Search

The stability of black soil carbon in the deep layers of Japanese volcanic ash soil (i.e., buried A horizons) is often explained by its unique chemical (molecular structure) and physical (associate...

The maximum ammonia oxidation potential (AOP) of a topsoil in Langhovde, East Antarctica was 22.1±2.4‍ ‍ng N g-1 dry soil h-1 (2‍ ‍mM ammonium, 10°C, n=3). This topsoil exhibited twin AOP peaks (1 and 2‍ ‍mM ammonium) at 10°C, but not at 20°C. Six and ten operational taxonomic units (OTUs) were identified for ammonia-oxidizing bacteria (AOB) and archaea (AOA) amoA, respectively. AOB were classified into Nitrosospira; the two dominant OTUs corresponded to the Mount Everest cluster. AOA were classified into three clusters; Nitrososphaera and Nitrosocosmicus were the two dominant clusters.

The response of soil organic matter (SOM) to global warming is a crucial subject. However, the temperature sensitivity of SOM turnover remains largely uncertain. Changes in the mineralization of na...

The characteristics of humus composition are important for understanding the mechanism of carbon storage in the Qinghai–Tibet Plateau. The aim of this study was to characterize the quality ...

We investigated a series of long-term soil samples (1976–2015) collected from a paddy field that underwent a conversion of cropping systems from double cropping to single cropping in 1991, with consistently different fertilization treatments. The fertilization treatments include (i) chemical fertilizer, (ii) chemical fertilizer + rice straw, (iii) chemical fertilizer + cattle manure compost, and (iv) chemical fertilizer + rice straw + fused phosphate + calcium silicate. We extracted dissolved organic matter (DOM) from the soil samples and analyzed it for the concentration of humic substances as well as for optical properties using ultraviolet-visible and excitation-emission matrix (EEM) spectroscopy. Different fertilization treatments did not significantly (P > 0.05) affect DOM and humic substance concentrations, while the soil total carbon (TC) content and DOM concentration consistently increased in the double cropping system and decreased in the single cropping system. The DOM/TC ratio, which is an indicator of the proportion of the labile fraction in TC pool, also showed a similar pattern. These results indicate that cropping systems had a larger effect on DOM concentration than the fertilization treatments. Five fluorescent components identified by parallel factor analysis of EEMs (three humic-like and two protein-like components) showed significant differences in the relative abundances under the different fertilization treatments. The manure compost application resulted in a higher tyrosine-like component relative abundance than the other chemical fertilizer applications. Overall, fertilization affected the DOM composition, while the cropping systems impacted both the concentration and spectroscopic property of paddy soil DOM.

A five-step sequential extraction procedure was developed for the partitioning of soil aluminum (Al) into five fractions: exchangeable, weakly organic bound, strongly organic bound, inorganic non-crystalline and crystalline. The results obtained by the sequential extraction method for Al were compared with those estimated from single extractions using identical operating conditions applied in each individual sequential fraction. The Al content in the extracts was measured by inductively coupled plasma optical emission spectrometry. The results indicated that the first four steps [potassium chloride (KCl), copper chloride (CuCl2), sodium pyrophosphate (Na4P2O7), acid ammonium oxalate ((NH4)2C2O4)] in the sequential procedure could be as effective as single extraction methods at estimating exchangeable Al, weakly organic bound Al, strongly organic bound Al, and non-crystalline Al. However, the crystalline Al content by sequential procedure was not in agreement with single extraction procedures. Further, the...

To examine the effect of vegetation type and grassland management regimen on the distribution of humus-degrading microorganisms, populations of humic acid-degrading (HAD) bacteria and fungi at three Andosol sites were investigated using the dilution plate method. Each site had three different vegetation types (Eulalia grassland, bamboo grassland, and coniferous plantations). Among the six grassland sites, two were maintained by burning and the others by cutting. HAD microorganisms were found in all soil samples. Low densities and small percentages of HAD bacteria were detected with no significant differences in the number of bacteria found between different vegetation types and grasslands managed in different ways. In contrast, the densities and percentages of HAD fungi differed according to vegetation type and management regimen. Specifically, the percentages of HAD fungi were significantly higher for burned grasslands. At burned sites, the numbers and percentages of HAD bacteria remained at a consistently low level, and no distinct seasonal changes were observed. In contrast, marked seasonal fluctuations in HAD fungi were detected. The percentages of these fungi remained relatively high between April and December. These fluctuations are likely due to the effects of burning on soil microorganisms.

