EN
The paper deals with the influence of main spatial characteristics of a field extent such as area, length and width, on cultivation costs. Performed analysis allowed to determine proper parameters of a field extent i.e. parameters whose further improvement generates insignificant lowering of cultivation costs. The parameters depend on the function describing cultivation costs, namely on the occurrence of minima and horizontal asymptotes. The determined parameters were based on general tendencies ruling the relationships in question. For a properly formed field on which low and medium tractors are used, the following values for the proper parameters were found: more than 150 to 250 m of length, over 30 to 70 m of width and the area bigger than 1 to 2 ha.