DRAINMOD-P: A Model for Simulating Phosphorus Dynamics and Transport in Drained Agricultural Lands: II. Model Testing

2021 ◽  
Vol 64 (6) ◽  
pp. 1849-1866
Author(s):  
Manal H. Askar ◽  
Mohamed A. Youssef ◽  
Dean L. Hesterberg ◽  
Kevin W. King ◽  
Aziz Amoozegar ◽  
...  
Keyword(s):  
Surface Runoff ◽  
Preferential Flow ◽  
Model Performance ◽  
Water Quality Modeling ◽  
List Type ◽  
Macropore Flow ◽  
Major Pathway ◽  
Phosphorus Loss ◽  
Particulate Form ◽  
Subsurface Drains

HighlightsDRAINMOD-P was tested using a dataset from a drained field with desiccation cracks.Surface and subsurface phosphorus losses were mainly in the particulate form.Surface runoff was a major pathway for phosphorus loss in this field.The model performance in predicting edge-of-field phosphorus loss is promising.Abstract. The recently developed phosphorus (P) model DRAINMOD-P was tested using a four-year dataset from a subsurface-drained field in northwest Ohio with significant potential for desiccation cracking or preferential flow. The model satisfactorily predicted subsurface drainage discharge, with a monthly Nash-Sutcliffe efficiency (NSE) of 0.59 and index of agreement (IOA) of 0.89. Lack of annual water budget closure was reported and was likely caused by uncertainty in measured surface runoff and/or modeling approaches representing macropore flow. More than 80% of predicted surface and subsurface P losses were in the particulate form. Surface runoff was the major pathway for P loss, contributing 78% of predicted total P (TP) load. On average, predicted macropore flow represented about 15% of drainage discharge and contributed 21% of DRP loss via subsurface drains. The performance of DRAINMOD-P in predicting monthly dissolved reactive P and TP losses through subsurface drains can be rated as poor (NSE = 0.33 and IOA = 0.60) and very good (NSE = 0.81 and IOA = 0.95), respectively. DRAINMOD-P demonstrated potential for simulating P fate and transport in drained cropland. More testing is needed to further examine newly incorporated hydrological and biogeochemical components of the model. Keywords: Agricultural drainage, Edge-of-field phosphorus load, Macropore flow, Phosphorus model, Sediment yield, Water quality modeling.

DRAINMOD-P: A Model for Simulating Phosphorus Dynamics and Transport in Drained Agricultural Lands: I. Model Development

2021 ◽  
Vol 64 (6) ◽  
pp. 1835-1848
Author(s):  
Manal H. Askar ◽  
Mohamed A. Youssef ◽  
Peter A. Vadas ◽  
Dean L. Hesterberg ◽  
Aziz Amoozegar ◽  
...  
Keyword(s):  
Water Quality ◽  
Soil Erosion ◽  
Best Management Practices ◽  
Management Practices ◽  
Subsurface Drainage ◽  
Water Quality Modeling ◽  
List Type ◽  
Macropore Flow ◽  
Drainage Systems ◽  
P Cycling

HighlightsDRAINMOD-P has been developed to simulate phosphorus (P) dynamics in drained croplands.Key hydrological and biochemical processes affecting P cycling are represented in the model.The model predicts surface and subsurface P losses as affected by weather, soil, and management factors.Abstract. High phosphorus (P) loads to streams and lakes can promote harmful algae blooms and cause water quality deterioration. Recent research has identified subsurface drainage as an important pathway for the transport of dissolved P from drained croplands to receiving surface water bodies, particularly when macropore flow contributes a considerable portion of the subsurface drainage outflow. Currently, a few models are capable of simulating P dynamics in poorly drained soils with artificial drainage systems. The objective of this study was to develop DRAINMOD-P, a field-scale, process-based model that simulates P cycling and transport in drained croplands. Processes represented in the model include atmospheric deposition, organic and inorganic fertilizer applications, plant uptake, sediment-bound and dissolved P losses in both surface runoff and subsurface drainage, tillage practices, and P mineralization and immobilization. The model predicts P losses under different management practices, climatic conditions, drainage systems, and crop rotations. The model is an extension to the nitrogen model DRAINMOD-NII, with full integration of the nitrogen and P model components. DRAINMOD-P uses the recently modified hydrology component that simulates macropore flow. A soil erosion component, based on the RUSLE approach, has been incorporated into the model to estimate sediment loss and associated particulate P loss. Sediment deposition in tile drains is considered to quantify particulate P settling in the drainage system. In this article, we review the approaches used in DRAINMOD-P for simulating P-related processes. Model testing against field-measured data from a subsurface-drained field in northwest Ohio is presented in a companion article. Keywords: Best management practices, Phosphorus model, Phosphorus processes, Soil erosion, Water quality modeling.

