Spatial distribution of total phosphorus and organic carbon in the salt-affected soils in the Meyghan Playa, Iran

Abstract

Due to widespread and fast-growing urban developments, large amounts of industrial, agricultural, and municipal wastewaters are produced which can change ecosystem functions after being released into rivers and lakes. The distributions of organic carbon (OC) and total phosphorus (TP) of soil were studied in the salt affected soils in the Meyghan Playa, Iran, to show the impacts of human activities on these soils and sediment properties in this arid region of the world. Samples were taken from 250 points and were analyzed geostatistically for electrical conductivity (EC), pH, TP, and OC. Although EC had the highest coefficient of variation (CV = 2.4) compared to CVs of the other soil properties, the sill/nugget ratio for EC in the geostatistical analysis was the highest one. Therefore, EC had the strongest spatial dependence compared to OC, TP, and pH with lower sill/nugget ratios and moderate spatial dependence. The maximum amount of OC was more than 2% which was observed near the entrance of municipal wastewater to the Meyghan Lake, and the highest soil TP was more than 400 kg mg<sup>-1</sup> near the entrance of municipal wastewater and also at river mouths, which can be attributed to leaching and runoff fertilizers from farmlands. Enrichment of OC in the entrance of municipal wastewater toward the lake is related to eutrophication and higher plant production.

Functional structure of plant communities along salinity gradients in Iranian salt marshes

“…The vegetation of this area has an extremely rich halophytic flora consisted of Halocnemum strobilaceum in muddy salt flats, Nitraria schoberi shrub vegetation (largely cultivated), annual C 4 dominated chenopods ( Climacoptera spp., Bienertia cycloptera , Halimocnemis rarifolia , and Petrosimonia glauca ), hydrophilous eury‐halophytic rush vegetation ( Phragmites australis ), and Stipa steppe (Akhani, 1989 ). The measured range of EC (0.1–97 dS m −1 ), pH (7.6–9.14) and the formation of saline crusts composed of halite (NaCl), glauberite (Na₂Ca[SO₄]₂), gypsum (CaSO 4 ·2H₂O), and calcite (CaCO₃) on the surface of the Meyghan Lake during summer indicate the saline and alkaline soil in this area (Akhani, 1989 ; Safari‐Sinegani et al, 2017 ). This area is part of the Irano‐Turanian Xeric Continental bioclimate (Mxc) (Djamali et al, 2011 ) (Figure 1b ).…”