Agriculture Reference
In-Depth Information
As expected, 15 gallon containers have higher water usage than 7 gallon containers
and that could be due to higher evapotranspiration rate of plants in them compared to
plants grown in 7 gallon containers (Fig. 3). It is evident from the fi gure that during
warm periods of the year the daily water usage is signifi cantly higher but it started to
decline as the temperature cooled down in September in both container sizes. Thus the
daily water use was well correlated with environmental factors such as air temperature
and solar radiation.
Volume of irrigation water applied was infl uenced by the timing of irrigation in
7 gallon containers (Table 2). Irrigation volume applied per day was highest in the
noon followed by PM and AM. Total water use for the irrigation treatment beginning
in noon was approximately 15% more than AM irrigation and about 10% more than
PM irrigation. But the variation in water use was not refl ected in main stem diameter
even though plants watered beginning at noon were the biggest. No change in stem
diameter could be attributed to a higher evaporative water loss even though cooling of
substrate in noon irrigation is an advantage. Total water use and daily water use were
not different between different timings of cyclic irrigation in a 15 gallon container.
Main stem diameter also did not differ between AM and noon treatments, however
plants irrigated in the evening (PM) had 30% smaller stem diameter compared to AM
and noon irrigations. Optimal irrigation timing could not be derived mainly due to
high precipitation and mild weather during the study period. This could be because
the plants might have experienced a mild water defi cit during midday period before
irrigation as Scagel et al. [41] noticed in container grown
Rhododendron
. From a wa-
ter conservation perspective, AM irrigation is better than other times and also plant
growth was similar to irrigation at other times of the day.
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