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BGU Researchers reveal that Organic Agriculture
can pollute groundwater
Organic vegetable cultivation
New Study Indicates that Liquid Fertilizing Techniques through
Drip Irrigation Result in Comparatively Lower Groundwater
Pollution Rates
R
esearchers from Ben-Gurion University of the Negev
(BGU), using specialized monitoring technology,
have determined that intensive organic agriculture can
cause significant pollution from nitrate leaching into
groundwater.
Public demand has led to the rapid development of
organic farming in recent years to provide healthy food
products that are free of chemical additives and to reduce
industrial and groundwater pollution worldwide.
But, according to the paper published in the Hydrology
and Earth System Sciencesjournal, intensive organic
matter using composted manure prior to planting resulted
in significantly higher groundwater pollution rates
compared with liquid fertilization techniques through drip
irrigation.
The study used Vadose Zone Monitoring System
technology developed at BGU and commercialized by
Sensoil Innovations Ltd. to compare the water quality
across the entire unsaturated zone under organic and
conventional greenhouses in Israel.
The system is designed to monitor liquid, gas and soil
hydraulic properties and allows real time continuous
tracking of water in deep sections of the vadose zone,
from land surface to groundwater. It is currently being
used in more than 25 commercial and research sites in the
United States, Israel, Spain, Namibia, and South Africa.
While groundwater pollution is usually attributed to a
large array of chemicals, high nitrate concentration in
aquifer water is the main cause for drinking-water well
shutdowns.
The down leaching of nitrates under intensive organic
farming is due to nutrient release from the compost to the
soil during the early stages of the growing season. In this
stage, nutrient uptake capacity of the young plants is very
low and down leaching of nitrates to the deeper parts of
the vadose zone and groundwater is unavoidable.
The study, funded by the Israel Water Authority, was
conducted in commercial greenhouses on the Southern
part of the coastal aquifer in Israel.
The BGU researchers included Dr. Ofer Dahan and Dr.
Naftali Lazarovitch of the Jacob Blaustein Institutes for
Desert Research and Efrat E. Russak of the Department
of Geological and Environmental Sciences. Dr. Daniel
Kurtzman, of The Volcani Institute of Water Research,
also participated.
SOURCE: American Associates, Ben-Gurion University of the
Negev
Africa Water, Sanitation & Hygiene • March - April 2014
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