This data set contains three ASCII files (.txt format). Two files contain above- and below-ground biomass and productivity data for a northern mixed prairie grassland, one file for an ungrazed treatment and the other for a heavily grazed treatment. The study site (46.90 N, -102.82 W, Elevation 784 m) is located in the northern Great Plains, near the city of Dickinson, about 160-km west of Bismarck, North Dakota. The third file contains climate data for the period 1891-1994 obtained from a weather station near Dickinson (46.88 N, -102.80 W, Elevation 750 m).

Dynamics of above-ground living and dead plant biomass were monitored by the harvest technique at roughly 2-week intervals during the growing season of 1970. Total below-ground biomass was sampled at the same intervals by manual coring within the harvested plots to a depth sufficient to include at least 90% of the root mass. Data were collected as part of a coordinated study over 1-3 years at ten grassland sites of the central and western United States, under the US Grassland Biome Project of the International Biological Program (IBP).

Above-ground net primary productivity (ANPP) was estimated conservatively by summing peak biomass of individual species. These values were 351 g/m2/year for ungrazed and 302 g/m2/year for grazed grassland plots. Below-ground net primary productivity (BNPP) was estimated as the sum of positive increments in total root biomass (including root crowns); 932 g/m2/year for ungrazed and 958 g/m2/year for grazed grassland plots. Revision Notes: Only the documentation for this data set has been modified. The files have been checked for accuracy and are identical to those originally published in 1998.