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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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until the commencement of fruit harvest (Sezen.,
2006). Soil moisture tension varied during pepper
growth phases and within the crop root zone depths:
surface soil (0–20 cm) and subsoil (20–60 cm) is
presented in Figure 4a and 4b. Soil moisture tension
also ranged from –7 to –10 and -8 to –14 bar for
surface soil and –3 to –8 and –2 to –8 bar at subsoil
depths for weekly and fortnight irrigation intervals. In
general, soil water potentials (tension) ranged between
–7 to –14 bar and –2 to -8 bar at the respective surface
and subsoil depths. The values ranged from – 7 to –10
bar and –10 to –14 bar for the respective seedling
establishment (1–7 WAT) and reproductive phase to
crop maturity (8–15 WAT). Averagely, while soil
water suction was low for weekly (–5 to –9 bar), it
ranged between –5 to –12 bar for fortnight irrigation
interval.
Figure 4a Trends of soil water potential during pepper growth
(weekly irrigation)
Figure 4b Trends of soil water potential during pepper growth
(fortnight irrigation)
Effect on rooting pattern and characteristics
Patterns of rooting and root characteristics of pepper
as affected by irrigation regimes are shown in Figure
5a. Higher root biomass and densities were obtained
for fortnight irrigation over weekly. Root penetration
was significantly lower in weekly compared to
fortnight irrigation, and lower root densities at surface
and subsoil depths were observed for fortnight
irrigation. The average length of primary roots raised
from the stem base and root biomass ranged from 17.8
cm in to 19.3 cm and 67.5 g to 73.4 g for weekly and
fortnight irrigations. Poorer root growth was observed
under the more frequent replenishment of depleted
moisture by weekly irrigation regime (Figure 5b). The
development and characteristics of root in weekly
irrigation may be attributed to frequent replenishment
of depleted moisture by weekly irrigation regime. Due
to insufficient moisture under fortnight irrigation,
plants exert maximum pressure for an enhanced root
growth and development (ramification of surface and
sub-surface horizons) to improve access to the
available soil moisture. Irrigation at fortnight intervals
enhanced root growth through greater root biomass
and densities even at deeper depths compared with
weekly irrigation. This trend suggests greater plant
access to water during mid-season and reproductive
growth phases when increasing intensities of soil and
air moisture and heat stresses obtain.
Figure 5a Pattern of rooting depth in weekly and fortnight
irrigation at 9 weeks after transplanting (WAT)
Figure5b Depth-wise pattern of soil moisture storage in weekly
and fortnight irrigation at 9 weeks after transplanting (WAT)
The two sowings (December and January: experiments 1
and 2) were characterized by situations in which the
lower half of the root zone is close to saturation (near
saturated hydraulic conductivities). This situation
coincides with the establishment and mid season