Organic Carbon and Nitrogen stocks in two soil types of Northwestern Tunisia: Temporal and spatial variation

2020 ◽  
Author(s):  
Ahlem Tlili ◽  
Imene Dridi ◽  
Moncef Gueddari
Keyword(s):  
Organic Matter ◽  
Global Warming ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Experimental Period ◽  
North West ◽  
Carbon And Nitrogen ◽  
Forest Region ◽  
Nitrogen Sequestration ◽  
Deep Horizon

<p>Soil organic matter has generated international interest in carbon and nitrogen sequestration. In reality, small fluctuations of soil organic stock could have large impacts on global warming. Therefore, quantification of Soil Organic Carbon (SOCs) and Total Nitrogen (TNs) stocks in surface and deep horizons are important to control the release of greenhouse gases. The present research was undertaken in order to determine SOCs and TNs evolution over 50 years. For this aim, we selected two soils (P1 and P2) developed under contrasted pedogenetic conditions in North-West of Tunisia (Beja governorate). P1 is a Luvisol located in a forest region. However, P2 is a Cambisol situated in an agriculture zone. Soil samples were gathered from surface (0-30 cm) and deep (50-100 cm) horizons in 1971, 2005, 2012 and 2019. SOCs declined in surface and deep horizons during the experimental period in both studied soils. In the case of Luvisol, the values declined from 91.01 t/ha to 75.54 t/ha and from 53.00 t/ha to 24.51 t/ha, respectively in surface horizons and deep horizons. Likewise, the SOCs values decreased from 84.24 t/ha to 25.52 t/ha in surface horizons and from 24.45 t/ha to 14.20 t/ha in deep horizons of the Cambisol. The TNs recorded lower values than SOCs. Nevertheless, they showed the same behavior. Our results showed that the highest values of SOCs and TNs were recorded in the Luvisol. This soil exhibited the greatest amount of organic matter since it was developed under forest vegetation. In addition, the results showed an enrichment in SOCs and TNs of superficial horizons to the detriment of the deep horizons. Nevertheless, this decrease in organic stocks with depth occurred following different patterns according to soil type. In fact, the Cambisol reported an important depletion of soil organic stocks as compared to the Luvisol. The loss of SOCs and TNs were estimated to be 69.71% and 54.17% in surface horizon, and 41.94 % and 28.28 % in deep horizon, respectively. Indeed, the land-use change increases the decomposition of soil organic matter principal source of SOCs and TNs. Such a reduction has wider implications on global warming and soil fertility.  </p>

Soil organic carbon and nitrogen sequestration and turnover in aggregates under subtropical leucaena–grass pastures

Soil Research ◽  
2018 ◽  
Vol 56 (6) ◽  
pp. 632 ◽  
Author(s):  
Kathryn Conrad ◽  
Ram C. Dalal ◽  
Ryosuke Fujinuma ◽  
Neal W. Menzies
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Soil Mass ◽  
Δ13c And Δ15n ◽  
Organic C ◽  
Carbon And Nitrogen ◽  
Nitrogen Sequestration ◽  
C And N

Stabilisation and protection of soil organic carbon (SOC) in macroaggregates and microaggregates represents an important mechanism for the sequestration of SOC. Legume-based grass pastures have the potential to contribute to aggregate formation and stabilisation, thereby leading to SOC sequestration. However, there is limited research on the C and N dynamics of soil organic matter (SOM) fractions in deep-rooted legume leucaena (Leucaena leucocephala)–grass pastures. We assessed the potential of leucaena to sequester carbon (C) and nitrogen (N) in soil aggregates by estimating the origin, quantity and distribution in the soil profile. We utilised a chronosequence (0–40 years) of seasonally grazed leucaena stands (3–6 m rows), which were sampled to a depth of 0.3 m at 0.1-m intervals. The soil was wet-sieved for different aggregate sizes (large macroaggregates, >2000 µm; small macroaggregates, 250–2000 µm; microaggregates, 53–250 µm; and <53 µm), including occluded particulate organic matter (oPOM) within macroaggregates (>250 µm), and then analysed for organic C, N and δ13C and δ15N. Leucaena promoted aggregation, which increased with the age of the leucaena stands, and in particular the formation of large macroaggregates compared with grass in the upper 0.2 m. Macroaggregates contained a greater SOC stock than microaggregates, principally as a function of the soil mass distribution. The oPOM-C and -N concentrations were highest in macroaggregates at all depths. The acid nonhydrolysable C and N distribution (recalcitrant SOM) provided no clear distinction in stabilisation of SOM between pastures. Leucaena- and possibly other legume-based grass pastures have potential to sequester SOC through stabilisation and protection of oPOM within macroaggregates in soil.

Studies on soil organic matter: Part III. The extraction of organic carbon and nitrogen from soil

1949 ◽  
Vol 39 (3) ◽  
pp. 280-282 ◽  
Author(s):  
J. M. Bremner
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Organic Nitrogen ◽  
Carbon And Nitrogen

A study has been made of the extraction of organic carbon and nitrogen from soil by various inorganic reagents. The results show that the organic carbon and nitrogen of soil are so intimately associated that, under the influence of any one of the reagents tested, the organic carbon is dissolved only along with, and in proportion to, the organic nitrogen. The relative proportions of carbon and nitrogen extracted vary, however, with both the soil and the extractant.

