One of the world’s longest-running scientific experiments has reached its 170th anniversary while continuing to reveal how fertilisers alter soil health and biodiversity.
The Park Grass experiment at Rothamsted Research in Hertfordshire was established in 1856 by agricultural scientists Sir John Bennet Lawes and Joseph Henry Gilbert. It began by examining how different fertilisers and organic manures affected hay production.
Individual plots have received controlled combinations of nitrogen, phosphorus, potassium and other nutrients year after year. Researchers have also applied different amounts of lime to create soil conditions ranging from neutral at pH 7 to highly acidic at below pH 4.
The grass has been managed consistently with annual hay cuts and detailed records of yields, soils and plant species maintained over successive generations.
Plots which initially looked almost identical gradually developed into distinct grassland ecosystems. The experiment provided some of the clearest early evidence that nutrient management can determine which plants survive and how much biodiversity land can support.
Its findings have demonstrated the importance of soil pH and shown how heavy fertiliser use can benefit some species while driving the decline of others. Park Grass has also helped researchers investigate the effects of atmospheric pollution and climate change on grassland.
Rothamsted scientists have now completed the first comprehensive survey of plant species across the plots since 2012 as part of the anniversary. Volunteers helped record the abundance and composition of plants under each treatment over six weeks.
The results will provide a new snapshot of how the grassland is changing and allow direct comparisons with records stretching back to the nineteenth century.
Park Grass also holds an extensive archive of soils, plants, crop yields and management records. Researchers can apply modern analytical techniques to samples collected decades before many current environmental problems were understood.
Dr Sarah Perryman, lead curator of the Park Grass data said: “Park Grass is much more than a field experiment – it’s a living record of ecological change.
“Every new survey adds another chapter to a dataset that allows scientists to ask questions across timescales that are almost impossible anywhere else in the world.
“Combined with this unparalleled long-term record the latest survey strengthens one of the world’s most important ecological datasets and provides an outstanding resource for researchers everywhere.”
The new survey data will be published through the Electronic Rothamsted Archive and made freely available to researchers worldwide. Records from the experiment now cover 170 years of ecological and agricultural change.
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