Evaluation of nutrient concentration of leaf and yield of hazelnut (Corylus avellana L.) as affected by Fe- and Zn-enriched vermicompost

In order to determine the concentrations of nutrients of leaf and yield of hazelnut as affected by Fe- and Zn-enriched vermicompost, an experiment was conducted in the orchards of Moghan Agro-Industrial Company, Moghan, Iran on hazelnut trees in a factorial form based on a randomized complete block design with three replications. The studied treatments included compost of cow manure (M), vermicompost of cow manure (Vm), vermicompost enriched with Fe and Zn (Vm+Fe+Zn), vermicompost enriched with iron filings (Vm+ID), soil application of zinc sulfate and iron sulfate (ZnSO4+FeSO4), spraying of Fe and Zn chelate (FCFe+Zn), spraying of iron sulfate and zinc sulfate (FMFe+Zn), soil application of Fe-EDDHA and Zn-EDDHA (EDDHAFe+Zn), sulfuric acid (H2SO4) and control. The results of leaf analysis showed Fe deficiency and Cu excess in the soil of the studied region. Enrichment of vermicompost with Fe and Zn decreased pH compared with compost and increased total and available concentration of Fe and Zn. The effect of mixing vermicompost with iron sulfate was better than mixing it with iron filings. The highest yield was obtained with Fe- and Zn-enriched vermicompost. Different treatments increased leaf Fe, Zn and chlorophyll concentration and yield compared with control, but enrichment with Fe and Zn was more effective than other treatments. The measurement of leaf chlorophyll is a simple, appropriate method for assessing the nutritional status of Fe and Zn of hazelnut trees because of the similar pattern of leaf chlorophyll content and their chlorophyll amount.