Start date

17th May 2016


6.30 pm to 9.00 pm


Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ

Registration deadline

Registration has now closed for this event

Event type


Rothamsted Research celebrates 160 years of the Park Grass Experiment. 

The Park Grass Experiment, a National Capability supported jointly by the BBSRC and the Lawes Agricultural Trust, is the oldest experiment on permanent grassland in the world. Started by the founding fathers of Rothamsted Research, Lawes and Gilbert, in 1856, the experiment continues to exemplify the value of long-term studies to investigate effects of biotic and abiotic factors on how the number of plants in a population changes over time, above- and below-ground plant community composition and microevolutionary change.

To celebrate the 160th anniversary of this world-famous experiment, Rothamsted Research invites you to ‘160 years of Park Grass’.

About the Park Grass Experiment

The Park Grass Experiment has been described as one of the most important experiments in the world in the area of bio-diversity and bio-ecology. It started in 1856, on a field that had been in pasture for at least a century. Various combinations of inorganic fertilisers (P, K, Mg, Na, nitrate-N, ammonium-N and Si) have been tested since the start; organic manures (farmyard manure and fishmeal) have been tested since 1905. In 1903 most plots were halved and the effects of regular liming tested. This was modified in 1965 with the division of most plots into four sub-plots, three of which are limed to maintain pHs of 5, 6 and 7. The fourth sub-plot receives no lime and the pH of these ranges from 3.5 to 5.7 depending on the fertiliser treatment. The plots are cut each year for hay, usually in June, and a second cut is taken in the autumn. Dramatically different swards have evolved as a result of the different pHs and nutrient statuses of the soils. There are 50 - 60 species on the unfertilised plots but only 2 or 3 species on some of the fertilised plots. Since 1990, nitrogen fertiliser has been withheld from half of all sub-plots formerly receiving 96 kg N ha-1 as either ammonium sulphate or sodium nitrate to study processes controlling soil acidification, heavy-metal mobilisation and botanical changes. 

Park Grass Video

This free public event takes place on Tuesday 17th May, 5.30pm to 8.00pm.

  • Doors of the Rothamsted Conference Centre open at 5.30pm.
  • Introductory talk in the Auditorium from 6.00pm to 6.30pm.
  • Walking tour of the Park Grass Experiment and exhibits from 6.30pm to 8.00pm. Please wear appropriate footwear.

Join us to learn about Park Grass:

  • Background - how the plots have been managed and modified over the years.
  • Botanical composition - information about the botanical surveys.
  • Data available via the electronic Rothamsted Archive (e-RA).
  • Contribution to agricultural research today - particularly a 2015 study published in the journal Nature which shows that grassland diversity on the Park Grass Experiment recovers once atmospheric nitrogen pollution reduces.