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1.
Allophane has been known to occur widely in volcanic ash soils in Japan and New Zealand. However, exact knowledge of its nature has not been well established, mainly because of extreme difficulty to separate it in pure state and of its x-amorphous nature. In the course of the studies on soil allophane, it was noticed that certain Ando soils contained two different mineral colloids together, in addition to crystalline clay minerals and free sesquioxides. X-ray examination revealed that one was x-amorphous colloid which would be called allophane, and the other an unknown colloid of low crystallinity. Imogolite*** Imogolite will be described in a subsequent paper by the present authors. was proposed as the name of the latter colloid by the present authors after imogo in which imogolite was first found. Imogo is a brownish yellow, volcanic ash soil. in the Kuma basin in the Kumamoto Prefecture3). When deferration treatment is applied to the soils, allophane disperses both in an acid and alkaline media, whereas imogolite disperses in an acid medium and flocculates in an alkaline one.  相似文献   

2.
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.  相似文献   

3.
The influence of mean annual rainfall and soil texture on the 137Cs vertical distribution in soils from southern Chile The influence of mean annual rainfall and soil texture on the vertical distribution of 137Cs from global fallout was studied in undisturbed volcanic ash soils from southern Chile. The areal concentration and translocation depth increase with the mean annual precipitation. In spite of the high rainfall at the sampled area (970 - 2500 mm a?1), the highest 137Cs contamination was found in the upper 10 cm layer. The vertical migration is reduced by the high adsorption capacity of these volcanic ash soils, but on the other side increased in soils with high large-pore volumen. The translocation depth reaches only up to 26 cm in the clay soils, 35 cm in the silty soils and 70 cm in the sandy soil.  相似文献   

4.
The environs of Mt. Daisen, Tottori Prefecture, are generally mountainous or hilly, and apart rom small areas of alluvial and coastal flats there is little level ground. The volcanic ash soils derived from the quartz biotite hornblende andesitic ejecta occur on the gently undulating foot-hill and on the level ground with exception of alluvial flats. Considering the fact that these soils were formed from not only volcanic ash but the coarser materials, they may be properly called volcanogenous soils. The volcanic ejecta have been deposited on the soils from diluvial series, andesite, basalt, granite, and tertiary sedimentary rocks. It was recognized that in an eruption the large ejecta, such as fine porous pumiceous lapiili descended first, then the smaller Particles such as sands, and finally the smallest, as ashes. All of these deposits have been highly weathered, but the quartz and hornblende remain in a fresh state1). The author has studied some characteristics of these volcanic ash soils.  相似文献   

5.
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.  相似文献   

6.
There are few pedological studies in Japan of fresh volcanic ash. Fundamental information of the material from which Japanese volcanic-ash soils have developed, is of importance to obtain a better understanding of pedogenesis of such soils. The present paper deals with the mechanical. mmeralogical, and chemical characteristics of fresh ash ejected from the Sakurajima and Aso volcanoes which are among the most active in Japan.  相似文献   

7.
ABSTRACT

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 (associated with short-range-order minerals) recalcitrance. However, the stability of black soil C in buried A horizons may be changed by labile C supply for soil microbes. Here, we hypothesized that the mineralization of black soil C in buried A horizons of Japanese volcanic ash soil could be easily accelerated by a supply of labile C (i.e., a priming effect; PE). To test our hypothesis, we investigated the direction and magnitude of the PE with a buried A horizon in Japan using 13C-labeled glucose (2.188 atom %) in a short-term (21 days) incubation study. We also investigated the effect of mineral nitrogen (N), which could contribute to microbial activity in this incubation study. We found that a positive PE occurred by glucose supply with (182%) or without (181%) mineral N input over the 21-day incubation, and its values were very similar to the PE ratios previously reported in other deep soils. The estimated mean residence time (MRT) of black soil C considering PE was clearly accelerated by glucose supply, regardless of mineral N input, compared with the initial soil MRT. These results strongly support our hypothesis that the mineralization rate of black soil C in buried A horizons is easily accelerated by a labile C supply, and it also demonstrates important implications for the effects of global warming on buried A horizons (e.g., increased root exudation, fine root biomass supply, and N deposition) in Japanese volcanic ash soils.  相似文献   

