scholarly journals Spatial molecular heterogeneity of POM during decomposition at different soil depths resolved resolved by VNIR hyperspectral imaging

2021 ◽  
Author(s):  
Julien Guigue ◽  
Christopher Just ◽  
Siwei Luo ◽  
Marta Fogt ◽  
Michael Schloter ◽  
...  
Keyword(s):  
Organic Matter ◽  
Hyperspectral Imaging ◽  
Green Manure ◽  
Molecular Composition ◽  
Molecular Characteristics ◽  
Molecular Heterogeneity ◽  
Soil Cores ◽  
Molecular Changes ◽  
Learning Ensembles ◽  
Organic Particles

Soil organic matter is composed of fractions with different functions and reactivity. Among these, particulate organic matter (POM) is the main educt of new inputs of organic matter in soils and its chemical fate corresponds to the first stages of the SOM decomposition cascade ultimately leading to the association of organic and mineral phases. We aimed at investigating the POM molecular changes during decomposition at a sub-millimetre scale by combining direct measurements of POM elemental and molecular composition with laboratory imaging VNIR spectroscopy. For this, we set up an incubation experiment to compare the molecular composition of straw and composted green manure, materials greatly differing in their C/N ratio, during their decomposition in reconstituted topsoil or subsoil of a Luvisol, and recorded hyperspectral images at high spatial and spectral resolutions of complete soil cores at the start and end of the incubation. Hyperspectral imaging was successfully combined with machine learning ensembles to produce a precise mapping of POM alkyl/O-N alkyl ratio and C/N, revealing the spatial heterogeneity in the composition of both straw and green manure. We found that both types of organic amendment were more degraded in the reconstituted topsoil than in subsoil after the incubation. We also measured consistent trends in molecular changes undergone by straw, with the alkyl/O-N alkyl ratio slightly increasing from 0.06 to 0.07, and C/N dropping by about 40 units. The green manure material was very heterogeneous, with no clear molecular changes detected as a result of incubation. The visualisation approach presented here enables high-resolution mapping of the spatial distribution of the molecular characteristics of organic particles in soil cores, and offers opportunities to disentangle the roles of POM chemistry and morphology during the first steps of the decomposition cascade of organic matter in soils.

scholarly journals Spatial molecular heterogeneity of POM during decomposition at different soil depths res olved by VNIR hyperspectral imaging

2021 ◽  
Author(s):  
Julien Guigue ◽  
Christopher Just ◽  
Siwei Luo ◽  
Marta Fogt ◽  
Michael Schloter ◽  
...  
Keyword(s):  
Organic Matter ◽  
Hyperspectral Imaging ◽  
Green Manure ◽  
Molecular Composition ◽  
Molecular Characteristics ◽  
Molecular Heterogeneity ◽  
Soil Cores ◽  
Molecular Changes ◽  
Learning Ensembles ◽  
Organic Particles

Soil organic matter is composed of fractions with different functions and reactivity. Among these, particulate organic matter (POM) is the main educt of new inputs of organic matter in soils and its chemical fate corresponds to the first stages of the SOM decomposition cascade ultimately leading to the association of organic and mineral phases. We aimed at investigating the POM molecular changes during decomposition at a sub-millimetre scale by combining direct measurements of POM elemental and molecular composition with laboratory imaging VNIR spectroscopy. For this, we set up an incubation experiment to compare the molecular composition of straw and composted green manure, materials greatly differing in their C/N ratio, during their decomposition in reconstituted topsoil or subsoil of a Luvisol, and recorded hyperspectral images at high spatial and spectral resolutions of complete soil cores at the start and end of the incubation. Hyperspectral imaging was successfully combined with machine learning ensembles to produce a precise mapping of POM alkyl/O-N alkyl ratio and C/N, revealing the spatial heterogeneity in the composition of both straw and green manure. We found that both types of organic amendment were more degraded in the reconstituted topsoil than in subsoil after the incubation. We also measured consistent trends in molecular changes undergone by straw, with the alkyl/O-N alkyl ratio slightly increasing from 0.06 to 0.07, and C/N dropping by about 40 units. The green manure material was very heterogeneous, with no clear molecular changes detected as a result of incubation. The visualisation approach presented here enables high-resolution mapping of the spatial distribution of the molecular characteristics of organic particles in soil cores, and offers opportunities to disentangle the roles of POM chemistry and morphology during the first steps of the decomposition cascade of organic matter in soils.

scholarly journals Spatial molecular heterogeneity of POM during decomposition at different soil depths resolved by VNIR hyperspectral imaging

