The influence of clay on the rate of decay of amino acid metabolites synthesized in soils during decomposition of cellulose

doi:10.1016/0038-0717(75)90015-2

Soil Biology and Biochemistry

Volume 7, Issue 2, March 1975, Pages 171-177

https://doi.org/10.1016/0038-0717(75)90015-2 Get rights and content

Abstract

¹⁴C-labelled cellulose was added to seven different soils containing silt + clay (particles < 0.02 mm) in amounts which varied from 8 to 75 per cent. The cellulose was allowed to decompose, and the amounts of labelled C transformed into metabolites hydrolyzable into amino acids were determined. The amounts of labelled amino acid C in the soils were proportional to their content of silt + clay. After 30 days of incubation labelled amino acid C remaining in the soil with the lowest content of silt + clay constituted 6 per cent of the carbon added in cellulose, as compared with 18 per cent in the soil with the highest content of silt + clay. These values had decreased to 5 and 13 per cent respectively after 2 years of incubation. The order between the soils in the content of labelled amino acid C established during the first month of incubation, was thus roughly maintained throughout the period of incubation. The biological half-life of the labelled C in amino acids varied in the seven soils during the last year of incubation from 3 to 8 years. The variation was, however, not related to the amount of silt + clay.

n the soils had been incubated with the labelled material for 2 years, samples of the soils were exposed to “stress” treatments: air drying-rewetting; increased biological activity caused by addition of glucose, and exposure to chloroform vapour. The treatments resulted in an evolution of labelled C in CO, which was 5–10 times larger than the evolution from untreated samples. The increase in the CO₂ evolution caused by the treatments in the different soils was, however, not related to the amount of silt + clay, and a high content of this material did not protect organic material against the effect of the treatments.

is concluded that the silt + clay fraction ensures stabilization of amino acid metabolites produced during the period of intense biological activity that follows the addition of decomposable, energy rich material to the soil. The amount of amino acid metabolites stabilized increased with increasing concentration of silt + clay, but the rate of decay of the amino acid material during later stages was largely independent of the concentration of silt + clay.

References (14)

M.M. Mortland
Clay-organic complexes and interactions
J. Murray
Liquid scintillation counting of ¹⁴CO₂ in a toluene/triton X-100 system
Int. J. appl. Radial. Isotopes
(1971)
L.H. Sørensen
Role of amino acid metabolites in the formation of soil organic matter
Soil. Biol. Biochem.
(1972)
L.H. Sorensen
Rate of decomposition of organic matter in soil as influenced by repeated air drying-rewettingand repeated additions of organic material
Soil Biol. Biochem.
(1974)
J.M. Bremner
Organic forms of nitrogen
D.J. Greenland
Interaction between clays and organic compounds in soils—I: Mechanisms of interaction between clays and defined organic compounds
Soils Fertil.
(1965)
D.J. Greenland
Interaction between clays and organic compounds in soils—II: Adsorption of soil organic compounds and its effect on soil properties
Soils Fertil.
(1965)

There are more references available in the full text version of this article.

Cited by (106)

