Yield determination in olive hedgerow orchards. I. Yield and profiles of yield components in north-south and east-west oriented hedgerows

A study of the vertical distribution of flowering and fruit set and of components of yield (fruit numbers, fruit size, and fruit oil content) was maintained for 2 years in N-S-and E-W-oriented olive hedgerows of comparable structure (row spacing 4m, hedgerow height to 2.5 m, width c. 1m) near Toledo, Spain (39.9 degrees N). Mean yield of the N-S orchard was 1854 kg oil/ha without difference between sides or years. Yield of the E-W orchard was greater in 2006, producing 2290 kg/ha, but only 1840 kg/ha in 2007, the same as the N-S orchard. The S side of the E-Worchard yielded more (59%) than the N side in 2007. In both orchards and years, most fruit was produced at 1.0-2.0m height and fruit density was the most influential component in these differences, reflecting more intense bud initiation in these upper layers. Other components that determined fruit number, fertile inflorescences, fruits per fertile inflorescence, and fruit drop were not significantly different between layers. Fruit characteristics depended on hedgerow position. In both N-S and E-W hedgerows, fruit high in the hedgerow was the largest, most mature, and with highest oil content. These differences were more marked in N-S than in E-W hedgerows. Fruit growth and development were concentrated from the middle of September until the end November. Oil content per fruit increased linearly during that period when 65% of final oil content was accumulated. Similar patterns were observed between sides. The results of yield and yield profiles are discussed in the general context of light interception. The results suggest the importance of hedgerow porosity, and distinct penetration patterns of direct-beam radiation through N-S and E-W hedgerows, as the basis for explanation of the high yield of the N side of E-W hedgerows.