Spectroscopic and chemical differences in organic matter of two vertisols subjected to long periods of cultivation

Soil Research ◽  
1987 ◽  
Vol 25 (3) ◽  
pp. 323 ◽  
Author(s):  
JO Skjemstad ◽  
RC Dalal
Keyword(s):  
Organic Matter ◽  
Continuous Cultivation ◽  
Clay Soils ◽  
Native Vegetation ◽  
Alkyl Chains ◽  
Degree Of Protection ◽  
13C Nuclear Magnetic Resonance ◽  
Humic Materials ◽  
Humic Fractions ◽  
Microbial Attack

The nature of a number of humic fractions extracted from the 0-0.1 m layers of two cracking clay soils was studied using 13C nuclear magnetic resonance and infrared spectroscopy. By comparing samples from sites under native vegetation and nearby sites which had been under continuous cultivation for cereal cropping for 35 years, two different mechanisms which act to protect organic matter against decline are evident. In both grey clays (Langlands-Logie clay) and black earths (Waco clay), a large proportion of the organic matter receives some degree of protection through association with clay. In grey clays, this is the only significant form of protection. The humic materials display little molecular recalcitrance and contain significant amounts of long alkyl chains and proteinaceous groups. In black earths, association of organic matter with clay is also the most significant factor but, in addition, the remaining humic materials are more stable to microbial attack. This results from higher aromaticity as well as shorter, more highly branched alkyl chains. Some implications of these findings are also discussed.

Activité phosphatasique de quelques sols tropicaux à argile 1: 1. Répartition dans les fractions granulométriques

1994 ◽  
Vol 74 (2) ◽  
pp. 121-129 ◽  
Author(s):  
C. Feller ◽  
E. Frossard ◽  
M. Brassard
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Phosphatase Activity ◽  
Mineral Soil ◽  
Clay Fraction ◽  
Continuous Cultivation ◽  
Clay Soils ◽  
Size Fractionation ◽  
Particle Size Fractionation ◽  
Low Activity

The objectives of this work were: (i) to study the acid monophosphoesterase activity (pH 6.5) of the surface horizons of low-activity tropical clay soils (West Africa, West Indies, Brazil), cultivated or uncultivated, with widely different textures and organic matter (OM) contents, (ii) to measure the phosphatase activity (Pase) in the organic and organo-mineral soil fractions obtained by particle size fractionation. Pase was most significantly correlated to the soil OM content and to a lesser extent to the texture and total P content. Therefore, any modification in soil management resulting in important changes in soil OM contents, leads to important variations in phosphatase activity: Pase decreases after clearing of the native vegetation and continuous cultivation, Pase increase when grass-fallows or meadows succeed to annual cropping. The Pase of all the size fractions (20–2000 μm, 2–20 μm and 0–2 μm) was controled by their OM content. However, the "potential Pase" defined as the ratio Pase/C was higher in the 20- to 2000-μm and 0- to 2-μm fractions than in the 2–20 μm ones This is attributed to a higher Pase renewal by root restitutions in the plant debris fraction (20–2000 μm) and by microbial activity and microbial metabolites in the organo-clay fraction (0–2 μm). More than 50% of the soil total Pase was associated with fractions coarser than 2 μm. Most of the changes in Pase (75–100%) associated with the cultivation were ascribed to these fractions. This illustrate the probably important role of the fractions coarser than 2 μm in the phosphorus dynamics in these soils. Key words: Phosphomonoesterase, organic matter, particle size fractionation, low-activity tropical clay soils

Effect of Native Vegetation Loss on Stream Ecosystem Processes: Dissolved Organic Matter Composition and Export in Agricultural Landscapes

Ecosystems ◽  
2013 ◽  
Vol 17 (1) ◽  
pp. 82-95 ◽  
Author(s):  
Darren P. Giling ◽  
Michael R. Grace ◽  
James R. Thomson ◽  
Ralph Mac Nally ◽  
Ross M. Thompson
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Ecosystem Processes ◽  
Agricultural Landscapes ◽  
Native Vegetation ◽  
Stream Ecosystem ◽  
Organic Matter Composition ◽  
Vegetation Loss

Continuous cultivation of West African soils: Organic matter diminution and effects of applied lime and phosphorus

1971 ◽  
Vol 35 (1-3) ◽  
pp. 401-414 ◽  
Author(s):  
E. A. Brams
Keyword(s):  
Organic Matter ◽  
Continuous Cultivation ◽  
West African

