In citrus production, iron acts as a catalyst in oxidation/reduction reactions; is involved in respiration; photosynthesis; and the reduction of nitrate and sulfate. It is also a co-factor in many enzymes.
Iron and yield
Iron deficiency is commonplace and widely recognized. The most obvious effects are restricted fruit set and reduced fruit size. This results in a lower yield, as you can see happening with navel oranges in Egypt.
Iron and yield
Trials in Egypt show that yield is reduced when iron is deficient.
Soil and Foliar applications
Trials with chelates (China, navel oranges) confirm that soil applications are more effective and provide bigger yield responses than foliar applications.
Iron and TSS
Iron also has a direct effect on crop quality improving the levels of total soluble solids in oranges and mandarins as well as increasing the TSS/Acidity ratio.
Iron and TSS in lemons and limes
In lemons and limes the effect is to reduce the TSS content, thereby boosting the acidity of these fruits.
Iron and vitamin C
Good iron nutrition also boosts the ascorbic acid content of mandarins and oranges.
The form of applied iron used to correct any deficiency is important. Chelates are more stable across a wide range of soil pHs and should be the preferred form to correct long-standing annual deficiencies, particularly on calcareous soils. Trials with chelates confirm that soil applications are more effective and provide bigger yield responses than foliar applications.
|Iron at citrus growth stages
||To maintain fruit yield and quality should be applied with each leaf flush
||When needed for post harvest foliage flush