Salinity influence on soil microbial population metabolism and enzymatic activities in lysimeter-grown Olea europaea and Nicotiana glauca
Since soil microorganisms are quite sensitive to changes in their habitat, their response in terms of selected metabolic and enzymatic activities was investigated as a possible indicator of the effects of saline irrigation in lysimeter-grown plants of Olea europea and Nicotiana glauca. Water electrical conductivity ranged from 0.8 dS/m in the control to 8.9,17.5, and 26.2 dS/m in treatments with 20%, 40% and 60% diluted seawater, respectively. While some results were non-significant, the following main conclusions could be drawn: Microbial biomass carbon, soluble soil carbon and respiration activity were not significantly correlated to salinity. In addition, the microbial biomass nitrogen was not correlated to salinity. Contrary to this, enzyme activities as shown by hydrolysis rate of fluorescein diacetate (FDA), acid and alkaline phosphatase, and β-glucosidase decreased consistently with salinity without any significant difference between the two plant species. FDA gave the most sensitive and consistent response.
KeywordsMicrobial Biomass Acid Phosphatase Microbial Biomass Carbon Fluorescein Diacetate Microbial Biomass Nitrogen
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