scholarly journals Real-time monitoring of nitrate transport in deep vadose zone under a crop field – implications for groundwater protection

2016 ◽  
Author(s):  
T. Turkeltaub ◽  
D. Kurtzman ◽  
O. Dahan
Keyword(s):  
Real Time ◽  
Water Table ◽  
Vadose Zone ◽  
Root Zone ◽  
Temporal Variations ◽  
Nitrate Transport ◽  
Natural Soil ◽  
Agricultural Field ◽  
Table Analysis ◽  
Concentration Time Series

Abstract. Nitrate is considered the most common non-point pollutant in groundwater. It is often attributed to agricultural management, when excess application of nitrogen fertilizer leaches below the root zone and is eventually transported as nitrate through the unsaturated zone to the water table. A lag time of years to decades between processes occurring in the root zone and their final imprint on groundwater quality prevents proper decision-making on land use and groundwater-resource management. In this study, water flow and solute transport through the deep vadose zone underlying an agricultural field were monitored using a vadose-zone monitoring system (VMS). Data obtained by the VMS over a period of 6 years allowed detailed tracking of water percolation and nitrate migration from the surface through the entire deep vadose zone to the water table at 18 m depth. The temporal variations in the vadose zone sediment water content were used to evaluate the link between rain patterns and water fluxes. A nitrate concentration time series, which varied with time and depth, revealed – in real time – a major pulse of nitrate mass propagating down through the vadose zone from the root zone toward the water table. Analysis of stable nitrate isotopes indicated that manure is the prevalent source of nitrate in the deep vadose zone, and these isotopes were barely affected by natural soil or industrial nitrogen components. Total nitrate mass estimations and simulated pore-water velocity using the analytical solution of the convection–dispersion equation indicated dominance of nitrate vertical transport, and excluded the possibility of lateral nitrate input. Accordingly, prevention of groundwater pollution from surface sources such as agriculture has to include effective and continuous monitoring of the entire vadose zone.

scholarly journals Real-time monitoring of nitrate transport in the deep vadose zone under a crop field – implications for groundwater protection

2016 ◽  
Vol 20 (8) ◽  
pp. 3099-3108 ◽  
Author(s):  
Tuvia Turkeltaub ◽  
Daniel Kurtzman ◽  
Ofer Dahan
Keyword(s):  
Real Time ◽  
Water Table ◽  
Vadose Zone ◽  
Land Surface ◽  
Agricultural Land ◽  
Root Zone ◽  
Isotopic Signature ◽  
Nitrate Transport ◽  
Mass Migration ◽  
Crop Field

Abstract. Nitrate is considered the most common non-point pollutant in groundwater. It is often attributed to agricultural management, when excess application of nitrogen fertilizer leaches below the root zone and is eventually transported as nitrate through the unsaturated zone to the water table. A lag time of years to decades between processes occurring in the root zone and their final imprint on groundwater quality prevents proper decision-making on land use and groundwater-resource management. This study implemented the vadose-zone monitoring system (VMS) under a commercial crop field. Data obtained by the VMS for 6 years allowed, for the first time known to us, a unique detailed tracking of water percolation and nitrate migration from the surface through the entire vadose zone to the water table at 18.5 m depth. A nitrate concentration time series, which varied with time and depth, revealed – in real time – a major pulse of nitrate mass propagating down through the vadose zone from the root zone toward the water table. Analysis of stable nitrate isotopes indicated that manure is the prevalent source of nitrate in the deep vadose zone and that nitrogen transformation processes have little effect on nitrate isotopic signature. The total nitrogen mass calculations emphasized the nitrate mass migration towards the water table. Furthermore, the simulated pore-water velocity through analytical solution of the convection–dispersion equation shows that nitrate migration time from land surface to groundwater is relatively rapid, approximately 5.9 years. Ultimately, agricultural land uses, which are constrained to high nitrogen application rates and coarse soil texture, are prone to inducing substantial nitrate leaching.

Estimating nitrate loading from an intensively managed agricultural field to a shallow unconfined aquifer

2013 ◽  
Vol 49 (1) ◽  
pp. 10-22 ◽  
Author(s):  
P. J. Kuipers ◽  
M. C. Ryan ◽  
B. J. Zebarth
Keyword(s):  
Water Table ◽  
Root Zone ◽  
Potential Evapotranspiration ◽  
Growing Season ◽  
Nitrogen Budget ◽  
Agricultural Field ◽  
Climate Data ◽  
Nitrogen Surplus ◽  
Nitrogen Budgets ◽  
Intensively Managed

