Water resource scarcity has been increasingly becoming
a threat to wheat (
Triticum aestivum
L.) production in
North China Plain. Thus, a water-saving irrigation strategy
should be urgently developed. We conducted a 2-yr
field experiment to examine the effects of supplemental
irrigation (SI) on the photosynthetic characteristics and
water use efficiency (WUE) of wheat. This study employed
two SI strategies: A quota SI using 60 mm water at jointing
and anthesis stages (W1) and soil moisture testing SI
(W2), which brings the target relative soil water content
of 0-40 cm soil layer to 70% field capacity at jointing and
anthesis stages. A non-irrigated treatment (W0) was used
as control. Results showed that W2 significantly improved
the water uptake in 80-160 cm soil layer compared with
W1. Moreover, flag leaf photosynthetic rate, stomatal
conductance, and transpiration 14-28 d after anthesis were
highest in W2 successively followed by W1 and W0, and
the difference was significant. Dry matter (DM) at maturity,
DM accumulation post-anthesis and its contribution
ratio to grain were significantly higher in W2 than in the
other treatments.
13CO
2 labeling results indicated that
W2 promoted δ
13C-photosynthate accumulation in grain.
In 2012-2013 growing season, the grain yield increased
by 56.05% and 5.74% and WUE increased by 26.17%
and 6.34% in W2 compared with those in W0 and W1,
respectively. In 2013-2014 growing season, the grain yield
increased by 41.82% and 5.90% and WUE increased by
28.24% and 13.03% in W2 compared with those in W0 and
W1, respectively. Therefore, W2 is a high-yield and water-saving
treatment.
