Citation. Wedin, D. A.; Tilman, D. 1996. Influence of nitrogen loading and species composition on the carbon balance of grasslands. Science 274:1720-1723. (Highlighted in Science Environment 274:1610-1611 by J. Kaiser, and The New York Times December 10, 1996.)   [1588  E001  LTER]

Abstract. In a 12-year experimental study of nitrogen (N) deposition on Minnesota grasslands, plots dominated by native warm-season grasses shifted to low-diversity mixtures dominated by cool-season grasses at all but the lowest N addition rates. This shift was associated with decreased biomass carbon (C):N ratios, increased N mineralization, increased soil nitrate, high N losses, and low C storage. In addition, plots originally dominated by nonnative cool-season grasses retained little added N and stored little C, even at low N input rates. Thus, grasslands with high N retention and C storage rates were the most vulnerable to species losses and major shifts in C and N cycling.