The objective was to analyze the performance and ideal size of sample (n) of the slip and the capacity of row a crop planter under no-till (NS) and prepared seedbed (PS). A random sample method was used to determine "n", considering infinite populations. To estimate the slip on PS, using α = 5% and precisions equal to 5, 10, 15, and 20%, it is necessary to perform a number of repetitions equal to 115, 29, 13, and 8, respectively. For the NS, 422, 106, 47, and 27 were observed, respectively. For the theoretical field capacity (tC) on PS, it is necessary to perform a number of repetitions equal to 27, 7, 3, and 2, respectively. For NS, 45, 12, 5, and 3 were observed, respectively. For the effective field capacity (eC) in PS, it is necessary to perform a number of repetitions equal to 33, 8, 4, and 2, respectively. For NS, 36, 9, 4, and 3 were observed, respectively. The slip for PS was 10.7%, and for NS it was 7.2%. The tC was 2.67 m² s-1 on PS, and 3.19 m² s-1 on NS. The eC was 1.72 m² s-1 on PS, and 2.08 m² s-1 on NS.
sampling; field capacity; slip