The objective of the work reported herein was to determine the variations in the yield measured by yield monitor and to determine principal characteristics of the variations. The power spectral density function of the yield and the threshing cylinder drive torque were found to be of 1/f character therefore these processes can be simulated by fractional Brownian motion. The analysis of the fractal dimension showed that the fractal dimension of the yield is between 1.62 and 1.70 for the test fields. The coefficient of variation is 0.12 to 0.17 for the test fields. The fractal dimension and the coefficient of variation seem to be appropriate characteristics to describe variability of the yield.