The Carbon-Nitrogen Ratio of Soil Organic Matter

1930 ◽  
Vol 20 (3) ◽  
pp. 348-354 ◽  
Author(s):  
W. McLean
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Arable Soils ◽  
Grassland Soils ◽  
Carbon And Nitrogen ◽  
Carbon Nitrogen Ratio ◽  
Nitrogen Ratio ◽  
Soil Climate ◽  
Range Of Variation

1. The average carbon-nitrogen ratio for fifty British soils from widely distributed areas approximates to the figure 10: 1 given by other investigators. The range of variation is from 6·5 to 13·5: 1. Sixteen foreign samples gave C/N ratios varying from 2·0 to 23·0: 1.2. Soils from limited areas, whether high or low in organic carbon, give approximately constant ratios, but these ratios vary from place to place according to soil, climate, etc. It is suggested that the C/N ratios may be specific.3. The C/N ratios of arable soils do not differ appreciably from those of grassland soils. The percentages of carbon and nitrogen are somewhat higher in the grassland samples than in the arable samples.

scholarly journals Combined Use of Carbon and Nitrogen Isotopes for Assessment of Soil Organic Matter Sources and Decomposition in a Typical Karst Area of Yunnan–Guizhou Plateau, Southwestern China

2021 ◽  
Author(s):  
Howard Omar Beckford ◽  
Changshun SONG ◽  
Cheng CHANG ◽  
Hongbing JI
Keyword(s):  
Organic Matter ◽  
Carbon Sequestration ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Nitrogen Isotopes ◽  
Karst Area ◽  
Soil Profiles ◽  
Carbon And Nitrogen ◽  
Karst Soil ◽  
Guizhou Plateau

Abstract Soil organic matter (SOM) has substantial influence on geochemical cycle, soil stability and global climate change, however total organic carbon sequestration mechanisms in karst soil remain poorly understood. For this study we assess, total organic content (TOC), total nitrogen (TN), C/N ratio and isotopes of carbon and nitrogen in four soil profiles over critical karst area to investigate organic matter source, mechanisms that influence fractionation and factors affecting SOM in Yunnan–Guizhou Plateau, Southwestern China. The results revealed that SOM comprised of mixed sources derived from both exogenous and endogenous materials. The soil profiles indicate intense vertical variation in δ13C and δ15N with an increase in both isotopes in the upper layers, deceased in δ13C below 20 cm and irregular fluctuation in δ15N with depth. Mechanisms such as mineralization and selective preservation influence isotopic fractionation in the upper soil surface, while translocation, nitrification and denitrification dominated the subsoil layers. Variation in TOC, TN and stable carbon and nitrogen isotopes were influence by vegetation cover, topography, soil water and external contribution. Moreover, the decrease in TOC and TN with depth were due to downward translocation of dissolved organic carbon and nitrogen caused by monsoon climate. Our results revealed that combination of TOC, TN, C/N, δ13C and δ15N can be used as proxy to decipher SOM source, external influence and stability of karst soils. Furthermore, the intense change in δ13C and δ15N throughout the soil profiles suggest that this karst soil is unstable which have implications for land management and carbon sequestration.

Linking soil organic matter thermal stability with contents of clay, bound water, organic carbon and nitrogen

Geoderma ◽  
2018 ◽  
Vol 316 ◽  
pp. 38-46 ◽  
Author(s):  
Jiří Kučerík ◽  
David Tokarski ◽  
Michael Scott Demyan ◽  
Ines Merbach ◽  
Christian Siewert
Keyword(s):  
Thermal Stability ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Bound Water ◽  
Carbon And Nitrogen

Soil organic matter formation is controlled by the chemistry and bioavailability of organic carbon inputs across different land uses

2021 ◽  
Vol 770 ◽  
pp. 145307
Author(s):  
Mohammad Bahadori ◽  
Chengrong Chen ◽  
Stephen Lewis ◽  
Sue Boyd ◽  
Mehran Rezaei Rashti ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Land Uses ◽  
Soil Organic Matter Formation

scholarly journals Microbiological properties and oxidizable organic carbon fractions of an oxisol under coffee with split phosphorus applications and irrigation regimes

2013 ◽  
Vol 37 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Adriana Rodolfo da Costa ◽  
Juliana Hiromi Sato ◽  
Maria Lucrécia Gerosa Ramos ◽  
Cícero Célio de Figueiredo ◽  
Géssica Pereira de Souza ◽  
...  
Keyword(s):  
Organic Matter ◽  
Acid Phosphatase ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Microbial Biomass Carbon ◽  
Block Design ◽  
Phosphorus Fertilization ◽  
Carbon Fractions ◽  
Irrigation Regimes ◽  
Organic Carbon Fractions

Phosphorus fertilization and irrigation increase coffee production, but little is known about the effect of these practices on soil organic matter and soil microbiota in the Cerrado. The objective of this study was to evaluate the microbiological and oxidizable organic carbon fractions of a dystrophic Red Latossol under coffee and split phosphorus (P) applications and different irrigation regimes. The experiment was arranged in a randomized block design in a 3 x 2 factorial design with three split P applications (P1: 300 kg ha-1 P2O5, recommended for the crop year, of which two thirds were applied in September and the third part in December; P2: 600 kg ha-1 P2O5, applied at planting and then every two years, and P3: 1,800 kg ha-1 P2O5, the requirement for six years, applied at once at planting), two irrigation regimes (rainfed and year-round irrigation), with three replications. The layers 0-5 and 5-10 cm were sampled to determine microbial biomass carbon (MBC), basal respiration (BR), enzyme activity of acid phosphatase, the oxidizable organic carbon fractions (F1, F2, F3, and F4), and total organic carbon (TOC). The irrigation regimes increased the levels of MBC, microbial activity and acid phosphatase, TOC and oxidizable fractions of soil organic matter under coffee. In general, the form of dividing P had little influence on the soil microbial properties and OC. Only P3 under irrigation increased the levels of MBC and acid phosphatase activity.

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