Tree Fruit Soils and Nutrition











 

 

The 17 essential elements are: 

C H O P K N S Ca Fe Mg B Mn Cu Zn Mo Cl Ni

Molybdenum (Mo)

Form used by plants:

MoO42-

Important functions:

  • Involved in the utilization of nitrogen (N fixation and nitrate reduction)
    (nitrogenase and nitrate reductase enzymes). In other words, plants can't transform nitrate nitrogen into amino acids with Mo.  Additionally, legumes can't fix N unless Mo is present.

Ideal foliage range for apple leaves:

In a study by Fernandez and Childers (1960), Mo levels in deficient leaves was 0.05 ppm as compared with 0.16 ppm in the leaves which had been supplied with Mo. 

It is uncommon for Mo deficiencies to occur as very few areas in the world are deficient in Mo and the amount that apple trees take up is extremely small. 

Ideal fruit concentration:

Ideal soil range:

Soil Mo concentrations are too low for most labs to evaluate.

Best indicators: 

Mobility in plant:

Remobilized within plant

Deficiency symptoms:

**very few areas of the world are deficient in Mo and apple trees use extremely small amounts of Mo.

  • Induced deficiency symptoms include:

  • mild but uniform chlorosis on young leaves

  • stunting and lack of vigor

  • marginal scorching and downward cupping or rolling of leaves

Increased risk of Mo deficiencies on:

Excess problems/Interactions with other elements:

  • Mo applied along with phosphate encourages the uptake of both elements in Mo-deficient soils.

  • Excess copper or sulfate reduces Mo uptake

  • Excess Mo encourages iron deficiency

 

 

Updated July 13, 2004

 

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