Last-century increases in intrinsic water-use efficiency of grassland communities have occurred over a wide range of vegetation composition, nutrient inputs and soil pH

A - Papers appearing in refereed journals

Kohler, I. H., Macdonald, A. J. and Schnyder, H. 2016. Last-century increases in intrinsic water-use efficiency of grassland communities have occurred over a wide range of vegetation composition, nutrient inputs and soil pH. Plant Physiology. 170, pp. 881-890.

AuthorsKohler, I. H., Macdonald, A. J. and Schnyder, H.
Abstract

Last-century climate change has led to variable increases of the intrinsic water-use efficiency (Wi; the ratio of net CO2 assimilation to stomatal conductance for water vapor) of trees and C3 grassland ecosystems, but the causes of the variability are not well understood. Here, we address putative drivers underlying variable Wi responses in a wide range of grassland communities. Wi was estimated from carbon isotope discrimination in archived herbage samples from 16 contrasting fertilizer treatments in the Park Grass Experiment, Rothamsted, England, for the 1915 to 1929 and 1995 to 2009 periods. Changes in Wi were analyzed in relation to nitrogen input, soil pH, species richness, and functional group composition. Treatments included liming as well as
phosphorus and potassium additions with or without ammonium or nitrate fertilizer applications at three levels. Wi increased between 11% and 25% (P , 0.001) in the different treatments between the two periods. None of the fertilizers had a direct effect on the change of Wi (DWi). However, soil pH (P , 0.05), species richness (P , 0.01), and percentage grass content (P , 0.01) were significantly related to DWi
. Grass-dominated, species-poor plots on acidic soils showed the largest DWi (+14.7 mmol mol21).
The DWi response of these acidic plots was probably related to drought effects resulting from aluminum toxicity on root
growth. Our results from the Park Grass Experiment show that Wi in grassland communities consistently increased over a
wide range of nutrient inputs, soil pH, and plant community compositions during the last century.

Year of Publication2016
JournalPlant Physiology
Journal citation170, pp. 881-890
Digital Object Identifier (DOI)doi:10.1104/pp.15.01472
Open accessPublished as ‘gold’ (paid) open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeThe Rothamsted Long-Term Experiments including Sample Archive and e-RA database [2012-2017]
Publisher's version
Output statusPublished
Publication dates
Online30 Nov 2015
Publication process dates
Accepted23 Nov 2015
PublisherAmerican Society of Plant Biologists, (ASPB), Rockville, MD
American Society of Plant Biologists (ASPB)
Copyright licenseCC BY
ISSN0032-0889

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