scholarly journals Soil organic matter fractions, chemical attributes and aggregation under forestry and agricultural systems

2018 ◽  
Vol 8 (3) ◽  
pp. 459-468
Author(s):  
Cristiane Figueira da Silva ◽  
Marcos Gervasio Pereira ◽  
Júlio César Fernandes Feitosa ◽  
Ariovaldo Machado Fonseca Júnior ◽  
João Henrique Gaia-Gomes ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Humic Substances ◽  
Secondary Forest ◽  
Agricultural Systems ◽  
Mean Weight Diameter ◽  
P Content ◽  
Chemical Attributes ◽  
Organic Matter Fractions

The aim of this work was to evaluate the influence of the conversion of forest systems to agricultural systems in the organic matter compartments, aggregation and soil chemical attributes, in the Atlantic Forest. The evaluated systems were: annual crop (ACr); perennial agriculture (PAg); pasture; and secondary forest early (SFES), medium (SFMS), and advanced stage (SFAS). Soil samples were collected at the layer of 0-5 cm depth and quantified the total organic carbon (TOC), C of humic substances, oxidizable C, granulometric fractions of soil organic matter (SOM), soil chemical attributes, soil aggregation and glomalin-related soil protein (GRSP-total and GRSP-easily extractable) in different aggregate classes. It was observed a reduction of the TOC, particulate organic carbon (POC), humic substances and oxidizable C in the PAg and ACr areas comparing to pasture and forest systems. Moreover, the pH values increased whereas P content decreased in comparison with SFAS. As for aggregation, the PAg and the ACr decreased by around 35% and 20% the mean weight diameter of aggregates, respectively, compared to the average values found in the forestry systems, and 34% and 45%, respectively in relation to pasture. In general, GRSP-total were reduced by agriculture. Thus, it appears that the agriculture which has been practiced is altering negatively the soil chemical, physical and biological attributes.

scholarly journals CHARACTERIZATION OF BIOGENIC, INTERMEDIATE AND PHYSICOGENIC SOIL AGGREGATES OF AREAS IN THE BRAZILIAN ATLANTIC FOREST

2017 ◽  
Vol 30 (1) ◽  
pp. 59-67 ◽  
Author(s):  
JÚLIO CÉSAR FEITOSA FERNANDES ◽  
◽  
MARCOS GERVASIO PEREIRA ◽  
EDUARDO CARVALHO DA SILVA NETO ◽  
THAÍS DE ANDRADE CORRÊA NETO
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Humic Substances ◽  
Soil Quality ◽  
Secondary Forest ◽  
Soil Aggregates ◽  
Geometric Mean ◽  
Mean Weight Diameter ◽  
Successional Stages ◽  
The Stability

ABSTRACT Aggregate formation and stability are related to soil quality, contributing significantly to the carbon storage and nutrient maintenance capacities of the soil. Soil aggregates are formed by two different process: physicogenic, related to moistening and drying cycles and input of organic matter; and biogenic, related to the action of macrofauna organisms and roots. The objective this work was to classify aggregates according to their formation process, quantify and compare organic carbon contents in humic substances and assess the stability of aggregates formed by different processes, in areas with different coverage in the Mid Paraiba Valley, Pinheiral, State of Rio de Janeiro, Brazil. Aggregated soil samples were collected at a depth of 0-10 cm, in a Cambisol (Cambissolo Háplico Tb Distrófico) under four plant covers: secondary forest in advanced (SFAS), medium (SFMS) and initial (SFIS) successional stages and managed mixed pasture (MMP). Aggregates were classified and identified into three morphological classes (physicogenic, biogenic and intermediate). The variables evaluated were mean weight diameter (MWD) and geometric mean diameter (GMD) of aggregates, chemical fractions of organic matter, total organic carbon (TOC) and humic substances: humin (C-HUM) humic acid (C-FAH) and fulvic acid (C-FAF). Biogenic aggregates were found in smaller quantities and showed higher TOC, C-HUM and C-FAH, compared to intermediate and physicogenic aggregates. Thus, biogenic aggregates have potential to be used as soil quality indicators for structured environments, which are able to maintain its intrinsic formation processes.

scholarly journals Chemical and physical fractions of soil organic matter under various management regimes in Roraima, Brazil

2017 ◽  
Vol 38 (4Supl1) ◽  
pp. 2419
Author(s):  
Marden Daniel Espinoza Guardiola ◽  
José Frutuoso Vale Júnior ◽  
Edmilson Evangelista da Silva ◽  
Celeste Queiroz Rossi ◽  
Marcos Gervasio Pereira
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Chemical Elements ◽  
The Other ◽  
Management Systems ◽  
Natural Fertility ◽  
Chemical Attributes ◽  
Pasture Area ◽  
Physical And Chemical

