Weathering features of a remineralizer in soil under different land uses

Rafael Cipriano Da Silva,Edilene Pereira Ferreira,Antonio Carlos De Azevedo

doi:10.1590/s1678-3921.pab2021.v56.01442

Rafael Cipriano Da Silva, Edilene Pereira Ferreira + Show 1 more

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https://doi.org/10.1590/s1678-3921.pab2021.v56.01442

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Abstract

Abstract The objective of this work was to analyze the mineralogical, morphological, and compositional modifications resulting from the weathering of diabase grains buried into soil under different land uses for up to 378 days. Samples of comminuted diabase were put into polyester bags and buried into soil under corn crop, elephant grass, and woods, being unburied and evaluated after four time periods. The samples of the remineralizer (RM) were analyzed by X-ray diffractometry, total chemical analysis, scanning electron microscopy, and Al (Ald and Alo) and Fe (Fed and Feo) contents extracted by sodium dithionite-citrate-bicarbonate (DCB) and ammonium oxalate (AAO) solutions. Plagioclases and pyroxenes were the most weathered minerals in all three land uses and showed the same pattern of elemental gains and losses. The characterization of Fe and Al solubility in DCB and AAO showed that the greatest change in these elements was from the lithogenic and crystalline to the pedogenic and amorphous phase, when compared with their total content. Plagioclases and pyroxenes were the most weathered minerals, and Fe and Al show a great transfer from the crystalline to the amorphous phase, with values up to 26 and 175, respectively, for the ratios between bags with RM/Feo and RM-control and bags with RM/Alo and RM-control.

Highlights

Remineralization, the application of powdered rocks into soils, is an agricultural practice to improve edaphic properties and increase biomass productivity (Harley & Gilkes, 2000; Leonardos et al, 2000; Van Straaten, 2006; Manning, 2010; Silva et al, 2017)
The samples of the remineralizer (RM) were analyzed by X-ray diffractometry, total chemical analysis, scanning electron microscopy, and Al (Ald and acid solution (Alo)) and Fe (Fed and Feo) contents extracted by sodium dithionite-citrate-bicarbonate (DCB) and ammonium oxalate (AAO) solutions
The characterization of Fe and Al solubility in DCB and AAO showed that the greatest change in these elements was from the lithogenic and crystalline to the pedogenic and amorphous phase, when compared with their total content

Summary

Introduction

Remineralization, the application of powdered rocks into soils, is an agricultural practice to improve edaphic properties and increase biomass productivity (Harley & Gilkes, 2000; Leonardos et al, 2000; Van Straaten, 2006; Manning, 2010; Silva et al, 2017). Its characterization by standard chemical parameters, such as thermodynamic stability constants and dissolution rates, is determined in laboratory conditions (Garrels & Christ, 1965; Palandri & Kharaka, 2004), which is very useful as a starting point, but may deviate from the dissolution rate in field conditions by a factor as great as 102 (White & Brantley, 2003; Yokoyama & Matsukura, 2006; Ganor et al, 2007) This is so because variables as the mineral:solution ratio, bioweathering, and seasonal variations in moisture and temperature, among others, greatly diverge from those in laboratory conditions (Benedetti et al, 1994; Yokoyama & Matsukura, 2006; Ganor et al, 2007). To properly evaluate and manage the use of RMs in soils, the dissolution of these rocks in field conditions must be well understood and parametrized

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