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Tips for iron management in crops

 Soil application of Fe is found to be inferior to foliar spray. 3-4 foliar application of un-
neutralized 1-2% foliar solution of FeSO 4 can effectively control Fe-induced leaf necrosis
in different crops.
 Chelated sources of iron are proved to be more effective that other inorganic sources of
Fe. However, they are costly and does not provide a suitable option for resource-poor
farmers.
 Puddling for rice nursery preparation coupled with FYM application can effectively
reduce the risk of Fe-induced leaf necrosis. In case, symptoms of Fe deficiency are
noticed, foliar application of 0.5% FeSO4 can made to control.
 As application green leaf manure, FYM, composts etc. can increase availability of Fe in
soils, there application before sowing/ transplanting can effectively reduce the risk of Fe
deficiency.
 In order to enhance Fe concentration in economic produce of different crops, 1.0% foliar
spray of FeSO4 at different growth stages is necessary. In legume crops, nipping and
defoliation (25% leaf removal) can also enhance Fe concentration in their seeds.

4. Recommendations for manganese application

Source of manganese
Different fertilizer sources to amend Mn deficiency are given in Table 10.

Table 10. Common sources of manganese and their content
Source Mn content (%)
Manganese sulphate 30.5
Manganese oxide 25.0
Manganese chloride 10-16

Recommendations for Mn application based on its availability in soil

Soils can be classified into six categories as per their Mn availability and correspondingly
suitable recommendation measures are given in Table 11.

Table 11. Different categories of Mn in soils and fertilizer recommendations
Status in soil Category Recommendations
-1
(mg kg )
-1
≤1.0 Acute deficient 50 kg MnSO 4 ha for each crop as basal dose + 3
foliar sprays of 0.5% MnSO 4
-1
>1.0 to ≤3.0 Deficient 50 kg MnSO 4 ha for each crop each year + 2 foliar
sprays of 0.5% MnSO 4
>3.0 to ≤5.0 Latent deficient 2-3 foliar sprays of 1-2% MnSO 4.
>5.0 to ≤7.0 Marginal Seed treatment with MnO or 1-2 times foliar sprays
sufficient of 1.0-2.0% neutralized MnSO 4
>7.0 to ≤9.0 High No need to apply any manganese fertilizer
>9.0 Very high No need to apply any manganese fertilizer