Soil properties relating to the sediment volume of Ando soils

Soil properties relating to the sediment volume of Ando soils varied depending on their physical state. The water content is a useful index property for the sediment volume of field-moist soils. The sediment volume of air-dried soils increased with decreasing clay content and with increasing organic carbon content. The water retention at 52% relative humidity was related to the sediment volume of soils subjected to a sonic wave treatment. An explanation of this behaviour is given in terms of the tendency of Ando soils to form water-stable aggregates.     

Microbial ecology in tea soils

The soil chemical properties and microbial numbers in three volcanic ash soils and two non-volcanic ash soils, which had been continuously subjected to the same tea cultivation practices (21 y), were investigated. The results obtained were as follows. 1) pH values of all the soils gradually decreased from the original pH value (near neutral or mildly acid pH) to strongly acid values of about 4 or lower. In contrast, long-term tea cultivation practices resulted in the increase of the total C and N contents in the surface layers (0–20 cm) while the contents remained stable in the subsurface layers (20–40 cm). The increase in the organic matter content in non-volcanic ash soils was presumably due to the accumulation of microbial residues. The availability of P increased markedly. 2) Numbers of bacteria, actinomycetes, fungi, and denitrifiers were higher in volcanic ash soils than in non-volcanic ash soils, and also higher in surface layers than in subsurface layers. The results suggest that in spite of the same cultivation practices, the soil depth and soil type affected the microbial numbers in the tea soils. Numbers of autotrophic NH₄ ⁺ oxidizers were low in comparison with the numbers of autotrophic NO₂ ^- oxidizers. Influence of soil type and soil depth on autotrophic nitrifiers was not clear. 3) Total C and N contents in the tea soils were parameters closely related to the numbers of bacteria, actinomycetes, and fungi. For actinomycetes and fungi, the prediction could be more accurate, especially for total N content, if the estimations could be made within the same soil layers. The numbers per unit of C or N were higher in the surface layers than in the subsurface layers. 4) High concentration of NO₃ ^--N in the tea soils used suggests that nitrification could occur despite the low pH value (3.2-3.8). The negative relationship between the number of total bacteria or actinomycetes and soil NH⁴ ₊-N concentration suggests that some NH₄ ⁺-N was converted to organic microbial biomass-No.     

Role of active aluminum in the formation of water-stable macroaggregates

Soil structure is determined by the arrangement of particles in soil and the particles of sand, silt, and clay bind together into aggregates of various sizes by organic and inorganic materials. Structural stability which is the ability of the aggregates and pores to remain intact when subjected to stress, markedly affects crop production and soil erosion (Tisdall 1996). Since water, either directly as rainfall or as surface runoff is the main agent of aggregate breakdown, in the analyzes of stable soil aggregation, the term water-stable aggregation is generally used (Lynch and Bragg 1985). Water-stable aggregates have been divided into micro aggregates < 0.25 mm dia.) and macro aggregates (> 0.25 mm dia.) (Edwards and Bremner 1967; Tisdall and Oades 1982). Microaggregates show a relatively high stability against physical disruption (Edwards and Bremner 1967). On the other hand, macro aggregates are sensitive to soil management (Tisdall and Oades 1982).

There are many reports on the relationships between the aggregate stability and the soil physicochemical properties. For example, significant correlations were found between the aggregate stability and the amounts of organic C (Tisdall and Oades 1982), total N, and carbohydrates or the CEC (Chaney and Swift 1984). However, most of these studies were conducted in non-volcanic ash soils. Volcanic ash soils are widely distributed in Japan and are very important soils for crop production. The objective of this study was, therefore, to obtain more information on the relationship between the degree of macro aggregation and the soil physicochemical properties in non-volcanic and volcanic ash soils.     

Soil microbial biomass and fluorescein diacetate hydrolytic activity in Japanese acidic tea field soils

The soil microbial biomass (SME) content and fluorescein diacetate (FDA) hydrolytic activity in 21 acidic tea field soils in Japan were determined. SM 3 content in the tea field soils was quantitatively similar to that in 13 arable soils with neutral soil pH previously reported. However, the ratio of the SMB content to organic matter content in the tea field soils classified as red-yellow soil, brown forest soil, and lithosol was clearly lower than that in the neutral arable soils classified as non-volcanic ash soil. FDA hydrolytic activity in the tea field soils was higher than the activity in various soils with neutral soil pH and showed a negative relationship with the soil pH.     

