Is tile drainage water representative of root zone leaching of pesticides?

2007 ◽  
Vol 63 (5) ◽  
pp. 417-428 ◽  
Author(s):  
Ole H Jacobsen ◽  
Jeanne Kjær
2007 ◽  
Vol 42 (3) ◽  
pp. 202-218 ◽  
Author(s):  
Imran Ahmed ◽  
Ramesh Rudra ◽  
Kevin McKague ◽  
Bahram Gharabaghi ◽  
John Ogilvie

Abstract This study focuses on the performance of the Root Zone Water Quality Model (RZWQM) for corn production in southern Ontario. The model was used to simulate the amount of subsurface tile drainage, residual soil nitrate-nitrogen (NO3-N), NO3-N in subsurface drainage water, and crop yield. A precalibration sensitivity analysis of the model was conducted for several key parameters using field data collected at the study site. The RZWQM's hydrology component was most sensitive to the Brooks and Corey fitting parameters and saturated hydraulic conductivity (Ks), while the tile drain flow and the water table depth were sensitive to the Brooks and Corey fitting parameters of bubbling pressure (ψbp) and pore-size-distribution index (λ). The fraction of dead-end pores had relatively little effect on tile drain N loss. The crop yield is most affected by N uptake, age, and evapotranspiration rate. RZWQM simulated evapotranspiration was within the range (568 ± 55 mm) of the observed evapotranspiration. The model simulated corn yield very well (-0.1% difference) at the calibration site; however, it underestimated yield (-14.1%) at the validation site. Overall, the RZWQM simulated tile drain flow, NO3-N loss to tile drainage water, and crop yield with reasonable accuracy, but tended to underestimate the amount of soil NO3-N (mean deviation, -0.971). The inability of the model to handle the spatial and temporal variability of the soil may have affected its prediction accuracy. The model also needs improvement in simulating early spring snowmelt hydrology.


1998 ◽  
Vol 38 (4-5) ◽  
pp. 103-110 ◽  
Author(s):  
C. S. Tan ◽  
C. F. Drury ◽  
M. Soultani ◽  
I. J. van Wesenbeeck ◽  
H. Y. F. Ng ◽  
...  

Conservation tillage has become an attractive form of agricultural management practices for corn and soybean production on heavy textured soil in southern Ontario because of the potential for improving soil quality. A controlled drainage system combined with conservation tillage practices has also been reported to improve water quality. In Southwestern Ontario, field scale on farm demonstration sites were established in a paired watershed (no-tillage vs. conventional tillage) on clay loam soil to study the effect of tillage system on soil structure and water quality. The sites included controlled drainage and free drainage systems to monitor their effect on nitrate loss in the tile drainage water. Soil structure, organic matter content and water storage in the soil profile were improved with no-tillage (NT) compared to conventional tillage (CT). No-tillage also increased earthworm populations. No-tillage was found to have higher tile drainage volume and nitrate loss which were attributed to an increase in soil macropores from earthworm activity. The controlled drainage system (CD) reduced nitrate loss in tile drainage water by 14% on CT site and 25.5% on NT site compared to the corresponding free drainage system (DR) from May, 1995 to April 30, 1997. No-tillage farming practices are definitely enhanced by using a controlled drainage system for preventing excessive nitrate leaching through tile drainage. Average soybean yields for CT site were about 12 to 14% greater than the NT site in 1995 and 1996. However, drainage systems had very little effect on soybean yields in 1995 and 1996 due to extremely dry growing seasons.


