title: Spatial distribution of inorganic nitrogen contents of marsh soils in a river floodplain with different flood frequencies from soil-defrozen period.
abstract: Contents of inorganic nitrogen (NH4(+)-N and NO3(-)-N) in soil profiles were measured in five typical zones ( including permanently flooded floodplain(B), 1-year floodplain (O), 5-year floodplain (F),10-year floodplain (T), and 100-year floodplain (H) )from Huolin River floodplain in Erbaifangzi, Jilin Province of China, in the soil-defrosted period (Mayof 1999). Contour maps and profile maps were constructed to describe the spatial distributions of NH4(+)-N and NO3(-)-N) in order to identify the influences of flood frequencies on them. Results showed that NH4(+)-N generally increased with depth in soil profiles from the five areas, but NH4(+)-N contents in T or H areas significantly differed from those in other areas. For NO3(-)-N, with the exception that there was a significant cumulative peak (6.77 +/- 0.08 mg kg(-1)) at 15-cm depth (10-20 cm) in B area, no significant difference was observed between NO3(-)-N contents in soil profiles from the other four areas. The horizontal distributions of NH4(+)-N and NO3(-)-N in top soils (0-10 cm) were different in the five areas,which were greatly influenced by flood frequencies. The highest content of NH4(+)-N or NO3(-)-N did not appear in B area but in the floodplain with certain flood frequency. For example, NH4(+)-N content (16.81 mg kg-(1)) in 5-year floodplain wetland was highest, and the highest content of NO3(-)-N(1.69 mg kg(-1)) appeared in 1-year floodplain wetland. In addition, NH4(+)-N contents were significantly correlated with soil pH, and NO3(-)-N contents had significant correlation with inorganic carbon, but there were no significant correlations between inorganic nitrogen and other selected soil properties.
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19 Xinjiekou Wai Street, Beijing 100875, People's Republic of China. junhongbai@163.com
authors.forename: Junhong
authors.initials: J
authors.lastname: Bai
authors.forename: Wei
authors.initials: W
authors.lastname: Deng
authors.forename: Qinggai
authors.initials: Q
authors.lastname: Wang
authors.forename: Baoshan
authors.initials: B
authors.lastname: Cui
authors.forename: Qiuyi
authors.initials: Q
authors.lastname: Ding
mesh_terms: D002681:China; D004190:Disasters; D009566:Nitrates / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis*; D010758:Phosphorus / Q000032:analysis*; D000644:Quaternary Ammonium Compounds / Q000032:analysis*; D045483:Rivers; D012989:Soil Pollutants / Q000032:analysis*; D053833:Wetlands
chemical_list: D009566:Nitrates; D000644:Quaternary Ammonium Compounds; D012989:Soil Pollutants; D010758:Phosphorus; D009584:Nitrogen