Dataset: Park Grass Fertilizer Treatments and Hay Yields 1856-1902

This dataset contains the fertilizer treatments and yields of hay (t/ha), for both the 1st and 2nd cuts, harvested from Park Grass Hay Experiment since its inception in 1856 to 1902, "Design Period 1" (In 1903, "Design Period 2" started on Park Grass when but in 1903, when most plots were split into two to test the effects of liming, as acidity had built up in the soil with fertilizer use during Period 1). The experiment was originally one plot per treatment since 1856 and yields are provided for all fertiliser treatment 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 variables such as the weather and atmospheric inputs). This data set is followed by that for Design Period 2, 1903-1964, and so includes plot numbers ("subsequent plots"), and dates of introduction, from that later design-period to provide continuity between datasets.

Park Grass was initiated to investigate the ways of improving the yield of hay by the application of inorganic fertilizers and organic manure. The fertilizer tests were made of farmyard manure, N, P, K, Mg, Na, Si, as well as sawdust and straw, in various combinations and amounts (fishmeal and poultry manure were not tested until the early 20th century).

As the experiment progressed, it was observed that the soil became more acidic and in 1903 plots were halved and the effects of lime tested - therefore this dataset ends in 1902. The next dataset is Design Period 2, 1903-1964 (see Related Datasets below). However, note that in 1881 Lawes and gilbert started investigating the effects of lime applications to small parts of the northern edge of some of the plots. In 1883 the west halves of plots received burnt lime, then in 1887 the eastern halves received burnt lime. These early tests of lime on yields are not included in this dataset but are available from the e-RA database. Notes made by Lawes & Gilbert and staff at that time are available in the "Rothamsted White Books". Therefore, note that all parts of every plot, even the un-limed sublots of Design Period 2 and the sub-plot d's of Design Period 3, received lime once in their history, although this was a small amount over >138 years ago.