The crop-livestock integration (CLI) and crop-livestock-forest integration (CLFI) management systems, have been shown to be viable approaches for increasing carbon sequestration in soils, resulting in the improvement of physical and chemical soil attributes. The objective of this study was to evaluate the chemical attributes and organic matter in soils under Natural Forest (NF) converted to different uses and managed differently: rotational pasture area (PAST), crop-livestock integration (CLI), and crop-livestock-forest integration (CLIF). The research was conducted at the São Paulo farm, in Iracema, located in the south-central region of the state of Roraima, Brazil. The studied soil type was classified as Ultisol. Soil samples were taken by opening ditches and examining layers at 0.1-m depth intervals from surface to 0.60-m depth. Total organic carbon (TOC), chemical and granulometric fractionation of soil organic matter (SOM), oxidizable fractions, and light organic matter in water were analyzed. Our results showed low levels of the analyzed chemical elements, a characteristic of a soil with low natural fertility. This matches conditions inherent in source material, weathered by high rainfall, a warm and humid climate, and flat topographic relief. In the 0-0.1 m layer, the PAST and CLI systems had the highest TOC contents relative to the other systems studied. At other depths, there were no statistical differences among TOC levels. The highest concentration of C in the particulate fraction (POC) was noted in the surface layer in all management systems. The pasture system had the highest concentration POC in the top 0.10 m. Our results also showed that the upper 0.10 m of soil in NF contained the lowest content of organic carbon associated with mineral (MOC) relative to the managed agrosystems. In addition, humin provided the largest contribution to SOM in all evaluated management systems. The crop-livestock integration (CLI) and crop-livestock integration forest (CLIF) systems, emerged as a strong alternative to carbon incorporation and subsequently the improvement of physical and chemical soil attributes. The objective of this work to evaluate the chemical attributes and organic matter in soils under Natural forest (NF) converted into different use and management systems: pasture (PAST), crop-livestock Integration (CLI) and crop-livestock Integration forest (CLIF). The research was conducted at São Paulo farm in Iracema, located in the Center-South region of the State of Roraima, Brazil. The soil studied was classified as Argissolo Amarelo Distrófico. The samples were taken by the opening of trenches in layers of 0-0.10, 0.10- 0.20, 0.20- 0.40, and 0.40-0.60 m depth. Total organic carbon (TOC), chemical and granulometric fractionation of soil organic matter (SOM), oxidizable fractions and organic matter in water were analyzed. The results showed low levels of the analyzed chemical elements which characterizes soils with low natural fertility, which matches the conditions of the source material, high rainfall and regional temperature, as well as the flat local relief. In the 0-0.1 m layer, the PAST and CLI systems had the highest TOC contents when compared to the other systems studied, in the other depths there were no statistical differences between the TOC levels. The highest amount of C in the particulate fraction (COp) was verified in the surface layer in all evaluated management systems. The pasture area was the system with the greatest contribution of COp to the depth of 0-0.0 m. In relation to the carbon content associated with minerals (COam), the results showed that the depth of 0-0.05 m NF area presented the lowest levels when compared to the other systems. Regarding the humic substances, there was a larger contribution of humin in all evaluated systems.

scholarly journals Short-Term Changes in Fertility Attributes and Soil Organic Matter Caused by the Addition of EM Bokashis in Two Tropical Soils

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Carlos Eduardo Pacheco Lima ◽  
Mariana Rodrigues Fontenelle ◽  
Luciana Rodrigues Borba Silva ◽  
Daiane Costa Soares ◽  
Antônio Williams Moita ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Poultry Manure ◽  
Principal Component ◽  
Tropical Soils ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Chemical Attributes

