~ 192 ~ ISSN Print: 2394-7500 ISSN Online: 2394-5869 Impact Factor: 5.2 IJAR 2017; 3(6): 192-197 www.allresearchjournal.com Received: 11-04-2017 Accepted: 12-05-2017 LB Ashok Department of Soil Science, University of Agricultural and Horticultural Sciences. Shivamogga, Karnataka, India Ashok S Alur Department of Soil Science, University of Agricultural and Horticultural Sciences. Shivamogga, Karnataka, India VS Doddamani Department of Soil Science, University of Agricultural and Horticultural Sciences. Shivamogga, Karnataka, India Correspondence LB Ashok Department of Soil Science, University of Agricultural and Horticultural Sciences. Shivamogga, Karnataka, India Overview of approaches in assessing / mapping micro- nutrients with a case of Ghataprabha command area LB Ashok, Ashok S Alur and VS Doddamani Abstract The importance of micronutrients and benefits in crop production are being increasingly recognized in modern agriculture. The incidence of micronutrient deficiencies has become more pounced consequent to the adoption of new strategy in agriculture. Although micronutrients are required in small quantity, they are considering to play a vital role in the plant growth and development and therefore to receive a greater attention in modern agriculture. The current paper throws light on various approaches in assessing / mapping micro-nutrients with a case of Ghataprabha command area was discussed. Studies on status of micronutrient cat ions (Fe, Mn, Cu and Zn) in soils of Ghataprabha command area of Belgam district revealed that the soils in different taluks namely Gokak, Raibag, Chikkodi, Athani and Hukkeri, these soils are alkaline in soil reaction and normal in electrical conductivity . The range and mean value of DTPA extractable iron, manganese, copper and zinc in soils of Ghataprabha command area vary from 0.32 to 11.02, 0.37 to 27.73, 0.54 to 8.28 and 0.03 to 3.88 ppm with a mean value of 3.77, 8.00, 2.54 and 0.51 ppm respectively. As per the limits of < 2.5, 2.5 to 4.5 and >4.5 ppm as deficient, marginal and sufficient in available iron, 21.1, 52.0 and 26.9 per cent of samples fall under deficient, marginal and sufficient category respectively. In respect of available manganese majority of the soil samples (97.1%) fall under category of sufficient (>2.0 ppm) and remaining (2.9%) samples fall under deficient category respectively. As per the deficiency (<0.2 ppm) and sufficient (>0.2 ppm) category for available copper, all the command area samples fall under sufficient category respectively. In respect of available manganese, majority of the soil samples (97.1%) fall under category of sufficient (>2.0 ppm) and remaining (2.9%) samples fall under deficient category. As per deficiency (< 0.2 ppm) and sufficiency (> 2.0 ppm) category for available copper, all the soils of command area fall under sufficient category. In case of zinc 76.9, 9.1 and 14.0 per cent of samples fall under deficiency (< 0.6 ppm), marginal (0.6-1.0 ppm) and sufficient (>1.0 ppm) category respectively. Keywords: Micronutrients, critical limit, deficient, marginal and sufficient Introduction The importance of micronutrients and benefits in crop production are being increasing!} recognized in modern agriculture. The incidence of micronutrient deficiencies has become more pounced consequent to the adoption of new strategy in agriculture, namely adoption of employing intensive cropping system with high yielding varieties and use of high analysis straight fertilizer and lesser use of organic manures leading to the imbalance of plant nutrients in soil. Although micronutrients are required in small quantity, they are considering to play a vital role in the plant growth and development and therefore to receive a greater attention in modern agriculture. The current paper throws light on various approaches with a case from mapping of micronutrients in Ghataprabha command area. Importance of micronutrients Usually the "importance" is defined as the product of the magnitude of the impacts per unit area and the area of impact. Impact is most commonly measured as crop yield. However, for a range of crops, aspects of crop quality such as oil. protein or fibre content, are equally important in markets. Peanuts sold for human consumption should be free of internal defects such as "hollow heart'', caused by boron deficiency. For mung bean, the viability and vigour of germinating seed may be a prime qualitv characteristic that determines market price in those pans of Asia favouring bean sprouts in the diet. For legumes, the main impact of micronutrients may be on amounts of N fixed. Limitations of symbiotic nitrogen fixation decrease current crop production, but may have equally significant impacts on subsequent International Journal of Applied Research 2017; 3(6): 192-197