2021 ◽  
Author(s):  
Julien Guigue ◽  
Christopher Just ◽  
Siwei Luo ◽  
Marta Fogt ◽  
Michael Schloter ◽  
...  
Keyword(s):  
Organic Matter ◽  
Hyperspectral Imaging ◽  
Green Manure ◽  
Molecular Composition ◽  
Molecular Characteristics ◽  
Molecular Heterogeneity ◽  
Soil Cores ◽  
Molecular Changes ◽  
Learning Ensembles ◽  
Organic Particles

Soil organic matter is composed of fractions with different functions and reactivity. Among these, particulate organic matter (POM) is the main educt of new inputs of organic matter in soils and its chemical fate corresponds to the first stages of the SOM decomposition cascade ultimately leading to the association of organic and mineral phases. We aimed at investigating the POM molecular changes during decomposition at a sub-millimetre scale by combining direct measurements of POM elemental and molecular composition with laboratory imaging VNIR spectroscopy. For this, we set up an incubation experiment to compare the molecular composition of straw and composted green manure, materials greatly differing in their C/N ratio, during their decomposition in reconstituted topsoil or subsoil of a Luvisol, and recorded hyperspectral images at high spatial and spectral resolutions of complete soil cores at the start and end of the incubation. Hyperspectral imaging was successfully combined with machine learning ensembles to produce a precise mapping of POM alkyl/O-N alkyl ratio and C/N, revealing the spatial heterogeneity in the composition of both straw and green manure. We found that both types of organic amendment were more degraded in the reconstituted topsoil than in subsoil after the incubation. We also measured consistent trends in molecular changes undergone by straw, with the alkyl/O-N alkyl ratio slightly increasing from 0.06 to 0.07, and C/N dropping by about 40 units. The green manure material was very heterogeneous, with no clear molecular changes detected as a result of incubation. The visualisation approach presented here enables high-resolution mapping of the spatial distribution of the molecular characteristics of organic particles in soil cores, and offers opportunities to disentangle the roles of POM chemistry and morphology during the first steps of the decomposition cascade of organic matter in soils.

scholarly journals Spatial molecular heterogeneity of POM during decomposition at different soil depths resolved by VNIR hyperspectral imaging

2021 ◽  
Author(s):  
Julien Guigue ◽  
Christopher Just ◽  
Siwei Luo ◽  
Marta Fogt ◽  
Michael Schloter ◽  
...  
Keyword(s):  
Organic Matter ◽  
Hyperspectral Imaging ◽  
Green Manure ◽  
Molecular Composition ◽  
Molecular Characteristics ◽  
Molecular Heterogeneity ◽  
Soil Cores ◽  
Molecular Changes ◽  
Learning Ensembles ◽  
Organic Particles

Soil organic matter is composed of fractions with different functions and reactivity. Among these, particulate organic matter (POM) is the main educt of new inputs of organic matter in soils and its chemical fate corresponds to the first stages of the SOM decomposition cascade ultimately leading to the association of organic and mineral phases. We aimed at investigating the POM molecular changes during decomposition at a sub-millimetre scale by combining direct measurements of POM elemental and molecular composition with laboratory imaging VNIR spectroscopy. For this, we set up an incubation experiment to compare the molecular composition of straw and composted green manure, materials greatly differing in their C/N ratio, during their decomposition in reconstituted topsoil or subsoil of a Luvisol, and recorded hyperspectral images at high spatial and spectral resolutions of complete soil cores at the start and end of the incubation. Hyperspectral imaging was successfully combined with machine learning ensembles to produce a precise mapping of POM alkyl/O-N alkyl ratio and C/N, revealing the spatial heterogeneity in the composition of both straw and green manure. We found that both types of organic amendment were more degraded in the reconstituted topsoil than in subsoil after the incubation. We also measured consistent trends in molecular changes undergone by straw, with the alkyl/O-N alkyl ratio slightly increasing from 0.06 to 0.07, and C/N dropping by about 40 units. The green manure material was very heterogeneous, with no clear molecular changes detected as a result of incubation. The visualisation approach presented here enables high-resolution mapping of the spatial distribution of the molecular characteristics of organic particles in soil cores, and offers opportunities to disentangle the roles of POM chemistry and morphology during the first steps of the decomposition cascade of organic matter in soils.

