Growth analysis and nitrogen dynamics in hazelnut 'Tonda Gentile Romana'

Leaf area development and dry matter accumulation were measured in ‘Tonda Gentile Romana’ hazelnut plants. Biomass partitioning in the above ground parts of the plants was affected by age and irrigation. In young plants, 50% of the dry matter came from leaves. The contribution of fruit and pruning weight was about 12% and 9% respectively. In the adult orchard, nuts represented 46% of the biomass. The highest concentration of nitrogen in the leaves was in spring, this decreasing during the growing season. Shoots showed the highest content on the first date of measurement (end of April). Nitrogen content in the shoot was higher in irrigated plants. In the adult orchard nitrogen accumulation in the shoots was low and started only after harvest. These differences are related to the different crop load and sink strength and to water availability in the soil.