Nitrate loading from an intensively managed commercial red raspberry field to groundwater in the Abbotsford-Sumas Aquifer, British Columbia was estimated over a 1 yr period and compared with the nitrogen surplus calculated using a simple nitrogen budget. Nitrate loading was estimated as the product of recharge (estimated from climate data as total precipitation minus potential evapotranspiration (PET)) and monthly nitrate concentration measured at the water table. Most nitrate loading occurred when nitrate, accumulated in the root zone over the growing season, was leached following heavy autumn rainfall events. Elevated groundwater nitrate concentrations at the water table during the growing season when recharge was assumed to be negligible suggested that the nitrate loading was underestimated. The estimate of annual nitrate loading to the water table was high (174 kg N ha−1) suggesting that the tools currently available to growers to manage N in raspberry production are not adequate to protect groundwater quality. The calculated nitrogen surplus from the nitrogen budget (180 kg N ha−1) was similar to the measured nitrate loading suggesting that simple nitrogen budgets may be relatively effective indices of the risk of nitrate loading to groundwater.

The Soil System

2003 ◽  
Author(s):  
Arthur W. Warrick
Keyword(s):  
Water Table ◽  
Vadose Zone ◽  
Soil Profile ◽  
Atmospheric Pressure ◽  
Root Zone ◽  
Pore Space ◽  
Critical Role ◽  
Chemical Properties ◽  
Parent Material ◽  
Capillary Fringe

Soil exists at the boundary between the atmosphere and the Earth’s subsurface. It plays a critical role in the hydrologic cycle, in addition to serving as the location of most human activity. An examination below the Earth’s surface generally reveals a profile similar to that shown in figure 1-1 A. The first zone encountered is the soil zone. This soil has developed from parent material through biological and other factors of weathering. If time is sufficient, then horizons will have formed with differing physical and chemical properties. At greater depths the soil merges with additional unconsolidated material. Eventually, at still greater depths, bedrock is encountered. The dimensions of these various zones are highly variable. For example, the soil profile may exist on bedrock that is partially exposed at the soil surface. Conversely, the unconsolidated layer can be hundreds of meters thick, as is the case in many alluvial basins. The subsurface can also be described in terms of water regimes that exist.The hydrologic profile consists of the vadose zone and the phreatic zone. The vadose zone is from the ground surface to the permanent water table, and includes the root zone, the soil profile, and the capillary fringe, which is a tension-saturated zone bordering the water table. The water at the water table is at atmospheric pressure; above the water table the pressure is less than atmospheric pressure and below the water table it is greater. The system is unsaturated above the capillary fringe, meaning that not only is the water under tension, but that some of the pore space is filled with air. The extent of the capillary fringe is dependent on the porous material. Generally, itextends a few centimeters for coarse material, or perhaps a meter for fine materials. A more complete depiction would include further saturated regions in the vadose zone, such as those due to surface infiltration or due to impeding layers that result in a perched water. Historically, the term groundwater was used to denote water beneath the permanent water table, but it is now commonly used to describe all subsurface water.

A New Automated Passive Capillary Lysimeter for Logging Real-Time Drainage Water Fluxes

2017 ◽  
Vol 33 (6) ◽  
pp. 849-857
Author(s):  
J. D. Jabro ◽  
W. M. Iversen ◽  
W. B. Stevens ◽  
B. L. Allen ◽  
U. M. Sainju
Keyword(s):  
Real Time ◽  
Vadose Zone ◽  
Spread Spectrum ◽  
Root Zone ◽  
Sandy Loam ◽  
Irrigation System ◽  
Cropping Systems ◽  
Soil Surface ◽  
Drainage Water ◽  
Water Fluxes

Abstract.Effective monitoring of chemical transport through the soil profile requires accurate and appropriate instrumentation to measure drainage water fluxes below the root zone of cropping systems. The objectives of this study were to methodically describe in detail the construction and installation of a novel automated PCAP (passive capillary) lysimeter design, and to evaluate the efficacy of this design for logging and monitoring real-time drainage water fluxes occurring below the root zone of corn ( L.) and soybean ( L.) under an overhead sprinkler irrigation system. Sixteen cylindrical PCAP lysimeters with outside dimensions of 32.39 cm in diameter ×74.8 cm height (1000 cm2 surface area) were designed, constructed, and placed 90 cm below the soil surface in a Lihen sandy loam. Two watermark soil moisture and temperature sensors were positioned at 30 and 76 cm depths above each PCAP to monitor soil temperature and water potential continuously. This new design incorporated wireless spread spectrum technology to enable an automated datalogger to transmit drainage water amounts simultaneously every 15 min to a remote host. Logged drainage amounts were compared with those manually collected using several statistical methods. The root mean square error (RMSE), the logging efficacy (EF), and the mean difference (MD) were 0.0375, 0.964 and 0.0335 cm, respectively, for 4-yr combined data. The MD between logged and collected drainage amounts was very small and not significantly different from zero for 4-yr combined results. Statistical results indicated that the new lysimeter performed exceptionally well and was capable of monitoring drainage water fluxes in the vadose zone. Real-time seamless monitoring and logging drainage water fluxes was thus possible without the need for costly time-consuming supportive procedures. Keywords: Drainage, Lysimeter, Root zone, Vadose zone.