Chemical properties of hydrophobic acid (HoA) fractions in water-soluble organic matter in soil and water are concerned with its interactions with mineral soil surfaces and organic pollutants. In 2004 we examined the seasonal and vertical changes in chemical properties of the HoA fraction in a Cambisol profile and compared these properties with those in the HoA fraction of an adjacent stream (aquatic humic substances) in a temperate forested watershed using high performance size exclusion chromatography (HPSEC) and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The HoA fractions from Oi, Oe/Oa, A and B horizon soils in summer had lower O-alkyl C proportions than those recorded in samples in other seasons. The proportions of aromatic C in HoA fractions from A and B horizons were highest in summer. These seasonal variations were less significant than variations with soil depth. O-alkyl C proportions in HoA fractions decreased with increasing soil depth from the Oi to the A horizon. The H...

14C ages and δ13C were examined for sclerotium grains to elucidate the characteristics of these grains distributed in forest soils. The ages of the grains from surface A horizons and buried A horiz...

To clarify the formation condition of Type A humic acids (HAs) from plant residues and to contribute to reducing CO2 emission, three plant residues were incubated for 0, 25, 50, 100 and 160 days with fresh volcanic ash and water at 90°C to produce humic acid like substances (HALS). The HALS of all incubation samples showed a decrease in log (A 400 /A 600 ) values and an increase in A 600 /C values with increasing incubation time. When HALS were classified, only rice straw HALS of 160 days (RS160) belonged to Type A, whereas broad leaf HALS of 160 days (BL160) and Japanese cedar sawdust HALS of 160 days (JCSD160) belonged to Type B. For elemental and nuclear magnetic resonance (NMR) analysis, the HALS samples were prepared according to the International Humic Substances Society (IHSS) method. Data from the elemental composition of all HALS showed high contents (45.98 to 56.55) of carbon (C), low (3.19 to 5.16) hydrogen (H), and low (0.33 to 2.36) nitrogen (N). Carbon content increased in RS and BL...

The vertical distribution of the content of the chloroform-extractable green fraction (CEGF) in the soil profiles of four Japanese Andosols, one Japanese Cambisol and one Nepalese Cambisol was examined using a colorimetric method with an ultraviolet and visible spectrophotometer. In addition, the relationship between the CEGF content and the soil chemical properties was examined by statistical analysis. CEGF was detected in all the soil samples, and the content ranged from 0.02 to 1.16 g kg−1. The CEGF content in the surface A horizon of the Andosol tended to be higher than in the Cambisol. The vertical distribution of the CEGF content in three soil profiles (two Andosol profiles and one Nepalese Cambisol) revealed maximum values in the subsurface horizon. In the Japanese Cambisol, the content of the CEGF was highest in the surface horizon. In the remaining two Andosol profiles containing a buried humus horizon, the content of the CEGF was highest in the buried humus horizon and the distribution ...

The chemical composition of the hydrophobic acid fraction, which is adsorbed to XAD-8 resin at low pH and desorbed with high pH solution, of water-extractable organic matter in soil probably influences its environmental role and, therefore, it is important to recognize the differences in its chemical composition with season and soil horizon. Hydrophobic acid fractions were collected seasonally in 2004 from Oi, Oe/Oa, A and B horizons of Cambisol and were investigated using elemental analysis, high-performance size exclusion chromatography and 1H nuclear magnetic resonance (NMR) spectroscopy. Atomic ratios of H/C and O/C decreased with increasing soil depth in winter and summer, suggesting that the hydrophobic acid fraction from lower mineral horizons had lower saturated bond content and carbohydrate content than the fractions from upper organic horizons. Based on high-performance size exclusion chromatography, the molecular weight at peak maximum of the hydrophobic acid fraction decreased signifi...

