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Israel Agriculture 2015

Covering Agricultural Crops

With Shade Nets to Increase Josef Tanny , Shabtai Cohen and

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Water Use Efciency the Yair Israeli 2
Institute of Soil, Water &
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Environmental Sciences,
Case of a Banana Plantation Agricultural Research Organization,
The Volcani Center, Bet Dagan, Israel
Jordan Valley Banana Experimental
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Station, Zemach, 15132, Israel

Fig. 1: A banana plantation inside a screenhouse with a hail trap. Fig. 2: Pan evaporation inside and outside a banana screenhouse in the
Photograph by J. Tanny Jordan Valley region of Northern Israel, at Zemach, near Lake Kinneret,
during the years 2008-2013. Blue line: inside; Red line: outside; Green
dashed line: ratio between inside and outside.

The use of screens and screenhouses is constantly increasing, station at a height of about 4 m, just above the plants and
especially in arid and semi-arid regions. One of the reasons below the screen. A similar class-A pan was installed in
for the wide use of screens is the potential increase in water a nearby open feld, at the same height. Evaporation from
use efciency, which is a crucial environmental issue in such the two pans was monitored over a period of 5 years and
regions. Screenhouses modify the crop microclimate and the results are shown in Fig. 2. The results show signifcant
thus may reduce the atmospheric water demand and lead to reduction in pan evaporation within the screenhouse, mainly
water saving. In Israel, much of the banana cultivation has during the months of May-October, where, on average, inside
moved inside screenhouses (Fig. 1) in order to save water evaporation was about 60% of the outside.
and improve fruit quality. Therefore research was focused on In a study conducted in a large banana screenhouse near the
measuring and estimating evapotranspiration (ET), namely, Sea of Galilee in northern Israel, we have measured ET by
the water loss from the whole canopy to the atmosphere, an eddy covariance system (Tanny et al., 2006), which directly
of banana plantations in screenhouses, in order to optimize measures the fux of water vapour from the canopy into the
irrigation management. atmosphere, and compared the measurements with two
In an attempt to illustrate the capability of screenhouses in types of models. The frst was the Penman-Monteith model
reducing ET, a class-A evaporation pan was installed within of reference evapotranspiration (Allen et al., 1998) under
a large banana screenhouse at the Zemach experimental external meteorological conditions, and the second was

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