Dataset: Park Grass Hay Yields, Fertilizer and Lime Treatments 1903-1964

This dataset contains the yields of hay (t/ha), for both the 1st and 2nd cuts, harvested from Park Grass Hay Experiment since 1903-1964. Details of the fertilizer, lime treatments and harvest dates are also included. In 1903, "Design Period 2", started on Park Grass. The experiment was originally one plot per treatment since 1856, but in 1903, most plots (1-13 and 16) were split into two to test the effects of liming, as acidity had built up in the soil with fertilizer use. One half of each plot was limed with chalk (L) and the other half left un-limed (U). In 1920 the remaining plots (14, 15 and 17) were split in half also, to join the liming scheme. Three other plots (18, 19 and 20) were split in to three in 1920 to receive light lime (LL), heavy lime (HL) and un-limed (U). Yields are provided for all fertiliser treatment plots and sub-plots. Yields are expressed as t/ha at 100% dry matter. Variations in yield reflect the various fertilizer treatments and liming regimes, as well as the local weather and atmospheric inputs. This data set is followed by that for post-1965 data and so includes plot numbers ("subsequent plots"), and dates of introduction, from that later design-period to provide continuity between datasets.

This 2nd version; In 2025 a new convention for plot ID format (new_plot_id) has been introduced that enables compatibility of plot names throughout the duration of the Park Grass Experiment datasets. This has been applied retrospectively to plots and more easily communicates plot changes over time and continuity between plots in the published data. It also aims to address the Excel date problem whereby a number of plot names that can be auto-converted to dates by Excel. The new conventions for plots split for fertilizer modifications uses '.' as the division separator. The new conventions for plots divided for new liming treatments uses '\' as the division separator. The traditional format is also kept in the dataset (plot_id).

This version also includes a note about the sunny and shaded parts of the south end of plot 14 - whereby a comparison was done to establish the shading effects of a large oak tree in 1920 and from, 1924-1959. This dataset contains the averaged data of 'shaded' vs 'sunny' (the separate data is available from the e-RA database).