ORGANIC MATTER CHARACTERISTICS OF UNDISTURBED AND CULTIVATED CHERNOZEMIC AND SOLONETZIC A HORIZONS

1979 ◽  
Vol 59 (4) ◽  
pp. 349-356 ◽  
Author(s):  
J. F. DORMAAR
Keyword(s):  
Organic Matter ◽  
Humic Substances ◽  
Chelating Resin ◽  
Anthropogenic Pressures ◽  
Organic C ◽  
Amide Bonds ◽  
Acid Ratio ◽  
Humic Materials ◽  
Fallow System ◽  
Extractable Organic Matter

Under a wheat-fallow system of farming practised on Brown, Dark Brown, and Black Chernozemic soils, on a Black Solodized Solonetz, and on Brown and Black Solods, organic C decreased by as much as 60%; the humic acid/fulvic acid ratio decreased little for the semiarid soils but up to 38% for the Black soils; ethanol/benzene-extractable organic matter increased by as much as 330%; chelating resin-extractable C increased by 27–115%; and total acidity of the extracted humic substances increased up to 36%. The ash contents of the humic substances from the Ah horizons were all less than 12%, whereas those of the Ap horizons varied between 20 and 28%. Apparent differences between the infrared spectra of the resin-extractable humic substances of the Ah and Ap horizons existed particularly near 2920 and 1550 cm−1 suggesting less aliphatic C-H and amide bonds. Anthropogenic pressures have wrought, therefore, distinct measurable qualitative changes, i.e., the general trend with cultivation was towards humic materials with a decreased proportion of side chain components, such as C-H and NH2 groups, but increased carboxyl group content.

Molecular characterization of soil organic matter from native vegetation–pasture–sugarcane transitions in Brazil

2016 ◽  
Vol 548-549 ◽  
pp. 450-462 ◽  
Author(s):  
Dener Márcio da Silva Oliveira ◽  
Judith Schellekens ◽  
Carlos Eduardo Pellegrino Cerri
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Molecular Characterization ◽  
Native Vegetation

Ozonation of natural organic matter and aquatic humic substances: the effects of ozone on the structural characteristics and subsequent trihalomethane formation potential

2020 ◽  
Vol 55 (2) ◽  
pp. 155-166
Author(s):  
Mehrnaz Sadrnourmohammadi ◽  
Kenneth Brezinski ◽  
Beata Gorczyca
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Structural Characteristics ◽  
Aromatic Rings ◽  
Formation Potential ◽  
Trihalomethane Formation Potential ◽  
Vis Spectroscopy ◽  
Reflectance Ftir ◽  
Main Components ◽  
Humic Fractions

Abstract The effect of ozonation on the structural and chemical characteristics of natural organic matter (NOM) and its isolated humic fractions, humic acid (HA) and fulvic acid, were studied using Fourier transform infrared coupled to attenuated total reflectance (FTIR-ATR), ultraviolet/visible (UV/Vis) spectroscopy, and synchronous scanning fluorescence (SSF) spectroscopy. The results were linked to the effect of ozonation on trihalomethane formation potential (THMfp) reduction for water standards with high THM precursors. Results showed that ozonation at a dose of 1 mg ozone/mg dissolved organic carbon (DOC) was capable of reducing DOC, UV absorbance at 254 nm (UV254), and THMfp by up to 42%, 95%, and 89% for the HA water standard, respectively. The study of UV/Vis, FTIR-ATR, and SSF revealed trends showing that ozone can alter the composition of DOC in the water standards, causing a significant reduction in aromaticity. The reduction of UV254 for each ozonated sample also affirms that ozone mainly targets aromatic moieties contained in NOM. FTIR-ATR results showed that the reduction of unsaturated functional groups, including aromatic rings and C = C bonds in the water standards tested, were the main components impacted by ozone application. SSF results also revealed that ozonation decreases the fluorescence intensity of the maximum peak – as well as the whole spectra.