Organic vegetable crop residue decomposition in soils
2023, Heliyon
Soil organic carbon (SOC) is an important property that influences soil chemical, physical, and biochemical processes and is a key indicator of soil health. Rapid decomposition of crop residues incorporated into soil reduces the potential of carbon (C) sequestration in the Southeast United States where SOC is very low rending residue management very critical. We investigated the C contents and the decomposition of cultivars of popular organic vegetable crops [southern pea (Vigna unguiculata), squash (Cucurbita maxima), sweet potato [Ipomoea batatas (L.) Lam] and tomato (Solanum lycopersicum)] in two soils under laboratory conditions. The C contents of the crop residues were determined by using a wet chemistry method. A non-linear regression model was used to determine the potentially mineralizable C (C₀) and the first-order rate constant (k) of the decomposition following incubation of soils treated with the vegetable crop residues for 30 days at room temperature. The average C contents varied between 304 and 437 g kg⁻¹. On average, the sweet potato cultivars showed a greater C₀ (19.4 g C kg⁻¹) in Cecil soil than in Hartsells soil while tomato cultivars showed the least C₀ (15.9 g C kg⁻¹) in Hartsells soil. The k values showed that squash cultivars decomposed faster (0.106 day^-1) than any other crop, whereas southern pea cultivars decomposed the least in Cecil and Hartsells soils. Strong relationships between C₀, k, and C/N were established. Organic growers are environmentally conscious framers who wants to mitigate the greenhouse effect and global warming by adopting cropping systems that would sequester more C into the soil. Thus, identifying and selecting vegetable crop cultivars that would incorporate more C in soil is of a great interest to them. These findings have potentials of guiding organic growers in selecting crop cultivars that would increase OC sequestration in soils.
The nature and dynamics of soil organic matter: Plant inputs, microbial transformations, and organic matter stabilization
2016, Soil Biology and Biochemistry
Citation Excerpt :
These observations have been confirmed in the more recent experiments on the effects of global warming (Alvarez et al., 1995; Steinweg et al., 2008; Conant et al., 2011). An extensive series of experiments, with 14C-labeled plant residues, glucose, and cellulose that were incubated for up to 6 yr (Sorensen, 1972, 1975, 1977, and 1981) showed that 14C cellulose produced less amino acid 14C than that added as 14C glucose. Due to the recycling of 15N in soil during microbial growth, and the preferential retention of amino compounds in clays, 15N compounds have greater MRTs than 14C labeled compounds.
This review covers historical perspectives, the role of plant inputs, and the nature and dynamics of soil organic matter (SOM), often known as humus. Information on turnover of organic matter components, the role of microbial products, and modeling of SOM, and tracer research should help us to anticipate what future research may answer today's challenges. Our globe's most important natural resource is best studied relative to its chemistry, dynamics, matrix interactions, and microbial transformations. Humus has similar, worldwide characteristics, but varies with abiotic controls, soil type, vegetation inputs and composition, and the soil biota. It contains carbohydrates, proteins, lipids, phenol-aromatics, protein-derived and cyclic nitrogenous compounds, and some still unknown compounds. Protection of transformed plant residues and microbial products occurs through spatial inaccessibility-resource availability, aggregation of mineral and organic constituents, and interactions with sesquioxides, cations, silts, and clays. Tracers that became available in the mid-20th century made the study of SOM dynamics possible. Carbon dating identified resistant, often mineral-associated, materials to be thousands of years old, especially at depth in the profile. The ¹³C associated with C₃C₄ plant switches characterized slow turnover pools with ages ranging from dozens to hundreds of years. Added tracers, in conjunction with compound-specific product analysis and incubation, identified active pools with fast turnover rates. Physical fractionations of the intra- and inter-aggregate materials, and those associated with silt and clay, showed that all pools contain both old and young materials. Charcoal is old but not inert. The C:N ratio changes from 25 to 70:1 for plant residues to 6 to 9:1 for soil biota and microbial products associated with soil minerals. Active, slow and passive (resistant) pool concepts have been well used in biogeochemical models. The concepts discussed herein have implications for today's challenges in nutrient cycling, biogeochemistry, soil ecosystem functioning, pollution control, feeding the expanding global population and global change.
Carbon sequestration and net emissions of CH<inf>4</inf> and N<inf>2</inf>O under agroforestry: Synthesizing available data and suggestions for future studies
2016, Agriculture, Ecosystems and Environment
Citation Excerpt :
