Abstract

Hazelnut is rapidly expanding in Chile, particularly in central zone, where the climate change has significantly diminished water availability, making irrigation vital. This study assesses hazelnut responses to different irrigation levels, focusing on yield and quality. The trials examined the response of adult plants of cultivar ‘Tonda di Giffoni’ to different levels of irrigation over the years 2021 to 2023, in the villages of Ñiquén and "El Carmen" in the region of Ñuble, Chile. The research evaluated four irrigation treatments in farmers' orchards: T1=125%, T2=100%, T3=75% and T4=50% irrigation, using a randomized complete block design with five replications, 100% being the farmer's irrigation. The applied water was converted to percentage in relation to the ETc, obtained from ETo and Kc. Additional drip lines, paralleling to the existing irrigation systems, made possible differentiated irrigation treatments, while homogenous fertigation was applied in all treatments, via the original system. Yield and yield component assessments, alongside xylem potential, stomatal conductance, and soil moisture measurement, were conducted. Yield was positively affected by irrigation in the second year, while in the first year there was not significant differences. At El Carmen, total yield showed a positive trend with increased irrigation, but there were no significant differences. The percentage of empty and defected nuts were significantly higher in T2 and T3. Additionally, a significantly higher husk percentage was observed in T3.At Ñiquen, the total yield showed a positive trend with increased irrigation, being significantly lower in T4. The percentage of empty and defected nuts was low and does not show significant differences. The percentage of husk increased with reduced irrigation, being significantly higher in T3. It is concluded that irrigation positively affects hazelnut yield and quality, although there may be local factors in the orchards that affect this trend.