Making the paper: Christopher Clark.

The article presents a study on soil nitrogen's damaging effects on plant diversity. Nitrogen is an important element for plants, but too much of it in the soil results in reduced plant diversity. David Tilman's project in studying the effects of nitrogen on plant biodiversity started in 1982. He situated varying amount of nitrogen-containing fertilizer onto a patchwork of grassland plots in three fields of Cedar Creek Natural History Area in Minnesota every summer up to 2004. During the spring and summer months, Tilman, and later, ecologist Christopher Clark, harvested and recorded the plants that had came out in the different plots. The results showed that even the lowest amount of nitrogen in the treatments led in the loss of 1 in 6 plant species.