Uncertainty in nutrient loads from tile-drained landscapes: Effect of sampling frequency, calculation algorithm, and compositing strategy

Williams, Mark R.; King, Kevin W.; Macrae, Merrin L.; Ford, William I.; Esbroeck, Chris Van; Brunke, R.; English, Michael; Schiff, Sherry L.

doi:10.1016/j.jhydrol.2015.09.060

Cited by 94 publications

(60 citation statements)

References 37 publications

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“…For both P forms monitored in drainage waters, no such differences were found. During the REs, a dilution of N-NO 3 in drainage waters usually prevailed, whilst for both P-PO 4 and P tot , the concentrations usually rose with elevated discharge, which is in accordance with many monitoring campaigns in tile-drained catchments [5,12,18,25,31]. The only exceptions were sites PD1 and PD2, with Cfw N-NO 3 higher in ESs than in RSs.…”

Section: Dynamics Of N and P Concentrationssupporting

confidence: 86%

“…M2 appeared to be quite a reasonable algorithm for the assessment of N-NO 3 loads, when only grab sampling (without continuous monitoring of discharge) was employed. However, it still gave large underestimations, especially for both phosphorus compounds, as the grab sampling rarely captured different REs with different P concentration values, as documented by [31][32][33][34].…”

Section: Comparison Of Load Assessment Methodsmentioning

confidence: 99%

“…To our knowledge, only a few studies have been published to compare monitoring approaches and nutrient load assessment methods for tile-drained fields or small catchments [6,25,27,31]. These studies often conclude that the most dominant factors influencing nutrient fluxes are precipitation characteristics and catchment hydrological connectivity.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Incorporating Rainfall-Runoff Events into Nitrate-Nitrogen and Phosphorus Load Assessments for Small Tile-Drained Catchments

Fučík

Zajíček

Kaplická

et al. 2017

Water

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Rainfall-runoff events significantly influence water runoff and the loss of pollutants from tile-drained agricultural land. We monitored ten small (4 to 38 ha) tile-drained catchments in Czechia for three to five years (2012 to 2016). The discharge was measured continuously; a regular 14-day scheme of water quality monitoring was accompanied with event sampling provided by automatic samplers in 20 to 120 min intervals. A new semi-automated algorithm was developed for the identification of runoff events (RE) based on discharge and water temperature changes. We then quantified the share of RE on the total runoff and the N and P losses, and we compared six methods for nutrient load estimation on an annual and monthly basis. The results showed considerable differences among the monitored sites, seasons, and applied methods. The share of RE on N loads was on average 5% to 30% of the total annual load, whereas for P (dissolved and total), the share of RE was on average 10% to 80% on the total annual load. The most precise method for nutrient load estimation included the RE. The methods based on point monitoring of the discharge and water quality underestimated the loads of N by 10% to 20% and of P by 30% to 80%. The acquired findings are crucial for the improvement of nutrient load assessment in tile-drained catchments, as well as for the design of various mitigation measures on tile-drained agricultural land.

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Section: Dynamics Of N and P Concentrationssupporting

confidence: 86%

Section: Comparison Of Load Assessment Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Incorporating Rainfall-Runoff Events into Nitrate-Nitrogen and Phosphorus Load Assessments for Small Tile-Drained Catchments

Fučík

Zajíček

Kaplická

et al. 2017

Water

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“…The resulting 10‐min concentration file was merged with the 10‐min discharge file to create a 10‐min loading file. This method has been shown to reduce the uncertainty associated with collecting both surface and subsurface samples for water quality loading in tile‐drained landscapes (Williams et al, 2015b). Loads were calculated as the product of the 10‐min concentrations and 10‐min discharges summed over the entire water year and the spring loading period.…”

Section: Methodsmentioning

confidence: 99%

Linking Soil Phosphorus to Dissolved Phosphorus Losses in the Midwest

Duncan¹,

King²,

Williams

et al. 2017

Agricultural & Env Letters

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Core Ideas Soil test phosphorus remains an important factor in studying dissolved reactive P loss. Identifying higher risk fields with STP could inform future management practices to reduce DRP loss. STP was linearly related to DRP concentration loads in tile‐drained fields. Monitoring STP in addition to implementing other BMPs should be considered to decrease DRP loss. Harmful and nuisance algal blooms resulting from excess phosphorus (P) have placed agriculture in the spotlight of the water quality debate. Sixty‐eight site years of P loading data (combined surface runoff and tile flow) from 36 fields in Ohio were used to see if a soil test P (STP) concentration could be identified that allowed P application while still meeting recommended loss thresholds. Regression analysis revealed that P application to soils with STP concentration in the “critical level” range would result in P losses above the recommended Annex 4 thresholds. In addition, fertilizer application increased the risk of dissolved reactive P (DRP) loss as compared to years in which fertilizer was not applied. We determined that STP was a good screening method to identify fields that are at risk for greater P loss, but STP alone was not a good predictor of DRP loss, suggesting that a more holistic approach that includes upland management, edge‐of‐field practices, and in‐stream approaches will be required to decrease DRP loading.

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“…Phosphorus loads were calculated by multiplying continuous discharge measurements with continuous concentration data that were constructed through linear interpolation between individual water samples. According to the findings of Harmel et al (2006) and Williams et al (2015b), P loads reported herein were likely within 5 to 20% of actual P loads, based on sampling strategy and frequency. Calculated P loads were aggregated to annual values, with data from the 40 fields totaling 112 site years.…”

Section: Discussionmentioning

confidence: 69%

Edge‐Of‐Field Evaluation of the Ohio Phosphorus Risk Index

et al. 2017

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The Phosphorus Index (PI) has been the cornerstone for phosphorus (P)-based management and planning over the past twenty years, yet field-scale evaluation of many state PIs has been limited. In this study, P loads measured in surface runoff and tile discharge from 40 agricultural fields in Ohio with prevailing management practices were used to evaluate the Ohio PI. Annual P loads were highly variable among fields (dissolved reactive P: 0.03-4.51 kg ha, total P: 0.03-6.88 kg ha). Both measured annual dissolved reactive P ( = 0.36, < 0.001) and total P ( = 0.25, < 0.001) loads were significantly related to Ohio PI score. The relationship between measured load and PI score substantially improved when averaged annual field values were used (dissolved reactive P: = 0.71, total P: = 0.73), indicating that the Ohio PI should be utilized to evaluate average annual risk of P loss, rather than as an annual risk tool. Comparison between the Ohio PI and other established local and national metrics resulted in large differences in potential P management recommendations for the monitored fields. In the near term, revision of Ohio PI risk categories and management recommendations using local P loading thresholds is needed. To meet the minimum criteria for state PI tools, future research efforts should focus on using measured field data (i) to incorporate new input factors (i.e., P application timing and leaching potential) into the Ohio PI, and (ii) to calibrate and validate the Ohio PI to provide better P risk assessments and management recommendations.

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Uncertainty in nutrient loads from tile-drained landscapes: Effect of sampling frequency, calculation algorithm, and compositing strategy

Cited by 94 publications

References 37 publications

Incorporating Rainfall-Runoff Events into Nitrate-Nitrogen and Phosphorus Load Assessments for Small Tile-Drained Catchments

Incorporating Rainfall-Runoff Events into Nitrate-Nitrogen and Phosphorus Load Assessments for Small Tile-Drained Catchments

Linking Soil Phosphorus to Dissolved Phosphorus Losses in the Midwest

Edge‐Of‐Field Evaluation of the Ohio Phosphorus Risk Index

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