Abstract
Changes in seasonality and form of precipitation alter the structure and function of grassland and steppe ecosystems and pose challenges for land management and crop production in regions like the Northern Great Plains, North America. This research uses isotopic composition of water (δ18O and δ2H) to explore the sources and fate of soil water in lower-elevation agricultural areas of the Judith River watershed, in the headwaters of the Missouri River, USA. Extensive non-irrigated cereal crop production in this area occurs on well-drained soils and depends on careful water management. Our observations indicate that colder precipitation contributes isotopically distinct water to cultivated terrace soils relative to downgradient groundwaters and streams. Riparian waters also exhibit a higher fraction of contributions from colder precipitation relative to terrace groundwaters and streams. Apparent contributions from colder precipitation in terrace and riparian soil waters suggest that snowmelt is a key component of the water supply to these systems. Riparian waters also show evidence of evaporation suggesting that water spends sufficient time in some ponds and open channels in the riparian corridor to reflect fractionation by evaporation. The evolution of water isotopic composition from soils to shallow aquifers to stream corridors indicates source water partitioning as precipitation moves through this semi-arid agricultural landscape. The apparent mixing processes evident in this evolution reveal source water dynamics that are necessary to understand plant transpiration, solute processing, and contaminant leaching processes.
| Original language | English |
|---|---|
| Article number | e15069 |
| Journal | Hydrological Processes |
| Volume | 38 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 2024 |
Funding
The authors thank the Consortium for Research on Environmental Water Systems (NSF EPSCoR Cooperative Agreement OIA-1757351), the MSU Nielsen Pedology Graduate Research Fellowship (2021), and the Montana Agricultural Experiment Station partially funded by USDA-NIFA (MAES project numbers MONB00364 and MONB00349) for funding this work. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation or the U.S. Department of Agriculture. The authors appreciate the support and data from the Montana Climate Office, the US Department of Agriculture Natural Resources Conservation Service, the U.S. Bureau of Reclamation, and the Montana Department of Agriculture. A special thank you to Dr. Ann Marie Reinhold for her help with building the conceptual framework. The authors thank Dr. Toby Koffman, Kevin Hyde, Sam Leuthold, Simon Fordyce, and Skye Keeshin for their help with data collection, analysis, and technical assistance. The authors sincerely thank two anonymous reviewers for their time and constructive feedback. The authors thank the Consortium for Research on Environmental Water Systems (NSF EPSCoR Cooperative Agreement OIA‐1757351), the MSU Nielsen Pedology Graduate Research Fellowship (2021), and the Montana Agricultural Experiment Station partially funded by USDA‐NIFA (MAES project numbers MONB00364 and MONB00349) for funding this work. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation or the U.S. Department of Agriculture. The authors appreciate the support and data from the Montana Climate Office, the US Department of Agriculture Natural Resources Conservation Service, the U.S. Bureau of Reclamation, and the Montana Department of Agriculture. A special thank you to Dr. Ann Marie Reinhold for her help with building the conceptual framework. The authors thank Dr. Toby Koffman, Kevin Hyde, Sam Leuthold, Simon Fordyce, and Skye Keeshin for their help with data collection, analysis, and technical assistance. The authors sincerely thank two anonymous reviewers for their time and constructive feedback.
| Funders | Funder number |
|---|---|
| OIA‐1757351 | |
| MONB00349, MONB00364 | |
| Natural Resources Conservation Service | |
Keywords
- Northern Great Plains
- groundwater
- non-irrigated
- prairie snow
- soil water
- stable isotope
