Research on buckwheat yield in intercropped system has been demonstrated in Djakovo where the 12-year-old walnut orchard is located. In both locations the experiment included a barley control field, control parts of orchards and intercropped plots where barley 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 and yield components was measured and the number of weeds was determined, and finally the land equivalent ratio (LER) was calculated. The results showed that insolation in the shade compared to measurement in direct sunlight ranged from 85% during March and April when there was no leaf mass, 12% during May and 5% during July, which contributed to smaller oscillations in temperature and humidity within the association. Also, sowing barley between rows of walnuts in a poorly productive orchard in the experimet in Djakovo can increase the productivity of the observed area because there is no statistically significant difference beetween the yield of barley in the consociation and the control field (LER=1.53). 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.