Abstract
ABSTRACT Sorption of selenium (Se) on soils may be influenced by factors that are changed though agricultural practices usually performed for crop production, such as soil pH, competing anion and organic matter contents, among others. This study aimed to evaluate the influence of soil management and ionic strength (IS) on Se retention in Brazilian soils, which is important to predict Se availability in both systems, native and cultivated soils. For that, adsorption and desorption reactions of Se were evaluated in 16 soil samples (eight from cultivated soils and eight from native soils), using solutions containing 100 and 500 µg L-1 Se in the form of sodium selenate and in two IS, 15 and 150 mM. Se adsorption varied as a function of IS for most soils, which may indicate that the adsorption mechanism by outer-sphere complex is important for selenate retention in the studied soils, but future studies involving other techniques, such as spectroscopic studies, are needed to more clearly confirm the adsorption mechanism. In general, adsorption varied in relation to soil characteristics, and native soils adsorbed larger Se amounts than the cultivated soils. In terms of desorption, soils which had larger Se adsorbed amounts also presented larger desorbed amounts. Finally, IS and soil management influenced the availability of selenate in the studied soils.
Highlights
Brazil stands out worldwide as a major agricultural producer, especially in the Cerrado biome
Comparing cultivated soils with the native ones, there are differences, especially for pH values and available contents of nutrients, such as P and S, which were lower for native soils due to long-term agricultural practices applied to the cultivated soils
The presence of these minerals reflects a high intensity of weathering, which would be expected for tropical soils
Summary
Brazil stands out worldwide as a major agricultural producer, especially in the Cerrado biome. The concern regarding the quality and capacity of products to supply essential nutrients, including selenium (Se), has increased in recent years. Se contents available in the soil can be absorbed and accumulated in the food for humans and animals (Lopes; Ávila; Guilherme, 2017; Wang et al, 2017). Se is essential for the human body and is directly linked to the elimination of free radicals, reducing several types of cancer (Roman; Jitaru; Barbante, 2014). In Brazil, studies have pointed to deficient Se intake by the Brazilian population (Maihara et al, 2004), which can be linked to the low Se contents in soils (Gabos; Alleoni; Abreu, 2014a; Matos et al, 2017)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
