Simple resource addition experiments often have surprising results. We added nitrogen and water in a factorial design to diverse prairie plots at Cedar Creek and found such initially confusing responses.

With a model of competitive plant allocation strategies we found an explanation for these responses and unification of the seemingly contradictory theories of Liebig's law of the minimum and optimal foraging for essential resources. 

Farrior, Tilman, Dybzinski, Reich, Levin, and Pacala (2013). Resource limitation in a competitive context determines complex plant responses to experimental resource additions. Ecology 94:2505-2517.

*In its supplements this paper also includes an analysis of the importance of territoriality in plant allocation strategies.

Cedar Creek diverse prairie plots where water and nitrogen were added in a factorial design.

Separating leaf biomass from structural and reproductive biomass. 



Plant biomass responses to resource additions.