The present work aimed to evaluate the behavior of ten fertility attributes of soil organic matter physical fractions and total organic carbon upon addition of three EM Bokashis to a Rhodic Ferralsol (FRr) and a Dystric Cambisol (CMd). An experiment was carried out in greenhouse in which the soils were placed into plastic trays and cultivated with tomato. A completely randomized design was used with four repetitions and factorial scheme of 2 × 3 + 2, consisting of two soils (FRr and CMd), three EM Bokashis (Poultry Manure Bokashi (BPM); CNPH Bokashi (BC); and Cattle Manure Bokashi (BCM)), and two controls (both soils without addition of Bokashi). The following fertility attributes were evaluated: pH, Ca2+, Mg2+, K+, Na+, P, SB, H + Al, CEC, andV. Particulate organic carbon (POC) and mineral-associated organic carbon (MOC) and total organic carbon (TOC) were also investigated. Finally, the Principal Component Analysis was conducted in order to identify possible patterns related to soils when fertilized with EM Bokashi. The addition of EM Bokashi increased the soil fertility and contents of POC. Different EM Bokashi presents distinguished effects on each soil. The PCA suggests that BPM presents higher capacity to modify the analyzed chemical attributes.

scholarly journals Soil fertility, organic carbon and fractions of the organic matter at different distances from eucalyptus stumps

2009 ◽  
Vol 33 (3) ◽  
pp. 571-579 ◽  
Author(s):  
Geraldo Erli Faria ◽  
Nairam Félix de Barros ◽  
Roberto Ferreira Novais ◽  
Ivo Ribeiro Silva
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Soil Layer ◽  
Chemical Properties ◽  
Soil Surface ◽  
Light Fraction ◽  
Forest Residues ◽  
Chemical Attributes ◽  
Topsoil Layer

Knowledge on variations in vertical, horizontal and temporal characteristics of the soil chemical properties under eucalyptus stumps left in the soil is of fundamental importance for the management of subsequent crops. The objective of this work was to evaluate the effect of eucalyptus stumps (ES) left after cutting on the spatial variability of chemical characteristics in a dystrophic Yellow Argisol in the eastern coastal plain region of Brazil. For this purpose, ES left for 31 and 54 months were selected in two experimental areas with similar characteristics, to assess the decomposition effects of the stumps on soil chemical attributes. Soil samples were collected directly around these ES, and at distances of 30, 60, 90, 120 and 150 cm away from them, in the layers 0-10, 10-20 and 20-40 cm along the row of ES, which is in-between the rows of eucalyptus trees of a new plantation, grown at a spacing of 3 x 3 m. The soil was sampled in five replications in plots of 900 m² each and the samples analyzed for pH, available P and K (Mehlich-1), exchangeable Al, Ca and Mg, total organic carbon (TOC) and C content in humic substances (HS) and in the free light fraction. The pH values and P, K, Ca2+, Mg2+ and Al3+ contents varied between the soil layers with increasing distance from the 31 and 54-monthold stumps. The highest pH, P, K, Ca2+ and Mg2+ values and the lowest Al3+ content were found in the surface soil layer. The TOC of the various fractions of soil organic matter decreased with increasing distance from the 31 and 54-month-old ES in the 0-10 and 10-20 cm layers, indicating that the root (and stump) cycling and rhizodeposition contribute to maintain soil organic matter. The C contents of the free light fraction, of the HS and TOC fractions were higher in the topsoil layer under the ES left for 31 months due to the higher clay levels of this layer, than in those found under the 54-month-old stumps. However, highest C levels of the different fractions of soil organic matter in the topsoil layer reflect the deposition and maintenance of forest residues on the soil surface, mainly after forest harvest.

scholarly journals HUMIFIED FRACTION OF ORGANIC MATTER DUE TO PLANT MIXTURE CULTIVATION

2016 ◽  
Vol 29 (3) ◽  
pp. 578-586
Author(s):  
TONY JARBAS FERREIRA CUNHA ◽  
VANDERLISE GIONGO ◽  
ALESSANDRA MONTEIRO SALVIANO ◽  
FLÁVIO ADRIANO MARQUES ◽  
LUCIANO PASQUALOTO CANELLAS
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Humic Substances ◽  
Green Manure ◽  
Mangifera Indica ◽  
Leguminous Species ◽  
Plant Mixture ◽  
Spontaneous Vegetation ◽  
Humic Fraction

ABSTRACT - The aim of this study was to assess the organic matter changes in quantity and quality, particularly of the humic fraction in the surface layer (0-20 cm), of a Typic Plinthustalf soil under different management of plant mixtures used as green manure for mango (Mangifera indica L.) crops. The plant mixtures, which were seeded between rows of mango trees, were formed by two groups of leguminous and non -leguminous plants. Prior to sowing, seeds were combined in different proportions and compositions constituting the following treatments: 100% non-leguminous species (NL); 100% leguminous species (L); 75% L and 25% NL; 50% L and 50% NL; 25% L and 75% NL; and 100% spontaneous vegetation, considered a control. The plant mixtures that grew between rows of mango trees caused changes in the chemical composition of the soil organic matter, especially for the treatments 50% L and 50% NL and 25% L and 75% NL, which increased the content of humic substances in the soil organic matter. However, the treatment 25% L and 75% NL was best at minimising loss of total organic carbon from the soil. The humic acids studied have mostly aliphatic characteristics, showing large amounts of carboxylic and nitrogen groups and indicating that most of the organic carbon was formed by humic substances, with fulvic acid dominating among the alkali soluble fractions.

