Guo Chengjiu

Study on the Influence of Nitric Solution Irrigation on Microorganism of Reed Wetland in China

Uaing wastewater as irrigation water presents arising tendency in China, however, little is known about the potential ecological impacts of the practice. Samples, such assoil and plants, were collected from the Panjin Shuangtaiestuarine wetland and used in the experiments to assess the effects of the soil microbial community added nitrogen. Supplemental nitrogen was added as NH4Cl to three treatments at nominal concentrations of 7, 15 and 20 mg/L(representing the hypothetical concentrations found in potential wastewater). In order to compare, a control (no added nitrogen)was added. Soil samples were collected on several days during the tests to assess soil microbial community composition (bacteria, actinomycetes and fungi). Results showed that while irrigation of the wetland soil with water containing progressively higher levels of NH4+ appears to promote some changes in the relative abundance of bacteria and actinomycetes, the differences are not substantial. Based on these data, meeting irrigation needs with certain types of wastewater is unlikely to cause severe environmental stress to the soil microbial balance although, since effluents vary in composition, pre-irrigation data collection and review may be appropriate to ensure the wastewater will not cause undue stress to receptor species.