Premium
Future carbon dioxide concentration decreases canopy evapotranspiration and soil water depletion by field‐grown maize
Author(s) -
Hussain Mir Zaman,
VanLoocke Andy,
Siebers Matthew H.,
RuizVera Ursula M.,
Cody Markelz R. J.,
Leakey Andrew D. B.,
Ort Donald R.,
Bernacchi Carl J.
Publication year - 2013
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.12155
Subject(s) - canopy , evapotranspiration , carbon dioxide , agronomy , transpiration , stomatal conductance , environmental science , photosynthesis , soil water , water content , chemistry , botany , soil science , biology , ecology , geotechnical engineering , organic chemistry , engineering , biochemistry
Maize, in rotation with soybean, forms the largest continuous ecosystem in temperate N orth A merica, therefore changes to the biosphere‐atmosphere exchange of water vapor and energy of these crops are likely to have an impact on the M idwestern US climate and hydrological cycle. As a C 4 crop, maize photosynthesis is already CO 2 ‐saturated at current CO 2 concentrations ([ CO 2 ]) and the primary response of maize to elevated [ CO 2 ] is decreased stomatal conductance ( g s ). If maize photosynthesis is not stimulated in elevated [ CO 2 ], then reduced g s is not offset by greater canopy leaf area, which could potentially result in a greater ET reduction relative to that previously reported in soybean, a C 3 species. The objective of this study is to quantify the impact of elevated [ CO 2 ] on canopy energy and water fluxes of maize ( Z ea mays ). Maize was grown under ambient and elevated [ CO 2 ] (550 μmol mol −1 during 2004 and 2006 and 585 μmol mol −1 during 2010) using Free Air Concentration Enrichment ( FACE ) technology at the Soy FACE facility in U rbana, I llinois. Maize ET was determined using a residual energy balance approach based on measurements of sensible ( H ) and soil heat fluxes, and net radiation. Relative to control, elevated [ CO 2 ] decreased maize ET (7–11%; P < 0.01) along with lesser soil moisture depletion, while H increased (25–30 W m −2 ; P < 0.01) along with higher canopy temperature (0.5–0.6 °C). This reduction in maize ET in elevated [ CO 2 ] is approximately half that previously reported for soybean. A partitioning analysis showed that transpiration contributed less to total ET for maize compared to soybean, indicating a smaller role of stomata in dictating the ET response to elevated [ CO 2 ]. Nonetheless, both maize and soybean had significantly decreased ET and increased H , highlighting the critical role of elevated [ CO 2 ] in altering future hydrology and climate of the region that is extensively cropped with these species.