8.
Abstract

Concern has been expressed that large amounts of volcanic ash from the May 18, 1980 eruption of Mount St. Helens may have created potential nutritional problems associated with forage production in northern Idaho and eastern Washington to the extent that adjustments need to be made in soil test correlation data. The objectives of this greenhouse study were to: (1) determine the effect of varying amounts of volcanic ash mixed into soils of northern Idaho on total alfalfa biomass production, and (2) to determine the effect of various soil/ash mixtures on the nutrient concentrations of P, K, S, Ca, Mg, Mn and Zn in alfalfa.

Alfalfa was grown in eight different northern Idaho soils amended with differing levels of volcanic ash (0, 20, 35, 50 and 75%) in the greenhouse. The alfalfa seeds were inoculated and fertilizer P and S were added to all treatments. Total plant biomass and P, K, S, Ca, Mg, Mn and Zn plant concentrations were measured.

The eight soils were pooled for analysis and it was found that increasing amounts of volcanic ash increased alfalfa biomass production. Plant P, S, Ca, Mg and Zn concentrations also increased with increasing levels of ash. Conversely, increasing levels of ash resulted in lower alfalfa tissue K and Mn concentrations. There is no evidence to suggest that the highest levels of ash which fell in northern Idaho (700,000 kg/ha) inhibited alfalfa production. Consequently, there is no need for adjustments in soil test calibration data presently used for fertilizer recommendations for alfalfa.  相似文献   

9.
Summary Populations of several bacterial groups on the root surface of wheat and in root-free soil were investigated in volcanic ash soil and non-volcanic ash soil throughout a series of predetermined intervals. Over time, the populations changed similarly both on the root surface and in root-free soil. The numbers of total bacteria, fluorescent Pseudomonas spp., phosphate-solubilizing bacteria, and NH inf+ sup4 -oxidizing bacteria, were consistently lower in the plots with volcanic ash soil than with nonvolcanic ash soil, but the numbers of cellulose-decomposing bacteria were opposite to those of the other groups. Superphosphate application improved the growth of wheat in the volvanic ash soil. It did not, however, bring about any significant changes in the bacterial populations among the volcanic ash soils supplemented with three different levels of superphosphate, though there were some variations with plant age.  相似文献   

10.
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.  相似文献   

11.
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.  相似文献   

12.
中国的火山灰土   总被引：5，自引：0，他引：5       下载免费PDF全文
赵其国 《土壤学报》1988,25(4):323-329
中国火山灰土的分布面积甚小,大致可分为蒙古高原、西藏高原及太平洋三个区,本文对中国海南岛的雷虎、云南的腾冲、黑龙江的德都及辽宁的长白山四地区火山灰土的发生特性及分类问题进行初步讨论。1.火山灰母质大多为火山灰,地形为台地、土层浅薄,色呈棕黑,土体含玻璃碎屑,粉砂中含有斜长石、辉石等可风化矿物。土壤容重小,孔隙度与持水能力高,毛管持水量接近饱和水含量。土壤呈微酸至中性,代换性Ca++及全磷、全钾含量甚高。2.火山灰土土体全量组成中CaO、MgO、Na2O、TiO2含量甚高,CaO含量几乎与母质含量相当。土壤微量元素以Ni、V与Zn为主,并随母质到土层有所增加。粘土矿物为硅酸盐非晶物质,以水铝英石为主。3.由于受不同的自然条件与发育年龄影响,火山灰土除具有上述共同特性外,它们之间,在有机质含量及酸度,铁与铝的富集度及土壤淋溶强度等方面均有所差别,这些差别正是火山灰土不同发育程度的反映。4.按研究结果,初步提出将中国火山灰土列入初育土土纲,并按其发育程度分为粗骨性火山灰土(D-117,T-8),轻度发育火山灰土(C-10,T-3)及中度发育火山灰土(R-4)。  相似文献   

