Micronutrient malnutrition or "Hidden Hunger" affects more than two billion people worldwide. It is particularly severe in places where cereals with low nutritional quality are the main diet. Modern agricultural systems have to provide enough micronutrient output to meet all the nutritional needs of people. Accordingly, knowledge on micronutrients status in soil and crop edible tissues is necessary. Rice is a major food in many Asian countries such as Iran . This study was carried out to investigate zinc (Zn) and cadmium (Cd) in paddy soil and rice grain produced in central Iran in relation to soil and plant factors. We collected 136 rice crops (shoot, husk and grain) and associated surface soils (0-25 cm) from fields in Isfahan , Khuzestan and Fars provinces. The sampled areas represent typical soils used for rice production in the provinces. Total and DTPA-extractable Zn, Fe, Mn, Cu and Cd were measured in the soil samples. Zinc, Fe, Mn, Cu and Cd concentrations were measured in shoot, husk and grain. The average soil pH, EC, CaCO 3, O.M and total phosphorus in the region were 7.6, and 2.7 dSm -1 , 37.5%, 1.6% and 0.08%, respectively. The concentrations of DTPA-extractable Fe, Mn and Cu were in the sufficiency range. In all the soils, the DTPA-extractable Zn was much less than the total Zn concentration. More than 16%, 66% and 75% of the DTPA-extractable Zn soils in Isfahan , Fars and Khuzestan, respectively were less than critical deficiency concentration of Zn for rice grown on calcareous soils. Zinc concentration in more than 54% of the rice grains was less than the suggested critical level. About 64% and 43% of rice contained less than the critical deficiency concentration of Mn and Cu, respectively. The concentration of Fe in rice grains was in the sufficient range. The combination of high pH, EC and CaCO 3 and low organic matter in the soils together with high Fe concentration are probably the major factors causing Zn deficiency in rice grown in in the provinces. A significant negative correlation was found between the percent CaCO 3 and soil DTPA-extractable Zn, Fe, Mn and Cu Zinc, Fe, Mn and Cu concentrations in soil increased significantly with organic matter and total phosphorus and the stepwise regression equations show that there are significant relationships between the total soil phosphorus soil an .
