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Citation. Tilman, D.; Dodd, M. E.; Silvertown, J.; Poulton, P. R.; Johnston, A. E.; Crawley, M. J. 1994. The Park Grass Experiment: Insights from the most long-term ecological study. Pages 287-303 in R. A. Leigh and A. E. Johnston, Eds., Long-term Experiments in Agricultural and Ecological Sciences. CAB International, Wallingford, Oxon, United Kingdom. [1197 LTER]
Introduction. In 1856 J. B. Lawes and J. H. Gilbert started an experiment still in progress, which is now, undoubtedly, the most long-term ecological study in the world. The Park Grass Experiment was initially designed to determine the effects of different amounts and combinations of mineral fertilizers and organic manures on the productivity of permanent grassland. However, there were such dramatic effects of the treatments on plant species composition and plant diversity that Lawes and Gilbert (1880) quickly concluded that the experiment was of greater interest to the botanist, vegetable physiologist, and the chemist than to the farmer. And this has proved to be so. As demonstrated below, the treatments within the experiment have continued to provide insights into issues in evolutionary, population, community and ecosystem ecology. The long-term data have become increasingly powerful with each additional sampling, despite the lack of replication and randomization. However, Lawes and Gilbert can hardly be faulted for their experimental design. Important contrasts were placed adjacent to each other so that treatment effects could be directly observed all along the 80 m boundary that the two plots shared. Moreover, it was during R. A. Fisher's tenure at Rothamsted that he articulated, more than 70 years after the establishment of Park Grass, the concepts upon which modern experimental design are based (Barnett, Chapter 10).