EN
The surveys referred to the estimation of crop yields, their variability and growing tendencies in yielding of cereals and potatoes, were carried out on private farms in Jelenia Góra region. The survey method included basic statistical measures such as: valorization index, variation coefficients, standard deviation and the least square method used in calculation of growing tendency in crop yielding. Positive and statistically significant indices of yielding per hectare and low level of variability were showed for basic cereals: wheat, rye, barley and oats at favourable soil and climate conditions. However, very high and high variability and unfavourable trends were shown in the profile of potato yielding in the whole population and also at estimating the efficiency of cereals, especially at cultivation of barley and oats on the soils of low valorization index.