Response to varying phosphorus application in perennial forages at an Ontario silt-loam site: Supplementary data

These data formed the basis of the MSc thesis "Response to varying phosphorus application in perennial forages at an Ontario silt-loam site". A phosphorus (P) fertility trial on common perennial forages was established in 2021 at Elora research station, at a site selected for its low initial soil test P (STP of 8.5 ppm Olsen P). Four P rates and 14 assortments of forage species were examined. Plots were cut with a plot scale forage harvester three times per year for a total of three years. Yield and tissue P were measured at each cut. Composition was determined once per year from sorted subsamples at first cut, and soil samples were taken for STP once per year after 3rd cut. In the third year, samples of roots were taken from monoculture plots and assessed for arbuscular mycorrhizal fungi. In the fall of 2024 (after the final harvest of the trial) samples of the plots were subjected to a simulated freeze-thaw experiment to assess potential for P loss from the plots over winter. Soil and tissue testing was conducted by SGS Canada's facility in Guelph Ontario. Water Extractable P (WEP) analysis was conducted at Agriculture and Food Laboratory at the University of Guelph. For a further explanation of methods, please see the MSc thesis "Response to varying phosphorus application in perennial forages at an Ontario silt-loam site", Chapters 2.3 (P fertility trial methods) and 3.3 (freeze-thaw experiment methods).