Effects of Cover Crops on Yield and Quality of Hazelnut (<i>Corylus avellana</i> L.)

Cultivation of cover crops for soil surface management of hazelnut orchards is important to control weeds and water erosion as well as to improve yield and quality of hazelnut. This study was carried out to investigate the effects of some cover crops on yield and quality of hazelnut. The field experiments were conducted in the Samsun province of Turkiye between 2012 and 2014, and the layout of the experiment was randomized blocks with four replications. Nine yield and quality related traits of hazelnut plants were determined to assess the effects of cover crop treatments. The cover crop treatments consisted of Trifolium repens L., Festuca rubra rubra L., F. arundinacea Schreb, a mixture (T. repens [40%]+ F. rubra rubra [30%]+ F. arundinacea [30%]), Vicia villosa Roth. and T. meneghinianum Clem. Control treatments were mechanical control, herbicide treatment and weedy control plots. The highest hazelnut yield (1513kg ha(-1)) was obtained in V. villosa (hairy vetch), while the lowest yield (1385kg ha(-1)) was recorded in mechanical control plots. The highest kernel rate (55.7%) was obtained in perennial cover crops sown as a mixture, while the lowest kernel rate (53.9%) was recorded in F. arundinacea treatment. The highest defective kernel ratio was recorded in V. villosa, while the lowest defective kernel ratio was in F. arundinacea treatments. The results revealed that cultivation of cover crops in hazelnut orchards does not cause a yield or quality loss, and the cover crops can be used in hazelnut orchards for sustainable ground management.