International Research Journal of Agricultural Science and Soil Science (ISSN: 2251-0044) Vol. 3(5) pp. 169- 173, May 2013 Available online http://www.interesjournals.org/IRJAS Copyright ©2013 International Research Journals Full Length Research Paper Assessment on the Status of Some Micronutrients in Vertisols of the Central Highlands of Ethiopia Yifru Abera and *Mesfin Kebede Debre Zeit Agricultural Research Center, P.O. Box 32, Debre Zeit, Ethiopia *Corresponding Author E-mail: ethiosoils@gmail.com Abstract Although the role of micronutrients in balanced plant nutrition is well established, information regarding their status in most Ethiopian soils is scanty. Even, the current fertilizer recommendation for major crops in Ethiopia is only for macronutrients; continuous application of one or two macronutrients may in due course deplete the soil reserve of other nutrients and limit the crop yield. In order to assess the status of Manganese (Mn), Iron (Fe), Copper (Cu) and Zinc (Zn) in the Vertisols of the central highlands of Ethiopia, fifty representative composite surface soil samples (0-30 cm depth) were collected from five districts viz., Akaki, Gimbichu, Ada’a, Lume and Minjar-Shenkora. These micronutrients were extracted using diethylenetriamine-penta-acetic acid (DTPA) and their concentration is determined using atomic absorption spectrophotometer (AAS). The analytical results confirmed that the status of Fe and Zn fall in the deficient range in the majority of the samples. Generally, 96 and 98% of the samples were found to be deficient in Fe and Zn, respectively. Manganese deficiency is evident only in 11% of soil samples whereas, the status of Zn was in sufficient range in all soil samples, Therefore, future research should focus on assessing the availability of these and other micronutrients by collecting large number of soil and plant samples and conducting field trials in the area. Keywords: Deficient, DTPA, Micronutrients, Vertisols. INTRODUCTION The drive for targeting higher agricultural production needs a balanced use of nutrients which otherwise create problems of soil fertility exhaustion and nutrient imbalances not only of major but also of secondary and micronutrients (Patel and Singh, 2009). Whenever either of the nutrients is deficient it resulted in abnormal growth, which sometimes cause complete crop failure. Most of micronutrients are associated with the enzymatic system of plants. Thus, micronutrient deficiency and toxicity can reduce plant yield (Tisdale et al., 1995). Besides, grain and flower formation does not take place in severe deficiency (Nazif et al., 2006). The availability of micro- nutrient to plant growth is particularly sensitive to change in soil environmental factors like organic matter, soil pH, lime content and soil texture (Nazif et al., 2006). Katyal and Randhawal (1983) reported a wide spread micronutrient deficiencies when high analysis fertilizers like DAP and Urea continued to be the only one used in India. These fertilizers have been applied continuously and with increase rate particularly due to the release and adoption of new crop varieties that have high demand of these nutrients. When micro-nutrients are not applied to the soil in conjunction with common fertilizers, fertilizing soils with macronutrients are likely to promote imbalance between these nutrients group and individual nutrients. Furthermore, increased yield through intensive cropping and use of high yielding varieties, losses of micronutrients through leaching, and decreased farm yard manure application compared to chemical fertilizers contribute towards acceleration exhaustion of the supply of available micronutrients from the soil bank. It has been reported that, in spite of favorable development in the use of nitrogen and phosphorus fertilizers to increase crop production two to six-time more of the micro-nutrients are being removed annually through crop harvest from the soil, than are applied to it (Kayal and Randhawal,1983). This could be significant particularly in Ethiopia, where there is no micronutrient application in the form of chemical fertilizers or organic elements (Asgelil et al., 2007). However, there is very little information available