Soil aggregation and soil organic matter in conventionally and organically farmed Austrian Chernozems / Bodenaggregation und organische Substanz in konventionell und biologisch bewirtschafteten österreichischen Tschernosemböden

Summary In order to study the soil aggregate distributions and soil organic matter (SOM), we sampled top- and subsoils in four intensively farmed croplands (two organic (Org-OB and Org-LA), and two conventional (Con-OB and Con-LA)) on Haplic Chernozems located in Marchfeld in the east of Vienna (Austria). Soil structure and SOM quantity, quality and distribution between free and occluded particulate organic matter and aggregate size fractions (<20 µm, 20-250 µm, 250-5000 µm) were studied by following a density fractionation procedure with low-energy ultrasound treatment. The relation of the soil physicochemical (e.g., particle size distribution, pH, organic carbon, total nitrogen) and biological properties (e.g., fungal biomass, active fungi) with stable soil aggregate size fractions and SOM was studied. The mean weight diameter (MWD) showed no significant difference between all studied sites and was between 3.8 mm and 10.0 mm in topsoils and between 6.7 mm and 11.9 mm in subsoils. In topsoils, the contents of calcium-acetate-lactate (CAL)-extractable P, active fungal biomass, dithionite-extractable Fe and sand were significantly positively correlated with the amount of the macroaggregates and with the MWD. We observed that most soil organic carbon, depending on soil texture, was stored in the microaggregate size classes <20 µm and 20-250 µm.

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Microbiological characterization of land set-aside before and after Roundup desiccation

Plant Soil and Environment ◽

10.17221/226/2010-pse ◽

2011 ◽

Vol 57 (No. 2) ◽

pp. 88-94 ◽

Cited By ~ 2

Author(s):

M. Růžková ◽

L. Růžek ◽

K. Voříšek ◽

P. Vráblík ◽

D. Musilová

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Microbial Biomass ◽

Organic Carbon ◽

Plant Biomass ◽

Lolium Multiflorum ◽

Biological Properties ◽

Basal Respiration ◽

Arylsulfatase Activity ◽

Pure Cultures

Luvic chernozem (set-aside from 1996) was evaluated. The first period, before Roundup desiccation (2002–2003), was characterized by black, spontaneous and controlled fallows (mowed with the removal of plant biomass or mulched); the following period (2003–2004) by black fallow with repeated Roundup applications; and the last period (2004–2006) involved re-grassing by a mowed Lolium multiflorum Lam. monoculture. The characterization included microbial biomass, available organic carbon, basal respiration, metabolic quotient, biomass-specific available organic carbon, arylsulfatase activity, soil organic matter carbon and total nitrogen. Mulching of pure cultures of grasses and legumes contributed to a high soil organic matter accumulation. Repeated Roundup desiccation caused a strong (highly significant) decrease of arylsulfatase activity (–28%), however highly significant increase of microbial biomass (+69%) and nitrate-nitrogen (+86%) were determined. The subsequent re-grassing compensated the changes described. The soil biological properties were best preserved on mulched fallow with Lotus corniculatus L. and Festuca pratensis L., also in regard to contamination with weeds.

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Agricultural mulching and fungicides—impacts on fungal biomass, mycotoxin occurrence, and soil organic matter decomposition

Environmental Science and Pollution Research ◽

10.1007/s11356-021-13280-3 ◽

2021 ◽

Author(s):

