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Agriculture 2011
Cucurbita Rootstocks
as Biological Filters
for Contaminants in
Vegetable Plants Grown
under Irrigation with
Marginal Water
M. Edelstein 1 and M. Ben-Hur 2
1.Department of Vegetable
Crops, Agricultural Research
Organization,
Newe Ya’ar Research Center,
P.O.Box 1021, Ramat Yishay 30095,
Israel
2. Institute of Soil, Water and
Environmental Sciences,
Agricultural Research
Organization,
Volcani Center, P.O.Box 6, Bet
Dagan 50250, Israel
Fig. 1: Melon plant grafted onto pumpkin rootstock (left) and in the
open field (right).
Fig 2: Microelement concentrations in fruits from grafted and
non-grafted melon plants irrigated with secondary effluent water.
Vertical bars represent ± SE (unpublished data).
Introduction
A major part of the Mediterranean region is characterized
by water scarcity, with long dry summers and short wet
winters. To satisfy the demand for food and to combat
desertification in this region, marginal water sources,
such as treated domestic sewage (effluent) and saline
water, are being increasingly used for irrigation (Ben-
Hur, 2004). Moreover, the pressure to avoid disposal of
nutrient-rich effluents into water bodies has contributed
to the rapid expansion of effluent reuse for irrigation
(Halliwell et al., 2001).
The electrical conductivity (EC) of saline water is much
higher than that of fresh water, and it may exceed 5
dS/m when the dominant ions are Na and Cl. Similarly in
effluents, the EC and pH values, and the concentrations
of microelements such as heavy metals and B, and of
nutrients and dissolved organic matter are, in general,
significantly higher than in fresh water. Long-term use
of these types of water for irrigation could increase the
accumulation and concentrations of microelements and
saline elements (Na, Ca, Mg, and Cl) in the soil (Ben-Hur,
2004; Feigin et al., 1991). Relatively high concentrations
of Na + , Cl - and microelements in the soil solution
could be toxic to plants and to humans. Absorption of
these elements by the plants could affect their growth
and yield, and increase the possibility of contaminants
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