Cyanobacteria constitute a group of prokaryotic microorganisms able to carry out oxygen photo-
synthesis [16]. The idea behind using bioassay technique to evaluate biodegradation of herbicide in soil based on
the fact that bioassay technique is more sensitive tool than chemical technique as previously reported [17]. The
bioassay technique allows us to determine a very low remaining concentration of herbicide in soil [18] [19]. The
objectives of this research are to: Evaluate the biodegradation behavior of Diuron in soil and liquid media by
Cyanobacterial mats and to provide answers to the following research questions: 1) Dose the application rate of
Diuron affects the degradation process? 2) Dose the number of Cyanobacterial mat cells affects the degradation
process? 3) Dose the degradation process is time controlled?