Soluble silicon in differently textured mollisols of Argentina

Abstract

Soluble compounds of silicon (Si), such as monosilicic acid and polysilicic acid, affect many of the soil chemical and physicochemical properties of the soil. In Argentina the Chaco Pampean Plain is hugely important as it is one of the main areas of global agricultural production. The main objectives of this study were to examine the distribution of the concentration of soluble Si in soils of different genesis of the Chaco Pampean Plain and to evaluate the relationship between the physical and chemical properties of soils and the Si solubility. A soil sampling in the Pampa region was performed; where 12 soil profiles samples were taken at 1.5 m depth. The Si soil levels were separated into two groups. Group A (fine texture) had a high Si content while Group B (coarse texture) was lower. All soils show poorly provided of soluble Si in the surface horizon, but differences were observed in the subsurface. A finer soil with >100 years of an agricultural system had 30/40% less of Si soluble. Si correlates positively with pH and with clay content. These clays and the phytoliths can be a source or adsorb silicic acid. There is a negative correlation between Si and sand content, so the sandy loam to sandy soils are to suffer the greatest impact of agriculturalization. There is a significant and negative relationship between Si and phosphorus suggesting a competition might exist between these two elements. Evaluation of Si in these soils is very important due to its relevance in agricultural production worldwide. Si values may directly affect the production since its deficiency may cause crops disease.