02394naa a2200361 a 450000100080000000500110000800800410001902200140006002400370007410000150011124501360012626000090026252012760027165000220154765000230156965000200159265000090161265000170162165300240163865300280166265300180169065300240170865300230173265300260175565300390178165300300182065300270185065300210187770000160189870000220191470000200193677300760195620893852019-01-24       2018    bl uuuu     u00u1 u    #d  a1678-992X7 a10.1590/1678-992X-2016-00892DOI1 aSIGNOR, D.  aQuantity and quality of soil organic matter as a sustainability index different land uses in eastern Amazon.h[electronic resource]  c2018  aSoil organic matter (SOM), which influences chemical, physical and biological soil attributes, is the main form of C found in the soil which can also be used as a soil sustainability index. The aim of this study was to use the quantity and quality of SOM as an indicator to determine the sustainability of different land uses (native vegetation, secondary vegetation, fruit orchards, horticultural areas, degraded pasture, improved pasture, and fields with annual crops) in the eastern Amazon. Improved pasture had higher soil C stock than the other land uses and was similar to the native vegetation, and also presented the highest quantity of C in a stable form in the soil (fraction &lt 53 ìm). According to the C management index, improved pasture is the most similar in use to native vegetation. Changes in land use reduced the soil microbial C content, although the more conservationist systems (fruit orchards, secondary vegetation, and improved pasture) had contents similar to those of the native vegetation. The highest soil microbial quotients were found in fruit orchards and horticultural areas. Well-managed pastures were effective in accumulating C as stable forms in the soil, which demonstrates the sustainability of this land use in the region studied.  aMicrobial biomass  aMatéria Orgânica  aPastagem nativa  aSolo  aUso da Terra  aBiomassa microbiana  aCarbon management index  aCarbon stocks  aChanges in land use  aEstoque de carbono  aFracionamento físico  aIndice de gerenciamento de carbono  aMudanças no uso da terra  aPhysical fractionation  aSustentabilidade1 aDEON, M. D.1 aCAMARGO, P. B. de1 aCERRI, C. E. P.  tScientia Agrícola, Piracicabagv. 75, n. 3, p. 225-232, may/jun. 2018.