13.
It is essential to analyze chemical properties including the amount of various materials and the soil colloid characteristics in forest soils to forecast wood production and the distribution of and variations in the environmental functions of forest soils, such as conservation of stream water and carbon sequestration. Approximately 70% of the forest soils in Japan consists of Brown Forest Soils (BFS), which are considered to be typical zonal soils under the humid-temperate and warm-temperate regime of Japan. BFS were subclassifled into several groups according to the soil moisture environment along the slope and morphological properties. However, even the same type of soil may display different properties depending on the climatic conditions, parent materials and vegetation types. In the present study, the variations in the carbon content, nitrogen content, cation exchange capacity and some properties depending on the parent materials, were clarified by using 34 sola of BFS, and 3 sola of black soils (BLS) for comparison, which were distributed in the submontane zone of the Kanto and Chubu districts in central Japan under the same climatic conditions. We observed differences in the pH, cation exchange capacity, base saturation and clay content among BFS samples derived from various parent materials. The BFS derived from volcanic ash contained obviously larger amounts of carbon and nitrogen than the BFS derived from other parent materials. However, the BFS derived from volcanic ash differed from the BLS derived from volcanic ash in the vertical distribution pattern of carbon and nitrogen. Thus, even in the submontane zone of the Kanto and Chubu districts, the chemical properties of BFS varied considerably with the parent materials. It was concluded that the classification of BFS by the parent materials was useful for evaluating the ability of the BFS, that cover 70% of the forests in Japan, to store various materials.  相似文献   

14.
Abstract

The objective of the present study was to clarify the influence of volcanic ash addition on soil carbon stocks and the carbon accumulation process in brown forest soils (BFS) in Japan. The degree of volcanic ash addition to the soil was estimated according to the acid ammonium oxalate extractable aluminum (Alox) and lithic fragment contents, and their vertical distribution patterns. The BFS was classified in order of increasing volcanic ash influence on the soil into the following types: high Alox content with no gravel (H-Alox-NGv), high Alox with a high gravel content (H-Alox-Gv), moderate Alox (M-Alox), and low Alox (L-Alox), and then analyzed for carbon content, carbon amount, carbon stock, Alox amount and pyrophosphate extractable aluminum (Alpy) amount. The correlation between the carbon and Alpy amounts and the relationship between the Alpy and Alox amounts in the BFS samples indicated that the amount of carbon is determined by Al—humus complex formation, which is defined by the active Al generated from additional volcanic ash in BFS soil samples of BFS. Therefore, soils with thicker horizons and greater amounts of Alox had higher carbon levels in deeper horizons. For this reason, soil carbon stocks at depths of 0–30 cm and 0–100 cm, and in the effective soil depth of BFS, were larger and followed the order H-Alox-NGv = H-Alox-Gv > M-Alox > L-Alox. Furthermore, successive accumulations of volcanic ash on the soil surface promoted soil carbon accumulation as a result of the development of the surface horizon in H-Alox-NGv BFS. Our results suggest that volcanic ash additions control the soil carbon accumulation of forest soil in Japan.  相似文献   

15.
Soils found on fan surfaces in the Kokoda Valley are derived from both volcanic ash and river alluvium. The alluvium is variable, some of it being mixed with volcanic ash. The main differences in the micromorphology of the soils appear to be related to the relative amounts of volcanic ash present in the soil profile. The plasma of soils formed on volcanic ash is isotropic in thin section. The plasma of alluvial soils exhibits increasing birefringence with decreasing amounts of volcanic ash. It is suggested that random structures in the clay fraction of the volcanic ash may account for its isotropic nature.  相似文献   