The effect of three inorganic minerals on the humification of three types of plant residues was determined by employing a model thermal incubation experiment. The plant residues consisiting of rice (Oryza sativa) straw, broadleaf tree (a mixture of oak/beech, Quercus serrata, Q. dentata, Q. acutissima etc.) sawdust and Japanese cedar (Cryptomeria japonica) sawdust were each mixed with Fe, Mn and Al in the form of hydroxides, oxides and sulfates. Humic materials were extracted after incubation and their composition was analyzed using a mixed solution of 0.02 M Na4P2O7 and 0.1 M NaOH. The pH values of the samples after a longer duration of the incubation period were all less than 5.0, with the lowest value of 2.16 for a sample incubated with Al2(SO4)3, except for the values of the samples incubated with MnO2, which ranged from 4.75 to 6.0. The ΔlogK values decreased with the increase of the duration of the incubation period, whereas the RF values increased, as well as the amount of humus extracted (HE) and ...

Chloroform-extractable green fraction (CEGF) was detected in the supernatant obtained by alkali precipitation from the HCI-dimethylsulfoxide (DMSO) extract of Pg-rich soil. In the alkaline solution, the color of CEGF was green and CEGF showed strong Pg-like absorption bands. Ultraviolet and visible (UV-VIS) spectral analysis and gel chromatography on Sephadex G-50 were performed to compare several properties between CEGF and Pg. CEGF, which was purified by gel chromatography on Bio-Beads SX-1, displayed strong absorption bands at 609, 562, 445 and 280 inn in the alkaline solution. These absorption bands were almost similar to those of Pg. Furthermore, the UV-VIS spectrum of CEGF in the organic solvents showed a similar characteristic pattern of 4,9-dihydroxyperylene-3,10-quinone (DHPQ), which was considered to be a chromophore of Pg. Based on the results of gel chromatography on Sephadex G-50, CEGF mainly consisted of two fractions, corresponding to the G2 and G3 fractions of Pg. These results indicated t...

The presence of aluminum oxyhydroxide and its micromorphological characteristics in sclerotium grains were examined by SEM, TEM, and EDX analyses. A spherical fraction with a diameter of 100 nm, which contained C and Al as the predominant elements, was recognized as the unit particle of the matrix of sclerotium grains. The Al polymorphs and the Si spherical structures found in the ignited grains were assumed to correspond to boehmite and opaline silica particles, respectively. SEMI analysis revealed the presence of a needle ball structure inside the hollow part of sclerotium grains. The relationship between the inner structure of sclerotium and biochemical processes of the host fungi was discussed.

Relationships between the distribution of fungal sclerotium grains and soil chemical properties were studied in forest soils of Podsole, Braunfahlerde, and Braunerde-Podsoles in Harz Mts., Germany. Development of sclerotium grains ns was dominant in surface horizons (Ah, E horizons) within a 10-cm depth and weight density of grains ranged from 0.01 to 4.99 g kg-1 soil. The SEMI-EDX analysis proved that the weight percentage (excluding C and N) of Al2O3 was 39.8–63.9% inside the grains. The content of elgosterol, a biomarker of viable fungal biomes, showed good correlations with weight density of sclerotium grains in grain-detected soils. The sclerotium. grains were likely to be formed in soils with high ratios (>0.6) of organic bonding Al (Alp) to amorphous Al (Alo), and with high contents of exchangeable Al (Al3+) (>0.54 g kg-1). The content and state of active Al were believed to be responsible for the development of sclerotium because sclerotium grains were not detected in acid soils which had...

It will be important in future analyses of humic acids (HAs) by various chromatographic and spectrometric methods to obtain high yields of methylated HAs. A derivatization procedure for permethylation of HAs was evaluated in relation to the yield of the chloroform-soluble fraction. The procedure involved a 3 h incubation of HAs (50 mg) with methylsulfinyl carbanion (MSC) obtained by mixing petroleum-purified NaH with anhydrous dimethylsulfoxide (DMSO), followed by incubation with methyl iodide (CH3I). Ten HAs isolated from different Japanese and American soils (three Andisols, four Inceptisols, one Histosol, one Alfisol, and one Ultisol) were used to optimize this procedure. Optimum derivatization was achieved within the first 6 h after the addition of MSC and CH3I; further incubation (up to 24 h) did not result in significant changes in the yield of the chloroform-soluble fraction (60–100%). For most HAs, the maximal yields of chloroform-soluble fractions were obtained at concentrations of 10 mM...

