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Version: 2.0
(October 6, 2006)

Aquifers and Salinification, Pt. 1

9/12/2006
Instead of transporting water onto a farm site, most farmers utilize the resources at hand, irrigating their crops with water from rivers, streams, and, more frequently, aquifers. An aquifer is "a body of permeable rock that can contain or transmit groundwater." It rests underneath the layer of farmable loam and above impermeable sediment, forming a well of water collected in rock pockets. Aquifers are a crucial resource in arid and semi-arid climates or in regions where there are few above-ground water bodies. Such areas comprise great portions of farmland in the US, from Ohio to California, Arizona to the Dakotas.





The heavy use of aquifers presents several problems. The most common issues occur when minerals from well water (which contains high concentrations of minerals due to its contact with sedimentary rock) accumulate either within the soil or on its surface. Additionally, "repeated irrigation may also raise the underground water table within reach of the plant root zone. Capillary action then will carry water close to the soil surface where it evaporates, leaving a salt residue (Brubaker and Crosson 128)." The process by which concentrations of salt collect in or on soil is termed salinification.

Salinification has two immediate effects. The salt that collects in the soil stresses crops by forcing the plants to work harder to draw water from the soil. Consequently, the plant grows as if it were under-watered: its growth is often shortened and it is difficult to keep the plant hydrated.

The second result of salinification extends beyond stunted plant growth. Salts that collect on the soil's surface are washed into streams, lakes, and rivers, increasing salinity downstream, in turn negatively affecting other farmland, wildlife, marshland, and estuaries. Salt-heavy mineralized water is often termed "hard water" which wears away pipes and water fixtures in homes. Salinization often creates a crust on the soil's surface, further inhibiting the plant's ability to absorb water.

Ironically, the West and Southwest - the regions of the country that irrigate most intensely - are also home to sedimentary rock with a high salt content. Thus, salinization has become a dramatic issue in areas like Central California, Colorado, Wyoming, and Utah. Furthermore, the Mid and Southwest are currently experiencing their sixth year of drought, relying heavily on their underground water reserves. Overdrawing aquifers may aggravate salinity by drawing salt water into the aquifers or pumping up the saltiest dregs of the well.

Crosson, Pierre R. and Sterling Brubaker Resource and Environmental Effects of U.S. Agriculture. 1982 The John Hopkins Press, Maryland.