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Denitrification potential and its correlation to physico-chemical and biological characteristics of saline wetland soils in semi-arid regions

Yu, Huibin, Song, Yonghui, Xi, Beidou, Du, Erdeng, He, Xiaosong, Tu, Xiang
Chemosphere 2012 v.89 no.11 pp. 1339-1346
Salicornia europaea, Sophora alopecuroides, Suaeda, agricultural land, carbon, denitrification, denitrifying bacteria, edaphic factors, exchangeable sodium, freshwater, halophytes, lakes, marshes, nitrates, nitrous oxide, principal component analysis, semiarid soils, semiarid zones, sewage, soil profiles, soil sampling, wastewater, wetland soils
Denitrification is an important pathway of NO₃ ⁻ removal depending on wetland soil characteristics. Most studies on denitrification have been conducted in the freshwater wetlands and coastal marshes, but little information is available on how soil and environmental factors affect denitrification of saline wetlands in semi-arid regions. We conducted a correlative study on denitrification potential in relation to the physico-chemical and biological characteristics. Composite soil samples of different depths were collected from different halophyte communities along a saline-impact gradient around Wuliangsuhai Lake, i.e. Comm. Salicornia europaea (CSE), Comm. Suaeda glauca (CSG), Comm. Kalidium foliatum (CKF) and Comm. Sophora alopecuroides (CSA). The CSA soil profile showed the fastest denitrification kinetics and tended to yield the largest amount of N₂O, followed by the CKF, CSG and CSE. The mean of potential denitrification rates was the highest across all depths of the CSA soil profile, followed by the CKF, CSG, and CSE. Principal component analysis indicated that exchangeable sodium percentage was a key factor to denitrification potential, apart from organic carbon, nitrate and denitrifying bacteria. The results could have significant implication in integrated assessment and management of salined wetlands for treating nutrient-rich return water from farmland, industrial wastewater and domestic sewage in the diverted trunk drain used for the lakeshore restoration.