Abstract:
Water is the most limiting factor in irrigated agric
ulture, mainly in Mediterranean
environments, as in the case of southwest Spain. In
this area, almond is one of the most
valuable crops due to its high drought tolerance. T
his work examines the crop coefficients
(K
C
) based on four drainage lysimeters installed in an
experimental young almond
orchard. Complementary, two deficit-irrigation trea
tments were tested: (1) moderate
deficit-irrigation (M
DI
), which received 100%
of the crop evapotranspiration (ET
C
)
during the irrigation period, except during the ker
nel-filling stage and pre-harvest, when
irrigation was 50%
of
ET
C
; and (2) severe deficit irrigation (S
DI
), in which water was
applied according to the values of leaf-water poten
tial at midday (
Ψ
leaf
), this being
maintained at between -1.6 and -2.0 MPa. The crop’s
physiological response to water
stress was monitored throughout the study period by
assessing the leaf-water potential
(
Ψ
leaf
) and canopy temperature (T
C
) dynamics. The
K
C
values changed from 0.4 at the
beginning of irrigation period to a maximum of 1.1
during the maximum evaporative
demand period. From this stage on, the
Kc
gradually decreased to 0.4 at the end of the
season. In physiological terms, both
Ψ
leaf
and
T
C
showed a temporal evolution according
to defined irrigation strategies. Moreover, signifi
cant relationship (r2 = 0.63, P<0.05) was
obtained between Yleaf and the difference between l
eaf and air temperature values (AT).
the difference between leaf and air temperature val
ues; evidencing the feasibility of using
T
C
for water-stress management. Thus, the findings hi
ghlight the importance of local
K
C
to optimize water use and irrigation scheduling in
almond orchards.
Keywords
: Almond, Deficit-irrigation, Drainage lysimeters,
Leaf temperature, Water stress.