Comparative Non-Darcian Modeling of Subsurface Preferential Flow Experimental Observations in a Riparian Buffer

2021 ◽  
Vol 64 (6) ◽  
pp. 1867-1881
Author(s):  
Enrique Orozco-López ◽  
Rafael Muñoz-Carpena
Keyword(s):  
Vadose Zone ◽  
Preferential Flow ◽  
Riparian Buffers ◽  
Riparian Buffer ◽  
Model Parameters ◽  
List Type ◽  
Dispersive Wave ◽  
Macropore Flow ◽  
Modeling Framework ◽  
Soil Matrix

HighlightsHigh ecohydrological activity drives macropore prevalence in riparian buffers.An abundance of macropore flow (MF) was confirmed in a field riparian buffer in Kenya.Source-response (SR) and multilayer kinematic diffusive wave (MKDW) MF models are compared.A novel MKDW modeling framework efficiently identifies and predicts preferential flow in riparian buffers.Abstract. The significant ecohydrological activity typical of riparian buffers makes them potential hotspots of macropores, i.e., structured preferential flow pathways, through the soil vadose zone. The prevalence of these preferential pathways can allow transported contaminants to bypass the soil matrix and quickly reach a seasonal shallow water table and the adjacent surface waterbody. This quick transport can ultimately limit the role of riparian buffers for runoff pollution control. Currently, there are no management tools that incorporate macropore flow (MF) when assessing riparian buffer performance. The objective of this study was to experimentally quantify and mathematically simulate macropore flow and arrival time in a riparian buffer under field conditions. Three infiltration experiments were conducted with a grid of 20 time-domain transmission (TDT) dielectric soil moisture sensors along a field riparian buffer transect in Kenya to quantify the presence of macropore flow and to test two non-Darcian soil MF models, including the source-responsive (SR) model and the modified kinematic-dispersive wave (MKDW) model developed in this study, by adding a user-defined multilayer convection scheme and a new hysteresis function between water flux and content. The abundance of MF in the riparian buffer was corroborated experimentally. Modeling results showed that the MKDW model was an efficient (average NSE of 0.937 and 0.721 for calibration and testing, respectively), flexible, and robust method to identify and represent non-linear and non-sequential MF signals at any soil depth and antecedent conditions. The SR model was computationally inexpensive and provided good calibration results (NSE = 0.867) but required piecemeal recalibration of the travel time and maximum water content at each layer and yielded lower performance in testing. The Akaike (AIC) and Bayesian (BIC) information criteria showed that MKDW outperformed SR when accounting for the trade-off between model complexity and efficiency. The results support further research focused on independent characterization of model parameters at the field scale, and the inclusion of MKDW in holistic riparian buffer management and decision-support tools such as VFSmod. Keywords: Kinematic-dispersive wave, Macropore flow, Numerical modeling, Preferential flow, Riparian vadose zone.

scholarly journals Prediction of leaching and groundwater contamination by pesticides

2006 ◽  
Vol 78 (5) ◽  
pp. 1081-1090 ◽  
Author(s):  
Werner Kördel ◽  
Michael Klein
Keyword(s):  
Maximum Concentration ◽  
Management Practices ◽  
Preferential Flow ◽  
Soil Depth ◽  
Sandy Soils ◽  
Field Studies ◽  
Macropore Flow ◽  
Eu Directive ◽  
Present Information ◽  
Silty Soils

