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Infrared Warming Affects Intrarow Soil Carbon Dioxide Efflux during Vegetative Growth of Spring Wheat
Author(s) -
Wall Gerard W.,
McLain Jean E. T.,
Kimball Bruce A.,
White Jeffrey W.,
Ottman Michael J.,
Garcia Richard L.
Publication year - 2013
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2012.0356
Subject(s) - canopy , soil water , environmental science , carbon dioxide , global warming , agronomy , transpiration , chemistry , climate change , photosynthesis , soil science , biology , botany , ecology , biochemistry , organic chemistry
Global warming will likely affect carbon cycles in agricultural soils. Our objective was to deploy infrared (IR) warming to characterize the effect of global warming on soil temperature ( T s ), volumetric soil‐water content ( θ s ), and intrarow soil CO 2 efflux ( Φ s ) of an open‐field spring wheat ( Triticum aestivum L. cv. Yecora Rojo) crop grown in the semiarid desert Southwest. A temperature free‐air controlled enhancement (T‐FACE) apparatus using IR heaters maintained canopy air temperature above 3.0‐m plots by 1.3 and 2.7°C (0.2 and 0.3°C below the targeted set‐points) during the diurnal and nocturnal periods, respectively. A randomized complete block (RCB) design with two IR warming treatments (i.e., Heated; Reference) in three replicates was planted on 10 Mar. and 1 Dec. 2008. Intrarow T s , θ s , and Φ s were measured from emergence (bare soil) up until inflorescence emergence (canopy closure). Under ample soil water supply with high θ s , midday Φ s was 10% greater in Heated [4.1 μmol (CO 2 ) m −2 s −1 ] compared with Reference [3.7 μmol (CO 2 ) m −2 s −1 ]. In contrast, as the soil dried and θ s decreased to a greater degree in Heated compared with Reference, a 10% decrease in Φ s occurred in Heated compared with Reference. Overall, θ s had the greatest impact on Φ s , whereas it was responsive to T s only under high θ s. Accurate predictions of global climate change effects on Φ s in agricultural soils require that interactive effects of T s and θ s be coupled. Infrared warming with T‐FACE proved to be an effective experimental methodology to investigate these interactive effects.