Changes in mean hay yield at Palace Leas for the FYM (20 t ha<sup>-1</sup>) and four ammonium sulphate-containing fertilizer treatments for the first 5 years of the experiment (1897–1901) and the more recent long-term average (1976–2015). KiddJonathan ManningPeter SimkinJanet PeacockSimon StockdaleElizabeth 2017 <p>Changes in mean hay yield at Palace Leas for the FYM (20 t ha<sup>-1</sup>) and four ammonium sulphate-containing fertilizer treatments for the first 5 years of the experiment (1897–1901) and the more recent long-term average (1976–2015).</p>