Spatial analysis of heavy metal and nutrient profiles concerning climate suitability for sustainable hazelnut cultivation across coastal and Inland Türkiye

This study examines the distribution of essential mineral elements, followed by an analysis of heavy metals and regional climate conditions of hazelnut (Corylus avellana L.) samples collected from Türkiye; Sakarya, Samsun, Tokat, Ordu, and Giresun provinces. Al, B, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, and Zn concentrations varied according to the local soil structure and climate characteristics. Notably, the soil samples taken from Giresun exhibited considerably high concentrations of B, Ca, Cu, Fe, Mg, Mn, and Zn in both kernel and shell samples, suggesting that the region’s soil and climate conditions contribute significantly to the mineral richness of hazelnuts. Similarly, K concentrations were higher in Samsun than in other provinces, highlighting the role of K in hazelnut development in this area. The measurements were evaluated with the recommended crop safety and hazard index (HI). Climate data indicate that although all regions generally meet the requirements for hazelnut cultivation, Tokat’s lower temperatures, steeper topography, and specific soil mineral composition and heavy metal content pose certain limitations. High levels of mineral elements support soil fertility and promote healthy hazelnut growth. Yet, elevated levels of heavy metals such as Cd and Pb may present environmental and health concerns, affecting both soil quality and crop safety. The region’s specific elemental composition and unique climatic and geographical conditions require careful monitoring and management to optimize hazelnut yield and quality. Excessively high temperatures during the kernel-filling period in summer could negatively impact yield. Additionally, Giresun’s shorter sunshine duration and higher rainfall increase regional humidity, which may benefit hazelnut growth by maintaining soil moisture levels. These findings reveal each region’s climatic and soil advantages, guiding targeted strategies for sustainable hazelnut cultivation in Türkiye. Region-specific soil management, tailored fertilization, and climate-adaptive techniques can enhance yield, ensuring long-term productivity and economic potential.