The FT-IR and 1H NMR spectra of humic acids, which were obtained from four soils of different types (a Fibric Histosol, Dystric Cambisol, Umbric Andosol, and buried Umbric Andosol) by sequential extraction with pyrophosphate solutions at different pH values (i.e. at pH 3, 5, 7, 9, 11, and 13), were measured. The shape of the IR spectra for each humic acid depended on the differences in the soil origin rather than the pH values. The IR spectra of humic acids in the Histosol and Cambisol showed typical absorption associated with lignin. The humic acids in the Andosol and buried Andosol were characterized by the disappearance of the absorption assigned to aliphatic C-H and the prominence of the absorption attributed to aromatic C=C and COOH groups. The humic acids in the Histosol and Cambisol showed aliphatic properties compared with those in the Andosol and buried Andosol. As the pH values of tile extractant increased, the absorption strength of the bands attributed to aliphatic and amide groups in...

Humic acids (HAs) from 15 different soil samples were added to Czapek-Dox media inoculated with Coriolus consors IFO 9078. After 14 d incubation, decolorization of these culture media at 600 nm absorbance was measured. The aromaticity, the E 1% 600 value, the total acidity, and the elemental composition of the HAs were also determined, and the relationships between the decolorization and the chemical properties of HAs were examined. Percentage of decolorization of these culture media ranged from 8.8 to 39.5%. Andisol HAs showed a lower percentage of decolorization than the Inceptisol HAs. Percentage of decolorization showed highly negative correlations for the aromaticity, the E 1% 600 value, and the O / H ratio, and highly positive correlations for the hydrogen content and the H / C ratio. In particular, the highest correlation coefficient (r = −0.836**) was obtained between the aromati city and the decolorization. In addition, the HAs with a lower decolorization were arranged in the direction o...

A small spherical black fungal sclerotium grain from podzolic soils, which was tentatively identified as the resting body of Cenococcum graniforme, was assumed as the source of green polynuclear quinone pigments in P type humic acid (K. Kumada and H.M. Hurst, Nature 214: 631-633, 1967). To examine the presence of bacteria inside sclerotium grains collected from an Andosol profile in Mt. Myoko, central Japan, the grains were repeatedly washed, ultrasonicated and then cultured on diluted nutrient broth. The sum of recovered bacteria as colony-forming units from the wash and ultrasonicate fractions was 1.46×106 (g fresh weight)-1: 88% of the count in the wash fractions (assumably resulting from grain surface and attached soil) and 12% in the ultrasonicate (inside grain). Thirty-one bacterial strains were isolated from the ultrasonicate fraction and their 16S rDNA partial sequences were determined. The predominant group was the Alphaproteobacteria (71%), chiefly the Sphingomonas group (52%). Representative isolates of the Sphingomonas group were examined for their ability to grow on naphthalenesulfonic acids as a model compound of polycyclic aromatic hydrocarbons (PAHs) and also on several phenolic acids. None of the isolates tested utilized the model PAH but many of them used p-hydroxy benzoic, vanillic, p-coumaric and ferulic acids for growth. Based on these results, the relationship between the predominance of Sphingomonas and the chemical character of the sclerotium grain was discussed.

The distribution of sclerotium grains, which are considered to be the resting bodies formed by fungi species, was studied in 5 Andosol profiles in central Japan. Sclerotium grains were detected in the surface A and buried A horizons of nonallophanic (Alp / Alo > 0.5) soils but not in allophanic (Alp / Alo < 0.5) soils. The maximum density of the sclerotium grains in each profile was approximately 2.5 g kg−1. A highly positive relationship was observed between the mean weight of the sclerotium grains and the content of exchangeable aluminum (Al3+) in soils. Aluminum concentration inside of the sclerotium grains was confirmed by energy dispersive X-ray spectrometer (EDS) analysis. The results obtained suggest that the status of active Al in soils is an important factor for sclerotium development.

