Scientists in Hertfordshire are celebrating 170 years of continuously observing the growth of grass, an experiment that began during the reign of Queen Victoria. The Park Grass Experiment at Rothamsted Research, near Harpenden, was initiated in 1856 by founders Sir John Bennet Lawes and Joseph Henry Gilbert. Their initial goal was to understand the effects of various fertilisers and manure on hay yields, laying the groundwork for what is now the world's oldest ongoing experiment on permanent grassland.
Spanning just under three hectares, the site is divided into numerous plots, each subjected to different treatments. This meticulous approach allows scientists to compare how nutrient applications influence the growth, soil composition, and botanical diversity of the grass. Andy Gregory, a soil scientist overseeing Rothamsted's long-term experiments, describes his role as a custodian of Park Grass as an 'incredible privilege,' emphasising its continued relevance for cutting-edge scientific research rather than being a mere historical relic.
The longevity of the experiment has enabled scientists to track significant environmental changes. For instance, researchers have observed the impact of historically high levels of atmospheric nitrogen and sulphur, which once acted as a natural fertiliser across the UK. Dr. Gregory notes that the drastic reduction in these depositions in recent decades, due to changes in power generation and vehicle technology, is visibly reflected in the altered botanical diversity within some of the plots at Park Grass.
Crucially, the foresight of Rothamsted's founders in meticulously collecting and archiving crop and soil samples has proven invaluable. This extensive archive, combined with on-site weather records, provides an unparalleled long-term dataset. Modern scientific techniques, such as DNA analysis, are now being applied to these historical samples, some dating back 170 years, to reveal previously unknown insights into past soil ecosystems and biodiversity.
Dr. Sarah Perryman, curator of the Park Grass data, describes the site as 'a living record of ecological change,' as she digitises grass species records collected since 1856. This ongoing work is building a comprehensive picture of land transformation over time. As the experiment enters its next century, a primary focus is on understanding the complex interactions with a changing climate. Researchers are already observing patterns, such as decreased yields following drier springs and early summers. While higher carbon dioxide levels might initially boost yields, this benefit could be negated by increased drought conditions.
The ongoing collection of samples today also holds promise for future discoveries. Dr. Gregory suggests that these contemporary samples may contain traits yet unknown, which could be measured by scientists decades from now, further enriching the experiment's enduring legacy and contributing to a deeper understanding of our natural environment.