Shigemitsu Arai

Comparison of two methods of preparation of humic and fulvic acids, IHSS method and NAGOYA method

Abstract Two methods for preparing soil humus samples, NAGOYA (Nagoya University) method and IHSS (International Humic Substances Society) method, were compared using A-horizons of an acid brown forest soil and an ando soil. Alkali-extractable humus was recovered more effectively by the NAGOYA method, while the IHSS method recovered only 80 and 26% of the maximum yield by extraction with 0.1 N NaOH from both soils, respectively. The recoveries of fulvic acids (FAs) by the IHSS method in which XAD-8 was used as adsorbent to obtain only humic substances in the FA fraction from the brown forest soil and the ando soil were only 1/5 and 1/40, respectively, of those by the NAGOYA method in which the whole FA fraction was recovered. The FAs obtained by the NAGOYA method were further fractionated into adsorbed and non-adsorbed fractions with XAD-8 or insoluble polyvinylpyr-rolidone (PVP). The recoveries of the XAD-8-adsorbed fraction increased 3.8 and 26 times by changing the volumes of the extractant and adsorbe...

Comparison of the composition of humic and fulvic acids prepared by the IHSS method and NAGOYA method

Abstract The composition of humic acids (HAs) and fulvic acids (FAs) prepared by the NAGOYA (Nagoya University) method and the IHSS (International Humic Substances Society) method was investigated using an an do soil and a brown forest soil. Extraction with a smaller volume of 0.1 N NaOH in the IHSS method yielded HAs containing larger amounts of 0, carboxyl groups, alcoholic hydroxyl groups, hexoses, and uronic acids than those prepared by the NAGOYA method. The contents of C, carbonyl groups, and amino acids were higher in the HAs obtained by the NAGOYA method. The relative content of aromatic C was higher in the HAs prepared by the NAGOYA method, especially in the ando soil. The FAs prepared by the IHSS method contained smaller amounts of H, N, alcoholic hydroxyl groups, saccharides, and amino acids than the F As obtained by the N AGOY A method, mainly due to the XAD-8 treatment in the IHSS method. The saccharide and amino acid contents in the XAD-8-adsorbed fractions obtained from the FAs prepared by ...

An interpretation of the conductometric titration curve of humic acid

Methods of fractionating the functional groups of humic acid by conductometric titration were examined. Replacement titration, in which a sample solution is titrated with a standard acid solution after adding an excess amount of a standard base, seems to be a suitable method. By this method, the functional groups of humic acid were fractionated into three clusters of different dissociation constants, designated as VW (very weak), W (weak), and S (strong) clusters. The VW cluster was presumed to include phenolic hydroxyl residues, carboxyl residues and nitrogenous bases of very high pKs. The W cluster was presumed to include various aliphatic and aromatic carboxyl residues and nitrogenous bases of medium pKs, whereas the S cluster was presumed to include carboxyl residues of low pK1 of salicylate or phthalate. A humic acid sample obtained from the A horizon of Shitara “kuroboku” soil had 0.78 me/g of the VW cluster, 3.24 me/g of the W cluster and 1.90 me/g of the S cluster.

Extraction of active aluminum from acid soils in Japan with different reagents

Abstract The paper deals with methods of determining active aluminum in acid soils. Extraction reagents examined were 4 acids, 4 salts, and 11 compounds of chelating agents. The effects of different conditions, such as pH, temperature, shaking time and the ratio of solution to soil were observed. Barium salicylate solutions, in which the normal concentration of barium and the molar concentration of salicylate were 1.0 and 0.1 respectively, were found promising as extractants. Initial pH of the solution, shaking time and the ratio of solution to soil were set at 7.0, 2 hours and 50:1, respectively. Ammonium salicylate and ammonium EDTA also extracted active aluminum but amounts varied according to different conditions. The most promising procedure was applied to a few kinds of soils and to soil treated with either lime or phosphate. The amounts of aluminum extracted from soils high in humus were larger than those from soils low in humus. Liming or phosphate application decreased the amounts of aluminum extracted.

Changes in Soil Organic Matter and Nitrogen Fertility during the Slash-and-Burn and Cropping Phases in Experimental Shifting Cultivation

At the experimental field for the study of shifting cultivation set up in the forest of Iriomote Island in Okinawa, changes in pH, organic matter, and nitrogen fertility of soils after forest clearing by burning and during crop cultivation were investigated. The soils were sampled at six periods, I (before forest clearing), II (immediately before burning), III (immediately after burning), IV, V, and VI (10, 20, and 30 months after burning). Tilled and nontilled and other treatment plots were laid out, and cassava was grown twice. Soil pHs rose from periods I to III or IV, and then decreased. Carbon and nitrogen contents, the amounts of mineralizable nitrogen and nitrogen mineralization percentages decreased during cultivation. The amounts of humic and fulvic acids increased from periods I to II and decreased afterwards. The increase in NH4−N due to the soil-burning effect was observed. The changes in the above-mentioned parameters during the cultivation period were greater for the first layer (0–5 cm) tha...

Fractional determination of functional groups of humic acids by conductometric titration

Abstract The conductometric replacement titration proposed in a previous report disclosed that the functional groups of humic acids are fractionated into three clusters of different dissociation constants, designated as VW, W and S clusters. In this paper, the method was examined to ascertain the relationship between the concentration of a sample and the amounts of fractionated clusters. The total amounts of fractionated clusters as well as the amount of the S cluster were directly proportional to the concentration of the sample, whereas the amount of the VW cluster decreased a little as concentration increased. The same method, applied to various types of humic acids in Japan, showed that the sums of the functional groups and the ratios of the S cluster to the sums likewise decreased in the order of A type > B and P types > Rp type. The total acidities determined by conductometry were nearly equal to the sums of carboxyl determined by Bloms method and phenolic hydroxyl determined by Folins method.

