Ratio of microbial biomass carbon to soil organic carbon as a sensitive indicator of changes in soil organic matter

Soil Research ◽  
1992 ◽  
Vol 30 (2) ◽  
pp. 195 ◽  
Author(s):  
GP Sparling
Keyword(s):  
Organic Matter ◽  
New Zealand ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Microbial Biomass Carbon ◽  
Native Forest ◽  
Soil Biol ◽  
Microbial Carbon ◽  
The Relationship

The sensitivity of soil organic carbon (Corg) and microbial carbon (Cmic) measurements, and the Cm~,/Co,, ratio, to reflect climatic, vegetation, cropping and management history was investigated using a range of topsoils in New Zealand. The Cmic generally comprised 1-4% of Corg, with the proportion being consistently greater under pastures, than the equivalent soil under native forest, exotic forest or arable cropping. However, absolute values differed markedly between soils and were greatly influenced by texture, mineralogy and the Corg content. The Cmic recovered more rapidly than Corg on returning to pasture following cropping. There was a generally greater Corg content in those soils from the areas with higher precipitation, but the precipitation-evaporation quotient proposed by Insam et al. (Soil Biol. Biochem. 1989, 21, 211-21) to predict the relationship between Cmic and Corg, greatly underestimated the Cmic content of New Zealand soils and there was too great a scatter in the data to derive a revised regression formula. The Cmic and the Cmic/Cor, ratio are useful measures to monitor soil organic matter and both provide a more sensitive index than COrg measured alone. However, under typical climatic and land use conditions in New Zealand, the values do not appear readily transferrable between soils. To ascertain whether a soil has achieved equilibrium in organic matter status, it will be necessary to establish reference values to which a tested soil can be compared.

scholarly journals Ratio of soil microbial biomass carbon to soil organic carbon in Himalayan rangeland

2018 ◽  
Vol 2 ◽  
pp. 96-101
Author(s):  
Dil Kumar Limbu ◽  
Madan Koirala
Keyword(s):  
Organic Matter ◽  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Microbial Biomass ◽  
Microbial Biomass Carbon ◽  
Biomass Carbon ◽  
Soil Microbial ◽  
Soil Microbial Biomass Carbon ◽  
Microbial Carbon

The soil microbial biomass carbon to soil organic carbon ratio is a useful measure to monitor soil organic matter and serves as a sensitive index than soil organic carbon alone. Thus, the objective of this study is to identify and quantify the present status of ratio of soil microbial biomass carbon to soil organic carbon in Himalayan rangeland and to make recommendations for enhancing balance between microbial carbon and organic carbon of the soil. To meet the aforementioned objective, a field study was conducted from 2011 to 2013 following the Walkley-Black, Chromic acid wet oxidation method, and chloroform fumigation method for analysis of microbial carbon and organic carbon respectively. The study showed that the heavily grazed plot had significantly less value of ratio than occasionally grazed and ungrazed plots. The ratio was significantly high on legume seeding plot compared to nonlegume plot, but the ratio was independent of soil depth. Soil microbial biomass appeared to be more responsive than soil organic matter.

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.

scholarly journals ORGANIC MATTER LABILE FRACTIONS AND CARBON STOCKS IN A TYPIC QUARTZIPSAMMENT CULTIVATED WITH SUGARCANE HARVESTED WITHOUT BURNING

2017 ◽  
Vol 30 (1) ◽  
pp. 24-31 ◽  
Author(s):  
JOSÉ DE SOUZA OLIVEIRA FILHO ◽  
◽  
MARCOS GERVASIO PEREIRA ◽  
BOANERGES FREIRE DE AQUINO ◽  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Carbon Stocks ◽  
Native Forest ◽  
Soil Organic Matter Dynamics ◽  
Sugarcane Crop ◽  
Organic Matter Dynamics ◽  
Straw Burning ◽  
Crop Area

ABSTRACT The permanence of sugarcane straw on the soil surface, in systems without the pre-harvest straw burning practice, directly affects the soil organic matter dynamics. The objective of this work was to evaluate the changes in total organic carbon (TOC), carbon in the light organic matter (CLOM) and particulate organic carbon (POC), and their carbon stocks in a typic Quartzipsamment cultivated for nine years with sugarcane crops, which were conducted without the pre-harvest straw burning practice, in Paraipaba, State of Ceará, Brazil. Disturbed and undisturbed soil samples were collected at depths of 0.0-0.025, 0.025-0.05, 0.05-0.10, 0.10-0.20 and 0.20-0.30 m, in the sugarcane crop area and in an adjacent native forest area, in order to quantify the TOC, CLOM and POC, as well as the carbon stocks accumulated in the layer 0.0-0.30 m related to these fractions (TOCSt, CLOMSt and POCSt). TOC content changes after nine years of sugarcane crops, conducted without pre-harvest straw burning, were found only in the layers 0.10-0.20 and 0.20-0.30 m. The CLOM varied only in the layer 0.025-0.05 m. The POC content changes were more noticeable than the changes in TOC and CMOL. The CLOM of the sugarcane crop area presented high similarity with TOC, which may affect their quantification in studies related to the soil organic matter dynamics. The sugarcane crop increased the TOCSt, POCSt and CLOMSt in the layer 0.0-0.30 m, compared with the adjacent native forest area.