Maximilian Meyer ◽

Dörte Diehl ◽

Gabriele Ellen Schaumann ◽

Katherine Muñoz

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Organic Carbon ◽

Soil Quality ◽

Fungal Biomass ◽

Soil Depth ◽

Soil Parameters ◽

Fungicide Application ◽

Soil Microbial ◽

The Impact

AbstractPlastic and straw coverage (PC and SC) are often combined with fungicide application but their influence on fungicide entry into soil and the resulting consequences for soil quality are still unknown. The objective of this study was to investigate the impact of PC and SC, combined with fungicide application, on soil residual concentrations of fungicides (fenhexamid, cyprodinil, and fludioxonil), soil fungal biomass, mycotoxin occurrence, and soil organic matter (SOM) decomposition, depending on soil depth (0–10, 10–30, 30–60 cm) and time (1 month prior to fungicide application and respectively 1 week, 5 weeks, and 4 months afterwards). Soil analyses comprised fungicides, fusarium mycotoxins (deoxynivalenol, 15-acetyldeoxynivalenol, nivalenol, and zearalenone), ergosterol, soil microbial carbon and nitrogen, soil organic carbon, dissolved organic carbon, and pH. Fludioxonil and cyprodinil concentrations were higher under SC than under PC 1 week and 5 weeks after fungicide application (up to three times in the topsoil) but no differences were observed anymore after 4 months. Fenhexamid was not detected, presumably because of its fast dissipation in soil. The higher fludioxonil and cyprodinil concentrations under SC strongly reduced the fungal biomass and shifted microbial community towards larger bacterial fraction in the topsoil and enhanced the abundance and concentration of deoxynivalenol and 15-acetyldeoxynivalenol 5 weeks after fungicide application. Independent from the different fungicide concentrations, the decomposition of SOM was temporarily reduced after fungicide application under both coverage types. However, although PC and SC caused different concentrations of fungicide residues in soil, their impact on the investigated soil parameters was minor and transient (< 4 months) and hence not critical for soil quality.

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Thermal alteration of soil organic matter properties: a systematic study to infer response of Sierra Nevada climosequence soils to forest fires

10.5194/soil-2016-57 ◽

2016 ◽

Cited By ~ 2

Author(s):

Samuel N. Araya ◽

Marilyn L. Fogel ◽

Asmeret Asefaw Berhe

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Sierra Nevada ◽

Forest Fires ◽

Global Climate ◽

Aggregate Size ◽

Fire Regimes ◽

Thermal Alteration ◽

Size Fractions ◽

C And N

Abstract. Fire is a major driver of soil organic matter (SOM) dynamics, and contemporary global climate change is changing global fire regimes. We investigated thermal alteration of SOM properties by exposing five different topsoils (0 to 5 cm depth) from the western Sierra Nevada Climosequence to a range of temperatures that are expected during prescribed and wild fires (150, 250, 350, 450, 550 and 650 °C), and determined temperature thresholds for major shifts in SOM properties. With increase in temperature, we found that the concentrations of C and N decreased in a similar pattern among all five soils that varied considerably in their original SOM concentrations and mineralogies. Soils were separated into discrete size classes by dry sieving. The C and N concentrations in the larger aggregate size fractions (2–0.25 mm) decreased with increase in temperature that at 450 °C temperature, the remaining C and N were almost entirely associated with the smaller aggregate size fractions (

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Characteristics and Driving Mechanism of Soil Organic Carbon Content in Farmland of Beijing Plain: Implication for the Fate of Engineered Polymers in Soil

Advances in Polymer Technology ◽

10.1155/2019/4837658 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10

Author(s):

Lanlan Zhang ◽

Zhen Li ◽

Shiwen Zhang ◽

Shasha Xia ◽

Hongguang Zou ◽

...

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Carbon Content ◽

Organic Fertilizer ◽

Driving Mechanism ◽

Organic Carbon Content ◽

Beijing Plain ◽

Significant Difference

Soil organic matter (SOM), as a kind of natural polymers, affects the migration and transport of ions and particles in soil system due to its surface characteristics and interaction and then causes significant changes in soil quality such as soil fertility loss and pollutant transfer. It is of great importance to study the temporal and spatial evolution of soil organic matter and its driving mechanism for soil health management. This study aims to fully reveal the evolution characteristics and driving mechanism of soil organic carbon (SOC) in farmland of the Beijing plain based on a six-year site monitoring. According to the research results, there is a significant difference in the overall soil organic content during the 6-year period. The temporal stability of SOC is moderate, and it is inversely proportional to SOC content in terms of spatial distribution. SOC content increases as organic fertilizer input rises, and an extra unit (15 kg·ha−1) of organic fertilizer input leads to an increase of 0.057 g·kg−1 in SOC content. The soil with higher clay content exhibits higher SOC content. The organic carbon content in different soil texture types increases with time, and there is a significant difference between the increases in medium loam and light loam. The grain field plantation system exhibited declining SOC content, while the protected vegetable fields, open vegetable fields, and orchards all showed an increase in SOC content. According to our results, the SOC content of farmland in the plain areas of Beijing is largely dependent on the input of organic carbon if other conditions remain unchanged or exhibit insignificant changes.

