Micronutrient Fertilizers and Their Management in Indian Agriculture

摘要

Reports of khaira disease in rice as zinc deficiency nutritional disorder, zinc deficiency in Mexican wheat varieties, rampant boron deficiencies on calcareous and acid soils of high rainfall areas, and subsequent manganese deficiencies in wheat on low organic matter light textured soils of South-Western Punjab led to intensification of micronutrient research in the country. With zinc and boron deficiencies increasingly limiting the crop production, intensive efforts were made to identify and develop the agronomically superior fertilizers containing these nutrients. A large number of products have been included in the Fertilizer (Control) Order 1985. Among them zinc sulphate, borax, ferrous sulphate, manganese sulphate, copper sulphate and ammonium molybdate hold promise. Zinc sulphate and borax as independent carriers of Zn and B and also fortified with major fertilizers have been the topics of intensive evaluation. Fifty years of intensive experimentation witnessed the efforts of enhancing the abysmally low use efficiency of micronutrients, but with limited success. Application of nano-technology in developing smart micronutrient delivery systems and use of nano micronutrient fertilizers like nano-zinc oxide are being explored. This review collates and presents information on micronutrient carriers, their agronomic effectiveness and future prospects in the light of the Government of India initiatives on sustenance of soil health through balanced crop nutrition.