Title: Crop water use indicators to quantify the flexible phenology of quinoa (Chenopodium quinoa L.) in response to drought stress
Authors: Geerts, Sam ×
Raes, Dirk
Garcia, Magali
Mendoza, Jorge
Huanca, Ruben #
Issue Date: Aug-2008
Publisher: Elsevier Scientific Pub. Co.
Series Title: Field crops research vol:108 issue:2 pages:150-156
Abstract: Models can play an important role in agricultural planning andmanagement. Thermal time accumulation
is a common way of describing phenological development in crop models, but the sensitivity of this
concept to water stress is rarely quantified. The effect of pre-anthesis droughts on the timing of anthesis
and physiological maturity was assessed for quinoa (Chenopodium quinoa Willd.) var. ‘Santa Maria’, with
the help of two field experiments (2005–2006 and 2006–2007) in the central Bolivian Altiplano. Various
treatments with different sowing dates and irrigation applications were considered. To evaluate the
effect of drought stress on crop development, drought stress during the first 60 days after sowing was
assessed with three different stress indicators: the number of days that the soil water content of the root
zone was above a threshold, the average relative transpiration, and the sum of daily actual transpiration,
standardized for reference evapotranspiration (P(Ta/ET0)). The best indicator to quantify the effect of
pre-anthesis drought stress on phenological development was P(Ta/ET0) cumulated until 60 days after
sowing. This indicator showed a significant logarithmic relation with the time to anthesis and time to
physiological maturity. Correlations of the drought stress indicator with thermal time accumulation were
better than with calendar time accumulation. Due to an effect of post-anthesis droughts, the correlations
of the drought stress indicator with the time to anthesis were stronger than with the time to physiological
maturity. It was also demonstrated that deficit irrigation can contribute to a better agricultural planning
due to a better control of the phenological development of quinoa. The proposed relations can be used for
modeling phenological development of quinoa in drought prone regions and for efficient deficit irrigation
ISSN: 0378-4290
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Division Soil and Water Management
× corresponding author
# (joint) last author

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