Therefore, soil C sequestration rates may be affected by plant and agroforestry types beyond the simple effects of total biomass in agroforestry. To further add to sources of variability, soil C sequestration rates in agroforestry can also be affected by soil properties, especially silt and clay content and aggregation, since silt and clay particles and microaggregates can stabilize SOC (e.g., Sorensen, 1975; Six et al., 2000; Shrestha et al., 2007; Takimoto et al., 2009; Haile et al., 2010). Comparing agroforestry and adjacent agricultural lands, agroforestry was reported to have lower bulk density (–9.6 ± 4.8%), and higher concentrations of SOC (23.5 ± 15.1%) and soil nitrogen (N) (27.1 ± 18.0%) in the surface soil (0–10 or 0–20 cm) than adjacent agricultural lands (Table 3, Supplementary information Table B).
While there have been many valuable individual studies of the effects of agroforestry on changes in net greenhouse gas (GHG) emissions, this information has not yet been brought together to provide an overall assessment of the effects of agroforestry. We therefore compiled and analysed data from 109 earlier observations from 56 peer-reviewed publications of net rates of change of biomass and/or soil carbon (C) stocks in agroforestry systems, and from 26 data sets from 15 peer-reviewed publications of net changes in the emissions of methane (CH₄) and nitrous oxide (N₂O). We categorized agroforestry into two distinct types: tree-crop coexistence types where trees and agricultural crops are grown together (type 1) and tree-crop rotation type where trees and crops are grown alternately on the same piece of land (type 2). We primarily assessed the changes in C storage and net GHG emissions between agriculture and type 1 agroforestry. The data showed high variability in net C sequestration rates in both biomass and soils depending on the type of agroforestry, with reported C increments ranging from 0.3 to 7.7 t C ha⁻¹ y⁻¹ in biomass and 1.0 to 7.4 t C ha⁻¹ y⁻¹ in soils. On average, type 1 stands sequestered 3.8 ± 1.3 t C ha⁻¹ y⁻¹ in above-ground biomass, with no evidence of changed rates for stands aged 5–25 years. All available studies exclusively reported increases in soil C stocks, with highest reported soil C sequestration rates of more than 8 t C ha⁻¹ y⁻¹ for the first year after agroforestry establishment. Averaged across all observations, soil C sequestration rates were about 2 t C ha⁻¹ y⁻¹ in youngest stands that gradually diminished with time since stand establishment. Overall, type 1 agroforestry stands (at an average age of 14 years) sequestered 7.2 ± 2.8 t C ha⁻¹ y⁻¹, with biomass and soil C sequestration contributing about 70% and 30% of that increment, respectively. Soils under agroforestry also oxidised 1.6 ± 1.0 kg CH₄ ha⁻¹ y⁻¹ and emitted 7.7 ± 3.3 kg N₂O ha⁻¹ y⁻¹. Comparing agroforestry and adjacent agricultural lands, we found only minor differences in net CH₄ and N₂O emissions, with no clear overall direction of change. Overall, agroforestry was estimated to contribute to mitigating 27 ± 14 t CO₂ equivalents ha⁻¹ y⁻¹ at least for the first 14 years after establishment. It is suggested that future studies should consider strategic approaches for data acquisition that develop comprehensive approaches to quantify all components of the GHG balance, relate net GHG emissions with quantification of the yield of produce, and develop models to summarise the findings.
Some concepts of soil organic carbon characteristics and mineral interaction from a review of literature
2016, Soil Biology and Biochemistry
Citation Excerpt :
Lützow et al. (2006) reviewed that all hypotheses fitted into three categories responsible for the delayed decomposition of SOC, namely ‘selective preservation’, ‘spatial inaccessibility’ and ‘interactions with surfaces and metal ions’. Although the mechanisms controlling SOC stability were summarized in a different way, the crucial role of association with soil minerals has been recognized by most researchers (Sørensen, 1969, 1972, 1975; Torn et al., 1997; Six et al., 2002; Chenu and Plante, 2006; Lützow et al., 2006; Wang et al., 2014; Throckmorton et al., 2015). In this case, we conducted an extensive review of the international literature to provide an overview of the findings on the impacts of the molecular structures of OC and soil minerals on the stability of OC in soils.
In the past decades, the molecular structure of soil organic carbon (SOC) has been regarded as a pivotal criterion for predicting organic carbon (OC) turnover in soils. However, newly emerging evidence indicates that molecular structure does not necessarily predetermine the persistence of OC in soils and that environmental factors (e.g., soil structure, availability of resources and diversity of microorganisms) exert an additional influence upon SOC turnover. Among these potential factors, adsorption to soil minerals and occlusion within soil aggregates have been universally demonstrated to shield SOC from decomposition. In this review, we identified the uncertainties involved in examining the turnover of specific SOC fractions (lignin, humic substances (HS), coal and black carbon (BC)) in soils. Moreover, we concluded that the role of minerals in SOC adsorption and stability depends on the mineralogy, chemical properties of SOC and soil conditions. Characterization of SOC chemical composition in different soil size fractions (e.g., sand, silt and clay) shows that different-sized minerals potentially protect different types of SOC. Aromatic C may be adsorbed to minerals in the coarse silt/sand fractions and preserved there, while fine-sized (fine silt and clay) minerals generally associate with microbial-derived SOC. Finally, by tabulating the data from the ¹³C turnover time and ¹⁴C ages of bulk SOC and specific SOC fractions (carbohydrate, lignin, aliphatic C, HS, and BC), we obtained further validation that molecular structure does not exclusively determine the turnover rate of OC in soils. Furthermore, the ¹³C turnover time and ¹⁴C age of SOC consistently increased with increasing soil depth, which may be partially attributed to the larger protective potential of SOC by minerals and the unfavorable conditions for biodegradation in the subsoils. Because the limitations of ¹³C and ¹⁴C-dating techniques have largely been neglected, they are emphatically discussed in this review. It is suggested that more geomorphic and spectroscopic evidence is paramount to further explore the mechanisms underlying the persistence of OC in soils.