Conception of vadose zone research in the area of Goczałkowice reservoir.

2013 ◽  
Vol 2 (1) ◽  
pp. 22-26
Author(s):  
Joanna Czekaj ◽  
Kamil Trepka
Keyword(s):  
Vadose Zone ◽  
Unsaturated Zone ◽  
Vertical Profile ◽  
Structural Model ◽  
Historical Data ◽  
Integrated System ◽  
Nitrate Transport ◽  
Strategic Research ◽  
Research Site ◽  
Observation Wells

Abstract Goczałkowice reservoir is one of the main source of drinking water for Upper Silesia Region. In reference to Water Frame Directive matter since 2010 the strategic research project: „Integrated system supporting management and protection of dammed reservoir (ZiZoZap)”, which is being conducted on Goczałkowice reservoir, has been pursued. In the framework of this project complex groundwater monitoring is carried on. One aspect is vadose zone research, conducted to obtain information about changes in chemical composition of infiltrating water and mass transport within this zone. Based on historical data and the structural model of direct catchment of Goczałkowice reservoir location of the vadose zone research site was selected. At the end of November 2012 specially designed lysimeter was installed with 10 MacroRhizon samplers at each lithological variation in unsaturated zone. This lysimeter, together with nested observation wells, located in the direct proximity, create the vadose zone research site which main aim is specifying the amount of nitrate transport in the vertical profile.

Dissolved Phosphorus Losses in Tile Drainage under Subirrigation

2006 ◽  
Vol 41 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Nicolas Stämpfli ◽  
Chandra A. Madramootoo
Keyword(s):  
Water Table ◽  
Residual Effect ◽  
Surface Water Quality ◽  
Soil Surface ◽  
Quality Standard ◽  
Tile Drainage ◽  
Agricultural Field ◽  
Shallow Water Table ◽  
Dissolved Phosphorus ◽  
Water Table Control

Abstract Recent studies have shown subirrigation (SI) to be effective in reducing nitrate losses from agricultural tile drainage systems. A field study was conducted from 2001 to 2002 in southwestern Québec to evaluate the effect of SI on total dissolved phosphorus (TDP) losses in tile drainage. In an agricultural field with drains installed at a 1-m depth, a SI system with a design water table depth (WTD) of 0.6 m below the soil surface was compared with conventional free drainage (FD). Subirrigation increased drainage outflow volumes in the autumn, when drains were opened and water table control was interrupted for the winter in the SI plots. Outflows were otherwise similar for both treatments. Throughout the study, the TDP concentrations in tile drainage were significantly higher with SI than with FD for seven out of 17 of the sampling dates for which data could be analyzed statistically, and they were never found to be lower for plots under SI than for plots under FD. Of the seven dates for which the increase was significant, six fell in the period during which water table control was not implemented (27 September 2001 to 24 June 2002). Hence, it appears that SI tended to increase TDP concentrations compared with FD, and that it also had a residual effect between growing seasons. Almost one-third of all samples from the plots under SI exceeded Québec's surface water quality standard (0.03 mg TDP L-1), whereas concentrations in plots under FD were all below the standard. Possible causes of the increase in TDP concentrations in tile drainage with SI are high TDP concentrations found in the well water used for SI and a higher P solubility caused by the shallow water table.

scholarly journals Evaluation of IMERG Level-3 Products in Depicting the July to October Rainfall over Taiwan: Typhoon Versus Non-Typhoon

2021 ◽  
Vol 13 (4) ◽  
pp. 622
Author(s):  
Wan-Ru Huang ◽  
Pin-Yi Liu ◽  
Ya-Hui Chang ◽  
Cheng-An Lee
Keyword(s):  
Real Time ◽  
Tropical Rainfall Measuring Mission ◽  
Temporal Variations ◽  
Rain Gauge ◽  
Advantages And Disadvantages ◽  
Level 3 ◽  
Spatio Temporal ◽  
Typhoon Season ◽  
Early Late ◽  
Better Than

