Effect of soil moisture on the release of alachlor from alginate-based controlled-release formulations.
J Agric Food Chem
; 56(4): 1322-7, 2008 Feb 27.
Article
en En
| MEDLINE
| ID: mdl-18193836
ABSTRACT
The release of alachlor from controlled-release formulations (CRFs) based on alginate-montmorillonite matrices into aqueous polyethylene glycol (PEG) solutions of different concentrations and into a soil at different moisture contents was studied. In distilled water and in PEG-containing solutions displaying -0.1 MPa potential and up, the beads imbibe water and swell. The ensuing increase in weight is about 5%, and the increase in the bead's diameter is about 10%. At water potentials of -0.5 MPa and lower, loss of weight and shrinkage of the beads were observed. The changes in weight and diameter of the alginate-clay beads incubated in a Hamra loamy sand soil at 26.5% moisture content (w/w; -0.18 MPa) were similar to those observed in PEG solutions of >-0.5 MPa moisture potential. The weight and diameter losses observed in the drier soils (12.0 and 7.1% water content; -0.49 and -1.11 MPa) were similar to those in the more concentrated PEG solutions. A decrease in the rate of release of the active ingredient from the beads into soil was observed as the water potential decreased (drier soils). The release of the active ingredient from the investigated CRFs displayed a linear relationship to the square root of time, suggesting a diffusion-controlled-release rate. Data extracted from this relationship enabled the formulation of a mathematical model that correlates rate of release to water content.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Suelo
/
Agua
/
Alginatos
/
Herbicidas
/
Acetamidas
Idioma:
En
Revista:
J Agric Food Chem
Año:
2008
Tipo del documento:
Article
País de afiliación:
Israel