Conservation Evidence strives to be as useful to conservationists as possible. Please take our survey to help the team improve our resource.

Providing evidence to improve practice

Individual study: Effect of species seed mix and fertilizer input on northern tallgrass prairie restorations, NDSU Albert Ekre Grassland Preserve, North Dakota, USA

Published source details

Biondini M. (2007) Plant diversity, production, stability, and susceptibility to invasion in restored northern tall grass prairies (United States). Restoration Ecology, 15, 77-87


Within the context of northern tall grass prairie restoration in the USA, a study was undertaken at the NDSU Albert Ekre Grassland Preserve, southeast North Dakota (46°33′N, 97°7′W), to identify the most efficacious seed mix and fertilizer addition combinations.

The experiment comprised 50 species mixtures fertilized with nitrogen (N) or phosphorous (P) at high (200 kg/ha/yr for N; 40 kg for P), or low levels (20 kg/ha/yr N; 4 kg P). N and P were applied in the early spring year as slow release prills.
In plots (3 x 3 m) 1, 2, 5, 10, or 20 plant species were hand broadcast and covered with a thin layer of soil (10 replications/treatment; total 400 plots). Most were sown in autumn 1999 (some in the following spring). Seeding rate was 400 seeds per m2 (equal amount/species).
Aboveground biomass by species, species foliar cover and number of species per plot was assessed in sample quadrats (2000-2004).

Overall, results indicate that invasion by unsown (and mostly undesired) species drastically declined as the number of species sown/established increased, and where there was greater functional form richness.
Overtime, aboveground biomass increased and year-to-year variation in productivity declined as species and functional form richness rose. Highest biomass occurred in the high N treatment, and next the low N. P addition had little effect, as expected, due to high available P in the soil prior to the experiment.
Note: If using or referring to this published study, please read and quote the original paper, this can be viewed at: