Organic Matter in Areas Under Secondary Forests and Pasture

Menezes, Carlos Eduardo Gabriel; Guareschi, Roni Fernandes; Pereira, Marcos Gervásio; Anjos, Lúcia Helena Cunha dos; Correia, Maria Elizabeth Fernandes; Balieiro, Fabiano de Carvalho; Píccolo, Marisa de Cássia

doi:10.1590/01047760201723032333

Cited by 4 publications

(5 citation statements)

References 17 publications

(24 reference statements)

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“…Because δ 13 C values may increase up to 3‰ with organic matter decomposition, we consider that in the context of the Cerrados biome, the δ 13 C value, −20‰, is a proxy for the documentation of past vegetation composed of a mixture of C4 grasses and trees (Silva et al, 2008, 2013). In contrast, arboreal elements within the plant community of tropical forests are C3 plants generating litters with a δ 13 C value in the order of −27 ± 0.1‰ (Menezes et al, 2017). Accounting for a 3‰ change in δ 13 C owing to decomposition processes, we assumed that in the context of Mata Atlântica forests and grass‐dominated biomes, a soil δ 13 C value of −24‰ can be considered as indicative of vegetation comprised of closed tree canopies (Silva et al, 2011; Silva & Anand, 2011).…”

Section: Methodsmentioning

confidence: 99%

Carbon stocks in umbric ferralsols driven by plant productivity and geomorphic processes, not by mineral protection

Martinez

Silva

Calegari

et al. 2021

Earth Surf Processes Landf

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Umbric ferralsols (UF) have organic carbon stocks within the first 1 m of soil profile depth that are nearly double the size (~19 kg C m−2) compared to the average carbon stocks of all other ferralsols (~10 kg C m−2). Here, we investigate processes that allow UF to gain and maintain such extraordinary carbon stocks. Using the International Soil Research and Information Center database, complemented with recently published datasets, we show that the carbon saturation capacity of the clay + silt fractions in UF (22.8 ± 5.7 g C kg−1 soil, n = 59) does not exceed the carbon saturation capacity in other ferralsols (23.3 ± 6.2 g C kg−1 soil, n = 165), thus eliminating a particularly retentive mineral matrix as a possible explanation. Rather, carbon stocks were correlated with the thickness of A horizons (106 ± 49 cm, n = 59 in umbric versus 35 ± 22 cm, n = 165 in non‐umbric ferralsols). We subsequently hypothesized that differences in A‐horizon thickness arose from two pedogenic scenarios: (i) superior carbon accrual resulting from a unique vegetation cover capable of allocating large quantities of carbon to belowground plant organs; and (ii) geomorphic processes that led to carbon burial. We evaluated the plausibility of these scenarios considering landscape history and associated carbon flux rates, hillslope position, as well as δ13C values and Ti/Zr ratios for subsets of ferralsol profiles studied by us in a region that encompasses latitudes from 26 to 7°S in eastern Brazil. We found that exceptional carbon stocks were most prevalent in the gradual transition zone (ecotone) between savanna and rainforest, likely resulting from erosion–deposition processes, historic changes of vegetation cover composed of grasses and arboreal elements, and active bioturbation. We suggest that attempts to sequester carbon in non‐umbric ferralsols will be most successful if they emulate or promote the biotic and abiotic processes prevalent in the savanna/rainforest ecotone.

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Section: Methodsmentioning

confidence: 99%

Carbon stocks in umbric ferralsols driven by plant productivity and geomorphic processes, not by mineral protection

Martinez

Silva

Calegari

et al. 2021

Earth Surf Processes Landf

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“…The high consumption of C can be seen when, with the use of bioactivator, the levels of FAC and TOC are reduced, and concomitantly greater presence of HUM are diagnosed. The carbon in the humin fraction is resistant to biological degradation, unlike FAC, which are more easily solubilized by the microbial population, contributing to the humification of organic matter (Ebeling et al, 2011;Menezes et al, 2017).…”

Section: Effect Of Phosphate Fertilization and Bioactivator On Soil M...mentioning

confidence: 99%

“…The higher C content of the humin fraction indicated that the bioactivators provided a stimulus for greater microbial activity, contributing to the humification of organic matter. The predominance of this fraction can be attributed to its low solubility and resistance to biological degradation due to the formation of metal complexes (Ebeling et al, 2011;Menezes et al, 2017).…”

Section: Effect Of Phosphate Fertilization and Bioactivator On Soil M...mentioning

confidence: 99%

Phosphate fertilization and bioactivator influences on fractions of organic matter and soil microbial biomass