scholarly journals Assessing soil carbon and soil quality for sustainable agricultural systems in tropical hillslope soils using spectroscopic methods

2017 ◽  
Author(s):  
◽  
Bunjirtluk Jintaridth
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Quality ◽  
Management Practices ◽  
Soil Management ◽  
Agricultural Systems ◽  
Wide Range ◽  
The World

Soil quality is a concept that integrates physical, chemical, and biological components and processes of soil across landscapes. Identifying and developing appropriate methods to quantify and assess changes in soil quality are necessary for evaluating soil degradation and improving management practices. Many parameters that are associated with soil quality depend on soil organic matter (SOM) levels and composition. The objectives of this research were to: 1) conduct a literature review of soil quality assessment techniques to evaluate soil quality across a wide-range of environments and agricultural practices; 2) determine if some standard soil sampling and analytical protocols could be identified or developed to enhance soil quality comparisons across a wide range of environments around the world; and 3) assess the efficacy of spectroscopic-based (i.e. near-infrared, mid-infrared, and visible range) analytical methods to evaluate soil organic matter fractions and soil quality. To assess soil quality for sustainable agricultural systems in hillslope soils using spectroscopic methods, surface soil samples (0-20 cm) were collected from hillslope agricultural sites in Bolivia, the Philippines and Indonesia which had differences in length of fallow, levels of soil degradation, and cultivation by landscape position. To determine the efficacy of spectroscopic-based on visible range, the use of the potassium permanganate test (MnOxC) for active organic carbon was studied. The MnOxC test was generally responsive to a range of fallow lengths among different agricultural fields and communities in Umala Municipality in Bolivia. A major objective of fallowing agricultural fields in this region is to restore soil fertility in the field after cropping. This general increase in MnOxC with increased length fallowing may be due to inputs of residue and roots from regrowth of native vegetation after cropping in fallowed areas and possible manure inputs from sheep that generally graze these fallow areas. In addition, higher concentrations of MnOxC were generally observed in non-degraded soil compared to that of degraded soil in all sampled communities in Cochabamba, Bolivia. Comparisons of soil quality among agroforestry and nonagroforestry sites were studied near Bogor, Indonesia. Both agroforestry and nonagroforestry sites had been managed with different types and rates (low, medium, and high) of amendments including manure, compost and chemical fertilizer. Soil MnOxC was generally higher with increasing amounts of added animal manure and in agroforestry areas compared to that of non-agroforestry areas. A set of soil samples was collected along a hill-slope transect from the top to the bottom of agricultural valley on Mindanao Island in the Philippines. The transect across the landscape was divided into summit, shoulder, backslope, footslope and toeslope landscape positions. Soil MnOxC from cultivated fields areas at each landscape position were generally lower than noncultivated areas at similar landscape positions. Among the non-cultivated sites, soil MnOxC was the highest at the summit position and the lowest at the backslope positions while soil MnOxC among cultivated sites were relatively similar across the hill-slope transect. This comparison of the use of the soil MnOxC test to determine changes in active C among a wide range of environmental conditions, cropping systems and soil management practices among agroecosystems with hillslopes in tropical countries around the world indicates that the soil MnOxC test is a sensitive indicator to assess changes in active C with changes in crop and soil management. Several advantages to using this procedure include its ease of use that requires a minimal of training for the field method, its low relative cost and growing research results that facilitate interpretation of the test results. Therefore, this method has potential for supporting management decisions, and sustainable management of agricultural systems in tropical hillslope ecosystems. The ability of visible/near-infrared (VNIR) spectroscopy to estimate soil organic carbon and carbon fractions from diverse soils in tropical hillslope agroecosystems around the world that were under different soil management and cropping systems was evaluated in this research. It was shown that VNIR spectroscopy could be an effective technique to estimate SOC and soil organic carbon fractions for a wide range of soils from tropical hillslope agroecosystems around the world. Several potential advantages of use of VNIR compared to conventional soil testing methods in developing countries are that it may allow for simultaneous evaluation of several soil properties and it can be done rapidly and possibly in the field. Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFT) is considered to be one of the most sensitive infrared techniques for analyzing the structural composition of soil organic matter. The benefit of the DRIFT technique is the ability to characterize the functional group composition of heterogeneous materials with minimal sample preparation. Results showed that this method can be used to characterize the functional groups of heterogeneous soil organic materials and it may be a more direct method to determine changes in soil organic matter and soil quality caused by soil management practices than several other chemical and spectral techniques. The high resolution of the spectra and quantitative estimations of functional groups can be used to analyze soil organic carbon composition. Therefore, in future work this technique has great potential to be an accurate and simple method for helping to understand the changes in the composition of soil organic carbon due to soil organic management practices and to estimate changes in soil quality resulting from those practices in these hillslope agroecosystems.