Some factors affecting behaviour of boron in soil

It has been reported by many workers that various soil properties influence the retention of boron added to soils, but there is little infomration on the relative importance of these properties to boron retention and there is something controversial in the published results regarding the effects of different soil properties such as organic matter content, soil reaction, available calcium content and texture on boron retention (15). The present study was undertaken to obtain more detailed informations on the relationships between boron adsorption and different properties of soils, and on comparative contribution of soil constituents such as organic matter, sesquioxides and inorganic colloids to boron adsorption of soils. In Japan, boron deficiency symptoms of crops often appear in the fields of volcanic ash soils, and many experiments on boron application have been conducted to amend the boron deficiencies of the soils. It is considered that volcanic ash soils may have special characteristics concerning boron retention in comparison with nonvolcanic ash soils. In the present study, therefore, some volcanic ash soils were also taken as samples in addition to non-volcanic ash soils to confirm their speciality to boron retention.     

Soil organic carbon in density fractions of tropical soils under forest – pasture – secondary forest land use changes

Our knowledge of effects of land use changes and soil types on the storage and stability of different soil organic carbon (SOC) fractions in the tropics is limited. We analysed the effect of land use (natural forest, pasture, secondary forest) on SOC storage (depth 0–0.1 m) in density fractions of soils developed on marine Tertiary sediments and on volcanic ashes in the humid tropics of northwest Ecuador. The origin of organic carbon stored in free light (< 1.6 g cm^?3) fractions, and in two light fractions (LF) occluded within aggregates of different stability, was determined by means of δ¹³C natural abundance. Light occluded organic matter was isolated in a first step after aggregate disruption by shaking aggregates with glass pearls (occluded I LF) and in a subsequent step by manual destruction of the most stable microaggregates that survived the first step (occluded II LF). SOC storage in LFs was greater in volcanic ash soils (7.6 ± 0.6 Mg C ha^?1) than in sedimentary soils (4.3 ± 0.3 Mg C ha^?1). The contribution of the LFs to SOC storage was greater in natural forest (19.2 ± 1.2%) and secondary forest (16.6 ± 1.0%) than in pasture soils (12.8 ± 1.0%), independent of soil parent material. The amount of SOC stored in the occluded I LF material increased with increasing silt + clay content (sedimentary soils, r = 0.73; volcanic ash soils, r = 0.58) and aggregation (sedimentary soils, r = 0.52; volcanic ash soils, r = 0.45). SOC associated with occluded I LF, had the smallest proportion of new, pasture‐derived carbon, indicating the stabilizing effect of aggregation. Fast turnover of the occluded II LF material, which was separated from highly stable microaggregates, strongly suggested that this fraction is important in the initial process of aggregate formation. No pasture‐derived carbon could be detected in any density fractions of volcanic ash soils under secondary forest, indicating fast turnover of these fractions in tropical volcanic ash soils.     

New classification systems for tropical organic-rich deposits based on studies of the Tasek Bera Basin,Malaysia

Most schemes in common use for field and laboratory classification of peats were developed in boreal and humid temperate regions and do not recognize the distinctive features and specific uses of tropical peats, such as those of the Tasek Bera Basin in tropical Peninsular Malaysia. The important aspects of peat texture (morphology of constituents and their arrangement) and laboratory ash content (residue after ignition) need modification to be valuable for classifying these and other tropical peat deposits. In the Tasek Bera Basin, most of the deposits would not be considered as peat according to some classification schemes, even though most have C contents >25%. We propose a new three-group (fibric, hemic, sapric) field texture classification applicable to tropical organic deposits, which is similar to the system of the US Soil Taxonomy. The classification is based on the following factors: (1) visual examination of the morphology of the peat constituents (texture); and (2) estimates of fiber content and matrix (finest fraction of peat consisting of highly humified organic matter and inorganic material). The classification is applicable to all organic deposits with <65% ash (i.e., >35% loss on ignition). We also present a new laboratory classification of organic soils based on ash and C content. The US Soil Taxonomy classifies organic soils as having more than 12–18% organic C, depending on clay content. Ash content and these limits for organic soils allow the discrimination of four main groups: peat, muck, organic-rich soil/sediment and mineral soil/sediment. Peat is defined as having an ash content of 0–55%, muck 55–65%, organic-rich soil/sediment 65–80% and mineral soil/sediment 80–100%. The peat class is further subdivided into very low ash (0–5%), low ash (5–15%), medium ash (15–25%), high ash (25–40%) and very high ash (40–55%) subclasses.     