Viscosity and molecular weight of particle size fractions obtained from an Andosol humic acid (HA) were determined. Viscosity was determined both in solutions with and without the addition of 0.1 M NaCl (Cs 0.1 and Cs 0, respectively) at pH 7.0. Polyelectrolytic character was observed in the particle size fractions based on the changes in the concentration dependence of reduced viscosity with NaCI concentrations. The use of a Cs 0.1 solution was suitable for the determination of the values of intrinsic viscosity ([η]) of the particle size fractions. The [η] value increased with increasing weight average molecular weight ( M w) determined by gel permeation chromatography (GPC), and ranged from 4.3 to 12.9 X 10-3 (L g-1) in the Cs 0 solution and from 3.5 to 6.6 × 10-3 (L g-1) in the Cs 0.1 solution. A linear relationship between [η] in the Cs 0.1 solution and M w on a logarithmic scale, which was similar to the MarkHouwink equation, was observed. The value of the constant a calculated from the rela...

The morphology and chemical composition of fungal sclerotium-like grains collected from the buried humic horizon of volcanic ash soil in Mt. Myoko were examined using a scanning electron microscope (SEM), energy dispersion xray micro-analyzer (EDX), and electron probe micro-analyzer (EPMA). A high C content, low level of Si and high concentration of Al characterized the grains considered to correspond to the sclerotia of Cenoccocum graniforme. The 27Al MAS NMR spectrum of the sclerotia showed the existence of 6- and 4-coordinated Al. X-ray diffraction analyses supported the presence of amorphous Al (ex. Al-humus complex) in the sclerotia.

The vertical distribution of main soil hydroxyanthraquinones (HAQs) in the soil profiles of five Japanese Andosols, one Japanese Gambisol, and one Nepalese Gambisol was analyzed quantitatively, using high performance liquid chromatography and thin Bayer chromatography with a two stage development accompanied by scanning densitormetry. The results were as follows: The vertical distribution patterns of chrysophanol (CIPL) and its dimers in Andosols profiles shewed maximum contents in the middle past of the surface horizon. The vertical distribution of physcion (PYS) and its dimers in soil profiles showed various patterns in each profile. AdditionaBPy, we investigated the vertical distribution of HAQs in AndosoPs under a Miscanthus sinensis grassland, and in an adjacent successional red pine (Pinus densiflora) forest at Sugadaira, Central Japan. En the surface soil (0–15 cm), the contents of the dimers of CPL (microcarpin and chrysotalunin) slightly increased and those of the dimers of PPS (7,7′-bip...

Elemental composition and solution 13C NMR spectra for six humic acid fractions with different particle sizes (i.e. 3K, 10K, 30K, l00K, 300K, and 500K) which were prepared from a humic acid in an Umbric Andosol by successive gel permeation chromatography were determined. Elemental composition of the particle size fractions clearly differed from one another. Contents of nitrogen and hydrogen increased with the increase of the particle size. Small and middle particle size fractions (3K to l00K) showed low contents of hydrogen and nitrogen corresponding to those in typical Andosol humic acids, while the contents in the large fractions (300K and 500K) were distributed in the ranges of those in the other humic acids. As the particle size increased, the HIC ratio increased whereas the O/H decreased. In the HIC versus OIC diagram, the large particle size fractions (300K and 500K) were observed in the area around humic acids with a low humification degree. Variation of the chemical structural properties ...

