + sandy soil (30%) during 12 months. The experimental design consisted of a randomized block design, with a 4 x 12 factorial design (treatments x months), with 3 replicates  and each plot measuring 3 x 4 m. During one full year, the following parameters were evaluated: surface traction of the turf, mechanical resistance of the base to penetration, humidity of the base, concentration of nutrients in grass clippings, and chemical analysis of the base. The tallest grass occurred in substrate of sand mixed with peat. This mixture also promoted the highest N and P levels in the leaves of Bermuda grass. Playability of the sports field, as determined by mechanical strength and surface traction, was unaffected by the type of substrate. The presence of peat, sand and clay soil mixed with sand promoted greater water retention at the base.