Storm phosphorus concentrations and fluxes in artificially drained landscapes of the US Midwest

Abstract

This study investigates phosphorus (P) concentrations and fluxes in tile drains, overland flow, and streamflow at a high temporal resolution during 7 spring storms in anagricultural watershed in Indiana, USA. Research goals include a better understanding of 1) how bulk precipitation and antecedent moisture conditions affect P concentrations and fluxes at the watershed scale; 2) how P concentrations and fluxes measured in tile drains translate to the whole watershed scale; 3) whether P losses to the stream are significantly affected by overland flow. Results indicate that bulk precipitation and antecedent moisture conditions are not good predictors of SRP or TP losses (either concentration or flux) to the stream. However, along with previously published storm data in this watershed, results indicate a threshold-based behavior whereby SRP and TP fluxes significantly increase with precipitation when bulk precipitation exceeds 4 cm. Although total SRP and TP fluxes are very much driven by flow, SRP and TP fluxes are somewhat limited by the amount of P available for leaching for most storms. On average, SRP fluxes in tile drains are 13% greater than in the stream, and stream SRP fluxes account for 45% of TP fluxes at the watershed scale. Our results indicate that when P is the primary concern, best management practices aimed at reducing P losses via tile drains are likely to have the most effect on P exports at the watershed scale

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

“…This can lead to different proportions of runoff components in drainage runoff, e.g., sites lying in higher positions on slopes (typically P53) have lower proportions of baseflow and higher numbers of REs. Similar (very variable) proportions of event water (12% to 50%) for similar amounts of precipitation (20 to 30 mm) are reported by other studies [21,[50][51][52]. This variability in REs is more probably caused by diverse hydrological conditions in the catchments preceding the rain, namely, soil moisture, the groundwater level in summer, and snow cover for winter events, than by the intensity of rainfall [51], although some other studies reported contrarily [21,53].…”

“…The within-site differences between the number and magnitudes of REs and their share of total runoff and between the N-NO 3 , P-PO 4 , and P tot loads were brought about most probably by the distinct hydrological connectivity and runoff formation pattern in particular drainage-catchment systems [7,21,34,46]. This connectivity is affected by the position of a drainage system in a particular part of a slope (higher, lower) and by local soil variability [42,43,[47][48][49].…”

“…While there is in-depth research for individual fields or paired catchments [8,14,[18][19][20][21], not many mid-term studies have been conducted to compare nutrient losses and load assessment methods for tile-drained fields or small catchments with different agricultural management and runoff characteristics, especially in central European conditions. In the Czech Republic, around 30% of the agricultural land is tile-drained, and in some regions land drainage exists on every field [22,23].…”

Assessing monitoring and modeling approaches to improve water quality in the Hickory Grove Lake

“…A sharp increase in P loads at the beginning of the event followed by a steady load for the remainder of the event was observed (Figure 2.7). A similar pattern for P loads was observed during events in a tile drained watershed in Illinois (Vidon et al, 2012). Cumulative load plots (Figure 2.7) show that the majority (>60%) of the TP load and DRP load at TO occurred within 5 h after the surface runoff began.…”

“…Phosphorus (P) transport from agricultural fields to surface waters is an important environmental concern around the world (NRC, 2005). Excess P in fresh waterbodies has Therefore there has been much interest on understanding the processes regulating the P mobility to streams in the US Midwest (Tomer et al, 2010;Vidon et al, 2012;Royer et al, 2006).…”