Marques

Fidélis²,

Cavazzini³

et al. 2022

RSD

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Soil organic matter is considered a potential source of phosphorus (P) for plants because of biological cycling. Bioactivators are characterized as tools that can help soil microbial activity and the availability of P demanded by plants. The objective of this study was to evaluate the influence of the use of bioactivators and phosphate fertilization on the activity of soil microbial biomass and humified fractions of organic matter. The experimental design was completely randomized in a factorial scheme (6 × 2), with the first factor consisting of six doses of phosphorus applied to the soil (0, 30, 60, 90, 120, and 150 kg ha-1 of P2O5), using triple superphosphate as the source, and the second factor being the presence or absence of soil and plant bioactivator application, with four replications. The evaluated characteristics were soil microbial biomass carbon (SMBC), soil basal respiration (SBR), microbial biomass nitrogen (MBN), metabolic quotient (qCO2), microbial quotient (qmic), total organic carbon (TOC), fulvic acid fraction carbon (FAC), humic acid fraction carbon (HAC), and humin fraction carbon (HUMC). The use of soil and plant bioactivators and mineral phosphate fertilizer promoted changes in soil microbial activity. Increasing doses of phosphate fertilization promoted a reduction in the carbon characteristics of microbial biomass and basal soil respiration in the presence or absence of soil and plant bioactivators. Moreover, the use of bioactivator promoted higher averages for soil microbial biomass carbon, soil basal respiration, metabolic quotient, humic acid and humin and reduced the levels of microbial quotient, total organic carbon and fulvic acid.

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“…In the other layers, the isotopic values decrease between -19.0‰ and -21.8‰, typical of vegetation mixed between C 3 and C 4 plants. Thus, it is possible to observe the evolution of a C 3 photosynthetic cycle vegetation to C 4 , but it still indicates that the organic matter in subsurface has remnants of the characteristics of transition from native vegetation to native pasture and of natural vegetation (Carvalho et al, 2010;Strey et al, 2016;Menezes et al, 2017).…”

Section: Natural Abundance Of 13 C and 15 Nmentioning

confidence: 99%

Isotopic variations of carbon and nitrogen and their implications on the conversion of Cerrado vegetation into pasture

Oliveira

Schiavo

Lima

et al. 2021

Rev. Bras. Ciênc. Ambient. (Online)

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Conversions of natural vegetation into pasture can, in a short time, change the carbon stock and the natural abundance of δ13C in the soil. The objective of this study was to evaluate changes in carbon (C) and nitrogen (N) stocks, as well as in the natural abundance of δ13C and δ15N of Argissolo Vermelho distrófico (Acrisol), in an area of natural vegetation and planted pasture in the Cerrado region of Aquidauana (MS), Brazil. In order to do this, an area of pasture (PA), cultivated for 25 years with Urochloa brizantha, and an area of natural vegetation (NV) were evaluated. Soil samples were collected at intervals of 0.05 m up to 0.60 m depth, and physical attributes, C and N stocks (CSt and NSt) and isotopic variations of δ13C and δ15N of soil were determined. In the 0–0.05 m layer, the highest C and N stocks occurred in NV, 21.99 and 1.9 Mg ha-1, respectively. In the conversion to PA, 14.62 Mg ha-1 of CSt and 1.36 Mg ha-1 of NSt were lost in the 0–0.05 m layer. The area with PA had greater isotopic enrichment of δ13C in the layers of 0–0.05 and 0.05–0.10 m, with values of -18.3 and -17.4‰, respectively, while in the other layers the isotopic values decreased with the mixture between C of C3 and C4 plants. NV showed enrichment in the isotopic signals, in the layers from 0.25–0.30 m up to 0.40–0.45 m, with values between -21.74 and -21.54‰, respectively, which is characteristic of mixed vegetation of C3 and C4 plants. The values of δ15 N showed isotopic enrichment as depth increased, indicating greater mineralization of soil organic matter in both areas. The conversion of Cerrado into pasture and its consequent fragmentation causes negative impacts on the C and N sequestration and storage capacity, both in pasture and in natural vegetation.

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Organic Matter in Areas Under Secondary Forests and Pasture

Cited by 4 publications

References 17 publications

Carbon stocks in umbric ferralsols driven by plant productivity and geomorphic processes, not by mineral protection

Carbon stocks in umbric ferralsols driven by plant productivity and geomorphic processes, not by mineral protection

Phosphate fertilization and bioactivator influences on fractions of organic matter and soil microbial biomass

Isotopic variations of carbon and nitrogen and their implications on the conversion of Cerrado vegetation into pasture

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