Effects of nitrogen supply on water‐use efficiency of higher plants |
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| Authors: | Holger Brueck |
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| Institution: | Institute for Plant Production and Agroecology in the Tropics and Subtropics, Section Crop Water Stress Management, University of Hohenheim, Garbenstr. 13, 70599 Stuttgart, Germany |
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| Abstract: | The worldwide increase of food demand and reduced sweet‐water availability in some important food‐producing regions raised interest in more efficient water use, which has become one of the central research topics in agriculture. Improved irrigation management and reduced bare‐soil evaporation have highest priority to increase agronomic water‐use efficiency (WUE). Compared to these technical (irrigation) and basic (crop production) management options, effects of nutrient management on WUE were less frequently considered. Twenty‐nine publications on nitrogen (N) effects on biomass WUE of container‐grown plants are considered in this review. Most of them indicate positive N effects on WUE, and relevance of N effects on intrinsic WUE and unproductive water and carbon loss is discussed. A plot of 90 published data of percent decreases of WUE and dry mass under variable N supply is presented. Extrapolation of biomass WUE from leaf measurements of intrinsic WUE is critically reviewed. The positive correlation between WUE and dry‐mass formation suggests that physiological rather than stomatal effects are more important in order to explain positive N effects on WUE. |
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| Keywords: | carbon‐isotope discrimination intrinsic WUE root‐weight ratio transpiration efficiency bare‐soil evaporation |
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