Hydrologic control of dissolved organic matter concentration and quality in a semiarid artificially drained agricultural catchment

Rebecca A. Bellmore, John A. Harrison, Joseph Needoba, Erin S. Brooks, C. Kent Keller

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Agricultural practices have altered watershed-scale dissolved organic matter (DOM) dynamics, including in-stream concentration, biodegradability, and total catchment export. However, mechanisms responsible for these changes are not clear, and field-scale processes are rarely directly linked to the magnitude and quality of DOM that is transported to surface water. In a small (12 ha) agricultural catchment in eastern Washington State, we tested the hypothesis that hydrologic connectivity in a catchment is the dominant control over the concentration and quality of DOM exported to surface water via artificial subsurface drainage. Concentrations of dissolved organic carbon (DOC) and humic-like components of DOM decreased while the Fluorescence Index and Freshness Index increased with depth through the soil profile. In drain discharge, these characteristics were significantly correlated with drain flow across seasons and years, with drain DOM resembling deep sources during low-flow and shallow sources during high flow, suggesting that DOM from shallow sources bypasses removal processes when hydrologic connectivity in the catchment is greatest. Assuming changes in streamflow projected for the Palouse River (which contains the study catchment) under the A1B climate scenario (rapid growth, dependence on fossil fuel, and renewable energy sources) apply to the study catchment, we project greater interannual variability in annual DOC export in the future, with significant increases in the driest years. This study highlights the variability in DOM inputs from agricultural soil to surface water on daily to interannual time scales, pointing to the need for a more nuanced understanding of agricultural impacts on DOM dynamics in surface water.

Original languageEnglish (US)
Pages (from-to)8146-8164
Number of pages19
JournalWater Resources Research
Volume51
Issue number10
DOIs
StatePublished - Oct 1 2015

Fingerprint

agricultural catchment
dissolved organic matter
catchment
drain
surface water
dissolved organic carbon
connectivity
bypass
agricultural practice
agricultural soil
low flow
fossil fuel
soil profile
streamflow
fluorescence
watershed
drainage
timescale
climate

Keywords

  • agriculture
  • artificial drainage
  • dissolved organic carbon
  • dissolved organic matter
  • fluorescence
  • hydrology

ASJC Scopus subject areas

  • Water Science and Technology

Cite this

Hydrologic control of dissolved organic matter concentration and quality in a semiarid artificially drained agricultural catchment. / Bellmore, Rebecca A.; Harrison, John A.; Needoba, Joseph; Brooks, Erin S.; Kent Keller, C.

In: Water Resources Research, Vol. 51, No. 10, 01.10.2015, p. 8146-8164.

Research output: Contribution to journalArticle

Bellmore, Rebecca A. ; Harrison, John A. ; Needoba, Joseph ; Brooks, Erin S. ; Kent Keller, C. / Hydrologic control of dissolved organic matter concentration and quality in a semiarid artificially drained agricultural catchment. In: Water Resources Research. 2015 ; Vol. 51, No. 10. pp. 8146-8164.
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