Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2000.549.551El-ghamryAyman M. Abid Subhani Huang Changyong Xu Jianming 4200034The effect of polyacrylamide (PAM) (synthetic soil conditioners) application on soil microbial biomass C (Cmic) and N (Nmic) were examined under laboratory conditions. Two types of polymers Acqua-Kept (P1) and Super-Hydro (P2) were mixed separately with a loamy sand soil in various concentrations of 25, 50 and 100 μg g1 soil. After 1, 7, 14 and 28 days of incubation, the soils were analyzed for Cmic and Nmic. The two PAMs have shown almost similar effects on the soil microbial biomass C and N. The amount of soil microbial biomass (Cmic and Nmic) was increased with the lower polymer applications of 25 and 50 μg g1 soil, while it decreased at the higher dose of 100 μg g1 soil addition. The response exhibited a parabolic curve. The response was found more pronounced with P2 than P1 application. A slight increase in Cmic and Nmic was observed with the advancement of incubation stages. The results indicate unpredictable changes in soil microbial biomass due to the application of different synthetic soil conditioners.]]>Alexander, M.,19772nd Edn.,pp: 115-380pp: 115-380Aly, S.M. and W.P. Miller,1995357183Amato, M. and J.N. Ladd,198014C- and 15N-labelled plant material.]]>12405411Brookes, P.C., J.F. Kragt, D.S. Powlson and D.S. Jenkinson,198517831835Brookes, P.C., A. Landman, G. Pruden and D.S. Jenkinson,19856837842Canarutto, S., R. Pini, N. Salem and G. Vigna-Guidi,1992122236241CoStat Statistical Software,1990Pages: 271Pages: 271De Boodt, M., M.B.H. Hayes and A. Herbillon,1991Pages: 598Pages: 598El-Ghamry, A.M.,19961996El Hedy, O.A. and R. Azam,198323243257Graham, N.B.,19881988pp: 4149Griffiths, E.,196540129142Grula, M.M., M.L. Huang and G. Sewell,1994158291300Reining, B.,196384849Jackson, M.L.,19581958Jenkinson, D.S.,19881988pp: 368-386pp: 368-386Molope, M.B., I.C. Grieve and E.R. Page,1987387177No, Y.P., Y.T. Jung, C.Y. Park and Y.H. Kim,198720209216Shainberg, I. and G.J. Levy,1994158267273Steinberger, Y., S. Sarig, A. Nadler and G. Barnes,19937303306Terry, R.E. and S.D. Nelson,1986141317320Vance, E.D., P.C. Brookes and D.S. Jenkinson,198719703707Wallace, A. and S.D. Nelson,1986141311312Wallace, A., G.A. Wallace, A.M. Abouzamzam and J.W. Cha,1986141390394Wu, J., R.G. Joergensen, B. Pommerening, R. Chaussod and P.C. Brookes, 19902211671169