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Effects of vegetation on ammonium removal and nitrous oxide emissions from pilot-scale drainage ditches

Author:
Zhang, Shunan, Liu, Feng, Xiao, Runlin, Li, Yong, He, Yang, Wu, Jinshui
Source:
Aquatic botany 2016 v.130 pp. 37-44
ISSN:
0304-3770
Subject:
Myriophyllum, Pontederia cordata, agricultural runoff, agricultural watersheds, ammonium nitrogen, aquatic plants, best management practices, botany, drainage channels, field experimentation, greenhouse gas emissions, models, nitrous oxide, pollutants, sediments, sorption, vegetation
Abstract:
Recently, vegetated drainage ditches have been used as one of the best management practices for controlling the transport of agricultural pollutants. In this study, a pilot-scale field experiment within a 135-km2 agricultural catchment was conducted to investigate the effectiveness of ditches vegetated with Pontederia cordata (Pontederia) and Myriophyllum elatinoides (Myriophyllum) and ditches without vegetation (Control) on ammonium (NH4+-N) removal and nitrous oxide (N2O) emissions. Compared to the control treatment, the ditches with both plant species (P. cordata and M. elatinoides) increased NH4+-N removal rates by 50.8% and 71.4% and decreased N2O emissions by 68.3% and 70.4% for NH4+-N loadings of 25mgL−1 and 70mgL−1, respectively. The linear mixed-effect model revealed that effluent NH4+-N concentrations were significantly decreased by 2.54% and 2.10% for each increase of one unit on sediment NH4+-N sorption and plant TN accumulations (p<0.0001). The dominant NH4+-N removal pathways in Myriophyllum ditch were plant uptake and microbial nitrification-denitrification. However, in Pontederia and control ditches, NH4+-N was mainly removed by sediment sorption. These findings may suggest that vegetated drainage ditches (e.g., M. elatinoides) are capable of removing NH4+-N from agricultural runoff and can additionally reduce N2O emissions.
Agid:
5257948