Micronutrient deficiency in soils and crops in developing countries like India is a rule rather than exception today. Most of the countries are witnessing multi-micronutrient deficiencies, dominated by zinc and boron, which are impacting the crop yield and quality adversely. Deficiencies of micronutrients like zinc and iron are also affecting the human health leading to micronutrient malnutrition. Krishi Jagran interacted with Shri Satish Chander, Director General of Fertilizer Association of India (FAI) on the eve of the Global Micronutrient Summit to be held on 5-6 September 2019 in New Delhi.
The role of Iron and Zinc in human nutrition is quite evident but in view of Soil health, how do you foresee the Micronutrients in Balanced Plant Nutrition?
The awareness of farmers about the importance and need of micronutrients in improving crop productivity is very limited. The state governments and major fertilizer companies can play an important role in knowledge dissemination. Right from the beginning, FAI has been promoting balanced use of fertilizers including micronutrients.
The Fertilizer Association of India in collaboration with the International Zinc Association has organized the 'Global Micronutrient Summit' with the objective to increase the awareness among the stakeholders and sensitize them on the importance of micronutrients in balanced fertilizer use.
How do you access the requirements of Crops for Micronutrients?
Micronutrient requirements of the crops are relatively small. Crops and crop cultivars grown on the same soil exhibit differential genotypic variability with respect to their micronutrient content/ ability to withstand the deficiency stress. Since total soil micronutrient content per se is sufficient, it may sustain higher yield of the cultivars which are capable of mobilizing these nutrients from difficultly available pools. Investigations on isolation of micronutrient-efficient landraces and established varieties present a vast scope on minimizing fertilizer use and maximizing potential on containing micronutrient malnutrition.
In view of Soil conditions, how the micronutrients are distributed in soil?
In soils, micronutrients are distributed in five pools namely, water soluble (soil solution); exchangeable; adsorbed, complexed and chelated; associated with secondary minerals and as sparingly soluble oxides; and constituents of primary minerals. The total micronutrient content of the Indian soils is enough to sustain and supply them to crops for a period varying from a few hundred to thousand years. Yet their deficiency continues to emerge menacingly because only first three pools of micronutrients (constituting only 2-5 percent of the total content), are in a state of dynamic equilibrium and supply these nutrients to plants.
How do you explain the growth in consumption of micronutrients in the last decade? Can you give an overview of requirement in the coming years, say upto another 5 years?
There has been good growth in consumption of micronutrients particularly in last 10 years. However, there exists a vast gap between application and requirement. The current annual consumption of about 180 thousand tonnes of zinc sulphate is much less compared to projected ZnSO4 requirement ranging between 0.3 to 1.5 Mt for 2025.
The situation in case of boron and iron, the 2nd and 3rd most limiting micronutrients, is even worse. The prevailing gap between the requirement and actual use of micronutrients will aggravate the problem of micronutrient deficiencies.
How do you explain the micronutrients deficiencies in India and their applications? What are the corrective measures?
The plant requirement of Fe is only one-trillionth of that present in the soil, yet occurrence of iron deficiency chlorosis is a common feature under high pH, calcareousness, low soil organic matter, poor water quality etc. Situation is further exacerbated with focus of micronutrient nutrition shifting from ‘overcoming micronutrient deficiencies in plants and sustaining crop yields’ to ‘producing micronutrient-dense grains to combat malnutrition in humans’. Unless corrective measures are taken, cultivation of the micronutrient-accumulating crops and crop cultivars without supplementation of these nutrients will further accentuate the onset of deficiencies. Impressive strides were made in India to combat micronutrient deficiencies in general and zinc in particular.
The uniform application of micronutrient fertilizers in field is a major challenge as these are applied in small quantities. The use of fertilizers fortified with Zn (e.g., zincated urea, zincated DAP, zincated SSP) and B (e.g., boronated SSP, boronated DAP, boronated NPK) and customized fertilizers can address this problem by facilitating the uniform application of small amounts of micronutrients in these fertilizers.
Any initiatives taken by the FAI to highlight the importance and need of micronutrients?
From the beginning, FAI has been promoting balanced use of fertilizers including micronutrients. FAI has instituted two annual awards to recognize the outstanding work done by the scientists and fertilizer industry in the field of micronutrients. It has also started bringing out annual publication ‘Specialty Fertilizer and Micronutrient Statistics’. This special issue on Micronutrients is another initiative of FAI to highlight the importance and need of micronutrients in improving crop yields and human health.