March 31, 2020

Flexible Approach to Molybdenum Application

The benefits of Molybdenum (Mo) application to clover based pastures has been clearly demonstrated. Molybdenum has two important roles; nitrogen fixation by legumes and conversion of nitrate to nitrite for protein synthesis in all plants. The amount required by plants is only small but varies by plant part, with higher concentrations found in root nodules.
Flexible approach to Molybdenum application
Flexible approach to Molybdenum application

Molybdenum availability in soil and subsequent plant uptake is influenced by;

  • Soil pH – as soil pH reduces the availability of Mo decreases, which is opposite to all other micronutrients.
  • Reaction with Iron and Aluminium – generally low pH soils have higher availability of iron & aluminium that adsorb Mo and make it unavailable for plant uptake.
  • Competing nutrients – high levels of sulphur can reduce uptake.
  • Soil Moisture – Low soil moisture tends to impair movement of Mo to the plant root for uptake.

Plant tissue analysis is the most reliable method for assessing Mo status and if in doubt, is a great place to start.  Legumes and pasture are more susceptible to Mo deficiency.

Traditionally, fertilisers such as super have been treated with Mo and applied every 5 years to supply adequate Mo nutrition.  Distribution of Mo across the field is related to rate of fertiliser applied, which determines the number of granules per unit area.  Applying Mo with a boom spray ensures improved coverage across the whole treated area.  Also, as super is generally handled in bulk, this makes it less convenient to target selected areas of your property.  Having the ability to target fields is important, particularly if lime has been applied or is planned to be applied this season.  The availability of Mo increases with increasing pH.  Avoid applying lime and Mo in the same fields in the same year.

There is a simple and flexible solution to applying Mo.  YaraVita MOLYTRAC 250 (25%Mo, 11%P) is a true liquid that can be easily and conveniently added to;

  • N400 (UAN - Urea ammonium nitrate)
  • Included in tankmix with herbicide during weed control operation

Recommended application rates are 125-250 mL/ha for pastures, brassicas and lugumes.  YaraVita Molytrac compatibilities can be found either with the mobile app - Tankmix™ or at