Journal article
How Paired Is Paired? Comparing Nitrate Concentrations in Three Iowa Drainage Districts
Journal of environmental quality, Vol.42(5), pp.1412-1421
09/2013
DOI: 10.2134/jeq2013.03.0085
PMID: 24216419
Abstract
Quantifying the effectiveness of perceived best management practices (BMPs) at the field and landscape-scale is difficult, so paired watershed studies are used to detect water quality improvements. We evaluated concentrations of NO3-N discharged from three tiled Iowa watersheds during a 4-yr period to assess their suitability for a paired watershed approach. Our objectives were to evaluate similarities in physical characteristics, concentration patterns, and correlation among the three paired sites and perform a minimum detectable change (MDC) analysis on paired site configurations. The study results demonstrate that concentration variability within and between sample sites affected correlation among the paired basins, even though the physical characteristics of the basins are quite similar. Restricting comparisons to the active tile drainage period (March-July) improved correlations. The lack of a suitable correlation will impair the ability to detect changes expected to result from BMP implementation. The MDC for NO3-N concentration change detection varied from 6.9 to 12.9% and averaged 8% for the best control-treatment pair. To ensure that conservation resources are being used effectively, implemented BMPs should focus on practices capable of achieving at least this magnitude of change. These practices may include reduced fertilizer applications, adoption of cover crops, and land use change.
Details
- Title: Subtitle
- How Paired Is Paired? Comparing Nitrate Concentrations in Three Iowa Drainage Districts
- Creators
- Keith E. Schilling - Iowa Geological and Water Survey, 109 Trowbridge Hall, Iowa City, IA 52242-1319Christopher S. Jones - Iowa Soybean Assoc, Ankeny, IA 50023 USAAnthony Seeman - Iowa Soybean Association
- Resource Type
- Journal article
- Publication Details
- Journal of environmental quality, Vol.42(5), pp.1412-1421
- Publisher
- Amer Soc Agronomy
- DOI
- 10.2134/jeq2013.03.0085
- PMID
- 24216419
- ISSN
- 0047-2425
- eISSN
- 1537-2537
- Number of pages
- 10
- Grant note
- Iowa Department of Natural Resources McKnight Foundation Iowa Soybean Association Nature Conservancy Des Moines Water Works
- Language
- English
- Date published
- 09/2013
- Academic Unit
- Earth and Environmental Sciences; IIHR--Hydroscience and Engineering
- Record Identifier
- 9984383891002771
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