Research on buckwheat yield in intercropped system has been demonstrated at two locations - in Djakovo where the 11-year-old walnut orchard is located and in Ivankovo, on a 4-year-old orchard. In both locations the experiment included a buckwheat control field, control parts of orchards and intercropped plots where buckwheat was sown between 5 low productive rows. During vegetation the agrochemical composition of the soil was determined, the width of the canopy was measured to determine the effect of shading and insolation, while during harvest the yield was measured and the number of weeds was determined, and finally the land equivalent ratio (LER) was calculated. The results showed that the correlation of direct solar radiation with respect to the sun radiation in the shade of the canopy is lowest in the summer (6-8%), then in October (20%), while in April it was 30%, and highest in November because of a leafless canopy (85%). Buckwheat yields statistics showed lower yield in an older orchard compared to control field due to overlapping vegetation with branched nuts, resulting in yield reduction of 28% but increased the overall productivity of such areas (LER = 1.05). The four year old walnut orchard had no statistically significant differences between the buckwheat yield in the orchard and the control field. Results point to the possibility of growing plants like buckwheat in intercropped system with walnut trees, but production of this kind is only profitable to an extent. Previous research on the subject shows that yields in the consociation system typically decline drastically about 8-10 years from planting, indicating that the shading effect is the force controlling the buckwheat yields in such combined systems.