2020 ◽  
Vol 12 (16) ◽  
pp. 6362
Author(s):  
Amninder Singh ◽  
Nigel W. T. Quinn ◽  
Sharon E. Benes ◽  
Florence Cassel

Environmental policies to address water quality impairments in the San Joaquin River of California have focused on the reduction of salinity and selenium-contaminated subsurface agricultural drainage loads from westside sources. On 31 December 2019, all of the agricultural drainage from a 44,000 ha subarea on the western side of the San Joaquin River basin was curtailed. This policy requires the on-site disposal of all of the agricultural drainage water in perpetuity, except during flooding events, when emergency drainage to the River is sanctioned. The reuse of this saline agricultural drainage water to irrigate forage crops, such as ‘Jose’ tall wheatgrass and alfalfa, in a 2428 ha reuse facility provides an economic return on this pollutant disposal option. Irrigation with brackish water requires careful management to prevent salt accumulation in the crop root zone, which can impact forage yields. The objective of this study was to optimize the sustainability of this reuse facility by maximizing the evaporation potential while achieving cost recovery. This was achieved by assessing the spatial and temporal distribution of the root zone salinity in selected fields of ‘Jose’ tall wheatgrass and alfalfa in the drainage reuse facility, some of which have been irrigated with brackish subsurface drainage water for over fifteen years. Electromagnetic soil surveys using an EM-38 instrument were used to measure the spatial variability of the salinity in the soil profile. The tall wheatgrass fields were irrigated with higher salinity water (1.2–9.3 dS m−1) compared to the fields of alfalfa (0.5–6.5 dS m−1). Correspondingly, the soil salinity in the tall wheatgrass fields was higher (12.5 dS m−1–19.3 dS m−1) compared to the alfalfa fields (8.97 dS m−1–14.4 dS m−1) for the years 2016 and 2017. Better leaching of salts was observed in the fields with a subsurface drainage system installed (13–1 and 13–2). The depth-averaged root zone salinity data sets are being used for the calibration of the transient hydro-salinity computer model CSUID-ID (a one-dimensional version of the Colorado State University Irrigation Drainage Model). This user-friendly decision support tool currently provides a useful framework for the data collection needed to make credible, field-scale salinity budgets. In time, it will provide guidance for appropriate leaching requirements and potential blending decisions for sustainable forage production. This paper shows the tie between environmental drainage policy and the role of local governance in the development of sustainable irrigation practices, and how well-directed collaborative field research can guide future resource management.


2010 ◽  
Vol 90 (3) ◽  
pp. 495-505 ◽  
Author(s):  
A C VanderZaag ◽  
K J Campbell ◽  
R C Jamieson ◽  
A C Sinclair ◽  
L G Hynes

Animal agriculture and the use of manure as a soil amendment can lead to enteric pathogens entering water used for drinking, irrigation, and recreation. The presence of Escherichia coli in water is commonly used as an indicator of recent fecal contamination; however, a few recent studies suggest some E. coli populations are able to survive for extended time periods in agricultural soils. This important finding needs to be further assessed with field-scale studies. To this end, we conducted a 1-yr study within a 9.6-ha field that had received fertilizer and semi-solid dairy cattle manure annually for the past decade. Escherichia coli concentrations were monitored throughout the year (before and after manure application) in the effluent from tile drains (at approximately 80 cm depth) and in 5- to 8-m-deep groundwater wells. Escherichia coli was detected in both groundwater and tile drain effluent at concentrations exceeding irrigation and recreational water-quality guidelines. Within two of the monitoring wells, concentrations of E. coli, and frequency of detections, were greatest several months after the manure application. In two monitoring wells and one tile drain the frequency of E. coli detections was higher before manure was applied than after. This suggests the presence and abundance of E. coli was not strongly related to the timing of manure application. A laboratory study using naladixic acid resistant E. coli showed the bacteria could survive at least two times longer in soil samples collected from the study field than in soil from the adjacent riparian area, which had not received manure applications. Together, field and lab results suggest that a consistent source of E. coli exists within the field, which may include “naturalized” strains of E. coli. Further studies are required to determine the specific source of E. coli detected in tile drainage water and shallow groundwater. If the E. coli recovered in subsurface water is primarily mobilized from naturalized populations residing within the soil profile, this indicator organism would have little value as an indicator of recent fecal contamination. Key words: Bacterial survival, naturalized Escherichia coli, groundwater, tile drainage


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.


