Physiologia Plantarum 133: 705–. 2008 Copyright ª Physiologia Plantarum 2008, ISSN 0031-9317 REVIEW Impact of climate change on crop nutrient and water use efficiencies Sylvie M. Brouder* and Jeffrey J. Volenec Department of Agronomy, Lilly Hall of Life Sciences, Purdue University, 915 W. State Street, West Lafayette, IN 47907-2054, USA Correspondence *Corresponding author, e-mail: sbrouder@purdue.edu Received 15 November 2007; revised 1 May 2008 doi: 10.1111/j.1399-3054.2008.01136.x Implicit in discussions of plant nutrition and climate change is the assumption that we know what to do relative to nutrient management here and now but that these strategies might not apply in a changed climate. We review existing knowledge on interactive influences of atmospheric carbon dioxide concen- tration, temperature and soil moisture on plant growth, development and yield as well as on plant water use efficiency (WUE) and physiological and up- take efficiencies of soil-immobile nutrients. Elevated atmospheric CO 2 will increase leaf and canopy photosynthesis, especially in C3 plants, with minor changes in dark respiration. Additional CO 2 will increase biomass without marked alteration in dry matter partitioning, reduce transpiration of most plants and improve WUE. However, spatiotemporal variation in these attributes will impact agronomic performance and crop water use in a site-specific manner. Nutrient acquisition is closely associated with overall biomass and strongly influenced by root surface area. When climate change alters soil factors to restrict root growth, nutrient stress will occur. Plant size may also change but nutrient concentration will remain relatively unchanged; therefore, nutrient removal will scale with growth. Changes in regional nutrient requirements will be most remarkable where we alter cropping systems to accommodate shifts in ecozones or alter farming systems to capture new uses from existing systems. For regions and systems where we currently do an adequate job managing nutrients, we stand a good chance of continued optimization under a changed climate. If we can and should do better, climate change will not help us. Introduction Climate change variables including precipitation (amount and distribution), temperature and atmospheric CO 2 con- centrations are expected to alter agricultural productivity patterns worldwide. Carbon dioxide is a plant nutrient, and atmospheric enrichment has the potential to enhance plant productivity. Schimel (2006) observed that, at least in some regions, agriculture may be one of the bright spots, ‘the silver lining in the climate change cloud’. But higher global temperatures and altered precipitation patterns are expected to accompany the higher CO 2 levels, and these factors may lessen or negate any pro- duction increases or even depress production below current levels. The myriad of modeling studies attempting to project the short- and long-term impacts of climate change on agriculture are consistent only in highlighting that the nature of the productivity change itself will vary. Realized yield changes will reflect differences in local environments as well as differences in access to seed and management technologies that may offset negative climate change impacts. Regardless, with any potential changes in agricultural productivity comes a potential for associated changes in crop nutrient use. Local potential yield levels are Abbreviations – AE, agronomic efficiency; FACE, free-air concentration enrichment; PE, physiological efficiency; Ps, net photosynthesis; Rd, dark respiration; UE, uptake efficiency; WUE, water use efficiency. Physiol. Plant. 133, 2008 705