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

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.

2016 ◽  
Vol 20 (8) ◽  
pp. 3099-3108 ◽  
Author(s):  
Tuvia Turkeltaub ◽  
Daniel Kurtzman ◽  
Ofer Dahan

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.


2016 ◽  
Vol 96 (2) ◽  
pp. 105-121 ◽  
Author(s):  
W. Daniel Reynolds ◽  
Craig F. Drury ◽  
Gary W. Parkin ◽  
John D. Lauzon ◽  
Joseph K. Saso ◽  
...  

The nitrogen (N) index for humid temperate southern Ontario, Canada (Ontario N index) incorporates previous and current crop type, fertilizer and (or) manure management, and hydrologic soil group (HSG) to estimate risk for contamination of tile drainage water and groundwater by nitrate leached below the primary crop root zone (top 60 cm of soil). The Ontario N index has received limited ground-truthing, and the leaching component was assessed using chloride tracer (ClTR) on five soils (one sandy loam, two loams, and two clay loams) representing four HSG-based risk levels (HSG-A, high risk; HSG-B, medium risk; HSG-C, low risk; HSG-D, very low risk). A square-wave pulse of ClTR was applied to the soil surfaces in fall 2007 as KCl, and movement and loss of ClTR was tracked over 1–1.2 years using monthly soil core samples collected from the top 60–80 cm. For all five soils, 60–96% of ClTR was leached out of the primary crop root zone (below 60 cm depth) during the noncropping period (October 2007 to March 2008 inclusive), and >80% was leached out of the root zone within 1 year. The percentage of ClTR that leached did not correlate with precipitation or HSG designation, but produced significant (P < 0.05) power function regressions with minimum and harmonic mean saturated soil hydraulic conductivity (Ksat) measured in the top 50–60 cm. ClTR leaching rate appeared to be controlled primarily by Ksat in a manner consistent with infiltration and solute transport theory. It was consequently proposed that solute leaching loss versus Ksat relationships may improve N index risk estimates for both southern Ontario and other humid temperate regions.


Soil Research ◽  
2007 ◽  
Vol 45 (2) ◽  
pp. 91 ◽  
Author(s):  
Greg Barkle ◽  
Tim Clough ◽  
Roland Stenger

Land use in the Lake Taupo catchment is under scrutiny, as early signs of deteriorating water quality in Lake Taupo have been observed. Although the fate of contaminants in soil and groundwater are comparatively well studied, the transformations in the lower vadose zone, i.e. the zone between the soil and the groundwater, are less well understood. The capacity for NO3-N removal via biological denitrification, based on utilising the resident C substrate, in the vadose zone of the Lake Taupo catchment is quantified in this work. Complete vadose zone profiles were sampled at 3 sites (Rangiatea, Waihora, and Kinloch), from the soil surface down to the watertable in approximately 0.5-m depth increments. Texture, allophane content, pH, and concentrations of extractable NO3-N, NH4-N, and dissolved organic carbon were determined. Incubations were undertaken to determine the denitrification capacity of the vadose zone materials amended with NO3-15N, but no added carbon substrate, and maintained under anaerobic conditions at 28°C. Gas samples were taken from the headspace after 48 h and analysed for N2 and N2O. In soil depths down to about 1.2 m, the denitrification capacity ranged from 0.03 to 9.18 kg N/ha.day, and below this depth it ranged from <0.01 to 0.09 kg N/ha.day. A palaeosol layer in the Waihora profile had an enhanced denitrification capacity compared with the other samples in deeper zones of the profiles. In the surface sampling, at least 99.9% of the gas recovered from the 15N applied was in the form of N2. In contrast, no N2 gas production could be detected in any sample from below the second sampling depth, with only N2O detected. Denitrification capacities of all vadose zone materials were low when compared with other studies. Thus, careful land management is required to avoid groundwater contamination by nitrate leaching from the root-zone of the pasture.


Soil Research ◽  
2012 ◽  
Vol 50 (1) ◽  
pp. 67 ◽  
Author(s):  
Mark Shepherd ◽  
Justin Wyatt ◽  
Brendon Welten

The nitrification inhibitor dicyandiamide (DCD) is mobile in drainage water, which has implications for its effectiveness in reducing nitrate leaching from urine patches. Lysimeters had been used to investigate the effect of soil type (clay, silt loam, or sandy loam) and precipitation (target ~1140 or 2280 mm/year) on the effectiveness of DCD to decrease nitrate leaching. This paper reports the associated effects on DCD in drainage water. DCD was applied in May and July at a rate of 10 kg/ha, and natural rainfall was supplemented with irrigation to ensure that the target precipitation was achieved for each treatment. The experiment was undertaken twice. The pattern of DCD concentrations in drainage water suggested that movement of DCD in the silt loam and sandy loam soils was typical of convective–dispersive flow. Although there was some preferential flow of DCD from the soil surface to depth in the clay soil, DCD concentration profiles suggested that the main transport mechanism was also by convective–dispersive flow. There were significant soil-type and precipitation effects on DCD leaching (P < 0.05). The soil-type effect could be attributed to differences in drainage volume between soils. Combining data from the two experimental years, DCD leaching losses ranged from 12 to 46% of applied, with annual drainage in the range 422–1292 mm. DCD was detected in drainage up to 15 months after application, demonstrating the longevity of the compound. The experiment demonstrates that leaching of DCD on all of the soil types tested can be substantial under high rainfall. This is likely to have implications for the effectiveness of DCD to decrease nitrogen losses from urine patches under such rainfall conditions, as well as being a source of nitrogen itself.