Factors controlling stability of Al-humate

Abstract Some of the factors controlling Al humate bonding, a major aspect of organo-mineral interactions in soils, were studied. The methods used were potentiometric titration and stability measurement. The samples consisted of 4 humic acids plus 2 polymeric and several monomeric carboxylic acids as model compounds. Humic acids as well as alginic complexes was shown to be controlled by polymerization of carboxyl-containing units and by the arrangement of carboxyl groups in the units. A contribution by salicyclate type units was doubtful.

Preparation of powdered sample of fulvic acid and analysis of its acid functional groups

It is important to study soil fulvic acid owing to the major role it plays in material transfer (1) and nutrient supply (2) in soil. Although Schnitzer and his coworkers (3) have carried out numerous studies, systematic data on the chemical properties of fulvic acid are still limited compared with those on humic acid. In Japan, several researchers reported on its preparation and characteristics (4–7). The difficulties in studying fulvic acid are considered to be mainly due to the complexity of the fulvic acid constituents and the difficulty in preparing powdered samples which do not contain ash. Fulvic acid is an assemblage of various kinds of organic matter components differing in their nature, properties and molecular weight. The removal of ash is often associated with the loss of low molecular weight components.

Applications in food quality and environmental contamination

Abstract The chemical forms of 36 trace elements (Li, Be, Sc, V, Co, Ni, Cu, Zn, Ga, As, Rb, Sr, Y, Ag, Cd, Sb, Cs, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Tl, Pb, Bi, Th and U) in 22 wastewater treatment sludges were determined in order to evaluate their mobility and bioavailability. The five‐step chemical fractionation procedure was used to partition the elements into exchangeable, carbonate bound, Fe‐Mn oxide bound, organic matter bound and residual fractions. The Li, Be, Sc, V, Ga, Rb, Y, Ag, Sb, Cs, lanthanoids, Tl, Pb, Bi, Th and U occurred mainly in residual fraction. The Co, Ni, Cu, Zn, As, Sr and Cd in sludges were predominantly bound within the oxide or organic components. None of the elements were mainly distributed in exchangeable fraction or carbonate bound fraction. The sum of the element concentrations of the first three fractions, regarded as relatively easily soluble forms, was compared between sludges and soil as an instance of application of the fractionation procedure to the evaluation of the accumulation of elements in sludge‐amended soil.The chemical forms of 36 trace elements (Li, Be, Sc, V, Co, Ni, Cu, Zn, Ga, As, Rb, Sr, Y, Ag, Cd, Sb, Cs, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Tl, Pb, Bi, Th and U) in 22 wastewater treatment sludges were determined in order to evaluate their mobility and bioavailability. The five-step chemical fractionation procedure was used to partition the elements into exchangeable, carbonate bound, Fe-Mn oxide bound, organic matter bound and residual fractions. The Li, Be, Sc, V, Ga, Rb, Y, Ag, Sb, Cs, lanthanoids, Tl, Pb, Bi, Th and U occurred mainly in residual fraction. The Co, Ni, Cu, Zn, As, Sr and Cd in sludges were predominantly bound within the oxide or organic components. None of the elements were mainly distributed in exchangeable fraction or carbonate bound fraction. The sum of the element concentrations of the first three fractions, regarded as relatively easily soluble forms, was compared between sludges and soil as an instance of application of the fractionation procedure to the evaluation of the accumulation of elements in sludge-amended soil.

Fractionation of trace elements in wastewater treatment sludges.

Abstract The chemical forms of 36 trace elements (Li, Be, Sc, V, Co, Ni, Cu, Zn, Ga, As, Rb, Sr, Y, Ag, Cd, Sb, Cs, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Tl, Pb, Bi, Th and U) in 22 wastewater treatment sludges were determined in order to evaluate their mobility and bioavailability. The five‐step chemical fractionation procedure was used to partition the elements into exchangeable, carbonate bound, Fe‐Mn oxide bound, organic matter bound and residual fractions. The Li, Be, Sc, V, Ga, Rb, Y, Ag, Sb, Cs, lanthanoids, Tl, Pb, Bi, Th and U occurred mainly in residual fraction. The Co, Ni, Cu, Zn, As, Sr and Cd in sludges were predominantly bound within the oxide or organic components. None of the elements were mainly distributed in exchangeable fraction or carbonate bound fraction. The sum of the element concentrations of the first three fractions, regarded as relatively easily soluble forms, was compared between sludges and soil as an instance of application of the fractionation procedure to the evaluation of the accumulation of elements in sludge‐amended soil.The chemical forms of 36 trace elements (Li, Be, Sc, V, Co, Ni, Cu, Zn, Ga, As, Rb, Sr, Y, Ag, Cd, Sb, Cs, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Tl, Pb, Bi, Th and U) in 22 wastewater treatment sludges were determined in order to evaluate their mobility and bioavailability. The five-step chemical fractionation procedure was used to partition the elements into exchangeable, carbonate bound, Fe-Mn oxide bound, organic matter bound and residual fractions. The Li, Be, Sc, V, Ga, Rb, Y, Ag, Sb, Cs, lanthanoids, Tl, Pb, Bi, Th and U occurred mainly in residual fraction. The Co, Ni, Cu, Zn, As, Sr and Cd in sludges were predominantly bound within the oxide or organic components. None of the elements were mainly distributed in exchangeable fraction or carbonate bound fraction. The sum of the element concentrations of the first three fractions, regarded as relatively easily soluble forms, was compared between sludges and soil as an instance of application of the fractionation procedure to the evaluation of the accumulation of elements in sludge-amended soil.