Hierarchical Bayesian calibration of nitrous oxide (N<inf>2</inf>O) and nitrogen monoxide (NO) flux module of an agro-ecosystem model: ECOSSE
2015, Ecological Modelling
With the position of nitrous oxide (N₂O) being the greenhouse gas with the highest global warming potential and its long atmospheric lifetime, the anthropogenic production of N₂O is of major concern. The process-based model, ECOSSE, was partly developed to quantify emissions of greenhouse gases with an input data requirement that is readily available at regional scale. Hierarchical Bayesian (HB) methods are potentially used to reduce the uncertainty and to explain the spatial variability of estimated parameters. Here, we used a Hierarchical Bayesian method to calibrate the parameters of the N₂O and nitrogen monoxide (NO) sub-model of ECOSSE and to quantify the uncertainty of model simulations and to investigate the model extrapolation using soil information. The sub model simulated N₂O emission from nitrification and denitrification, while the simulated NO from nitrification. The HB calibration reduced the uncertainty in the N₂O and NO simulations. The model's root mean square error (RMSE) was decreased by 18% and 29% for N₂O and NO across field sites compared to an uncalibrated model. Parameters for nitrification could be considered universal, while parameters for denitrification challenged the assumption that these parameters may be considered universal constant values across sites. Parameters of the NO module could be considered constant for model extrapolation to regional scale. The calibrated parameters derived from soil-specific calibration could be served as default values for the N₂O module extrapolation for similar soil types. Otherwise, the mean value of posterior distribution of calibration parameters in multi-dataset could be served as the parameter for model up scaling at regional scale.
Integrated Soil Fertility Management: Aggregate carbon and nitrogen stabilization in differently textured tropical soils
2013, Soil Biology and Biochemistry
Soil organic matter is important to improve and sustain soil fertility in tropical agroecosystems. The combined use of organic residue and fertilizer inputs is advocated for its positive effects on short-term nutrient supply, but the effect of the integrated use on long-term stabilization of soil organic C and N is still unclear. We conducted a 1.5-y soil incubation experiment with maize (Zea mays) residue and urea fertilizer to examine the stabilization of C and N in four Sub-Saharan African soils differing in texture (sand, sandy loam, clay loam, and clay). The inputs were enriched with ¹³C and ¹⁵N in a mirror-labelling design to trace the fate of residue-C and N, and fertilizer-N in combination. We hypothesized that combining inputs would enhance the stabilization of C and N relative to either input alone across a range of soil textures. The treatments were destructively sampled after 0.25, 0.5, and 1.5 y to assess input-derived C and N stabilization in soil macro- and microaggregate fractions. The combination treatment had a significant but small (2% of residue-applied C) increase in residue-C stabilized in the total soil after 0.25 y, but this increase did not persist after 0.5 and 1.5 y. While combining residue and fertilizer decreased the amount of residue-N stabilized within 53- to 2000-μm sized soil aggregates (e.g., 7% less at 1.5 y), it increased the stabilization of fertilizer-N at all sampling times (e.g., 20% more at 1.5 y). The increased amount of fertilizer-N stabilized was significantly greater than the amount of residue-N lost in the combined input treatments in the three finer textured soils at 1.5 y, indicating an interactive increase in the stabilization of new N. Our results indicate that combining residue with fertilizer inputs can increase the short-term stabilization of N, which has the potential to improve soil fertility. However, benefits to N stabilization from combining organic residues and fertilizer seem to be less in coarser-textured soils.

View all citing articles on Scopus

View full text

The influence of clay on the rate of decay of amino acid metabolites synthesized in soils during decomposition of cellulose

Abstract

Int. J. appl. Radial. Isotopes

Soil. Biol. Biochem.

Soil Biol. Biochem.

Organic forms of nitrogen

Interaction between clays and organic compounds in soils—I: Mechanisms of interaction between clays and defined organic compounds

Soils Fertil.

Interaction between clays and organic compounds in soils—II: Adsorption of soil organic compounds and its effect on soil properties

Soils Fertil.