Wetting agent effect on physical properties of new and reused rockwool and coconut coir waste

Published Date
10 March 2008, Vol.116(1):104–108, doi:10.1016/j.scienta.2007.10.030

Author

Miguel Urrestarazu ^a,,

Carlos Guillén ^a

Pilar Carolina Mazuela ^b

Gilda Carrasco ^c

• aDepartamento de Producción Vegetal, Universidad de Almería, E-04120 Almería, Spain
• bFacultad de Agronomía, Universidad de Tarapacá, Arica, Chile
• cFacultad de Ciencias Agrarias, Universidad de Talca, Talca, Chile

Received 7 April 2007. Revised 28 July 2007. Accepted 26 October 2007. Available online 19 December 2007.

Abstract

Wettability of growing medium in horticulture is an important practical factor of this industry. With a proper choice and a right application, wetting agent in the nutrient solution would improve wettability and some other physical properties of growing media. The aim of this study was to evaluate the effects on some physical properties of new and reused rockwool and coconut coir dust substrates with different doses of wetting agent (2, 10, 20, 100, 200, 1000, 2000, 10,000 and 20,000 mg L⁻¹) applied to the nutrient solution and their effects measured by using bioassays. The wetting agent was ether poly-ethylene-glycol nonil-phenol with 20% (w/v) as an active ingredient of a non-ionic surfactant. Bioassay results showed differences among species. For this, the method can be suggested as a good tool to be utilized through fertigation in soilless crops; however, other studies should be proposed for each species in particular. Except to the 2 mg L⁻¹ wetting agent content in reused coir waste, the total water-holding capacity increased with the wetting agent. With 2 mg L⁻¹ wetting agent content there was an important and significant increase the easily available water (over 600%) in both substrates (including the reused ones), while higher doses show no significant differences. The effect of adjuvants added through fertigation is directly dependant on the substrate type evaluated. The substrate reutilized after one crop, reduces the air capacity and increases the easily available water and total water-holding capacity. 2 mg L⁻¹ is the wetting agent concentration more adequate in coir waste and rockwool.

Keywords

Wettability

Growing media

Soilless culture

Reused substrate

Air–water relationships

Unavailable water

Available water

Surfactant

Adjuvant

Phytotoxicity bioassays

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• ⁎ 
  Corresponding author.

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