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MICRONUTRIENTS MANAGEMENT OPTIONS IN SOILS AND
CROPS

A series of recommendations has been prepared by the scientists of All India Coordinated
Research Project on Micro and Secondary Nutrients and Pollutant Elements in Soils and
Plants Project on the basis crop demand and availability micro and secondary nutrients in
soils. The nutrient and cropwise recommendations are as follows.

1. Recommendations for sulphur application
The use of sulfur in sulfur-deficient soils not only increases the yield of crops but also
improves the quality of the produce. For example, the use of sulphur increases the amount of
oil and protein in the seeds of oilseed, whereas it improves nitrogen: sulfur ratio and protein
content in fodder crops. Apart from this, the application of sulfur increases starch content in
tuber crops like potato, backing quality of wheat, sugar content in sugarcane, quality of copra
in coconut and lint quality of cotton and jute.

Sources of sulphur
On the basis of market value and availability as a nutrient, sulfur supply is mainly done as
gypsum, single super phosphate, elemental sulfur, ammonium sulphate, bentonite sulphur and
some extent potassium sulphate, magnesium sulphate etc. The quantity of sulfur and other
nutrients in major sulfur containing fertilizers is given in Table 1.

Table 1. Different sources of sulphur

Name of Nutrient element (%) Quantity of
fertilizer/source Sulphur Nitrogen Phosphorous Potash Zinc fertilizer/source for
supply of
1 kg sulphur (kg/kg
of sulfur)
Ammonium 24 21 - - - 4.167
sulphate
Ammonium 15 16 20 - - 6.667
phosphate sulphate
Gypsum 15-18 - - - - 6.667
Phospho gypsum 13-18 - - - - 6.667
Elemental sulphur 85-95 - - - - 1.111
Single super 12 - 16 - - 8.333
phosphate
Potassium sulphate 18 - - 60 - 5.555
Zinc sulphate 11 - - - 22 9.090
Iroon pyrite 22 - - - - 4.545

Results of field experiments reveal that sulphur fertilizers like ammonium sulphate, single
super phosphate, gypsum and sulphur bentonite are equally good in mitigating sulphur
deficiency in mustard, soybean, toria, peanut, wheat, maize crops grown in various soils and
crop management situations. Pyrites and elemental sulphur are less effective because of low