The study of biological properties of soils in joining places of surface water-inflows in Meyghan playa in Arak

Healthy lifestyle on dry land depends on monitoring and maintenance of the ponds. The aim of this study was to assess the effects of surface water-inflows on biological characteristics of wetland soils around Arak Meyghan-Lake. Two soil layers (0-30 and 30-60 cm) in the 4 sites of surface water-inflows were sampled in May and November 2014. The sites were the release sites of treated-municipal-wastewater, Shahrab-River, Farah-River and sodium sulfate-processing plant wastewater. The number of culturable microorganisms in the samples was counted on solid media and the soil basal-respiration (BR), substrate-induced-respiration (SIR), metabolic-quotient (MQ) and microbial-coefficient (MC) were measured. The number of soil fungi in the site Farahan-River site and the numbers of soil bacteria, enteric bacteria and actinomycetes in the release site of municipal wastewater especially in topsoil and in spring were significantly higher compared to those in the 3 other sites (respectively 4.85, 6, 5.51 and 3.92 log numbers). The numbers of the studied microorganisms in soil in the release site of sulfate-plant wastewater were significantly low and the numbers of fungi and actinomycetes were negligible in the most samples. Soil SIR was the most susceptible and responsive index among the studied biological properties. The release of municipal-wastewater in the playa improved the soil biological indices like BR (0.102 mg CO2 g-1 soil day-1), SIR (3.688 mg CO2 g-1 soil day-1), and MC (0.196 mg Cmic mg-1 Corg) significantly. In contrast, the MQ was significantly high in the release site of Shahrab-River and sulfate-plant wastewater (2.60 and 2.52 (mg C-CO2 g-1 Cmic h-1) respectively), showing the negative effects and the higher salt tension in these sites. Although the release of municipal-wastewater in Meyghan-Lake had positive effects on soil biological characteristics, it may have negative effects on biodiversity of these salty soils.