N2-BET SPECIFIC SURFACE AREAS OF SOME LOW ACTIVITY CLAY SOILS AND THEIR RELATIONSHIPS WITH SECONDARY CONSTITUENTS AND ORGANIC MATTER CONTENTS

Soil Science ◽  
1992 ◽  
Vol 153 (4) ◽  
pp. 293-299 ◽  
Author(s):  
CHRISTIAN FELLER ◽  
ELISABETH SCHOULLER ◽  
FABIEN THOMAS ◽  
JAMES ROUILLER ◽  
ADRIEN J. HERBILLON
Keyword(s):  
Organic Matter ◽  
Specific Surface ◽  
Clay Soils ◽  
Surface Areas ◽  
Specific Surface Areas ◽  
Low Activity

ESTIMATION OF SOIL EROSION AND DEPOSITION BY A LANDSCAPE ANALYSIS TECHNIQUE ON CLAY SOILS IN SOUTHWESTERN SASKATCHEWAN

1983 ◽  
Vol 63 (4) ◽  
pp. 727-739 ◽  
Author(s):  
A. R. MERMUT ◽  
D. F. ACTON ◽  
W. D. EILERS
Keyword(s):  
Organic Matter ◽  
Landscape Analysis ◽  
Clay Soils ◽  
Erosion And Deposition ◽  
Swelling Clay ◽  
Analysis Technique ◽  
Native Grassland ◽  
Close Relationship ◽  
Organic Matter Loss ◽  
The Relationship

The thicknesses of self-mulching A horizons were studied in native grassland and cultivated glaciolacustrine clay soils in southwestern Saskatchewan to estimate the extent of erosion and evaluate the relationship between slope characteristics, erosion and sedimentation. It has been shown that under similar gradient, the thickness of the A horizon, in the erosional portion of slopes, is less under cultivated than native grassland conditions; whereas, in the depositional portion the thickness of the A horizon is greater under cultivation. Erosion equations were developed which indicated 7.4 kg∙m−2∙yr−1 or 0.57 cm/yr for a 7.5% backslope and 2.1 kg∙m−2∙yr−1 or 0.16 cm/yr for 2% backslope. Calculated losses of organic matter from the most severely eroded slopes amounted to 650 kg∙ha−1∙yr−1. Comparable losses of nitrogen were 65 kg∙ha−1∙yr−1. This represents a 41% and 35% loss in organic matter and nitrogen, respectively, under nearly 70 yr of cultivation. The very close relationship shown in this study between various slope attributes and erosion clearly indicates the importance of slope considerations in all erosion studies. Key words: Erosion, deposition, swelling clay soils, landscape analysis, organic matter loss

Genesis of podzols on coastal dunes in southern Queensland .IV . Nature of the organic fraction as seen by 13C nuclear magnetic resonance spectroscopy

Soil Research ◽  
1992 ◽  
Vol 30 (5) ◽  
pp. 667 ◽  
Author(s):  
JO Skjemstad ◽  
AG Waters ◽  
JV Hanna ◽  
JM Oades
Keyword(s):  
Organic Matter ◽  
Carboxylic Acid ◽  
Signal To Noise Ratio ◽  
Coastal Dunes ◽  
Resonance Spectroscopy ◽  
Organic Fraction ◽  
Aromatic Rings ◽  
13C Nuclear Magnetic Resonance ◽  
Close Proximity ◽  
Inorganic Components

The organic matter in the A, Bh, Bhs and Bs horizons from a number of profiles from a chronosequence of podzols spanning some 7x105 years was studied using solid state 13C n.m.r. spectroscopy. Organic matter was effectively concentrated without chemicals using a Spex mixer and sedimentation. Acid dithionite treatment of samples containing appreciable amounts of iron significantly improved the signal to noise ratio. Acid oxalate treatment had a lesser effect. The organic matter from the A horizon was highly aromatic but was low in carboxylic acids. In the B horizons, aromaticity decreased in the order Bh-Bhs-Bs and increased with the degree of profile development. Only in the Bh horizons of the older highly developed profiles did aromatic carbon exceed alkyl carbon. The 'core' structure of these materials appeared to be aromatic rings heavily substituted (>90%) with alkyl and carboxylic acid groups. The Bhs and Bs horizons contained substantial amounts of carboxylic acid substituted alkyls with structures similar to the polymaleic or hydroxy acid models. Sixty per cent of the organic matter removed with iron on dithionite treatment was found to be alkyl. The aromatic and alkyl dominated horizons can exist in close proximity, occurring less than 10 cm apart in the case of the giant pipey podzols. None of the current theories on podzol genesis can adequately explain the arrangement of organic and inorganic components found in these profiles and a revised model based on existing theories is proposed.

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