2003 ◽  
Vol 83 (1) ◽  
pp. 73-87 ◽  
Author(s):  
S. Beauchemin ◽  
R. R. Simard ◽  
M. A. Bolinder ◽  
M. C. Nolin ◽  
D. Cluis

Subsurface drainage systems can be a significant pathway for P transfer from some soils to surface waters. The objective of the study was to determine P concentration in tile-drainage water and its relationship to P status in surface soils (A horizons) from an intensively cultivated area in the Montreal Lowlands. The profiles of 43 soil units were characterized for their P contents and pedogenic properties. Tile-drainage water P concentrations were monitored over a 3-y r period on a weekly basis on 10 soil units, and four times during each growing season for the other 33 units. The soil units were grouped into lower and higher P sorbing soils using multiple discriminant equations developed in an earlier related study. The A horizons of the lower P sorbing soils had an elevated P saturation degree [mean Mehlich(III) P/Al = 17%] associated with total P concentrations in tile-drainage water consistently greater than the surface water quality standard of 0.03 mg total P L-1. Conversely, low P concentrations in tile-drainage waters (< 0.03 mg L-1) and a moderate mean Mehlich(III) P/Al ratio of 8% were observed in the higher P sorbing soil group. Total P concentrations in drainage systems were significantly related to soil P status in surface soils. Grouping soils according to their P sorption capacities increased the power of prediction based on only one soil variable. However, accurate predictions in terms of drain P concentration can hardly be obtained unless large dataset and other factors related to field management practices and hydrology of the sites are also considered. Therefore, a better alternative to predict the risk of P leaching is to work in terms of risk classes and rely on a multiple factor index. Key words: Tile-drainage water, phosphorus, P transfer, P loss, degree of soil P saturation, phosphorus index


Soil Research ◽  
2011 ◽  
Vol 49 (5) ◽  
pp. 408 ◽  
Author(s):  
P. E. Tolmie ◽  
D. M. Silburn ◽  
A. J. W. Biggs

Increases in deep drainage below the root-zone can lead to secondary salinity. Few data were available for drainage under dryland cropping and pastures in the Queensland Murray–Darling Basin (QMDB) before this study. Modelled estimates were available; however, without measured drainage these could not be validated. Soil chloride (Cl) mass-balance was used to provide an extensive survey of deep drainage. The method is ‘backward-looking’ and can detect low rates of drainage over longer times. Soil Cl and other soil properties were collated for a number of soils, mostly Vertosols and Sodosols, for paired native vegetation, cropped and sometimes pasture sites, from historical data and new soil sampling. Large amounts of salt and Cl had accumulated under native vegetation (Cl mean 25 t/ha, range 6–54, in 2.4 m depth), due to low rates of drainage. Steady-state Cl balances for native vegetation gave average drainage of 1.2 mm/year at wetter, eastern sites and 0.3 mm/year for Sodosols and Grey Vertosols in drier, western areas. Chloride profiles were mostly of a shape indicating matrix/piston flow. One site (Hermitage fallow trial) appeared to be affected by diffusion of Cl to a watertable. The Cl profiles from 14 longer term cropping sites (18–70 years), mainly used for winter cropping/summer fallow, indicate: (i) large losses of Cl since clearing (mean 50%, range 13-85% for 0–1.5 m soil); and (ii) drainage rates from transient Cl balance are a relatively low percentage of rainfall but are considerably higher than under native vegetation. Drainage averaged 8 mm/year and ranged from 2 to 18 mm/year. This variation is partly explained by rainfall (R2 = 0.63) (500–730 mm/year) and soil plant-available water capacity (R2 = 0.77) (80–300 mm). Deep drainage increases with increasing rainfall and with decreasing available water capacity. Drainage under pasture was less than under cropping but greater than under native vegetation. The deep drainage water (leachate) was of poor quality and will increase salinity if added to good quality groundwater. Leachate at nine sites was too saline to be used (undiluted) for irrigation (>2500 mg Cl/L) and was marginal at the remainder of sites (~800 mg Cl/L). Cropping areas in the QMDB have the precursors for secondary salinity development—high salt loads and an increase in drainage after clearing. The Vertosols and Sodosols studied occur in 90% of croplands in the QMDB. Salinisation will depend on the properties of the underlying regolith and groundwater systems.


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