Comparison of Different Cover Crops on DTPA-Extractable Micronutrients in Hazelnut and Apple Orchards

This study was conducted to compare the effect of different cover crop treatments on DTPA-extractable micronutrients (Fe, Mn, Zn, Cu) and soil pH in a hazelnut orchard with clay loam texture located in Samsun province and in an apple orchard with sandy loam texture located in Kayseri province of Turkey. For this purpose, Trifolium repens (TR), Festuca rubra subsp. rubra (FRR), Festuca arundinacea (FA), T. repens (40%) + F. rubra rubra (30%) + F. Arundinacea (30%) mixture (TFF), Vicia villosa Roth. (VV) and Trifolium meneghinianum Celm. (TM) were used as cover crops in the experiments. Experiments also included a plot mechanically cultivated (MC), herbicide treatment (HC) and bare control plot (BC). Soil samples were taken from two different depths (0-20 and 20-40 cm) in each plot. Experiments were conducted in randomized complete blocks design with 4 replications. While the highest mean extractable Fe content was determined in the VV treatment in the hazelnut orchard (74.35 mg kg-1) and in the apple orchard (3.12 mg kg-1), the highest mean extractable Zn content in the hazelnut and apple orchards were obtained in the TR treatment (2.45 and 1.08 mg kg-1, respectively). While the highest mean extractable Mn content was also obtained in the VV (92.87 mg kg-1) in the hazelnut orchard, the highest mean extractable Mn content was determined in the TR (6.35 mg kg-1) in the apple orchard. The greatest significant negative correlations in the TFF treatment were observed between pH and extractable Mn content (0.914**) in the hazelnut orchard and in the TR treatment between pH and extractable Fe content (0.968**) in the apple orchard