Elemental Sulphur as pH and Soil Fertility Amendment for Some Chileans Soils of Regions III and IV

Carlos Sierra B1*, Angelus Lancelloti M.2, Iván Vidal P.2

Soils containing calcite are common in Northern Chile, and this condition decreases the availability of nutrients for plants. The effect of the application of elemental sulphur (S°) was evaluated on soil pH, electrical conductivity and the available micronutrients content in six soils of the III and IV Regions of Chile. This was applied in doses of 500 and 1000 mg S° kg-1 and the soils were incubated for periods of 60 and 120 days at 80% of field capacity and 26°C. The experimental design was completely randomized with a factorial design and the treatments included soil, doses of elemental sulphur and times of incubation. The soil characteristics having the greatest influence on acidification by sulphur addition were the CaCO3, organic matter and sand contents. A highly significant reduction of soil pH occured in those soils with a smaller buffering capacity, as a consequence of lower CaCO3 and organic matter contents. Electrical conductivity increased by the application of elemental sulphur as a result of the rise of soluble salts in the soil. When the pH diminished significantly, the levels of Fe, Mn and Cu micronutrients increased in the soils; Mn was the most strongly influenced by the acidification. This information is useful for the application of amendment programs for the calcareous soils of Northern Chile.

Keywords: alkaline soils, pH, electrical conductivity, micronutrients.
1 Instituto de Investigaciones Agropecuarias, Centro Regional de Investigación Intihuasi, Colina San Joaquín s/n, Apartado postal 36/B, La Serena, Chile. E-mail: csierra@inia.cl. *Autor para correspondencia.
2 Universidad de Concepción, Facultad de Agronomía, Casilla 537, Chillán, Chile. E-mail: ividal@udec.cl