Irrigating with Saline Water

Kirsten Kaplan

Agriculture in Israel• In 2010, 42% of Israel’s exports ($2.13 billion) were

agricultural•60% of fresh vegetable exports come from Arava region (in Negev desert)

• In 2011 1,189 million cubic meters (mcm) of water was used in agricultural production•680 mcm was recycled and brackish water

• Water is a major issue in Israel and the Middle East, so increasing the use of marginal water is important

• In the Arava region (in Negev desert): drip irrigation, greenhouses, irrigation with saline water

Challenges for Irrigation with Saline Water• Irrigating with saline water requires a unique approach• Salty water makes it harder for plants to take in water

– Salt gradient between water and intracellular fluid is reduced– If saline water is sprayed directly on leaves, can cause leaf

damage– If water is too salty, osmosis can actually be reversed and water

will be pulled out from plant cells• Plant then looses moisture and enters a state of extreme stress

• To effectively irrigate with brackish water, Israel turned to grafting– Use rootstocks that are better adapted to regulating the

transport of excess salt ions– With certain grafted roots, can get an 80% increase in yield

Grafting• Grafting essentially involves taking the scion (bud or

shoot) of one plant and attaching it to the rootstock of another

Grafted tomato plant

• For tomatoes, this process involves growing two different varieties of tomatoes, cutting the stem of both plants when each has about 2 sets of leaves, and attaching the scion and rootstock of the two plants together using a silicon clip– Takes about 5 weeks from planting the

seeds until plants are successfully grafted and ready to be moved to the field

Success with Saline Irrigation• Israel developed the Desert Sweet tomato, which is

irrigated with saline water– This tomato is actually sweeter than other tomatoes!– How does that work? The salt changes the osmolarity of the water, which

stresses the plant/plant cells causing them to produce more sugars– Israel has achieved similar results with sweet peppers and melons

• Negev farmers have been able to time their peak growing seasons between typical peak growing seasons– Allows them to export and sell fresh produce at a higher price,

especially in Europe– The higher price is important to compensate for higher water

prices in Israel/the Negev and the increased distance between the site of production and the market

Works Cited• Bringing water to the desert. Jewish National Fund.

http://www.jnf.org/work-we-do/our-projects/research-development/bringing-water-to-the-desert.html

• Brown, A. S. 2011, April 27. Hidden water holds the key to a changing desert. Inside Science. http://www.insidescience.org/content/hidden-water-holds-key-changing-desert/1234

• Byczynski, L. 2011, March. Grafted tomatoes: worth the trouble? Growing for Market. http://www.growingformarket.com/articles/Grafted-Tomatoes

• Cross, N. 2001. Using saline water for irrigation. Primary Industries Agriculture. http://www.dpi.nsw.gov.au/agriculture/resources/soils/salinity/crops/saline-irrigation

• Edelstein, M. and M. Ben-Hur. 2011. Grafting to prevent contaminants’ penetration into vegetable plants. Israel Agriculture. http://www.israelagri.com/?CategoryID=396&ArticleID=627

• Estan, M. T., Martinez-Rodriguez, M. M., Perez-Alfocea, F., Flowers, T. J. and M. C. Bolarin. 2005. Grafting raises the salt tolerance of tomato through limiting the transport of sodium and chloride to the shoot. Journal of Experimental Botany 56(412): 703-712.

• Garrett, A. 2011. Grafting vegetables- is it worth the trouble? Many growers say yes. Small Farms, Oregon State University. http://smallfarms.oregonstate.edu/sfn/su11graftveg

• Moisa, S. (ed.). Israel’s Agriculture. The Israel Export and International Cooperation Institute. http://www.moag.gov.il/agri/files/Israel's_Agriculture_Booklet.pdf