e-RA: the electronic Rothamsted Archive

Park Grass open access data

Park Grass mean species numbers over time

Last updated 11/02/2016

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Creative Commons License This work is licensed under a Creative Commons Attribution 4.0 International License.

YOU MUST CITE AS: Rothamsted Research (2016). Park Grass changes in species number over time. Electronic Rothamsted Archive https://doi.org/10.23637/KeyRefOAPGspecies.

Park Grass Species

Click the chart above for a pdf version.Summary data used for this chart is available to download as an Excel Spreadsheet: Species data and treatments.

This summary data is derived from annual plot data for the relevant selected plots and treatments. The original raw data is available, after registering, from the e-RA database. Contact the e-RA curators to arrange a password.


The Figure shows the impact of selected treatments on the number of species comprising 1% or more of the biomass. Applying N as sodium nitrate (orange line N*) or ammonium sulphate (blue line N) quickly decreased species numbers relative to the unfertilised control.  The continued application of ammonium decreases species numbers further because of its acidifying effect on the soil (pH 3.6 in 2011, solid blue line), reducing the number of species to one or two, Holcus lanatus (Yorkshire Fog) and Anthoxanthum odoratum (Sweet Vernal Grass). However, even on the nil plot (solid green line) the number of species has decreased. This may be due to changes in atmospheric inputs and/or changes in sward management.

Applying chalk (dotted lines) increased soil pH (pH 6.2 in 2011, dotted blue line) and helped some of the species return to the original numbers. Recent work (Storkey et al 2015) showed that on some plots withholding N helped increase species diversity as did decreased atmospheric N deposition, as evident in the species numbers of the nil plot (solid green line).


Fertiliser treatments since 1856;
No fertiliser - Plot 3: No fertilizer or manure
N*2PKNaMg - Plot 14: 96kgN as sodium nitrate plus P,K,Na and Mg
N2PKNaMg - Plot 9: 96kgN as ammonium sulphate plus P, K, Na and Mg

Chalk: Ground chalk (CaCO3) applied approximately every four years 1903 - 1964 then as required to maintain pH at around 6.


Park grass long-term experiment
Long-term experiments
Permanent grasslands
Species diversity

Further Information

For further information about the experiment, see Park Grass Experiment. For more information about species diversity on Park Grass, refer to the Key References below.

Further details can be obtained from the e-RA Curators and the Rothamsted Guide to the Classical Experiments (2006) pp 20-31.

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Key References











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