Maximum soil organic matter decomposition along temperature gradient in Colombian topsoils: Dry Forests

2021 ◽  
Author(s):  
Gerardo Ojeda ◽  
Hernando García ◽  
Susanne Woche ◽  
Jorg Bachmann ◽  
Georg Guggenberger ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Temperature Gradient ◽  
Soil Organic Carbon ◽  
Soil Respiration ◽  
Maximum Rate ◽  
Field Capacity ◽  
Total Carbon ◽  
Som Decomposition

<p><strong>Contextualization</strong>: In 2011, it was published a curious conundrum, which forms the basis of the present study: why, when organic matter is thermodynamically unstable, does it persist in soils, sometimes for thousands of years? The question challenges the idea that the recalcitrant or labile character of soil organic matter (SOM) is a sufficient argument to ensure SOM persistence. Temperature could play an important role in SOM decomposition, especially in tropics. Particularly, tropical dry forest (TDF) represents an important ecosystem with unique biodiversity and fertile soils in Colombia. At present, the increase in population density and consequently, in the demands of energy and arable land, have led to its degradation.</p><p> </p><p><strong>Knowledge gap</strong>: Although the mentioned question was formulated several years ago, it has still to be answered, hence limiting the development of new soil organic carbon (SOC) models or the quantification of its ecosystem services. A key point, in terms of soil carbon storage, is to determine the maximum rate of CO<sub>2</sub> emissions from soils (Rmax). Traditionally, it is considered that Rmax occurs at the 50% of field capacity. Unfortunately, information about the environmental conditions under which this maximum occurs is scarce.</p><p><strong> </strong></p><p><strong>Purpose</strong>: The main objectives of this study were: (a) determine the maximum rate of soil respiration or CO<sub>2</sub> emissions from soil in TDF soils and (b) to estimate the main environmental drivers of maximum SOM decomposition along a temperature gradient (20°, 30°, 40°C) in incubated soils.</p><p><strong> </strong></p><p><strong>Methodology</strong>: Soils pertained to permanent plots were sampled in six different TDF of Colombia. The evolution of CO<sub>2</sub> emissions (monitored by an infrared gas analyser), relative humidity and soil temperature were recorded in time on incubated soils samples. Temperature was maintained constant at 20°C, 30°C and 40°C during soil incubations under soil drying conditions. Additionally, elemental composition (Fe, Ca, O, Al, Si, K, Mg, Na) of SOM and chemical composition of soil organic carbon (SOC: aromatic-C, O-alkyl-C, Aliphatic-C, Phenolic and Ketonic-C) were determined by X-ray photoelectron spectroscopy (XPS).</p><p><strong> </strong></p><p><strong>Results and conclusions</strong>: The majority of TDF soil samples (90.7%) presented that its peak of CO<sub>2</sub> emissions occurs at soil-water contents higher than saturation (0 MPa), at 20°, 30° and 40°C. Clearly, to consider that the maximum soil respiration rate could be observed at the 50% of field capacity, underestimated the real maximum value of carbon mineralization (48-68%.) Globally, increases in the Rmax values corresponded to increases in electrical conductivity, soil desorption rates, total carbon and nitrogen contents, and decreases in bulk density (BD) and aggregate stability. Taking into account the temperature gradient, increments in calcium and aromatic carbon contents corresponded to decrements in Rmax values but only at 30°C and 40°C, respectively. Some authors indicated that at high soil moisture contents, iron reduction could be release protected carbon. However, no significant relation between Fe and Rmax was observed. Consequently, physical and chemical properties related to SOM accessibility and decomposability by microbial activity, were the main drivers and controls of maximum SOM decomposition rates.</p>

scholarly journals ORGANIC CARBON AND TOTAL NITROGEN IN THE DENSIMETRIC FRACTIONS OF ORGANIC MATTER UNDER DIFFERENT SOIL MANAGEMENT

2016 ◽  
Vol 29 (2) ◽  
pp. 263-273 ◽  
Author(s):  
MARCELO RIBEIRO VILELA PRADO ◽  
FABRICIO TOMAZ RAMOS ◽  
OSCARLINA LÚCIA DOS SANTOS WEBER ◽  
CAIO BATISTA MÜLLER
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Total Nitrogen ◽  
Agroforestry System ◽  
Native Forest ◽  
Land Use Systems ◽  
System 2 ◽  
Heavy Fractions

