Application of Fertilizer Manganese Doubled Yields of Lentil Grown on Alkaline Soils

Abstract

The yield increase of 45‐day‐old lentil (Lens culinaris Medik) seedlings to applications of two sources of manganese (Mn) fertilizer was compared in a glasshouse experiment using two alkaline soils from southwestern Australia. The Mn sources were manganese sulfate (24.6% Mn), the usual source of Mn for crops in southwestern Australia, and Manganese oxide (MnO; 77.3% Mn). Both sources were finely powdered, applied at equivalent amounts of Mn and were mixed throughout both soils. The effectiveness of the two Mn fertilizers was compared using yield and Mn content (Mn concentration multiplied by the dried yield) of dried lentil shoots harvested 45 days after sowing. Applications of Mn about doubled shoot yields on both soils. For both soils, relative to the Mn sulfate fertilizer, the Mn oxide was about half as effective for producing dried shoots and about 40% less effective in increasing the Mn content of dried shoots so about twice as much Mn as the oxide was required to produce the same yield or Mn content in shoots as MnSO4·4H2O. The concentration of Mn in youngest mature growth (YMG) and in dried shoots was used to determine critical concentrations of Mn in tissue associated with 90% of the maximum yield. The critical concentration (mg/kg) of Mn was found to be 18 for YMG and about 21 in dried shoots.