Performance of the Cenlarged Rice-FACE System using pure Co2 installed In Tsukuba, Japan

Abstract

Free-air CO2 enrichment (FACE) provides a unique platform for testing the response of future ecosystems to higher atmospheric CO2 concentration ([CO2]) without disturbing various ecosystemscale interactions. To investigate adaptations to climate change, it is crucial to test the responses of diverse cultivars and management conditions to higher [CO2]. The older rice-FACE facility at Shizukuishi had an effective area of about 80 m2 for [CO2] treatment in each replicate, which was not large enough to test multiple genotypes and management practices. We report the first-year performance of the Tsukuba rice-FACE system installed at Tsukubamirai, Ibaraki, Japan. The new system was designed to have twice the usable area (>160 m2) of the Shizukuishi system without deteriorating the ability to control [CO2]. We adopted a pure-CO2 injection type system to elevate [CO2] in the FACE ring by 200 μmol mol-1 above ambient (control) plots. Overall temporal [CO2] control of the Tsukuba FACE system was slightly better than of the Shizukuishi system; mean [CO2] in the FACE plots was 584 μmol mol-1, nearly equal to the target [CO2] of 586 μ;mol mol-1. The one-minute mean [CO2] deviated by