Although there was no significant difference between 12 and 24 kgS/rai application on S concentration, sulfur concentration of grass applied with these two levels was significantly higher than that of the control treatment. No difference response in plant S concentration was observed from both rates of application. This may be contributed to the nature of plant that can absorb S only at optimal level. Kanwar and Mudahar, 1986 reported that S recovery from S sources applied to the soil was dependent on a number of factors, such as nature of the crop and the soil condition. Pasricha et al., 1977 compared the effect of levels of S application (25 and 50 ppm) on S recovery rate of Maize and found that there was no difference in plant S concentration. Sulfur concentrations of grass
applied with S fertilizer had increased up to two times comparing to the control treatment (Table 4). This was consistent with the report of Arthington et al., 2002 who reported that S concentration in bahiagrass fertilized with ammonium sulfate was greater than those which were unfertilized and fertilized with ammonium nitrate. Hardt et al., 1991 also reported that applying ammonium sulfate to oat-wheat pastures had also increased forage S concentration at least 27%.