Green revolution has greatly increased the food crop production in
India, but continuous cultivation of high yielding crop varieties have led to
depletion of native micronutrient soil fertility and now most of the soils are
showing sign of fatigue for sustaining higher crop production to meet the
increasing food demand of the country. In the post-Green Revolution period,
deficiencies of zinc (Zn) and boron (B) have constrained sustainable growth in
productivity of several field crops. Among micronutrients, Zn deficiency was
found widespread in Indian soils. Analysis of soils samples from different
states of India indicated that on an average 44, 33, 15, 13, 8 and 6% of the
samples were deficient in available Zn, B, iron (Fe), molybdenum (Mo), copper
(Cu) and manganese (Mn), respectively. Extensive micronutrient deficiencies
lead to decline in factor productivity even with balanced NPK fertilization.
Although the crop response to micronutrients application varies with soil type,
crops and genotype, agro-climatic conditions and severity of deficiency, an
enormous response to micronutrient fertilization has been reported in a wide
variety of crops including horticultural crops across the country. The results
indicated that soil application of 5 to 10 kg Zn ha-1 before sowing is the most
suitable method to manage Zn deficiency. The most effective method to
ameliorate Fe deficiency is to apply 3-4 foliar sprays of 0.5 to 1.0% ferrous
sulphate in standing crop at an interval of 10 days. For management of Mn
deficiency 3-4 foliar applications of 0.5-1.0% manganese sulphate are
economical than soil application of 40-50 kg Mn ha-1. Response of crops to B
application (0.5-2.5 kg B ha-1) was observed on boron deficient soils. The soil
application of boron is a better method of fertilization than foliar
application or seed soaking. - See more at:
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