Effects of Watershed‐Scale Land Use Change on Stream Nitrate Concentrations

Schilling, Keith E.; Spooner, Jean

doi:10.2134/jeq2006.0157

Cited by 109 publications

(95 citation statements)

References 43 publications

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“…2) were indicative of degraded stream conditions throughout the study watershed. Nitrate concentrations at study sites generally exceeded summer values recently reported from streams in other row-crop dominated watersheds of the Midwestern U.S.A., where nitrate concentrations are consistently among the highest in the nation (Bernot et al, 2006;Figueroa-Nieves et al, 2006;Schilling and Spooner, 2006;Heatherly et al, 2007;Renwick et al, 2008;Wagner et al, 2008;Diebel and Vander Zanden, 2009;Warrner et al, 2009). Additionally, nitrate concentration at each of our study sites (range 5 5.6-29.0 mg/L) was higher than 3.2 mg/L, a threshold value that, based on a USEPA Wadeable Streams Assessment, is indicative of poor conditions in Midwestern streams (Van Sickle and Paulsen, 2008).…”

Section: Results Land Cover Stream Habitat and Invertebrate Assemblagescontrasting

confidence: 56%

“…Although constituting a comparatively small percentage of area, urban land cover has increased as the number of people residing in Iowa's urban centers has increased (e.g., from 1.26 million in 1950 to 1.71 million in 2009; IDNR, 2000;USCB, 2010). Due to intensive land use and associated contaminant inputs to aquatic ecosystems, 77% of monitored Iowa river and stream segments and 69% of Iowa lakes are classified as ''impaired'' or ''potentially impaired,'' and pollutant loads from Iowa contribute to hypoxia in the Gulf of Mexico (Schilling and Spooner, 2006;IDNR, 2010). With urban expansion and greater economic incentives to intensify agricultural production, threats to aquatic ecosystem condition in Iowa are expected to increase (Secchi et al, 2008;Rayburn and Schulte, 2009).…”

Section: Introductionmentioning

confidence: 99%

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Land Use, Stream Habitat and Benthic Invertebrate Assemblages in a Highly Altered Iowa Watershed

Herringshaw

Stewart

Thompson

et al. 2011

The American Midland Naturalist

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Knowledge of relationships between land cover (i.e., land use) and abiotic and biotic features of headwater streams enhances our ability to predict and effectively assess conditions in a variety of aquatic ecosystems. We evaluated land use effects on stream condition in an Iowa watershed dominated by intensive row crop agriculture and low-intensity urban development by quantifying relationships among land cover, stream invertebrate assemblages and other stream biophysical characteristics (i.e., invertebrate habitat) at 29 sites. On average, 81% of subbasin land cover was agricultural and 6% of land cover was urban across study sites. High nitrate concentrations (range = 5.6-29.0 mg/L) and high relative abundance of oligochaetes and chironomid midges reflected degraded conditions at all sites. However, agriculture and urban land use appeared to have different effects on stream features. Nitrate concentrations were positively related to agricultural land cover, and turbidity and nitrate concentrations were negatively related to urban land cover (P ≤ 0.05). Invertebrate densities and taxonomic diversity (i.e., total taxa richness, % EPT) were also positively related to agricultural land cover and negatively related to urban land cover. Regardless of land use, highest invertebrate abundance and taxonomic diversity occurred at sites with abundant coarse particulate organic matter, plants and coarse inorganic substrate. Relationships between land cover and invertebrate variables were strong at both local and subbasin measurement scales. Based on invertebrate assemblages, which integrate multiple instream features, we conclude that urban land use had greater adverse effect on stream condition than agriculture in our study watershed. ABSTRACT.-Knowledge of relationships between land cover (i.e., land use) and abiotic and biotic features of headwater streams enhances our ability to predict and effectively assess conditions in a variety of aquatic ecosystems. We evaluated land use effects on stream condition in an Iowa watershed dominated by intensive row crop agriculture and lowintensity urban development by quantifying relationships among land cover, stream invertebrate assemblages and other stream biophysical characteristics (i.e., invertebrate habitat) at 29 sites. On average, 81% of subbasin land cover was agricultural and 6% of land cover was urban across study sites. High nitrate concentrations (range 5 5.6-29.0 mg/L) and high relative abundance of oligochaetes and chironomid midges reflected degraded conditions at all sites. However, agriculture and urban land use appeared to have different effects on stream features. Nitrate concentrations were positively related to agricultural land cover, and turbidity and nitrate concentrations were negatively related to urban land cover (P # 0.05). Invertebrate densities and taxonomic diversity (i.e., total taxa richness, % EPT) were also positively related to agricultural land cover and negatively related to urban land cover. Regardless of land use, highest invertebr...