Author(s):  
Alexsandro C. S. Almeida ◽  
Tarlei A. Botrel ◽  
Steven R. Raine ◽  
Antonio P. de Camargo ◽  
Marinaldo F. Pinto ◽  
...  

ABSTRACT In this study, a field evaluation of the performance of an irrigation controller mechanically actuated by soil-water tension (SWT) was performed. The controller employs a tensiometer used as a sensor of SWT to directly control a mechanically actuated hydraulic valve. Six controllers were installed in an orchard to control the irrigation for six rows of plants over 64 days. Each controller controlled the irrigation of one lateral drip line. The drip irrigation system was gravity-fed from a water source placed 7 m above the soil surface. The SWT and the pressure in each lateral line were measured to evaluate the performance of the controllers. All the controllers tested in the field autonomously initiated and terminated the irrigation during the evaluation. Irrigation events were initiated when values close to the set soil-tension values were reached and were terminated at lower soil-tension values. As the SWT in the root zone was maintained close to the setup threshold plus 20% tolerance for at least 90% of the evaluation period, the performance of the controllers was considered satisfactory. The proposed controller was shown to be functional and was operated effectively for an SWT range of up to 30 kPa, which is commonly encountered under high-frequency irrigation conditions.


2007 ◽  
Vol 42 (3) ◽  
pp. 219-230 ◽  
Author(s):  
Imran Ahmed ◽  
Ramesh Rudra ◽  
Kevin McKague ◽  
Bahram Gharabaghi ◽  
John Ogilvie

Abstract Loss of nitrogen from the agricultural production system is of concern in Ontario. The challenge for researchers and farmers is to fulfill crop water requirements while limiting chemical movement with surface and subsurface runoff. The main objective of this study was to evaluate the long-term effects of current N management practices for corn production for two different soil types using the Root Zone Water Quality Model (RZWQM) for southern Ontario conditions. The model simulated the amount of subsurface tile drainage, residual soil nitrate-nitrogen (NO3-N), NO3-N in subsurface drainage water, and crop yield. The validated RZWQM for silt loam and sandy loam soils showed that the relative long-term effectiveness of the most economic rate of nitrogen (MERN) for corn production fluctuates significantly from year-to-year in response to weather patterns. In addition, soil type had a small but significant effect on the MERN. Side-dress application of N on sandy loam resulted in significant reduction in corn yield and NO3-N loss to shallow groundwater. Also, crop rotation from corn-soybean to corn-soybean-soybean resulted in a greater reduction of NO3-N loads in the tile outflow on silt loam soil than on sandy loam soil. Overall, the RZWQM simulated tile drain flow, NO3-N loss, and crop yield with reasonable accuracy. However, more field work is needed to assist with identifying suitable values for a number of coefficients used in the RZWQM's nutrient component for Ontario conditions.


Author(s):  
M Gayathri ◽  
D Arun Shunmugam ◽  
A Ishwariya

In this work we use drip irrigation where the water was allowed to drip slowly to the roots of plant either from above the soil surface or buried into the surface so that the water can be placed directly into the root zone and minimize evaporation. It uses temperature sensor, soil humidity sensor to collect and monitor field information and also uses float switches to monitor ground water level through web page. When the field gets dry and ground water level falls down it will be notified through SMS. This provides a solution for the problems in developing a smart farming system. It uses node MCU, relay and water pump.


2019 ◽  
Vol 8 (2) ◽  
pp. 4338-4341

Water is flattering more and more scares and precious resources as population and utilization hike. Elevation of those elements as well as technology and action to support fine water supplies is obligatory to get control of the condition. Agriculture usage of water consumption is almost 70 % of the water used throughout the world and more than half of this water is used for irrigation purpose.For solving the problem of water scarcity in agriculture, it is important to expand water saving irrigation which has become the need of the time. Currently there are varying types of water saving methods include drip irrigation, sprinkler irrigation. Between these irrigation system drip irrigation system is the most successful way in arid and semi-arid areas and its make use of rate can get up to 90 %. Drip irrigation also known as trickle irrigation is a method which minimizes the use of water and filterers by admitting water to drip at a slow and steady pace to the plant root, rather onto the soil surface or openly onto the root zone, a network process of pipes, valves, emitters and tubing.Water is one of the most precocious assets that we have . The level to which water is abundant or hard to get, polluted or clean, advantageous or devastating, deeply effect the size and standard of human life. The relentless elevation in population and the resulting spurt in the request for water and the need to be cautious in organizing and the management of the restricted water resources.


2016 ◽  
Author(s):  
T. Turkeltaub ◽  
D. Kurtzman ◽  
O. Dahan

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.


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