Growth, yield and water use of potato under free air carbon dioxide enrichment

This study evaluated potato water use under elevated CO2 by monitoring actual crop evapotranspiration for two consecutive years. Potato cv Bintje was grown for in a free air CO2 experiment (FACE), under both ambient and elevated CO2 (550 ?mol mol-1). FACE. Evapotranspiration was monitored throughout the crop cycle, on an hourly basis by using the residual energy balance approach. Mean daily water use in 1998 was 6.82 ± 0.12 and 7.19 ± 0.14 mm day-1 for FACE and control respectively. On a seasonal basis, FACE used 355 mm of water compared with 374 mm used by the crop under ambient conditions. During the second year of the study, the effect of fumigation on the water use by the crop was more evident. Daily mean water use in FACE was 5.09 ± 0.24, compared with it was 5.78 ± 0.25 under ambient conditions; total seasonal water consumption was 301 and 341 mm. The overall FACE water saving across both years was 9.1 %. These figures are higher than reported in previous FACE experiments, for either cool or warm seasons crops and suggest that this basic commodity will take a substantial benefit from a CO2 enriched air, both in terms of yield performance and water savings.