Six hydroxyanthraquinones (chrysophanol, chrysotalunin, microcarpin, physcion, 7,7′-biphyscion, and hinakurin) present in the samples of 26 surface soils were quantitatively analyzed, and the contents of HAQs in soil types were compared. The soil samples had been collected from 19 Umbric Andosols and seven Distric Cambisols, and the Andosols were further subdivided into those with allophanic soil materials (exchange acidity (y 1

The relationships between surface active properties and humic acid (HA) particle sizes were investigated. Two HAs from an Ando soil and a Brown forest soil were separated into 6 particle size fractions by gel permeation chromatography. Surface-active properties characterized by surface excess value (\gT mol cm-2), cross-sectional surface area per molecule (A nm2), critical micelle concentration (CMC g L-1), efficiency and effectiveness of water surface tension reduction were obtained by the measurement of the surface tension of HA solutions from different particle size fractions. For the HA from the Ando soil, except for the smallest particle size fraction, increasing particle size enhanced the efficiency of reduction of the water surface tension and decreased the CMC, while the effectiveness of reduction of the water surface tension was about the same. The surface activity of the HA from the Ando soil increased with increasing particle size. This phenomenon was similar to the surface activity of...

Humic acids (HAs) extracted from an Umbric Andosol (UA) and a Dystric Cambisol (DC) were fractionated into 7 fractions by successive gel permeation chrontatography (GPC) and their fractions were studied by spectral analysis. With increasing particle sizes, the absorption of methylene groups and amide of peptides increased in the IE spectra of both HAs and that of carboxylic groups decreased in the IR spectra of UA, the HA obtained from an Umbric Andosol. Based on the 1? NMR data in UA, there was a significantly negative linear correlation (−0.950, p< 0.001) between Har (δ 6.0-9.0 ppm) and HC-O (δ 3.0-4.3 ppm). Such a negative linear correlation (−0.868, p

Electromagnetic scattering (e.g., light scattering, small-angle X-ray scattering, and small-angle neutron scattering) provides information on the size and shape of colloidal particles in a highly dispersed system (Feigin and Svergun 1987). The technique has been applied to various materials including biological macromolecules, synthetic polymers, amorphous solids, and other colloidal compounds (Feigin and Svergun 1987). Several attempts have also been made to evaluate the size and shape of humic acid in solution using the scattering techniques (Wershaw and Pinckney 1989; Osterberg et al. 1993).

Humic acid (HA) are too polydispersed to obtain information about their particle weight, size and shape. It is, therefore, desirable about determination of physicochemical parameters of HA to reduce the HA polydispersion by using fractionation techniques.

The occurrence of chrysotalunin (CLN), a major soil anthraquinone pigment, has been reported in various soils of the world (McGrath 1967, 1970, 1972; Matsui and Kumada 1974; Foo and Tate 1977). The concentration of CLN occasionally amounted to ca. 120 mg kg-1 in the Irish podzol Bh horizon (McGrath 1972) or ca. 200 mg kg-1 in the Kauri podzol Bh horizon from New Zealand (Foo and Tate 1977). However, little attention had been paid to the occurrence and distribution of CLN hitherto. Recently, we have developed a method for the isolative determination of CLN in soils by HPLC (high performance liquid chromatography) coupled with the acetylation of CLN (Fujitake et al 1991b). Subsequently, we observed that CLN was ubiquitous in the Japanese surface soils and there was a certain regularity in the distribution of the CLN contents among different soil types or under different vegetation cover (Fujitake et al. 1991a). In this paper the vertical distribution of CLN in various soil profiles of Japan is repo...

The contents of chrysotaiunin (CLN) in Japanese surface soils were first measured by isolative determination using high performance liquid chromatography (HPLC). These soil samples (N=67) which consist of red soils, yellow soils, dry podzolic soils, brown forest soils, black soils, and immature soils, were taken from various locations in Japan extending from the southern subtropical to the northern subarctic regions. All the soil samples (N=67) gave CLN contents ranging from 0.1 to 29.1 ppm. The average CLN content of the black soils which was 10.2 (±1.4, S.E.) ppm (N=36), was about two times as high as that of the brown forest soils (4.8±1.2 ppm, N=19). A significant difference was found in the CLN contents among black soils, brown forest soils, and the soils belonging to other types (p

A variety of higher plants and microorganisms, especially soil fungi, form anthra-quinone pigments (Thomson 1987) and, although many of these compounds are biologically active as antibiotics, chelating agents and possible contributors of humic substance formation (Kumada 1987), little information is available about their distribution and role in soil systems.