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12 © Abu-Zahra and Ateyyat 2016 | Effect of Various Shading Methods
3. Results and Discussion Vegetative Growth
Plastic cover permeability The results of vegetative growth have been
illustrated in Table 2. Data obtained indicated
At the end of the experimental period, environ- that there are significant differences in vege-
mental factors (temperatures, relative humidity tative parameters. The highest results were
and light intensity) were recorded. The results obtained by the GS1 treatment, while the lowest
obtained are summarized in Table 1. Plastic results were obtained by the control treatment.
house temperature was significantly reduced by Results obtained showed that vegetative growth
using GS1 and/or whitewash treatments was improved by the use of shading materials
compared to the mud and control treatments. because in the control treatment the light
This means that the plastic houses’ permeability intensity was very high, which induced an
was reduced by using GS1 or whitewash as increase in the temperature to be more than
shading materials. A significant high relative optimum and adversely reflected on cucumber
humidity percentage was observed in the vegetative growth (Iglesias and Alegre, 2006).
control treated plastic houses compared to On the other hand, the results of the present
other treatments because using shading treat- study are in agreement with Lorenzo (Lorenzo
ments reduced temperatures that kept more et al., 2003) in which vegetative growth of the
relative humidity inside the plastic houses. GS1 cucumber plants under shade cover was higher.
and whitewash reduced the light intensity The results obtained proved that shading is
readings, which means that these treatments recommended and required in this area of
(GS1 and whitewash) have a harmful effect on Jordan during summer months.
the plastic cover
Flowering Measurements
These results do not coincide with those
obtained in the high land experiment (Abu- Significant differences were observed in the
Zahra and Ateyyat, 2015), which may be due to number of days required for 50 % of cucumber
the differences in the climate (higher temper- plants in bloom (Figure 1.). Flowering date was
ature, dryer conditions, etc.) that reacted with accelerated by the use of shading materials and
the covering materials and reflected on the delayed by the use of control treatment, which
plastic houses’ permeability. coincides with results obtained by Nageib
(Nageib et al., 2012) and with the high land
Table 1 experiment (Abu-Zahra and Ateyyat, 2015).
Results of Final readings of Temperature, b ab b a
Relative humidity, and Light intensity, after
removing the shading treatments*
Treatments Temperature Relative Light
(ºC) humidity intensity
(%) (Lux)
976 b
GS1 33.9 b** 40.1 b 1051 b
1492 a
Whitewash 34.1 b 38.1 b 1548.3 a
339.5
Mud 34.8 a 41.4 b
Control 35.0 a 52.4 a
LSD 0.05 0.7 7.6
* Values are the mean of four replicates. Figure 1: Effect of shading methods on
cucumber number of days for 50 % of plants in
**: Means within each column having different letters are
significantly different according to LSD at 5 % level. bloom. Means with the same letter are not
significantly different using LSD at 0.955 C.L.
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