EVALUATION OF COPPER AND MANGANESE NUTRITION OF SPRING WHEAT GROWN ON ORGANIC SOILS

Abstract

A growth chamber experiment with six organic soils was conducted to assess the Cu and Mn nutrition of spring wheat grown on organic soils. Three rates of Cu (0, 5, and 10 μg∙g−1 of equivalent volume of a fsl) and three rates on Mn (0, 25, and 50 μg∙g−1 of equivalent volume of a fsl) were applied in all combinations to spring wheat grown on six organic soils. Normal growth of wheat plants was achieved only in soils and treatments where a proper balance on Mn and Cu was achieved. Dry matter yield responses at 45, and 60 days and grain yields reflected the significance of this balance. The major conclusion from this study is that normal wheat growth was achieved on organic soils only when the DTPA-extractable soil (soil: extractant ratio of 1:5) Mn/Cu ratio was between 1–15. At Mn/Cu ratio below 1 and above 15, yield reducion and death of plants occurred due to Mn and Cu deficiency, respectively. Key words: Organic soils, spring wheat, available soil Mn and Cu, Mn/Cu interaction, Mn/Cu ratio