Saccharides of ectomycorrhizal fungal sclerotia as sources of forest soil polysaccharides

ABSTRACT

The neutral monosaccharide composition of forest soils differs from that of non-forest soils suggesting there is an accumulation of microbial saccharides. Ectomycorrhizal (ECM) fungi can be responsible as the fungi are typical in forest soils. We investigated neutral saccharides of ECM fungal sclerotia to determine what part it might play in the origin of forest soil polysaccarides. Sclerotial grain (SG) was collected from the O, A1 and A2 horizons of a soil of subalpine forest of Mt. Ontake, central Japan. Neutral saccharides in soil and SG were analyzed by two step hydrolysis with sulfuric acid and gas-chromatography of alditol acetate derivatives. Saccharides accounted for 6.0?16% of the SG by carbon content. The SG contained predominantly easily hydrolysable (EH)-glucose, which accounted for 75–85% of the composition depending on grain size and the soil horizon, followed by mannose (7.7?15%), galactose (2.2?4.8%) and non-easily hydrolysable (NEH)-glucose (1.7?6.1%). The SG contained all of these sugars irrespective of its size. The SG collected from the A1 and A2 horizons contained all sugar components found in that from the O horizon, except for fucose in that from A2 horizon. The monosaccharide composition of SG indicates that accumulation of ECM fungal sclerotial polysaccharides might have been responsible for enlarging the molar ratios of (galactose + mannose) /(arabinose + xylose) and EH-glucose/NEH-glucose of forest soils. The proportions of SG saccharides relative to soil saccharides were 3.6, 1.2, and 0.83% for the O, A1 and A2 horizons, respectively. These levels of the proportion are considerable as ECM fugal sclerotia are the products of a limited species among hundreds and thousands of microbial species inhabiting forest soils. The sclerotia forming ECM fungal species such as Cenococcum geophilum may be key sources of forest soil polysaccharides.     

Water repellency of fly ash‐enriched forest soils from eastern Germany

Fly ash‐enriched soils occur widely throughout the industrial regions of eastern Germany and in other heavily industrialized areas. A limited amount of research has suggested that fly ash enrichment alters the water repellency (WR) characteristics of soil. This study concentrates on the influence of fly ash enrichment on WR of forest soils with a focus on forest floor horizons (FFHs). The soils were a Technosol developed from pure lignite fly ash, FFHs with lignite fly ash, and FFHs without lignite fly ash enrichment. Three different methods (water drop penetration time, WDPT, test; water and ethanol sorptivity measurement and the derived contact angle, θ_R; and the Wilhelmy‐plate method contact angle, θ_wpm) were used to characterize soil WR. Additionally, carbon composition was determined using ¹³C‐NMR spectra to interpret the influence of the organic matter. This study showed that the actual WR characteristics of undisturbed, fly ash‐enriched soils can be explained in terms of the composition of soil organic matter, with the fly ash content playing only a minimal role. Regardless of the huge amounts of mainly mineral fly ash enrichment, all undisturbed FFHs were comparable in their WR characteristics and their carbon compositions, which were dominated by recently‐formed organic substances. The pure fly ash deposit was strongly influenced by lignite remains, with the topsoil having a greater content of recent plant residues. Thus, the undisturbed topsoil was more repellent than the subsoil. When homogenized samples were used, we found a distinct effect of fly ash enrichment and structure on WR. Water repellency of the pure fly ash horizons did not differ distinctly, while the fly ash enrichment in the FFHs caused a significant reduction in WR. The methods used (WDPT, θ_R and θ_wpm) identified these differences similarly. These results led to the assumption that water‐repellent structures of the topsoils were probably the result of hydrophobic coatings of recently formed organic substances, whereby the initially high wettability of the mainly mineral, hydrophilic fly ash particles was reduced.     

