In high rainfall areas or low lying acreages, drainage is fundamental to removing excess water from the soil. For hazelnuts, surface roots may take up moisture from top levels of the soil but if not properly drained. Lower roots may encounter extended periods of waterlogging which will reduce tree health and productivity. At the planning stage, the soil profile of the orchard should be determined and soil composition tested prior to planting. Depending on these investigations and in locations where natural drainage of soil moisture is not adequate, additional drainage, such as tile drainage, may need to be installed prior to planting. Hazelnut orchards located on deep sand or gravel-sand soil on high ground may not need tile drainage installed before the orchard is planted.
To provide adequate drainage of orchards, space perforated tiles need to be located 9-12 m between parallel drains in sandy to sand-loam soil, and 7.5-9 m between tiles on heavier soil. The tiles should be approximately 1-1.5 m deep to help maintain the water table at or below this depth. Tile drainage at this spacing will drain excess soil water from the orchard quickly and prevent flooding injury to hazelnut root systems. Consult with a local drainage specialist for specifics in your region.