Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2009.388.392ShahsavaniS. 42009124In order to evaluate the relationship between sulphur (S), glucose (G), nitrogen (N) and plant residues (st), on sulphur immobilization and microbial transformation. Five soil samples from 0-30 cm of Bastam farmer’s fields of Shahrood area were collected. Eleven treatments with different levels of S, G, N and plant residues (wheat straw) were applied in a randomized block design with three replications and incubated over 20, 45 and 60 days. The immobilization of SO4-2-S presented as a percentage of that added, was inversely related to its addition rate. Additions of glucose and plant residues increased with the C-to-S ratio of the added amendments, irrespective of their origins (glucose and plant residues). In the presence of C sources (glucose or plant residues). N significantly increased the immobilization of SO4-2-S, whilst the effect of N was insignificant in the absence of a C amendment. In first few days the amounts of added SO4-2-S immobilized were linearly correlated with the amounts of added S recovered in the soil microbial biomass. With further incubation the proportions of immobilized SO4-2-S remaining as biomass-S decreased. Decrease in biomass-S was thought to be due to the conversion of biomass-S into soil organic-S. Glucose addition increased the immobilization (microbial utilization and incorporation into the soil organic matter) of native soil SO4-2-S. However, N addition enhance the mineralization of soil organic-S, increasing the concentration of SO4-2-S in soil and the extent to which available-S can be immobilized is determined by both the amount of available-S and the availability of an utilizable C source.]]>Bhupinderpal, S., Z. Rengel and J.W. Bowden, 2006383242Chowdhury, H., K.M. Kouno and T. Ando, 200032310317Ghani, A., R.G. McLaren and R.S. Swift,199335S in soil: Effects of soil conditioning and glucose or sulphate additions.]]>2327335Massoumi, A. and A.H. Cornfield, 196388321322O'Donnell, A., G.J. Wu and J.K. Syers, 19942615071514Pennanen, T., S. Caul, J.J. Daniell, B.S. Griffiths, K. Ritz and R.E. Wheatley, 200436841848Vong, P.C., S. Piutti, S.S Deschaumes, E. Benizri and A. Guckert,20081487984Wu, J., A.G. O'Donnell and J.K. Syers, 19932515671573Wu, J., A.G. O'Donnell, Z.L. He and J.K. Syers,199426117125Eriksen, I.,20053722162224