Denitrification Bates and Associated Soil Characteristics of Wetlands Created on Oxidized and Reduced Mine Spoil in East Texas.

摘要

Recovery of wetland function is the primary goal of wetland creation and restoration. Denitrification is a wetland function and part of the nitrogen (N) biogeochemical cycle in which nitrate (NO3~-) and nitrite (NO_2~-) forms of N are converted to gaseous forms and lost to the atmosphere. Measurement of denitrification rate may therefore be an important tool for evaluating wetland function. This study examines denitrification rates and associated soil variables on wetlands created on lignite mine spoil in East Texas. Wetlands created on oxidized and reduced mine spoil were selected as study sites. Soil cores were removed from recently-created (age 4-8 years), older-created (age 10 years) and reference (natural) wetlands. Denitrification was quantified using an acetylene inhibition/gas chromatography method. Soil texture, pH, total N, and organic matter content were also measured. Soil pH range from 4.5 to 7.8 and varied by age and spoil type (#alpha# <=0.05). Total N ranged from 342 to 1564 mg kg~(-1) and varied only by spoil type. Organic matter content varied by spoil type with values ranging from 1.2 percent to 3.0 percent. Denitrification rate did not differ among wetlands and ranged from 0.2 kg N ha~(-1) yr~(-1) to 105 kg N ha~(-1) yr~(-1). Older-created and recently-created wetlands on both oxidized and reduced mine spoil had denitrification rates similar to natural wetlands. Denitrification appears to flinction as well in wetlands created on mine spoil as in natural wetlands.