EFFECT OF MOLYBDENUM APPLICATIONS ON PLANT MOLYBDENUM CONCENTRATION AND CROP YIELDS ON SPHAGNUM PEAT SOILS

Studies were conducted on peat soils to determine the effect of Mo application on crop yields and plant tissue Mo concentrations. In a greenhouse experiment Mo applications resulted in highest crop yield increases for cauliflower with lesser increases for onions and red clover. Plant tissue Mo levels of less than 0.06, 0.04, and 0.03 mg kg−1 in onions, cauliflower, and red clover, respectively were in the deficiency range. Sufficiency levels for Mo were 0.1 mg kg−1 for onions, 0.07 mg kg−1 for cauliflower, and 0.27 mg kg−1 for red clover. No response to Mo was found on carrots even at plant tissue Mo concentrations as low as 0.04 and 0.15 mg kg−1 under greenhouse and field experiments, respectively. In the field study liming and Mo both increased carrot leaf Mo concentrations but only liming increased carrot yields. Key words: Molybdenum concentration, vegetables, red clover, sphagnum peat, liming