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Thermal alteration of soil organic matter properties: a systematic study to infer response of Sierra Nevada climosequence soils to forest fires

SOIL ◽

10.5194/soil-3-31-2017 ◽

2017 ◽

Vol 3 (1) ◽

pp. 31-44 ◽

Cited By ~ 15

Author(s):

Samuel N. Araya ◽

Marilyn L. Fogel ◽

Asmeret Asefaw Berhe

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Sierra Nevada ◽

Temperature Increase ◽

Aggregate Size ◽

Fire Regimes ◽

Thermal Alteration ◽

Size Fractions ◽

Temperature Thresholds ◽

C And N

Abstract. Fire is a major driver of soil organic matter (SOM) dynamics, and contemporary global climate change is changing global fire regimes. We conducted laboratory heating experiments on soils from five locations across the western Sierra Nevada climosequence to investigate thermal alteration of SOM properties and determine temperature thresholds for major shifts in SOM properties. Topsoils (0 to 5 cm depth) were exposed to a range of temperatures that are expected during prescribed and wild fires (150, 250, 350, 450, 550, and 650 °C). With increase in temperature, we found that the concentrations of carbon (C) and nitrogen (N) decreased in a similar pattern among all five soils that varied considerably in their original SOM concentrations and mineralogies. Soils were separated into discrete size classes by dry sieving. The C and N concentrations in the larger aggregate size fractions (2–0.25 mm) decreased with an increase in temperature, so that at 450 °C the remaining C and N were almost entirely associated with the smaller aggregate size fractions ( <  0.25 mm). We observed a general trend of 13C enrichment with temperature increase. There was also 15N enrichment with temperature increase, followed by 15N depletion when temperature increased beyond 350 °C. For all the measured variables, the largest physical, chemical, elemental, and isotopic changes occurred at the mid-intensity fire temperatures, i.e., 350 and 450 °C. The magnitude of the observed changes in SOM composition and distribution in three aggregate size classes, as well as the temperature thresholds for critical changes in physical and chemical properties of soils (such as specific surface area, pH, cation exchange capacity), suggest that transformation and loss of SOM are the principal responses in heated soils. Findings from this systematic investigation of soil and SOM response to heating are critical for predicting how soils are likely to be affected by future climate and fire regimes.

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Study of soil aggregate breakdown dynamics under low dispersive ultrasonic energies with sedimentation and X-ray attenuation

International Agrophysics ◽

10.1515/intag-2015-0057 ◽

2015 ◽

Vol 29 (4) ◽

pp. 501-508 ◽

Cited By ~ 2

Author(s):

Jasmin Schomakers ◽

Franz Zehetner ◽

Axel Mentler ◽

Franz Ottner ◽

Herwig Mayer

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Size Distribution ◽

Aggregate Stability ◽

Aggregate Size ◽

Soil Aggregate ◽

X Ray ◽

Aggregate Size Distribution ◽

Aggregate Breakdown ◽

Wet Sieving

Abstract It has been increasingly recognized that soil organic matter stabilization is strongly controlled by physical binding within soil aggregates. It is therefore essential to measure soil aggregate stability reliably over a wide range of disruptive energies and different aggregate sizes. To this end, we tested highaccuracy ultrasonic dispersion in combination with subsequent sedimentation and X-ray attenuation. Three arable topsoils (notillage) from Central Europe were subjected to ultrasound at four different specific energy levels: 0.5, 6.7, 100 and 500 J cm-3, and the resulting suspensions were analyzed for aggregate size distribution by wet sieving (2 000-63 μm) and sedimentation/X-ray attenuation (63-2 μm). The combination of wet sieving and sedimentation technique allowed for a continuous analysis, at high resolution, of soil aggregate breakdown dynamics after defined energy inputs. Our results show that aggregate size distribution strongly varied with sonication energy input and soil type. The strongest effects were observed in the range of low specific energies (< 10 J cm-3), which previous studies have largely neglected. This shows that low ultrasonic energies are required to capture the full range of aggregate stability and release of soil organic matter upon aggregate breakdown.

