Alexander J Koiter^*1 and Tamaragh Y Malone²

^*corresponding author

¹Brandon University, Department of Geography & Environment
270 18th St, Brandon, MB Canada, R7A 6A9
email: koitera@brandonu.ca
ORCID: 0000-0002-9355-9561

²Brandon University, Department of Biology, 270 18th St, Brandon, MB Canada, R7A 6A9
ORCID: 0009-0002-5887-5574

This manuscript that has been accepted for publication at the Journal of Environmental Quality. A preview of the manuscript, including notebooks for analysis, can be found at https://alexkoiter.ca/riparian-grazing-manuscript/

The published article is open access and found at http://doi.org/10.1002/jeq2.70012

To cite the paper or the data please use the following:

Koiter AJ, Malone TY (2025) Effects of riparian grazing on distinct water-extractable phosphorus sources. J Environ Qual 1–13. https://doi.org/10.1002/jeq2.70012

A BibTeX entry for LaTeX users is

@article{, title = {Effects of riparian grazing on distinct water-extractable phosphorus sources},
doi = {10.1002/jeq2.70012},
journal = {Journal of Environmental Quality},
author = {Koiter, Alexander J. and Malone, Tamaragh Y.},
year = {2025},
note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/jeq2.70012},
pages = {1--13},
}

Riparian areas play an important role in maintaining water quality in agricultural watersheds by buffering sediment, nutrients, and other pollutants. Additionally, these areas are also an important sources of forage, particularly during drought. Recent studies have shown that riparian areas are less effective buffers and, in some cases, are a net source of phosphorus (P) in cold climates. The repeated freeze-thaw cycles increase the availability of P in both the vegetation and soil sources. Cattle grazing or harvesting of riparian areas prior to the onset of winter conditions may be a viable management practice to reduce the loss of P during the spring snowmelt. This study measured the water-extractable phosphorus (WEP) in four distinctive sources: biomass, litter, organic layer, and Ah horizon. Overall, the Ah (0-10cm) soil was the largest (~44%) source of WEP; however, the biomass (i.e., standing vegetation) was a considerable proportion (~25%) of the total. In addition to control plots, the riparian areas were subjected to grazing, high density grazing, and mowing treatments. Findings revealed significant reductions in biomass WEP with high density grazing and mowing treatments, particularly in lower riparian zones. There were no detectable changes in the other sources of WEP. This suggests that autumn short-term grazing may be a mechanism to use this important forage resource and reduce the potential P loss during the snowmelt period.

The data sets and accompanying Quarto (.qmd) files used in this publication can be found in the notebooks.

1. P_concentration.csv contains the Water Extractable P concentration for each sample (mg kg^-1)

2. mass.csv contains the dry mass for the biomass and litter samples

3. bulk density.csv contains the bulk density measurements for the organic layer and Ah horizon samples (only measured in 2023)

4. Forrest-Daily-TempRainSoil-20192021-AKoiter.xlsx contains weather data from the onsite weather station operated by MB Agriculture

5. MBFI EXT 28 Keep Grazing Data 2019.xlsx contains all the plants species ID collected in 2019. Data collected by the MB Beef and Forage Initiatives

This project was undertaken with the financial support of the Government of Canada through the federal Department of Environment and Climate Change and a Lake Winnipeg Basin Program grant awarded to the Manitoba Association of Watersheds. Additional research funding was provided through a Brandon University Research Committee grant awarded to AK

Data is also available via the Dryad repository and any use of the data should cite: Koiter, Alexander; Malone, Tamaragh (2025). Effects of Riparian Grazing on Distinct Phosphorus Sources [Dataset]. Dryad. https://doi.org/10.5061/dryad.nzs7h4526