BIODIVERSITY APPEARS TO INFLUENCE NUTRIENT RETENTION BY ECOSYSTEMS
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FIGURE 7.2 Seeding with greater numbers of grassland species in experimental field plots resulted in lower concentrations of nitrate, an easily leached form of soil nitrogen, below the reach of roots in grassland plots. (Data from Tilman et al., 1996) These results indicate lower nutrient loss by leaching from the topsoil of higher-diversity experimental grassland ecosystems. Tilman’s study included 147 experimental plots covering an area of 9 square meters (100 square feet), seeded with a range of plant species native to North American prairies: 1, 2, 4, 6, or 8 species (20 plots each), 12 species (23 plots), or 24 species (24 plots).
(David Tilman, UMN)