scholarly journals Chemical and physical fractions of soil organic matter under various management regimes in Roraima, Brazil

2017 ◽  
Vol 38 (4Supl1) ◽  
pp. 2419
Author(s):  
Marden Daniel Espinoza Guardiola ◽  
José Frutuoso Vale Júnior ◽  
Edmilson Evangelista da Silva ◽  
Celeste Queiroz Rossi ◽  
Marcos Gervasio Pereira
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Chemical Elements ◽  
The Other ◽  
Management Systems ◽  
Natural Fertility ◽  
Chemical Attributes ◽  
Pasture Area ◽  
Physical And Chemical

The crop-livestock integration (CLI) and crop-livestock-forest integration (CLFI) management systems, have been shown to be viable approaches for increasing carbon sequestration in soils, resulting in the improvement of physical and chemical soil attributes. The objective of this study was to evaluate the chemical attributes and organic matter in soils under Natural Forest (NF) converted to different uses and managed differently: rotational pasture area (PAST), crop-livestock integration (CLI), and crop-livestock-forest integration (CLIF). The research was conducted at the São Paulo farm, in Iracema, located in the south-central region of the state of Roraima, Brazil. The studied soil type was classified as Ultisol. Soil samples were taken by opening ditches and examining layers at 0.1-m depth intervals from surface to 0.60-m depth. Total organic carbon (TOC), chemical and granulometric fractionation of soil organic matter (SOM), oxidizable fractions, and light organic matter in water were analyzed. Our results showed low levels of the analyzed chemical elements, a characteristic of a soil with low natural fertility. This matches conditions inherent in source material, weathered by high rainfall, a warm and humid climate, and flat topographic relief. In the 0-0.1 m layer, the PAST and CLI systems had the highest TOC contents relative to the other systems studied. At other depths, there were no statistical differences among TOC levels. The highest concentration of C in the particulate fraction (POC) was noted in the surface layer in all management systems. The pasture system had the highest concentration POC in the top 0.10 m. Our results also showed that the upper 0.10 m of soil in NF contained the lowest content of organic carbon associated with mineral (MOC) relative to the managed agrosystems. In addition, humin provided the largest contribution to SOM in all evaluated management systems. The crop-livestock integration (CLI) and crop-livestock integration forest (CLIF) systems, emerged as a strong alternative to carbon incorporation and subsequently the improvement of physical and chemical soil attributes. The objective of this work to evaluate the chemical attributes and organic matter in soils under Natural forest (NF) converted into different use and management systems: pasture (PAST), crop-livestock Integration (CLI) and crop-livestock Integration forest (CLIF). The research was conducted at São Paulo farm in Iracema, located in the Center-South region of the State of Roraima, Brazil. The soil studied was classified as Argissolo Amarelo Distrófico. The samples were taken by the opening of trenches in layers of 0-0.10, 0.10- 0.20, 0.20- 0.40, and 0.40-0.60 m depth. Total organic carbon (TOC), chemical and granulometric fractionation of soil organic matter (SOM), oxidizable fractions and organic matter in water were analyzed. The results showed low levels of the analyzed chemical elements which characterizes soils with low natural fertility, which matches the conditions of the source material, high rainfall and regional temperature, as well as the flat local relief. In the 0-0.1 m layer, the PAST and CLI systems had the highest TOC contents when compared to the other systems studied, in the other depths there were no statistical differences between the TOC levels. The highest amount of C in the particulate fraction (COp) was verified in the surface layer in all evaluated management systems. The pasture area was the system with the greatest contribution of COp to the depth of 0-0.0 m. In relation to the carbon content associated with minerals (COam), the results showed that the depth of 0-0.05 m NF area presented the lowest levels when compared to the other systems. Regarding the humic substances, there was a larger contribution of humin in all evaluated systems.

