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International Journal of Horticulture 2014, Vol.4, No.14, 1
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http://ijh.biopublisher.ca
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(higher surface width and depth of wetting) under
weekly irrigation while wetting and zone of active
root water uptake occur at depths with fortnight
irrigation interval.
Figure 2a Soil water potential at 2 days after irrigation
Figure 2b Soil water potential at 5 days after irrigation
Effects on soil moisture storage and suction
Typical volumetric water contents during pepper
growth for the respective weekly and fortnight
irrigation intervals are presented in Figure 3a and b.
Irrigation regimes considerably enhanced soil
moisture storage within crop root zone depths. Within
the crop root zone, and across irrigations, soil
moisture contents ranged between 14.7 and 11.8% for
the respective surface (0–20cm) and lower (30-45 and
45–60 cm) soil depths. Between transplanting,
establishment and mid season (1–7 WAT), available
soil water at the surface was higher in weekly
compared with fortnight irrigation (14.9 to 14.5%
respectively). However, at lower depths and during
reproductive growth (8 to 16 WAT), available water
was lower (10.8%) for weekly compared with
fortnight (11.9%) irrigation (Figure 3a and b). Across
sampling dates, soil moisture contents were lowest for
plots irrigated at fortnight intervals compared with
weekly irrigation. The changes in profile (0–10 cm
depth) soil water storage during pepper growth for the
weekly and fortnight irrigation frequency in
comparison with field capacity and permanent wilting
moisture contents is shown in Figure 3c. In both
irrigation treatments, available soil water was above
50% throughout the growing season. In the weekly
irrigation treatment plots, soil water contents remained
fairly high as compared to fortnight irrigation.
However, in the fortnight irrigation treatment,
available water fell below 50% after 40 DAT during
the growing season and resulted in lower yield
presumably due to moisture stress occurring prior to
flowering. The period at the be-ginning of the
flowering period is most sensitive to water shortage
and soil water depletion in the root zone during this
period should not exceed 25% percent. For high yields,
an adequate water supply and relatively moist soils are
required during the total growing period. Reduction in
water supply during the growing period in general has
adverse effect on yield and the greatest reduction in
yield occurs when there is a continuous water shortage
Figure 3a Trends of soil moisture storage during pepper growth
(weekly irrigation)
Figure 3b Trends of soil moisture storage during pepper growth
(fortnight irrigation)
Figure 3c Changes in soil water content 0-10 cm depth) during
pepper growth (weekly and fortnight irrigation)