EVALUATION OF PLANT TISSUE CRITERIA FOR PREDICTING MANGANESE DEFICIENCY IN OATS

Abstract

The Mn status of oat (Avena sativa L. ’Harmon’) plants grown on an organic soil in a field study was assessed using three plant criteria: whole plant samples when the first node of stem is visible at the base of shoot (FEEKES 6), whole plant samples when the sheath of the last leaf was completely extended and the ear was swollen but not yet visible (FEEKES 10), and just the flag leaf at FEEKES 10. The critical Mn levels corresponding to a 10% yield reduction were 16, 9 and 10 μg∙g−1 dry matter, respectively. Of these, the level of Mn in the whole plant at FEEKES 10 was the most accurate plant indicator of grain yield. However, correction of Mn deficiency by foliar application of Mn at FEEKES 10 was not as satisfactory as at FEEKES 6.Key words: Mn deficiency, oats (Avena sativa L.), organic soils, plant analysis, critical deficiency levels