Soil Organic Matter Fractions and Enzymes Activities under No-tillage System: Effects of Organomineral and Mineral Fertilizer with Humic Substances

2021 ◽  
pp. 1-13
Author(s):  
Rafael Felippe Ratke ◽  
Marcela Christovam Bertechini ◽  
Cícero Célio De Figueiredo ◽  
Adriana Miranda De Santana Arauco ◽  
Bruno De Oliveira Dias ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Substances ◽  
Mineral Fertilizer ◽  
No Tillage ◽  
Soil Organic Matter Fractions ◽  
Enzymes Activities ◽  
Tillage System ◽  
Organic Matter Fractions

scholarly journals Podzolisation affects the spatial allocation and chemical composition of soil organic matter fractions

Soil Research ◽  
2020 ◽  
Vol 58 (8) ◽  
pp. 713
Author(s):  
Agnes Krettek ◽  
Ludger Herrmann ◽  
Thilo Rennert
Keyword(s):  
Organic Matter ◽  
Infrared Spectroscopy ◽  
Chemical Composition ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Spatial Allocation ◽  
Organic Matter Fractions ◽  
Som Decomposition

Podzols are soils that display a unique vertical distribution of soil organic matter (SOM). We hypothesise that podzolisation, as a pedogenetic process, influences or even controls content, allocation and quality of SOM. We determined soil organic carbon (SOC) and nitrogen (N) contents in six SOM fractions obtained from mineral horizons of five soils with increasing degree of podzolisation: sand and stable aggregates (S + A), particulate organic matter (POM) > 63 µm and <63 µm, silt and clay (s + c), resistant SOC and dissolved organic matter. We applied infrared spectroscopy to evaluate SOM decomposition state, relative abundance of functional groups and SOM-metal complexation. In topsoil horizons, relative SOC allocation shifted from the larger to the smaller size POM fraction with increasing podzolisation. Accompanied with size reduction, the POM < 63 µm fraction was progressively less decomposed, as derived from infrared spectroscopy and C:N ratios. In illuvial subsoils, the proportion of SOC in the S + A fraction increased with increasing podzolisation, implying SOM accumulation in aggregates and coatings on sand grains. Elevated abundance of carboxylate and aromatic C in the s + c fractions of subsoil horizons indicated their preferred sorption. Additionally, metal-carboxyl complexation increased during podzolisation.

Effect of long-term cultivation on soil organic carbon fractions and metal distribution in humic and fulvic acid in black soil, Northeast China

Soil Research ◽  
2012 ◽  
Vol 50 (7) ◽  
pp. 562 ◽  
Author(s):  
C. Y. Sun ◽  
J. S. Liu ◽  
Y. Wang ◽  
N. Zheng ◽  
X. Q. Wu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Fulvic Acid ◽  
Humic Substances ◽  
Binding Capacity ◽  
Black Soil ◽  
Systematic Change

Cultivation affects soil organic matter and its fractions. Fulvic acid (FA) and humic acid (HA) make up an important part of soil organic matter, and their binding capacity influences heavy metal behaviour in soil. This research studied changes in soil organic components and the distribution of copper (Cu), lead (Pb), and zinc (Zn) in HA and FA affected by long-term cultivation in black soils. Uncultivated sites and their adjacent cultivated sites (18, 50, and >200 years) were selected. Alkaline sodium hydroxide/pyrophosphate extraction of humic substances and precipitation of HA by acidification were used to separate the HA and FA fractions. Concentrations of Cu, Pb, and Zn in HA and FA were determined. The content of soil organic carbon (C) had decreased by 30% after 200 years of cultivation. Cultivation led to a moderate decrease (38%) in HA and a minor decrease (7%) in FA. The CHA/CFA ratio, which is a humification parameter, decreased from 2.05 in the uncultivated soil to 1.38 in the soil cultivated for 200 years, indicating a lower degree of humification of organic matter in cultivated soils. Of the Na4P2O7 + NaOH-extracted Pb and Zn, 47–60% and 63–76%, respectively, was associated with FA, showing that FA has a high affinity for Pb and Zn. Of the Na4P2O7 + NaOH-extracted Cu, 55% was in the HA fraction. The share of Cu and Zn in the HA fraction decreased with cultivation time, but cultivation did not bring about a systematic change in Pb distribution in humic substances. The results show that cultivation can decrease the humified C content and metals bound to the HA fraction, and suggest that cultivation may potentially increase the mobility of heavy metals.

Sign in / Sign up

Export Citation Format

Share Document