Articles
Reconciling physiological and agronomic effects of irrigation frequency
Article number
1253_34
Pages
253 – 260
Language
English
Abstract
To investigate the effects of irrigation frequency independently of changes in irrigation volume, container-grown basil or tomato plants were exposed to three different treatments.
Well-watered (WW) plants received 100% of the previous day’s evapotranspiration (determined gravimetrically) daily.
Deficit irrigated (DI) plants received 75% (basil) or 50% (tomato) of the previous day’s WW evapotranspiration daily.
Plants exposed to drying and re-wetting (DRW) received the same irrigation volume as DI plants, but in single irrigation events applied every 3-6 days.
DI and DRW tomato plants had the same shoot biomass, water use efficiency (WUE) and stomatal regulation.
In contrast, DI basil plants had greater shoot biomass but lower WUE than DRW plants, which was correlated with maintenance of stomatal conductance in DI plants as the soil dried.
Further experiments are needed to determine whether species differences or the severity of deficit irrigation explain these discrepancies, and whether altered stomatal regulation affects whole plant carbon gain.
Nevertheless, maintenance of biomass accumulation in DI basil plants suggests that irrigation frequency may be adjusted for commercial benefit.
Well-watered (WW) plants received 100% of the previous day’s evapotranspiration (determined gravimetrically) daily.
Deficit irrigated (DI) plants received 75% (basil) or 50% (tomato) of the previous day’s WW evapotranspiration daily.
Plants exposed to drying and re-wetting (DRW) received the same irrigation volume as DI plants, but in single irrigation events applied every 3-6 days.
DI and DRW tomato plants had the same shoot biomass, water use efficiency (WUE) and stomatal regulation.
In contrast, DI basil plants had greater shoot biomass but lower WUE than DRW plants, which was correlated with maintenance of stomatal conductance in DI plants as the soil dried.
Further experiments are needed to determine whether species differences or the severity of deficit irrigation explain these discrepancies, and whether altered stomatal regulation affects whole plant carbon gain.
Nevertheless, maintenance of biomass accumulation in DI basil plants suggests that irrigation frequency may be adjusted for commercial benefit.
Authors
M.A. Busari, P. Gao, R.K.A. Boyle, I.C. Dodd
Keywords
basil, deficit irrigation, irrigation frequency, stomatal conductance, tomato
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