TY - JOUR
T1 - Three-dimensional modeling of nitrate-N transport in vadose zone
T2 - Roles of soil heterogeneity and groundwater flux
AU - Akbariyeh, Simin
AU - Bartelt-Hunt, Shannon
AU - Snow, Daniel
AU - Li, Xu
AU - Tang, Zhenghong
AU - Li, Yusong
N1 - Funding Information:
This research was supported by a project entitled “Influence of Climate and Agricultural Clustering on Groundwater Contamination by Trace Organics”, which was sponsored by the United States Department of Agriculture Grant No. 2014-67003-22072 . We would also like to thank the MSEA site cooperators for their assistance in collection of additional samples from their fields, as well as extensive assistance from previous Nebraska MSEA site investigators.
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/4
Y1 - 2018/4
N2 - Contamination of groundwater from nitrogen fertilizers in agricultural lands is an important environmental and water quality management issue. It is well recognized that in agriculturally intensive areas, fertilizers and pesticides may leach through the vadose zone and eventually reach groundwater. While numerical models are commonly used to simulate fate and transport of agricultural contaminants, few models have considered a controlled field work to investigate the influence of soil heterogeneity and groundwater flow on nitrate-N distribution in both root zone and deep vadose zone. In this work, a numerical model was developed to simulate nitrate-N transport and transformation beneath a center pivot-irrigated corn field on Nebraska Management System Evaluation area over a three-year period. The model was based on a realistic three-dimensional sediment lithology, as well as carefully controlled irrigation and fertilizer application plans. In parallel, a homogeneous soil domain, containing the major sediment type of the site (i.e. sandy loam), was developed to conduct the same water flow and nitrate-N leaching simulations. Simulated nitrate-N concentrations were compared with the monitored nitrate-N concentrations in 10 multi-level sampling wells over a three-year period. Although soil heterogeneity was mainly observed from top soil to 3 m below the surface, heterogeneity controlled the spatial distribution of nitrate-N concentration. Soil heterogeneity, however, has minimal impact on the total mass of nitrate-N in the domain. In the deeper saturated zone, short-term variations of nitrate-N concentration correlated with the groundwater level fluctuations.
AB - Contamination of groundwater from nitrogen fertilizers in agricultural lands is an important environmental and water quality management issue. It is well recognized that in agriculturally intensive areas, fertilizers and pesticides may leach through the vadose zone and eventually reach groundwater. While numerical models are commonly used to simulate fate and transport of agricultural contaminants, few models have considered a controlled field work to investigate the influence of soil heterogeneity and groundwater flow on nitrate-N distribution in both root zone and deep vadose zone. In this work, a numerical model was developed to simulate nitrate-N transport and transformation beneath a center pivot-irrigated corn field on Nebraska Management System Evaluation area over a three-year period. The model was based on a realistic three-dimensional sediment lithology, as well as carefully controlled irrigation and fertilizer application plans. In parallel, a homogeneous soil domain, containing the major sediment type of the site (i.e. sandy loam), was developed to conduct the same water flow and nitrate-N leaching simulations. Simulated nitrate-N concentrations were compared with the monitored nitrate-N concentrations in 10 multi-level sampling wells over a three-year period. Although soil heterogeneity was mainly observed from top soil to 3 m below the surface, heterogeneity controlled the spatial distribution of nitrate-N concentration. Soil heterogeneity, however, has minimal impact on the total mass of nitrate-N in the domain. In the deeper saturated zone, short-term variations of nitrate-N concentration correlated with the groundwater level fluctuations.
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U2 - 10.1016/j.jconhyd.2018.02.005
DO - 10.1016/j.jconhyd.2018.02.005
M3 - Article
C2 - 29605158
AN - SCOPUS:85044541856
SN - 0169-7722
VL - 211
SP - 15
EP - 25
JO - Journal of Contaminant Hydrology
JF - Journal of Contaminant Hydrology
ER -