This data set contains three ASCII files (.txt format). Two files contain above- and below-ground biomass and productivity data for a desert grassland in the Jornada Experimental Range, New Mexico, one file for an ungrazed treatment and the other for a light to moderately grazed treatment. The study site (32.60 N 106.85 W Elevation 1,350 m) is located in the Basin and Range geomorphic province at ... the northernmost extent of the Chihuahuan Desert, near the city of Las Cruces, New Mexico, about 60 km northwest of El Paso, Texas. The third file contains climate data for the period 1954-1992 obtained from a weather station located near the study site (32.62 N 106.73 W Elevation 1,300 m). Dynamics of above-and below-ground plant biomass were monitored at roughly 2-week intervals during the growing season from 1970 to 1972. Data on above-ground live biomass, recent and old dead matter, and root-crown biomass are available for one to two replications of grazed and "ungrazed" (relatively undisturbed) treatments. Total below-ground biomass was also sampled. 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 U.S. Grassland Biome Project of the International Biological Program (IBP). Annual above-ground net primary production (ANPP) was estimated, conservatively, by summing peak biomass of individual species, and annual below-ground net primary production (BNPP) estimated as the sum of positive increments in total root biomass.