When drought occurs, plants often exhibit a trade-off between productivity and survival. Here we report water deficit effects on biomass production of perennial plants in a pot experiment. We grew experimental plant communities containing monocultures (legume, grasses and shrub) and mixtures (legume+grasses, grasses+shrub and legume+grasses, grasses+shrub). Results from the
experiment showed that: 1) compared to well-watered treatment, two water treatments (85 and 70% of field capacity) significantly decreased above-ground biomass of both monoculture and mixture (P<0.0001); 2) The mixture of alfalfa and blue grama had the highest biomass production; and 3) a significant positive (P<0.0001) linear relationship was found between the three water treatments and above-ground biomass.