Mapping molecular information of organic amendments during their decomposition in soil derived from hyperspectral imaging

2021 ◽  
Author(s):  
Julien Guigue ◽  
Christopher Just ◽  
Siwei Luo ◽  
Marta Fogt ◽  
Michael Schloter ◽  
...  
Keyword(s):  
Organic Matter ◽  
Wheat Straw ◽  
Hyperspectral Imaging ◽  
Spatial Resolution ◽  
Organic Material ◽  
Green Manure ◽  
Organic Matter Decomposition ◽  
Fine Spatial Resolution ◽  
Decomposition Dynamics ◽  
Organic Particles

<p><span>O</span><span>rganic matter added to agricultural soil </span><span>determines</span><span> the C balance and the nutrient cycling in these ecosystems. Organic fertilisation can result </span><span>in</span><span> the accumulation of </span><span>C in soil but can also stimulate the decomposition of the existing </span><span>soil </span><span>C pool, as the incorporation of an easily accessible energy-rich substrate often trigger the growth and activity of decomposer. We monitor</span><span>ed</span><span> the fate of two types of organic material (wheat straw and green manure) during </span><span>the first stages of </span><span>their decomposition in</span><span>to</span><span> the soil. For this, we incubated 1-m soil columns </span><span>amended</span> <span>with the two </span><span>organic fertilisers either into the topsoil or into the subsoil. We </span><span>measured changes</span><span> in C and N contents, and </span><span>used <sup>13</sup>C-NMR to resolve the </span><span>structural group composition of the added organic material. We also </span><span>scanned </span><span>the incubated samples </span><span>with a hyperspectral camera </span><span>and developed predictive models for C to N and for alkyl to O-alkyl ratios at a very fine spatial resolution (53 x 53 </span><span>µm</span><sup><span>2</span></sup><span> per pixel</span><span>) for </span><span>organic particles in </span><span>the whole soil cores.</span></p><p><span>T</span><span>he approach based on hyperspectral imaging</span><span> was </span><span>successful</span><span> to follow the decomposition dynamics of POM </span><span>during</span><span> the incubation, and the associated d</span><span>ecreases</span><span> in C to N and in</span><span>creases in</span><span> alkyl to O-alkyl ratios </span><span>at a very fine spatial resolution, showing how different part</span><span>s</span><span> of the organic particles underwent distinct decomposition. </span><span>We also observed </span><span>contrasting</span><span> decomposition dynamics between the wheat straw and the green manure. </span><span>This method can bring new information about the first steps of fresh organic matter decomposition in soils and develop our general understanding of the soil organic matter decomposition continuum.</span></p>

C stocks and subsoil management in agroecosystems: application of hyperspectral imaging to study organic matter dynamics in the top one metre of soil

2020 ◽  
Author(s):  
Julien Guigue ◽  
Christopher Just ◽  
Siwei Luo ◽  
Eleanor Hobley ◽  
Ingrid Kögel-Knabner
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Hyperspectral Imaging ◽  
Environmental Changes ◽  
Crop Productivity ◽  
Soil Cores ◽  
Deep Soil ◽  
Demographic Pressure ◽  
Soil C ◽  
C Stocks

<p><span>While the demographic pressure for food demand is continuously rising, global environmental changes are threatening the productivity of agroecosystems. Climatic events like floods or droughts, and long-term decrease in soil organic matter stocks due to intensive agriculture are examples pointing to the necessity to find solutions for sustainable performance of agroecosystems.</span></p><p><span>Significant amounts of water and nutrients are stored in deep soil horizons, and thus subsoil management is being considered as an alternative to sustain high demand in crop productivity. </span></p><p><span>We used samples from an ongoing field experiment in Germany where the agricultural management was adapted to investigate the potential benefits of deep ploughing with OM incorporation. We recorded hyperspectral images of soil cores (depth = 1 m) using Vis-NIR reflectance spectroscopy and the C distribution within the soil was modeled at a very high spatial resolution (53×53 μm). The SOC mapping revealed an increase in SOC stocks resulting from deep ploughing, and the high resolution images generated allows the observation of OM distribution in the subsoil and the response in SOM stocks to different types of organic matter incorporation (compost vs green manure). The same imaging technique was also combined with solid-state <sup>13</sup>C NMR measurements to track the molecular composition of the organic amendment during decomposition.</span></p><p><span>Hyperspectral imaging of soil cores allows the quantification of OM stocks and changes at the pedon scale, and fine scale resolution of heterogeneity in the spatial distribution of soil organic matter is helping to understand and quantify the processes related to changes in soil C stocks in subsoils.</span></p>