ABSTRACT: The evaluation of land use and management by the measurement of soil organic matter and its fractions has gained attention since it helps in the understanding of the dynamics of their contribution to soil productivity, especially in tropical environments. This study was conducted in the municipality of Colorado do Oeste, state of Rondônia, Brazil and its aim was to determinethe quantity of organic carbon and total nitrogen in the light and heavy fractions of organic matter in the surface layers of a typic hapludalf under different land use systems: Native Forest: open evergreen forest, reference environment; Agroforestry System 1: teak (Tectona grandis LF) and kudzu (Pueraria montana); Agroforestry System 2: coffee (Coffea canephora), marandu palisade grass (Brachiaria brizantha cv. Marandu), "pinho cuiabano" (Parkia multijuga), teak and kudzu.; Agroforestry System 3: teak and cocoa (Theobroma cacao); Silvopasture System: teak, cocoa and marandu palisade grass; and Extensive Grazing System: marandu palisade grass. The experimental design was a randomized block in split-split plots (use systems versus soil layers of 0-0.05 and 0.05-0.10 m) with three replications. The results showed that relative to Native Forest, the Agroforestry System 2 had equal- and greater amounts of organic carbon and total nitrogen respectively (light and heavy fractions) in the soil organic matter, with the light fraction being responsible for storage of approximately 45% and 70% of the organic carbon and total nitrogen, respectively. Therefore, the light densimetric fraction proved to be useful in the early identification of the general decline of the soil organic matter in the land use systems evaluated.

scholarly journals From Laboratory to Proximal Sensing Spectroscopy for Soil Organic Carbon Estimation—A Review

2020 ◽  
Vol 12 (2) ◽  
pp. 443 ◽  
Author(s):  
Theodora Angelopoulou ◽  
Athanasios Balafoutis ◽  
George Zalidis ◽  
Dionysis Bochtis
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Management Practices ◽  
Near Infrared ◽  
Wavelength Region ◽  
Soil Condition ◽  
Short Wave ◽  
Proximal Sensing

Rapid and cost-effective soil properties estimations are considered imperative for the monitoring and recording of agricultural soil condition for the implementation of site-specific management practices. Conventional laboratory measurements are costly and time-consuming, and, therefore, cannot be considered appropriate for large datasets. This article reviews laboratory and proximal sensing spectroscopy in the visible and near infrared (VNIR)–short wave infrared (SWIR) wavelength region for soil organic carbon and soil organic matter estimation as an alternative to analytical chemistry measurements. The aim of this work is to report the progress made in the last decade on data preprocessing, calibration approaches, and system configurations used for VNIR-SWIR spectroscopy of soil organic carbon and soil organic matter estimation. We present and compare the results of over fifty selective studies and discuss the factors that affect the accuracy of spectroscopic measurements for both laboratory and in situ applications.

Changes in soil organic carbon and nitrogen after 47 years with different tillage, stubble and fertiliser management in a Vertisol of north-eastern Australia

Soil Research ◽  
2020 ◽  
Vol 58 (4) ◽  
pp. 346
Author(s):  
K. L. Page ◽  
R. C. Dalal ◽  
S. H. Reeves ◽  
W. J. Wang ◽  
Somasundaram Jayaraman ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Management Practices ◽  
Crop Residues ◽  
Residue Management ◽  
Eastern Australia ◽  
North Eastern ◽  
Over Time

No-till (NT) farming has been widely adopted to assist in reducing erosion, lowering fuel costs, conserving soil moisture and improving soil physical, chemical and biological characteristics. Improvements in soil characteristics are often driven by the greater soil organic matter accumulation (as measured by soil organic carbon (SOC)) in NT compared to conventional tillage (CT) farming systems. However, to fully understand the effect of NT it is important to understand temporal changes in SOC by monitoring over an extended period. We investigated the long-term effect of NT and stubble retention (SR) on changes in SOC and total soil nitrogen (STN) using results from an experiment that has been running for 50 years in a semi-arid subtropical region of north-eastern Australia. In this experiment, the effects of tillage (CT vs NT), residue management (stubble burning (SB) vs SR), and nitrogen (N) fertiliser (0 and 90 kg-N ha–1) were measured in a balanced factorial experiment on a Vertisol (Ustic Pellusert). The use of NT, SR and N fertiliser generally improved SOC (by up to 12.8%) and STN stocks (by up to 31.7%) in the 0–0.1 m layer relative to CT, SB and no N fertiliser, with the greatest stocks observed where all three treatments were used in combination. However, declines in SOC (up to 20%) and STN (up to 25%) occurred in all treatments over the course of the experiment, indicating that changes in management practices were unable to prevent a loss of soil organic matter over time in this farming system. However, the NT and SR treatments did lose less SOC than CT and SB treatments, and SR also reduced STN loss. The δ13C analysis of samples collected in 2008 and 2015 highlighted that crop residues have significantly contributed to SOC stocks at the site and that their contribution is increasing over time.

scholarly journals Spatial Distribution of Soil Organic Matter and Soil Organic Carbon Stocks in Semi-Arid Area of Northeastern Syria

2019 ◽  
Vol 10 (12) ◽  
pp. 415-432
Author(s):  
Hussam Hag Husein ◽  
Mohammad Mousa ◽  
Wahib Sahwan ◽  
Rupert Bäumler ◽  
Bernhard Lucke
Keyword(s):  
Organic Matter ◽  
Spatial Distribution ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Stocks ◽  
Arid Area ◽  
Soil Organic Carbon Stocks ◽  
Semi Arid

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.

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