Dynamics of soil organic matter associated with particle-size fractions of water-stable aggregates

Stable macroaggregates (> 200 μm) of cultivated soils are reported in the literature to be richer in organic carbon, and in young organic carbon in particular, than microaggregates (< 200 μm). However, the nature of this additional carbon is not yet known. To determine it, we compared the composition of organic matter in stable macroaggregates with that in unstable ones. Macroaggregates 2–3 mm in diameter were separated from two silty cultivated soils from the Paris basin. They were slaked, and the primary particle composition of the resulting fractions was analysed. We used the natural abundance of ¹³C to quantify the amount of young carbon, derived from a maize crop, in the various size fractions. The stable macroaggregates were richer in total C and in young C (younger than 6 and 23 years respectively in the two soils studied) than the unstable ones. This young C comprised 50% particulate organic matter, 20% associated with silt and 30% with clay particles. We propose a schematic composition of aggregates in these soils in which stable aggregates are formed by the binding of microaggregates by additional young organic matter, predominantly plant debris. Young organic matter is preferentially incorporated and is responsible for aggregation, though it is eventually redistributed among aggregate classes through the destruction and re‐formation of the aggregates. We have developed a model to simulate this redistribution. The model shows that stable macroaggregates have a life of a few years, but that microaggregates may exist for decades. We suggest that the stabilization and de‐stabilization of macroaggregates in soils is linked to the incorporation and biodegradation of plant debris.     

Laboratory studies of crust development in Irish and Iraqi soils II. Effects of some physico-chemical constituents on crust strength and seedling emergence

The influence of soil constituents including sand, silt, clay, organic substances, aluminium and iron on crust development and seedling emergence was investigated in a selection of 30 soils. After treatment with simulated rain, soil crust strength as measured by penetration resistance to an upward-moving probe tended to decrease with increasing total organic carbon content, but the relationship was not a simple one. Consideration of other factors showed that in some soils (soils of 1.5–2% total organic carbon), alkali-exractable carbon and clay contents had the greatest influence on penetration resistance values whereas in other soils (2.4–3% total organic carbon), coarse sand, fine sand, EDTA-extractable aluminium and humic acid carbon were highly correlated with penetration resistance. In a group of soils with around 4% total organic carbon, oxalate-extractable aluminium appeared to exert a dominant influence. There was a good correlation between humic acid carbon and penetration resistance after rain treatment in soils containing less than 40% sand. A similar relationship was also noted with EDTA-extractable iron.Combination of all factors in a multiple regression analysis accounted for a considerable proportion of the variation in penetration resistance of soils with and without simulated rain application and in seedling emergence of barley. Organic carbon, and the humic acid fraction in particular, were most important in determining crust strength for all soils as a group.A significant correlation between plastic limit moisture and the logarithm of penetration resistance is explained partially, at least, by the relationships that exist between organic carbon alone, clay alone and a combination of both, with variation in moisture.     

Changes in cation exchange capacity of some Andosols with dithionite-citrate treatment

Andosol is a soil widely distributed throughout Japan and is one of the important soils for the agriculture. The name “Ando soil” was given by THORP and SMITH (19) which means dark soil with an organic matter content ranging up to 30 per cent in the darkest members of the group. In 1964, the Soil Correlation Meeting on Volcanic Ash Soils (8), organized by FAO, adopted “Andosol” for volcanic ash soil of which the active fraction is predominated by amorphous material. Andosol, moreover, has many special properties such as high sorption capacity, high accumulation of organic matter, low bulk density and low stickiness. TAYLOR (18), accordingly, named them “amorphic soils”. The latest soil classification system, 7th Approximation (15) includes andosol under the suborder andepts.     

Cultivation-Induced Effects on the Organic Matter in Degraded Southern African Soils

We studied quantitative and qualitative changes in soil organic matter (SOM) due to different land uses (reference woodland versus cultivated) on six soils from Tanzania (Mkindo and Mafiga), Zimbabwe (Domboshawa and Chickwaka), and South Africa (Hertzog and Guquka). Structural characteristics of the humic acids (HAs) were measured by Curie-point pyrolysis–gas chromatography/mass spectrometry (P_y–GC/MS) and solid-state ¹³C nuclear magnetic resonance (CPMAS ¹³C NMR) spectroscopy. Significant changes in concentration and composition of SOM were observed between land uses. Losses of organic carbon after cultivation ranged from 35% to 50%. Virgin soils showed large proportions of colloidal humus fractions: humic acids (HAs) and fulvic acids (FAs) but negligible amounts of not-yet decomposed organic residues. The change in land use produced a contrasting effect on the composition of the HAs: a noteworthy “alkyl enhancement” in Mkindo soil and “alkyl depletion” in Chikwaka and to a lesser extent in Domwoshawa. The remaining soils displayed only minor alterations.     