This study assesses the performance of satellite precipitation products (SPPs) from the latest version, V06B, Integrated Multi-satellitE Retrievals for Global Precipitation Mission (IMERG) Level-3 (including early, late, and final runs), in depicting the characteristics of typhoon season (July to October) rainfall over Taiwan within the period of 2000–2018. The early and late runs are near-real-time SPPs, while final run is post-real-time SPP adjusted by monthly rain gauge data. The latency of early, late, and final runs is approximately 4 h, 14 h, and 3.5 months, respectively, after the observation. Analyses focus on the seasonal mean, daily variation, and interannual variation of typhoon-related (TC) and non-typhoon-related (non-TC) rainfall. Using local rain-gauge observations as a reference for evaluation, our results show that all IMERG products capture the spatio-temporal variations of TC rainfall better than those of non-TC rainfall. Among SPPs, the final run performs better than the late run, which is slightly better than the early run for most of the features assessed for both TC and non-TC rainfall. Despite these differences, all IMERG products outperform the frequently used Tropical Rainfall Measuring Mission 3B42 v7 (TRMM7) for the illustration of the spatio-temporal characteristics of TC rainfall in Taiwan. In contrast, for the non-TC rainfall, the final run performs notably better relative to TRMM7, while the early and late runs showed only slight improvement. These findings highlight the advantages and disadvantages of using IMERG products for studying or monitoring typhoon season rainfall in Taiwan.

Nitrate transport in the chalk vadose zone in in Picardy (France)

2021 ◽  
pp. SP517-2020-164
Author(s):  
N. Surdyk ◽  
L. Gourcy ◽  
V. Bault ◽  
N. Baran
Keyword(s):  
Groundwater Quality ◽  
Vadose Zone ◽  
Nitrate Concentration ◽  
Agricultural Practices ◽  
Nitrate Transport ◽  
Transport Time ◽  
Major Question ◽  
Noticeable Effect ◽  
Fertiliser Application ◽  
The Impact

AbstractSince the 1980s, nitrate has been shown to be present in soils and the vadose zone of various types of geological materials years after fertiliser application. In chalk where the vadose zone is thick, nitrate storage can be considerable and its transport time toward groundwater can be lengthy.In this context, evaluation of the impact of changes in agricultural practices on groundwater quality remains a major question. Improvement of groundwater quality can in certain cases be greatly delayed after the implementation of environmental agricultural practices.The principal objective of this study is to improve our knowledge of when changes in agricultural practices will have a noticeable effect on groundwater quality.To meet this objective, nitrate concentration profiles were performed in agricultural plots in Picardy (France). A crop marker event was used to calculate the transport velocity of water and associated solutes. This method is useful when other tracers (as tritium or chlorine) cannot be used. Estimated velocities range from 0.51 to 0.54 m/year; these values are similar to those described in similar chalk aquifers.

scholarly journals Usability in 4D AR: Visualising Multi-temporal Real-time Geo-data in Augmented Reality Environments

2015 ◽  
Vol 9 (4) ◽  
pp. 23 ◽  
Author(s):  
Bernd Resch ◽  
Andreas Wichmann ◽  
Nicolas Göll
Keyword(s):  
Augmented Reality ◽  
Real Time ◽  
Temporal Variations ◽  
Time Base ◽  
Future Research ◽  
Time Data ◽  
Orientation Data ◽  
Information Density ◽  
Real Time Data ◽  
Multi Temporal

Even though advantages of 3D visualisation of multi-temporal geo-data versus 2D approaches have been widely proven, the particular pertaining challenge of real-time visualisation of geo-data in mobile Digital Earth applications has not been thoroughly tackled so far. In the emerging field of Augmented Reality (AR), research needs comprise finding the optimal information density, the interplay between orientation data in the background and other information layers, using the appropriate graphical variables for display, or selecting real-time base data with adequate quality and suitable spatial accuracy. In this paper we present a concept for integrating real-time data into 4D (three spatial dimensions plus time) AR environments, i.e., data with “high” spatial and temporal variations. We focus on three research challenges: 1.) high-performance integration of real-time data into AR; 2.) usability design in terms of displaying spatio-temporal developments and the interaction with the application; and 3.) design considerations regarding reality vs. virtuality, visualisation complexity and information density. We validated our approach in a prototypical application and extracted several limitations and future research areas including natural feature recognition, the cross-connection of (oftentimes monolithic) AR interface developments and well-established cartographic principles, or fostering the understanding of the temporal context in dynamic 4D Augmented Reality environments.

LONG-TERM TILLAGE AND CROP ROTATION EFFECTS ON RESIDUAL NITRATE IN THE CROP ROOT ZONE AND NITRATE ACCUMULATION IN THE INTERMEDIATE VADOSE ZONE

1997 ◽  
Vol 40 (5) ◽  
pp. 1321-1327 ◽  
Author(s):  
A. Katupitiya ◽  
D. E. Eisenhauer ◽  
R. B. Ferguson ◽  
R. F. Spalding ◽  
F. W. Roeth ◽  
...  
Keyword(s):  
Crop Rotation ◽  
Vadose Zone ◽  
Root Zone ◽  
Nitrate Accumulation ◽  
Crop Root ◽  
Residual Nitrate
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