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PH-Dependent surface properties of perlite: Effects of plant growth
Year:
2010
Source of publication :
Geoderma
Authors :
Bar-Yosef, Bnayahu
;
.
Levkovitch, Irit
;
.
Silber, Avner
;
.
Suriano, Shoshi
;
.
Volume :
158
Co-Authors:
Silber, A., Institute of Soils, Water and Environmental Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50250, Israel
Bar-Yosef, B., Institute of Soils, Water and Environmental Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50250, Israel
Levkovitch, I., Institute of Soils, Water and Environmental Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50250, Israel
Soryano, S., Institute of Soils, Water and Environmental Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50250, Israel
Facilitators :
From page:
275
To page:
281
(
Total pages:
7
)
Abstract:
Perlite is a glassy volcanic rock with a rhyolitic composition, traditionally used in the construction and chemical industries. In the last two decades perlite has become an important soilless growing medium, and is used for potting mixes in the horticultural industry. Plant growth induces significant changes in the medium and, therefore, growing plants in perlite poses an interesting dilemma regarding the applicability of the predetermined properties of the fresh material to the changing conditions as the plants develop. To fill this gap in our knowledge we have investigated the influence of plants on the surface properties of perlite, and the kinetics of release of pH- and ionic-strength-dependent elements from perlite, both in intact and used (after plant growth) systems. The effects of plants on the chemical composition of perlite were found to be significant, especially in enhancing the water-soluble P, Ca and Mg concentrations. Reaction kinetics were characterised by rapid H+ consumption and element releases during the first 24h, followed by constant-rate (zero-order) H+ consumption and dissolution reactions. Release of nutritional elements such as Ca, Mg, K and P into solution was higher in used perlite (Up) than in new intact perlite (Np) and the rate decreased with advancing time and increasing pH in both Up and Np suspensions. The pH titration lines obtained with three different NaCl concentrations overlapped and it was not possible to detect any intersection point. The quantities of acid needed for reaching the desired pH were higher in Up, but most of this difference resulted from H+ consumption through dissolution reactions that enhanced release of ions into the solution. Solution-Si concentrations exhibited pH-dependent behaviour and, contrary to the trend for cations, decreased as ionic strength increased. Caution is advised when new perlite used as a growth substrate is maintained below pH 5, because the Al concentration could exceed toxic levels. © 2010 Elsevier B.V.
Note:
Related Files :
Growth substrates
pH
plant growth
rhizosphere
soil chemistry
Surface properties
Show More
Related Content
More details
DOI :
10.1016/j.geoderma.2010.05.006
Article number:
Affiliations:
Database:
Scopus
Publication Type:
article
;
.
Language:
English
Editors' remarks:
ID:
18472
Last updated date:
02/03/2022 17:27
Creation date:
16/04/2018 23:22
Scientific Publication
PH-Dependent surface properties of perlite: Effects of plant growth
158
Silber, A., Institute of Soils, Water and Environmental Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50250, Israel
Bar-Yosef, B., Institute of Soils, Water and Environmental Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50250, Israel
Levkovitch, I., Institute of Soils, Water and Environmental Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50250, Israel
Soryano, S., Institute of Soils, Water and Environmental Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50250, Israel
PH-Dependent surface properties of perlite: Effects of plant growth
Perlite is a glassy volcanic rock with a rhyolitic composition, traditionally used in the construction and chemical industries. In the last two decades perlite has become an important soilless growing medium, and is used for potting mixes in the horticultural industry. Plant growth induces significant changes in the medium and, therefore, growing plants in perlite poses an interesting dilemma regarding the applicability of the predetermined properties of the fresh material to the changing conditions as the plants develop. To fill this gap in our knowledge we have investigated the influence of plants on the surface properties of perlite, and the kinetics of release of pH- and ionic-strength-dependent elements from perlite, both in intact and used (after plant growth) systems. The effects of plants on the chemical composition of perlite were found to be significant, especially in enhancing the water-soluble P, Ca and Mg concentrations. Reaction kinetics were characterised by rapid H+ consumption and element releases during the first 24h, followed by constant-rate (zero-order) H+ consumption and dissolution reactions. Release of nutritional elements such as Ca, Mg, K and P into solution was higher in used perlite (Up) than in new intact perlite (Np) and the rate decreased with advancing time and increasing pH in both Up and Np suspensions. The pH titration lines obtained with three different NaCl concentrations overlapped and it was not possible to detect any intersection point. The quantities of acid needed for reaching the desired pH were higher in Up, but most of this difference resulted from H+ consumption through dissolution reactions that enhanced release of ions into the solution. Solution-Si concentrations exhibited pH-dependent behaviour and, contrary to the trend for cations, decreased as ionic strength increased. Caution is advised when new perlite used as a growth substrate is maintained below pH 5, because the Al concentration could exceed toxic levels. © 2010 Elsevier B.V.
Scientific Publication
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