Khao Dok Mali (KDML) 105 rice is one of the most popular fragrant rice in the world with very high demand in world market. There have been a number of studies on nutrient management, mainly focusing on major plant nutrients. There is none of zinc (Zn) with this rice, thus; a research on the effects of Zn on KDML 105 rice was undertaken in different soils using pot experiment in greenhouse, objectively to obtain preliminary results that can be further examined in the field. Comparisons were examined to assess the reliability of 9 chemical methods of Mehlich 1, Mehlich 3, 0.1M HCl, 1M NH4OAc at pH 4.8, 1M NH4OAc pH 7.0., AB-DTPA, DTPA, 1M MgCl2 and 0.01M CaCl2 for evaluating the availability of Zn in soils to KDML 105 rice and for calculating rates of Zn fertilizer for rice. KDML 105 rice showed a slightly negative response to Zn applied at the rate of 3–42 mg/kg, despite the soils having different Zn contents. Extractable Zn derived from all extractants had a positive correlation with water-soluble- and exchangeable Zn (r= 0.54*–0.92**) indicating that these solutions dissolved Zn were mostly in water-soluble and exchangeable forms. The indices from all extractant methods, except DTPA and Mehlich, were identically suitable for the assessment of soil Zn availability for growing rice (r= 0.57*–0.70**), with the NH4OAc pH 4.8 showing a slight superiority over the method. The equations for calculating Zn fertilizer for rice from these chemical soil Zn analyses gave a highly significant correlation between the actual yields and the predicted yields (r2 = 0.84**–0.95**). The equation of use NH4OAc pH 4.8 of log (100-y)=2-1.370b-0.042x; when y was yield estimated from the rate of Zn fertilizer applied (x) and Zn content in soil (b), was the most reliable, having 95% accuracy for rice yield assessment.