Sorption of atrazine, 2,4‐D,nitrobenzene and pentachlorophenol by urban and industrial wastes

This study was carried out to investigate the sorption properties of man‐made soil developed from sewage sludge, municipal wastes, brick and mortar debris, harbour sludge, sand fills, fly ash, and wastes from coking plants and coal mines. The composition of organic matter in the samples was analysed, and the sorption isotherms of four reference chemicals (nitrobenzene, atrazine, 2,4‐D, pentachlorophenol) were determined. Fly ash, which contains up to 89% of its carbon as Black Carbon, showed a strong affinity to all four chemicals. For the other waste materials, a strong correlation between the logarithm of the Freundlich adsorption constant, K_f, and the logarithm of organic carbon, C_o, was established (r = 0.85–0.96). This holds for the non‐ionic nitrobenzene and also, within a certain pH range depending on the pK_a of the compound, for the three ionizable organic compounds (atrazine: pH > 4; 2,4‐D: pH > 5; PCP: pH > 6). At pH near the pK_a value the sorption is sensitive to pH. There were no statistically significant differences between the waste materials and the natural soils in the relations between logK_f and logC_o for either ionic or non‐ionic chemicals. This result suggests that the method devised for estimating the sorption of organic chemicals in natural soils based on their content of organic carbon is equally valuable for the waste materials, with the exception of fly ash which contains a large amount of Black Carbon.     

Properties,weathering and classification of some soils formed in peralkaline volcanic ash in Kenya

Physical, chemical and mineralogical properties were determined for six profiles in and west of the Great Rift Valley in Kenya. Data include morphology, information on gross composition of horizons (organic carbon, cation exchange capacities, extractable cations, etc.), and detailed characterization of the clay fractions by means of transmission electron microscopy, X-ray diffraction, infrared spectroscopy and additional techniques.The three least weathered profiles (Nos. 1–3 of Table I) have morphologies typical of Andepts but lack certain other characteristics common to such soils. Their clay fractions were largely amorphous to X-rays and consisted mainly of poorly ordered siliceous Feoxides with virtually no allophane. All of the clays contained halloysite. The peralkaline nature of the ash parent-material seems responsible for the clay mineralogy of the soils which differs from that generally found in Andepts. The high proportions of iron in the amorphous materials depart from the composition widely reported for such soils. One distinctive feature was the presence of pantelleritic trachyte, found in ash from a number of sites in addition to those of the profiles.How the six profiles may best be classified is an open question. None of the profiles qualifies as Andept. Nor would they be included in the proposed order of Andisols as presently defined. Modifications of the definition of Andisols so as to include some of these soils would seem desirable.     

Saccharides in some Japanese paddy soils

Monosaccharides released by acid hydrolysis from paddy field soil, from the light and the heavy fraction of soil, front some plant fragment were determined using automated anio-exchange chromatography.

Between 5 and 12 per cent of the organic carbon was present as saccharides.

The monosaccharide composition of the different soils was very similar, in spite of differences in the absolute amount of saccharides present. The amount of the various monosaccharide in the whole soil was found to be in the order glucose»xylose galactose, mannose, arabinose rhamnose ribose.

The monoccharide composition of the soils showed a marked contrast to that of the rice ra8ment, and partially decomposed plant remains taken from the soil. Glucose, xylose, arabi-the predominant saccharides in the rice fragments and the plant remains, while the amounts of galactose, mannose, rhamnose were negligibly small.

It was found that the proportion of galactose, mannose, rhamnose and ribose in the heavy fraction Of soil was greater than that of glucose, xylose, and arabinose

The present observation was in agreement with the view that soil sauharides comprised Pentoses originates in plant materials.

The molar ratio of xylose to mannose was calculated to show the characteristics of the mono-saccharide composition of soils and some plant muerials.     