RESTORING PRODUCTIVITY TO AN ARTIFICIALLY ERODED DARK BROWN CHERNOZEMIC SOIL UNDER DRYLAND CONDITIONS

1986 ◽  
Vol 66 (2) ◽  
pp. 273-285 ◽  
Author(s):  
J. F. DORMAAR ◽  
C. W. LINDWALL ◽  
G. C. KOZUB
Keyword(s):  
Organic Matter ◽  
Soil Erosion ◽  
Green Manure ◽  
Soil Structure ◽  
Management Practices ◽  
Fertilizer Application ◽  
Sweet Clover ◽  
Yield Losses ◽  
Critical Factors ◽  
Structure Characteristics

A field was artificially eroded by levelling in 1957 and then continuously cropped to barley for 7 yr. Subsequently, a wheat-fallow experiment was conducted from 1965 to 1979 to determine the effects of four fertilizer treatments and green manure (yellow sweet clover) on restoring the productivity to soil that had been "eroded" to various depths. After 22 yr and 14 crops, the productivity of the land from which soil was removed has been improved but not fully restored. Although green manuring with yellow sweet clover improved soil structure, wheat yields were not improved because of competition for soil moisture and poorer in-crop weed control in this part of the rotation. The addition of 45 kg N plus 90 kg P2O5 per hectare in each crop year to sites from which 8–10, 10–20, or 46 + cm of soil had been removed resulted in yield increases of 18, 46, and 70%, respectively, over the unfertilized check of each treatment; the average yields were 104, 91, and 70%, respectively, of the undisturbed, unfertilized (check) treatment. On "erosion" treatments where only 8–10 cm of soil were removed, 45 kg N plus 22 kg P2O5 per hectare were sufficient to restore the productivity. Precipitation apparently had a greater effect than fertilizer application on wheat yields. The loss of organic matter and associated soil structure characteristics seemed to be critical factors contributing to yield losses associated with soil erosion. These results show that it is more practical to use management practices that prevent soil erosion than to adopt the practices required to restore eroded soil. Key words: Soil erosion, topsoil loss, water-stable aggregates, soil organic matter, green manure, precipitation

scholarly journals Molecular characterization of an end-residue of humeomics applied to a soil humic acid

RSC Advances ◽  
2014 ◽  
Vol 4 (45) ◽  
pp. 23658-23665 ◽  
Author(s):  
A. Nebbioso ◽  
A. Piccolo ◽  
M. Lamshöft ◽  
M. Spiteller
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Molecular Characterization ◽  
Natural Organic Matter ◽  
Molecular Composition ◽  
Chemical Fractionation ◽  
Soil Humic Acid

Humeomics encompasses step-wise chemical fractionation and instrumental determination to fully characterize the heterogeneous molecular composition of natural organic matter.

scholarly journals Zonal features of the dynamics of humus content in soils of Chernihiv region

2021 ◽  
pp. 115-125
Author(s):  
O. Grischenko ◽  
S. Romanova ◽  
V. Zapasnyi ◽  
I. Shabanova
Keyword(s):  
Organic Matter ◽  
Green Manure ◽  
Sharp Increase ◽  
Humus Content ◽  
Weighted Average ◽  
Sharp Decrease ◽  
Organic Fertilizers ◽  
Climatic Zones ◽  
Sown Area ◽  
Green Manure Crops

The humus condition of soils of Chernihiv region has been studied. The dynamics of humus content in the soils of the region during six rounds (1986–2015) of agrochemical certification of agricultural lands is generalized and analyzed. In comparison with the 5th round (1986–1990), there was a discrepancy between the processes of stabilization and increase of humus content in most districts and in the region as a whole in the ninth round (2006–2010), and in some districts in the tenth round (2011–2015) against the background of a sharp decrease in the application of organic fertilizers. It was found that the stabilization of humus content in the soils of the region during the V–VIII rounds of agrochemical certification and a sharp increase in its content in the ninth round, against a significant reduction of organic matter, correlates with the withdrawal of eroded, low-yielding lands with low humus content (r=0.76). Analyzing the dynamics of humus content over thirty years of research,it was found that its content has increased in all climatic zones, as well as in nineteen of the twenty-two districts of the region. The increase of the indicator is in the range of 0.01–0.72%, while in all districts there is a significant reduction of the surveyed areas and only in three districts of the region there is a decrease in the humus content. According to the results of the 10th round of agrochemical certification, the soils of Chernihiv region are characterized by an average humus content of 2.41%. The highest humus content is characterized by the soils of Bakhmatsky (3.56%), Talalaivsky (3.33%) and Pryluky (3.32%) districts, and the lowest — NovgorodSiversky (1.57%). Increasing the sown area of green manure crops, plowing straw and the use of other elements of biologization of agriculture are important factors in increasing the weighted average humus content in the soils of Chernihiv region.

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