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Sunday, 17 November 2013

Soil Salinization

By Ashley Gervais-LeClaire, Kijana Henry, and Melody Tadeo
This was a group project for an environmental science class about the causes, effects, and potential solutions of soil salinization. This is the handout, and you can follow this link to see Ashley's Prezi.


Soil Salinization


The buildup of salt in soil occurs when there is insufficient irrigation, and salts from the water remain in the soil increasing the salt concentration, degrading the soil. Soil salinization affects approximately 33% of the world’s irrigated land, and can cause damage to biodiversity, agriculture, and water sources.


Natural Causes:

- Water movement causes salt to accumulate in soil increasing salt concentration when water evaporates and leaves salts behind. Risk increases with arid soil and when there is more meltwater than plants need, and decreases with more rainfall.
- Overwashing and seepage of saline waters and salt spray from crashing waves in saltwater bodies.
- Rising of the water table.
Anthropogenic Causes:
- Road salts washing onto land.
- Overuse of fertilizers.
- Improper water management
- Over-exploitation of groundwater leading to intrusion of saline water in the water table.
- Fallowing and overgrazing in dryland areas.

Soil Salinization in Canada:

-  Occurs in the Southern areas of the prairies. Saskatchewan and Alberta are at greater risk because they are more arid than Manitoba.
-  The decrease in Summer Flow farming had decreased the salt content of the prairie soil. (Summer Flow is a farming practice that leaves farmland out during growing season so the nutrients in the soil are retained for future crops.)
-  Along with the nutrients the salt in the soil is also retained making the soil for salt.

Effects:

- Many plants are intolerant of high levels of salt, because the salts decrease water uptake from the roots, excepting halophytes (salt-tolerant plants).
eg. red buckeye, white ash, honeylocust, saltbush, St. John’s wort, and bayberry.
Mosses are often very tolerant to to sodium salts (such as the most common in salinization, NaCl), but are susceptible to potassium salts.
- Kills plants, lowering biodiversity of plants and reduces food sources for other species.
- Potential desertification of arid lands.
- Many crops are harder to cultivate in agriculture, decreasing human food sources, reducing sales for farmers, and having a negative impact on the economy.
- Water sources can be tainted by salinization in surrounding soil, decreasing water quality and affecting aquatic ecosystems and other species relying on the water source.

Solutions and Preventative Measures:

- Minimize the use of fertilizers, and ensure that fertilizer use is in safe doses.
- Planting trees in agricultural areas (“agroforestry”) reduces risk of soil salinization.
- Using organic matter to improve soil structure, drainage and moisture holding capacity.
- The planting of salt-sensitive plants uphill or away from salted roads, and planting salt-tolerant plants where there is high risk of salinization.
- Mulching to prevent evaporation and buildup of salts.


- Leaching through sufficient irrigation and monitoring the quality of irrigated water, ensuring that it has safe amounts of salt (< 0.5 g/L is best).


Bibliography
Appleton, B. e. (2009, May 1). Trees and Shrubs that Tolerate Saline Soils and Salt Spray Drift - Home -
Virginia Cooperative Extension . Publications and Educational Resources - Home - Virginia Cooperative Extension . Retrieved February 19, 2013, from http://pubs.ext.vt.edu/430/430-031/430-031.html

Dregne, H. E. (n.d.). Desertification of Arid Lands. Center for International Earth Science
Information Network. Retrieved March 8, 2013, from http://www.ciesin.columbia.edu/docs/002-193/002-193.htm

Eblin, J. (n.d.). Use of Salt to Kill Moss | eHow.com. eHow | How to Videos, Articles & More -
Discover the expert in you. | eHow.com. Retrieved February 19, 2013, from http://www.ehow.com/facts_7201481_use-salt-kill-moss.html

Food and Agriculture Organization of the United Nations. (n.d.). Forests, Trees and Food. FAO:
Food and Agriculture Organization of the United Nations, for a world without hunger. Retrieved February 19, 2013, from http://www.fao.org/docrep/006/U5620E/U5620E05.htm

Food and Agriculture Organization if the United Nations. (n.d.). Water quality for agriculture. FAO: Food
and Agriculture Organization of the United Nations, for a world without hunger. Retrieved March 5, 2013, from http://www.fao.org/docrep/003/T0234E/T0234E02.htm

Gergely, T. (n.d.). Soil Salinisation. EUSOILS - European Soil Portal Home Page. Retrieved February
19, 2013, from http://eusoils.jrc.ec.europa.eu/library/themes/salinization/

Department of Primary Industries. (n.d.). Chapter B7. Managing saline soils. NSW Department of

Primary Industries. Retrieved May 3, 2013, from www.dpi.nsw.gov.au/__data/assets/pdf_file/0008/127259/Managing-saline-soils.pdf

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