Qualidade e relações pedogenéticas da matéria orgânica de alguns solos da região de Irecê (BA)

Collier

et al. 2016

Rev. Bras. Ciênc. Solo

ABSTRACT:The Bambuí Group, formed from siliciclastic sediments deposited on an extensive epicontinental platform at the end of the Neoproterozoic era, is characterized by limestones with fine to very fine texture. Limestone-derived soils in the southeast of Tocantins state, Brazil, are less notorious than similar soils in other regions of Brazil and their characterization could contribute to the Brazilian System for Soil Classification (SiBCS). Given that little is known of these soils, despitetheir agricultural potential, the objective of this study was to characterize their properties and the processes leading to soil of genesis, and also contribute to developing the Brazilian System of Soil Classification (SiBCS). Soils profiles were located on the summit (P1), shoulder (P2), backslope (P3), and footslope (P4) of a toposequence in the municipality of Lavandeira, Tocantins. Morphological, physical, chemical, and mineralogical properties of the profiles were determined. The soils were classified as: P1 -Chernossolo Rêndzico Lítico típico (Lithic Haplustolls); P2 -Cambissolo Háplico Ta Eutrófico léptico hipocarbonático (Lithic Haplustolls); P3 -Cambissolo Háplico Carbonático léptico (Lithic Haplustepts); and P4 -Luvissolo Háplico Órtico típico (Typic Rhodustalfs). All the profiles showed high contents of silt, calcium, and magnesium, which resulted in high pH and low exchangeable aluminum content. Base saturation and calcium carbonate equivalent contents were also high, and the horizons showed dark colors due to high organic matter content, which contained humin as the dominant fraction. Mineralogical analysis of the clay fraction indicated predominance of hydroxy-interlayered vermiculite, followed by illite, kaolinite, and quartz, whereas the sand fraction exhibited reflections characteristic of the quartz mineral. Given P4 contents of calcium carbonate equivalent above 50 g kg -1 and the relevance of this feature for agriculture, we propose the inclusion of hypocarbonate as a criterion for classification of Luvissolos Háplicos Órticos at the subgroup level.

Section: Carbon and Humic Fractions Of Organic Mattersupporting

confidence: 81%

Section: Physical and Chemical Propertiescontrasting

confidence: 64%

Section: Carbon and Humic Fractions Of Organic Mattermentioning

confidence: 99%

See 1 more Smart Citation

Genesis and Classification of Soils Containing Carbonates in a Toposequence of the Bambuí Group

Maranhão

Collier

et al. 2016

Rev. Bras. Ciênc. Solo

“…This result instead may be related to the decrease in the exchangeable aluminum content since liming decreases the forms of exchangeable aluminum and those associated with organic molecules (MENDONÇA; ROWELL, 1996). Cunha and Ribeiro (1998), who worked with soils from calcareous rocks in the state of Bahia in the municipality of Irecê, observed a strong influence of calcium on humic substances, mainly on C-FAF (calcium precipitates C-FAF), followed by polymerization caused by iron, which favor more condensed HS formations. This may explain the higher C-FAH values found in that study.…”

Section: Depth (Cm) Regionsmentioning

confidence: 99%

Fractions of soil organic matter in the vineyards of altitude regions in Santa Catarina

Dortzbach¹,

Assunção

et al. 2017

SCA

The implementation of agricultural systems such as viticulture can quantitatively and qualitatively affect the contents of soil organic matter (SOM). These changes may modify the edaphic features of the soil as well as the soil quality. The objective of this study was to evaluate the chemical and physical fraction of SOMand to analyze changes in the carbon stock and C management index in areas of implanted vineyards in altitude regions of Santa Catarina. Four regions were selected: Region I (Urubici); Region II (San Joaquim); Region III (Campos Novos) and Region IV (Água Doce). In each region, we selected vineyards implanted between 2001 and 2005 as well as surrounding forested areas. Disturbed and undisturbed samples were collected from the 0-5, 5-10, and 10-20 cm layers of the soil. Samples were prepared in the laboratory to obtain air-dried soft soil, which was then used for the analysis of several parameters, namely total organic carbon (TOC), carbon stock,and chemical fractionation of the soil. The chemical fractionation was then used to determine carbon content in the fulvic acid fraction (C-FAF), humic acid fraction (C-HAF), and humin fraction (C-HUM). We also analyzed particle size, quantified the levels of particulate carbon (COp) and carbon associated with clay and silt (COam), and calculated the carbon management index (CMI). We evaluated normality and homogeneity for all data. The results were evaluated with an analysis of variance and subsequent F-test. Mean values were compared using a 5% Student's t-test and subsequently submitted to a Tukey's test. The highest TOC levels were observed in Region II in the 0-5 cm layer in both vineyard and forested areas. Vineyard areas exhibited lower values of TOC, Cop, and COam compared to forested areas indicating that the management adopted in these areas contributed to the reduction of these fractions. Forested areas exhibited a higher proportion of Cop compared to vineyard areas. The humin fraction represented the largest portion of the TOC and comprised the highest values in both forested and vineyard areas. The carbon management index indicated a low contribution of vineyard areas or a reduction in carbon storage in their soils. Key words: Soil management. Organic matter fractionation. Viticulture. ResumoA implantação de sistemas agrícolas como a viticultura pode afetar quantitativamente e qualitativamente o conteúdo de matéria orgânica no solo (MOS). Estas transformações podem modificar os Foram coletadas amostras deformadas e indeformadas nas camadas de 0-5; 5-10;10-20 cm. As amostras foram preparadas em laboratório para obtenção da terra fina seca ao ar, material este que foi utilizado para realizar as análises de carbono orgânico total (COT), o estoque de carbono no solo, fracionamento químico, determinando-se os teores de carbono na fração ácido fúlvico (C-FAF), fração ácido húmico (C-FAH) e fração humina (C-HUM) e granulométrico, quantificando-se os teores de carbono particulado (COp) e o associado a argila e silte (COam), além do cálculo do ...

“…Avaliando solos formados sob calcário, Cunha & Ribeiro (1998) constataram, no horizonte A chernozêmico, que compostos de alto grau de polimerização na matéria orgânica do solo atuavam como agente estabilizador dos agregados do solo. Volkoff (1980); Volkoff & Cerri (1981) relataram que a composição mineralógica com argilas 2:1, associada às condições do meio, com complexo sortivo apresentando predomínio de bases, favorece a polimerização das moléculas orgânicas em substâncias altamente condensadas e pouco móveis, que atuam no processo de cimentação e estabilização dos agregados.…”

Section: Introductionunclassified

Substâncias húmicas como suporte à classificação de solos brasileiros

Fontana

Benites²,

et al. 2008

Rev. Bras. Ciênc. Solo