Irrigation of Corylus avellana L.: effects on canopy development and production of young plants

The response of vegetative growth, plant yield and nut quality to the irrigation was studied from the fifth to the sixth year of hazelnut plants, cv. Tonda Gentile Romana in Viterbo, central Italy. The restitution of 50 %, 75 %, 100 % of ETc measured from class A evaporation was compared to a non-irrigated treatment. Vegetative growth (trunk basal diameter, pruning weight, leaf area and LAI) and yield components were positively affected by water availability. The percentage of nut defects (blanks, shrivelled, poorly filled and mouldy kernels, etc.) was generally not affected by water availability, except shell split. The optimal balance between vegetative growth and production was observed at 75 % ETc.