Adsorption of Acrylonitrile on Some Soils and Minerals from Aqueous Solutions

Equilibrium and kinetic studies have been made on the adsorption of acrylonitrile(CH2=CHCN) on three soils and four minerals from aqueous solutions.It was shown that the organic matter was the major factor affecting the adsorption process in the soils.The conformity of the equilibrium data to linear type(one soil) and Langmuir type(two soils) isotherms indicated that different mechanisms were involved in the adsorption.This behavior appears bo be related to the hydrophobicity of soil organic matter due to their composition and E4/E6 ratio of humic acids.The adsorption kinetics were also different among the soils,indicating the difference in porosity of organic matter among the soils,and the kinetics strongly affected the adsorption capacity of soils for acrylonitrile.Acrylonitrile was slightly adsorbed from aqueous solutions on pyrophyllite with electrically neutral and hydrophobic nature,and practically not on montmorillonite and kaolinite saturated with Ca.However,much higher adsorption occurred on the zeolitized coal ash,probably caused by high organic carbon content(107g/kg).     

Calcium requirements for peanuts

Abstract

Surface soils from ten soil series representing five great groups were collected from Alaska. These soils were selected from the important agricultural areas covering a wide geographic distribution. These soils can be divided into two distinct groups based on their parent material: loess and volcanic ash. Phosphorus sorption maxima were calculated based on the Langmuir isotherms. The volcanic ash soils (Cryandept and Cryorthods) showed an average P‐sorption maxima of 10,122 mg/kg and loess soils averaged 3,934 mg/kg. Both groups have similar portions of phosphorus in the organic form (19%) and occluded form (8 to 9%). The nonoccluded‐P in the volcanic ash soils and the loess soils was 68% and 43% respectively, and the Calcium‐P was 4% and 29% respectively.

Regression analysis indicated that aluminum and iron are primarily responsible for P‐sorption. The dithionite extractable Al is responsible for P‐sorption in volcanic ash soils, while oxalate extractable Al is responsible for P‐sorption in loess soils. Dithionite and oxalate extractable Fe probably play a secondary role in P‐sorption. The sorption isotherm, regression analysis and the P‐fractionation data provide the agronomist with useful information to estimate P requirement of newly cleared soils.     

Characterization of the Organic Matter in Wood Ash from Biomass Power Plants in Relation to the Potential Use as Amendments in Agriculture

As a result of the increased demand for bioenergy, wood ash (WA), the main residue generated, may become a major source of pyrogenic organic matter. WA contains organic aromatic structures and could be used in agriculture, in a similar way to biochar, to improve the amount and quality of soil OM (OM). However, the organic composition of WA may differ from that of biochar, which has not yet been addressed. In the present study, different types of fly wood ash (FWA) and mixed wood ash (MWA), generated in industrial boilers, were characterized and compared with biochar generated from different feedstocks and at different temperatures (300 and 600 °C). WA differed in the amount and composition of the OM. The OM in MWA consisted of condensed carbon as well as substantial amounts of lightly charred plant biomass. Because of the low degree of carbonization of this OM, it may be susceptible to microbial degradation after application to soil. By contrast, the OM in FWA comprises highly carbonized and condensed organic compounds, similar to those in biochar. Selection of the most suitable type of WA will be determined by the requirements of the specific soils. MWA could be used to amend soils requiring high amounts of OM, whereas FWA might be more appropriate for application in acid soils rich in OM. Thermal analysis proved a useful tool for characterizing the charred material in these by‐products in order to determine the best strategy for use of the material in agriculture. Copyright © 2017 John Wiley & Sons, Ltd.     

Testing the suitability of the Rothamsted Carbon model for long-term experiments on Japanese non-volcanic upland soils

We evaluated the suitability of the Rothamsted Carbon (RothC) model for long-term experiments on Japanese non-volcanic upland soils using 6 long-term experimental data sets: 2 Brown Lowland Soils, 2 Yellow Soils, 1 Gray Lowland Soil, and 1 Brown Forest Soil. The predicted changes in the content of soil carbon with time were very close to the observed values in almost all the treatments at all the 6 sites. These 6 sites were distributed from North to South across Japan and included a variety of climatic conditions, soil textures, and land management practices. We therefore concluded that the RothC model adequately simulated changes in the soil carbon content with time in Japanese non-volcanic upland soils.