Organic matter dynamics and aggregation in soils under rain forest and pastures of increasing age in the eastern Amazon Basin

Koutika, Lydie‐Stella; Bartoli, F.; Andreux, F.; Cerri, Carlos Clemente; Burtin, G.; Choné, Thérèse; Philippy, R.

doi:10.1016/s0016-7061(96)00105-x

Cited by 83 publications

(47 citation statements)

References 29 publications

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“…This 13 C enrichment is negatively correlated with the TOC content. These results are similar to those observed by Balesdent et al (1993), Balesdent and Mariotti (1996), for mainland French soils, and for other soils in equilibrium with C3 plants under tropical forests in Amazon basin (Andreux et al, 1990;Desjardins, 1991;Desjardins et al, 1994;Koutika et al, 1997). The observed pattern of 13 C enrichment over the top meter is typically interpreted as the stable carbon isotopic fractionation of SOM by decomposing organisms (Mariotti and Balesdent, 1990;Mariotti, 1991;Boutton, 1996), and is supported by the correlation between …”

Section: Production and Evolution Of Som In Volcanic Tropical Soilssupporting

confidence: 90%

“…During SOM decay, the decomposers preferentially use 12 C, enriching the remaining SOM in 13 C (e.g. Andreux et al, 1990;Desjardins et al, 1994;Koutika et al, 1997;Amiotte-Suchet et al, 1999, and consequently depleting the soil solution produced in 13 C relative to SOM (Agren et al, 1996;Amiotte-Suchet et al, 2007).…”

Section: Doc Production and Cycling In Tropical Volcanic Soilsmentioning

confidence: 99%

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Sources of dissolved organic carbon in small volcanic mountainous tropical rivers, examples from Guadeloupe (French West Indies)

et al. 2016

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Section: Production and Evolution Of Som In Volcanic Tropical Soilssupporting

confidence: 90%

Section: Doc Production and Cycling In Tropical Volcanic Soilsmentioning

confidence: 99%

Sources of dissolved organic carbon in small volcanic mountainous tropical rivers, examples from Guadeloupe (French West Indies)

et al. 2016

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“…In contrast to the clay-textured Oxisols in central and eastern Amazon, soils in Rondônia are coarser textured Ultisols. This difference in texture may lead to rapid SOM turnover and Nmineralization rates in Rondônia (Desjardins et al, 1994;Moraes et al, 1996;Neill et al, 1999), whereas in the eastern Amazon, the higher clay content may protect SOM against rapid mineralization (Koutika et al, 1997). Furthermore, the variation in soil mineralogy on P availability likely contributed to the differences in pasture productivity and N cycling across the Amazon basin (see Davidson et al, 2004).…”

Section: Factors Controlling N 2 O Fluxes From Forest and Pasture Sitesmentioning

confidence: 99%

Nitrous oxide fluxes and nitrogen cycling along a pasture chronosequence in Central Amazonia, Brazil

et al. 2005

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Abstract. We studied nitrous oxide (N 2 O) fluxes and soil nitrogen (N) cycling following forest conversion to pasture in the central Amazon near Santarém, Pará, Brazil. Two undisturbed forest sites and 27 pasture sites of 0.5 to 60 years were sampled once each during wet and dry seasons. In addition to soil-atmosphere fluxes of N 2 O we measured 27 soil chemical, soil microbiological and soil physical variables.Soil N 2 O fluxes were higher in the wet season than in the dry season. Fluxes of N 2 O from forest soils always exceeded fluxes from pasture soils and showed no consistent trend with pasture age. At our forest sites, nitrate was the dominant form of inorganic N both during wet and dry season. At our pasture sites nitrate generally dominated the inorganic N pools during the wet season and ammonium dominated during the dry season. Net mineralization and nitrification rates displayed large variations. During the dry season net immobilization of N was observed in some pastures. Compared to forest sites, young pasture sites (≤2 years) had low microbial biomass N and protease activities. Protease activity and microbial biomass N peaked in pastures of intermediate age (4 to 8 years) followed by consistently lower values in older pasture (10 to 60 years). The C/N ratio of litter was low at the forest sites (∼25) and rapidly increased with pasture age reaching values of 60-70 at pastures of 15 years and older.Nitrous oxide emissions at our sites were controlled by C and N availability and soil aeration. Fluxes of N 2 O were negatively correlated to leaf litter C/N ratio, NH

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“…In the Amazon, although in some cases forest substitution by pasture reduces SOM contents, (Desjardins et al, 1994;Trumbore et al, 1995), in other cases higher C levels were observed several years after pasture implantation, which exceeded even the contents observed in forest areas (Choné et al, 1991;Koutika et al, 1997;Desjardins et al, 2004). According to Desjardins et al (2004), these opposite tendencies of soil C content development are caused by factors such geographical location and soil type, grass species, and cultural practices and management techniques.…”

Section: Introductionmentioning

confidence: 94%

Carbon content in Amazonian Oxisols after forest conversion to pasture

Júnior

Desjardins

Sarrazin³

et al. 2009

Rev. Bras. Ciênc. Solo

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Soil plays an important role in the C cycle, and substitution of tropical forest by cultivated land affects C dynamic and stock. This study was developed in an area of expansion of human settlement in the Eastern Amazon, in Itupiranga, State of Pará, to evaluate the effects of native forest conversion to Brachiaria brizantha pasture on C contents of a dystrophic Oxisol. Soil samples were collected in areas of native forest (NF), of 8 to 10 year old secondary forest (SF), 1 to 2 year old SF (P1-2), 5 to 7 year old SF (P5-7), and of 10 to 12 year old SF (P10-12), and from under pastures, in the layers 0-2, 2-5 and 5-10 cm, to evaluate C levels and stocks and carry out separation of OM based on particle size. After deforestation, soil density increased to a depth of 5 cm, with greater increase in older pastures. Variation in C levels was greatest in the top soil layer; C contents increased with increasing pasture age. In the layers 2-5 and 5-10 cm, C content proved to be stable for the types of plant cover evaluated. Highest C concentrations were found in the silt fraction; however, C contents were highest in the clay fraction, independent of the plant cover. An increase in C associated with the sand fraction in the form of little decomposed organic residues was observed in pastures, confirming greater sensitivity of this fraction to change in soil use.Index terms: soil carbon stock, particle-size fractions, tropical soil, Amazon rain forest.(

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Organic matter dynamics and aggregation in soils under rain forest and pastures of increasing age in the eastern Amazon Basin

Cited by 83 publications

References 29 publications

Sources of dissolved organic carbon in small volcanic mountainous tropical rivers, examples from Guadeloupe (French West Indies)

Sources of dissolved organic carbon in small volcanic mountainous tropical rivers, examples from Guadeloupe (French West Indies)

Nitrous oxide fluxes and nitrogen cycling along a pasture chronosequence in Central Amazonia, Brazil

Carbon content in Amazonian Oxisols after forest conversion to pasture

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