Molybdenum Fertilizers


Historical Information
  Determination of Essentiality
  Function in Plants
    - Nitrogenase
    - Nitrate Reductase
    - Xanthine Dehydrogenase
    - Aldehyde Oxidase
    - Sulfite Oxidase
Diagnosis of Molybdenum Status of Plants
  Molybdenum Concentration and Distribution in Plants
  Analytical Techniques for the Determination of Molybdenum in Plants
Assessment of Molybdenum Status of Soils
  Soil Molybdenum Content
  Forms of Molybdenum in Soils
  Interactions with Phosphorus and Sulfur
  Soil Analysis
    - Determination of Total Molybdenum in Soil
    - Determination of Available Molybdenum in Soil
Molybdenum Fertilizers
  Methods of Application
    - Soil Applications
    - Foliar Fertilization
    - Seed Treatment
  Crop Response to Applied Molybdenum

Several molybdenum sources can be used to prevent or alleviate molybdenum deficiency in crop plants (Table 13.4). These sources vary considerably in their solubility and in molybdenum content, and their effectiveness often depends primarily on the method of application, plant requirements, and on various soil factors (87). The relative solubilities of some molybdenum fertilizers are as follows:

sodium molybdate > ammonium molybdate > molybdic acid > molybdenum trioxide > molybdenum sulfide (114).

Molybdenum frits can also be used to supply Mo, but because of their limited solubility, they must be ground finely to be effective (89). Because of the low plant requirement for molybdenum and its mobility in plant tissues, several methods of molybdenum application are possible including soil application, foliar fertilization, and seed treatment with various molybdenum sources.