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Section: Results Land Cover Stream Habitat and Invertebrate Assemblagescontrasting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Land Use, Stream Habitat and Benthic Invertebrate Assemblages in a Highly Altered Iowa Watershed

Herringshaw

Stewart

Thompson

et al. 2011

The American Midland Naturalist

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“…We argue that summer riparian NO 2 3 production is enhanced by subdaily variations in surficial soil oxygen caused both by precipitation events and by soil evaporation and transpiration. These events induce diurnal fluctuations in groundwater tables during the summer, which can be several centimeters during the growing season (Figure 8) as has been seen elsewhere [Loheide et al, 2005;Schilling and Spooner, 2006;Flewelling et al, 2011]. A second source region of NO 2 3 is deeper riparian hollow soils (on the order of 10-50 cm).…”

Section: 1002/2015wr016937mentioning

confidence: 66%

Mechanisms driving the seasonality of catchment scale nitrate export: Evidence for riparian ecohydrologic controls

Duncan

Band

Groffman

et al. 2015

Water Resources Research

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Considerable variability in the seasonal patterns of stream water nitrate (NO 2 3 ) has been observed in forested watersheds throughout the world. While many forested headwater catchments exhibit winter and early spring peaks in NO 2 3 concentrations, several watersheds have peak concentrations during the summer months. Pond Branch, a headwater catchment in Maryland monitored for over 10 years, exhibits recurrent and broad summer peaks in both NO export from June to September is particularly surprising, given that these summer months typically have the year's lowest discharge. A key challenge is identifying the source(s) of NO 2 3 and the mechanism(s) by which it is transported to the watershed outlet during the summer. In this study, we assessed multiple hypotheses (not mutually exclusive) that could account for the seasonal trend including proximal controls of groundwater-surface water interactions, instream processes, and riparian groundwater-N cycling interactions, as well as two distal controls: geochemical weathering and senescence of riparian vegetation. A combination of long-term weekly and limited duration high-frequency sensor data reveals the importance of riparian ecohydrologic processes during base flow. In this watershed, patterns of seasonal stream water NO 2 3 concentrations and fluxes depend fundamentally on interactions between groundwater dynamics and nitrogen (N) cycling in the riparian zone. Groundwater tables control nitrification-denitrification dynamics as well as hydrologic transport. Our results suggest that in many watersheds, a more sophisticated exploration of NO 2 3 production and NO 2 3 transport mechanisms is required to identify critical points in the landscape and over time that disproportionately drive patterns of watershed NO 2 3 export.

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“…Located at the central portion of the Walnut Creek Watershed, the NSNWR was established in 1990 to reconstruct native tall-grass prairie on the landscape (Schilling and Spooner 2006), with new prairie seedings added each year. Portions of the NSNWR awaiting restoration are either leased to farmers in the area for crop production or maintained in perennial cover.…”

Section: Methodsmentioning

confidence: 99%

Nutrient removal by prairie filter strips in agricultural landscapes

Zhou¹,

Helmers²,

Asbjornsen³

et al. 2014

Journal of Soil and Water Conservation

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Nitrogen (N) and phosphorus (P) from agricultural landscapes have been identified as primary sources of excess nutrients in aquatic systems. The main objective of this study was to evaluate the effectiveness of prairie filter strips (PFS) in removing nutrients from cropland runoff in 12 small watersheds in central Iowa. Four treatments with PFS of different spatial coverage and distribution (No-PFS, 10% PFS, 10% PFS with strips, and 20% PFS with strips) were arranged in a balanced incomplete block design across four blocks in 2007. A no-tillage two-year corn (Zea mays L.) -soybean (Glycine max [L.] Merr.) rotation was grown in row-cropped areas beginning in 2007. Runoff was monitored by H flumes, and runoff water samples were collected during the growing seasons to determine concentrations of nitrate-nitrogen (NO 3 -N), total nitrogen (TN) and total phosphorus (TP) through 2011. Overall, the presence of PFS reduced mean annual NO 3 -N, TN, and TP concentrations by 35%, 73%, and 82%, respectively, and reduced annual NO 3 -N, TN, and TP losses by 67%, 84%, and 90%, respectively. However, the amount and distribution of PFS had no significant impact on runoff and nutrient yields. The findings suggest that utilization of PFS at the footslope position of annual row crop systems provides an effective approach to reducing nutrient loss in runoff from small agricultural watersheds. Runoff was monitored by H flumes, and runoff water samples were collected during the growing seasons to determine concentrations of nitrate-nitrogen (NO 3 -N), total nitrogen (TN) and total phosphorus (TP) through 2011. Overall, the presence of PFS reduced mean annual NO 3 -N, TN, and TP concentrations by 35%, 73%, and 82%, respectively, and reduced annual NO 3 -N, TN, and TP losses by 67%, 84%, and 90%, respectively. However, the amount and distribution of PFS had no significant impact on runoff and nutrient yields. The findings suggest that utilization of PFS at the footslope position of annual row crop systems provides an effective approach to reducing nutrient loss in runoff from small agricultural watersheds.

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Effects of Watershed‐Scale Land Use Change on Stream Nitrate Concentrations

Cited by 109 publications

References 43 publications

Land Use, Stream Habitat and Benthic Invertebrate Assemblages in a Highly Altered Iowa Watershed

Land Use, Stream Habitat and Benthic Invertebrate Assemblages in a Highly Altered Iowa Watershed

Mechanisms driving the seasonality of catchment scale nitrate export: Evidence for riparian ecohydrologic controls

Nutrient removal by prairie filter strips in agricultural landscapes

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