Herein, we describe how pesticide leaching is assessed in Europe in order to fulfill EU Directive 91/414. The assessment schemes were developed to protect groundwater from unacceptable effects caused by pesticide use. They presently focus on chromatographic flow processes, which are dominant in sandy soils. Nevertheless, important regions in Europe are characterized by structured soils where transport through macropores is most relevant.Comparison of parallel field studies with isoproturon performed in sandy and silty soils showed that maximum concentration in the structured soil at a soil depth of 1 m may exceed respective concentrations in sandy soils by a factor of 60. Similar results were obtained by lysimeter studies using silty soil cores with maximum concentration of 40 μg/l at the soil bottom. These results demonstrate that preferential flow is more the rule than the exception in well-structured fine-textured soils, and pesticide losses via macropore flow may exceed losses via matrix transport considerably. All present information available for macropore flow suggest the need for greater regional assessments. Other recommendations include analysis of the influence of different soil management practices on the formation of macropores.

Phosphorus Loss Mitigation in Leachate and Surface Runoff from Clay Loam Soil Using Four Lime-Based Materials

2018 ◽  
Vol 229 (3) ◽  
Author(s):  
Faezeh Eslamian ◽  
Zhiming Qi ◽  
Michael J. Tate ◽  
Tiequan Zhang ◽  
Shiv O. Prasher
Keyword(s):  
Surface Runoff ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Phosphorus Loss ◽  
Loss Mitigation ◽  
Loam Soil

Rainfall Sequence Effects on Phosphorus Loss in Surface Runoff from Pastures that Received Poultry Litter Application

2010 ◽  
Vol 53 (4) ◽  
pp. 1147-1158 ◽  
Author(s):  
T. Demissie ◽  
D. E. Storm ◽  
M. S. Friend ◽  
N. T. Basta ◽  
M. E. Payton ◽  
...  
Keyword(s):  
Surface Runoff ◽  
Poultry Litter ◽  
Phosphorus Loss ◽  
Sequence Effects

scholarly journals Spatial Variability of Preferential Flow and Infiltration Redistribution along a Rocky-Mountain Hillslope, Northern China

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1102
Author(s):  
Si-yuan Zhao ◽  
Yang-wen Jia ◽  
Jia-guo Gong ◽  
Cun-wen Niu ◽  
Hui-dong Su ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Preferential Flow ◽  
Fractal Dimensions ◽  
Rocky Mountain ◽  
Clay Content ◽  
Northern China ◽  
Infiltration Rate ◽  
Macropore Flow ◽  
Infiltration Process ◽  
Rock Fragments

Rock fragments in soil strongly increase the complexity of hydrological processes. Spatial variability of preferential flow and infiltration characteristics, especially along a rocky-mountain hillslope are poorly understood. In this study, five rainfall–dye tracer experiments were performed in the rocky Taihang Mountains, northern China, to investigate the spatial variability of preferential flow and infiltration redistribution on different hillslope positions. Tracers were used to distinguish macropore flow and actual water flow patterns, and preferential flow indices and spatial non–uniformity of the infiltration redistribution were calculated using image analysis. Results showed increasing trends in the dye coverage, maximum infiltration depth, and steady infiltration rate with increased hillslope position, with a preferential flow fraction of 0.10, 0.11, 0.15, 0.29, and 0.26 for the bottom–, down–, mid–, upper–, and top–slope positions, respectively. With increased hillslope position, the spatial non–uniformity of the infiltration redistribution gradually increased in orthogonal and parallel directions to the stained section, and was supported by the fractal dimensions. Positive (gravel mass ratio, saturated water content, altitude, hydraulic conductivity and roots) and negative (bulk density and clay content) impacts on preferential flow and infiltration redistribution were quantitatively emphasized. The characteristic and mechanism of infiltration process were further identified along a rocky-mountain hillslope.

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