The effect of sodicity on the strength of a soil surface

✍ Scribed by Dr David William Rycroft; Nicholas Kyei-Baffour; Trevor Tanton

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 97 KB
• Volume: 51
• Category: Article
• ISSN: 1531-0353
• DOI: 10.1002/ird.64

✦ Synopsis

Abstract

Concern that sodicity developing at a soil surface might increase soil strength, and thus have an indirect adverse effect on germination, stimulated this investigation. The aim was to investigate the link between the strength developing at a soil surface and rising salinity and sodicity.

A soil containing small amounts of a swelling clay, of a type known to suffer from capping, was deliberately salinised in order to impose a range of salinities and sodicities at the soil surface. It was found that the strength at the surface increased during the actual salinisation process, but this was almost exclusively related to the rise in sodicity, and was not influenced to any great extent by the rising salinity.

Further strengthening occurred on leaching, and this was also strongly linked to the sodicity at the soil surface immediately before leaching. The strength of the surface increased with rising sodicity up to a maximum consistent with values indicated in the literature as being likely to cause problems due to swelling and dispersion. Above these critical sodicity levels, the strength of the surface remained constant but at a high value. It was concluded that these processes could account for the observed poor germination on similar soil textures under long‐term irrigation. Copyright © 2002 John Wiley & Sons, Ltd.