Spatial Variability of Soil Chemical Elements in Different Uses for River Basin Vacacaí-Mirim, Rio Grande do Sul

Abstract

The soil has a fundamental role in human society, it plays diverse functions in the ecosystem, among the main functions is the filter function, it retains some substances that are deposited on the soil. Thus, with the increase levels of inadequade waste disposal, the contamination levels are increasing. In this context, the present study aimed to characterize the physical properties under different uses in a hydrographic basin. In the Vacacaí-Mirim River Basin, the points were chosen randomly, where the samples were collected and analyzed in EDXRF equipment. After, the values were specialized with the aid of Software Surfer 10. The variations of the concentrations of the elements analyzed were as follows: for the Element Aluminum varied of D.L. from 52.952,11 to 271.077,00 mg kg-1. For the calcium element, values ranged from the detection limit (D.L.) to 7.677,376 mg kg-1. The concentrations of iron elemente ranged of 14.118,56 to 156.695,50 mg kg-1. The yttrium concentrations varied of D.L. to 192, 36 mg kg-1, values of Magnesium varied of D.L. to 31.944,05 mg kg-1, values the potassium ranged from 1.256,236 to 60.693,230 mg kg-1. Among the elements analyzed, the following showed a correlation: Ca and Al (-0,32), Ca and Al (0,03), K and Fe (-0,02), Mg to Fe (-0,27), Mg and K (-0,03) and Mg and Y (-0,02). After the data analysis it was observed that the concentration of the elements is affected by use and soil type in the Hydrographic Basin, and this is accentuated by anthropic action, principally in areas of pastures and rice crops in the region. In the present study it was observed that the uses of soil, native field, soybeans, pasture, rice and native forest had a greater influence on the concentrations of the elements aluminum, potassium and magnesium.