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The role of SOM and CaCO3 on soil aggregate development in reclaimed soils

10.5194/egusphere-egu2020-13644 ◽

2020 ◽

Author(s):

Evelin Pihlap ◽

Markus Steffens ◽

Ingrid Kögel-Knabner

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Extracellular Polymeric Substances ◽

Aggregate Size ◽

Soil Aggregate ◽

Parent Material ◽

Size Class ◽

Aggregate Formation ◽

Structural Formation ◽

Size Classes

Soil organic matter (SOM) and extracellular polymeric substances (EPS) from biological processes are considered to be major contributors in aggregate formation. But there is limited knowledge on soil structural formation after reclamation &#8211; the step when SOM content is low and soil properties are mostly controlled by the parent material. In our study we used a chronosequence approach in the reclaimed open-cast mining area near Cologne, Germany to elucidate the development of soil structure and soil organic matter during initial soil formation in a loess material. We selected six plots with different ages of agricultural management after reclamation (0, 1, 3, 6, 12, and 24 years after first seeding). In each reclaimed field 12 spatially independent locations were sampled with stainless steel cylinders (100 cm3) at two depths in the topsoil (1-5 cm and 16-20 cm). Samples were wet sieved into four aggregate size classes of <63 &#181;m, 63-200 &#181;m, 200-630 &#181;m and 630-2000 &#181;m. Each aggregate size class was characterized by organic carbon (OC), total nitrogen (TN) and CaCO3 concentration. The chemical composition of the SOM of selected samples was characterized using solid-state 13C NMR spectroscopy.Wet sieving into aggregate size classes showed different trends along the chronosequence. Contradicting relation between CaCO3 and OC contribution to aggregate size classes display two different mechanisms on soil aggregate formation in young loess derived soils. CaCO3 influenced aggregation predominantly in finer aggregate size classes, where the highest concentration and contribution was measured. SOM, on the other hand, played an important role on formation of large macro-aggregates after organic manure application in year 4. Furthermore, the loss of total OC after year 12 was connected with the loss of OC contributing to the largest aggregate size class. Our findings reveal that SOM and CaCO3 role on stabilizing aggregates is not equally distributed and is aggregate size class dependent.

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A modeling approach to quantifying soil macroaggregate dynamics

Canadian Journal of Soil Science ◽

10.4141/s01-024 ◽

2002 ◽

Vol 82 (2) ◽

pp. 181-190 ◽

Cited By ~ 41

Author(s):

A F Plante ◽

Y. Feng ◽

W B McGill

Keyword(s):

Organic Matter ◽

Aggregate Size ◽

Soil Aggregate ◽

Size Fractions ◽

Significant Control ◽

Modeling Approach ◽

Growing Seasons ◽

Organic Matter Dynamics ◽

Aggregate Turnover ◽

Aggregate Dynamics

While several researchers have suggested that soil aggregate turnover is a significant control on organic matter dynamics, the quantification of soil aggregate dynamics has yet to be achieved. Quantification of soil aggregate turnover is essential to testing any hypothesis concerning the relationship between aggregate turnover and organic matter dynamics. The goal of the current work was to propose a modeling approach to the quantification of soil macroaggregate dynamics. The approach taken was to define model compartments representing water-stable soil aggregate size fractions and describing the flows between compartments using first-order kinetics. Soil aggregate data from a 2-yr field study on two contrasting soils were used to calibrate the model and yielded soil aggregate mean residence times ranging from 4 to 95 d, where aggregate dynamics were generally two to three times more rapid in a Gray Luvisol compared to a Black Chernozem. The model was subsequently used to predict the distribution of applied tracer spheres in water-stable aggregate size fractions from an initially free state. The models closely predicted the Dy "mean weight diameters" (Dy-MWD) after two growing seasons. While the models have several limitations, they offer the first attempt to quantitatively describe soil macroaggregate dynamics, which is essential to predicting the response in organic matter dynamics to changes in aggregate dynamics. Key words: Soil aggregation, macroaggregate turnover, tracer, model

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