16.
We examined soils derived from volcanic ash of Kikai-Akahoya tephra on Yakushima Island, Japan, and classified them according to the Unified Soil Classification System of Japan, 2nd Approximation (USCSJ 2nd) and the World Reference Base for Soil Resources (WRB). Five pedons with horizons showing high (>20%) volcanic glass content were investigated. Soils developed under evergreen broad-leaved forests had high acid oxalate-extractable aluminum (Alo) and acid oxalate-extractable silicon (Sio) concentrations, and low acid oxalate-extractable iron (Fe)/dithionite-citrate-extractable Fe ratio. This indicates a warmer climate and less severe leaching conditions compared with soils developed under coniferous forests dominated by Cryptomeria japonica and grasslands dominated by Pseudosasa owatarii. All soils contained considerable amount of hydroxyl-Al-interlayered 2:1 clay minerals. The surface horizons of the pedons developed under the cool-temperate C. japonica forests contained smectite as a result of podzolization. However, the surface horizon of the pedon developed under cool-temperate P. owatarii grasslands did not contain smectite. All pedons belonged to the Kuroboku soils great group (USCSJ 2nd) and Andosols (WRB). Pedons in mountainous areas did not contain horizons with more than 6?g?kg?1 of Sio and hence were classified as non-allophanic Andosols. In mountainous areas, it was observed that allophane formation was inhibited by Al leaching due to intense rainfall (>10,000?mm year?1); Al consumption due to the formation of the Al-humus complex; and Al incorporation into the interlayers of vermiculite. The low soil water pH [pH(H2O)] and leaching of silicon (Si) in mountainous areas would support these anti-allophanic effects.  相似文献   

17.
ABSTRACT

In the present study, two volcanic ash soils (soil A and B) from a temperate broad-leaved forest in eastern Japan were aerobically incubated under repeated dry-wet cycles and continuously constant moisture conditions. The primary aims were to quantify the potential for enhancement of carbon dioxide (CO2) release owing to increased water fluctuation and to examine differences in the responses of volcanic ash soils with different physicochemical properties. Soil B, rather than soil A, was a typical Andosol. During incubation at 20°C for 120 days with five dry-wet cycles, the CO2 release rate was measured periodically. Abundance of the stable carbon isotope in CO2 (δ13C-CO2) was measured to capture changes in the origin of decomposed soil organic matter (SOM) owing to the dry-wet cycles. The CO2 release rate under the dry-wet cycles was up to 49% higher than the values predicted from a parabolic relationship between CO2 release and water content during incubation under the continuously constant moisture condition. The magnitude of CO2 release enhancement was 2.7-fold higher in soil B relative to that in soil A. The δ13C-CO2 value in the dry-wet cycles was enriched by 0.3–2.3‰ compared to that during incubation under the continuously constant moisture conditions, suggesting that the decomposition of well-metabolized and/or old SOM was enhanced by the dry-wet cycles. Thus, the present study suggests that Andosols, which have been believed to have a strong SOM stabilization ability, are vulnerable to dry-wet cycles. Then, increased water fluctuation in a future warmer world would have significant potential to stimulate CO2 release from soils.  相似文献   

18.
《Geoderma》1987,39(4):323-330
Cristobalite was isolated from four Ando soils and a Podzolic soil developed on volcanic ashes in French West Indies, Indonesia and Japan by selective chemical dissolution with 6 M HCl, 0.5 M NaOH and H2SiF6 treatments followed by specific gravity separation. All the cristobalite isolates give X-ray diffractograms with a strong and sharp peak at 4.10–4.11 Å and associated peaks at 2.8 and 2.5 Å, which are characteristic for cristobalite of high-temperature origin. Four out of five isolates show a peak at 4.06–4.07 Å ascribed to low-temperature cristobalite. The oxygen isotopic ratios (δ18OSMOW) of cristobalite isolates show a range of +5.3 to +11.0%. which suggests a high-temperature igneous origin. These X-ray diffraction and oxygen isotopic data indicate that the cristobalite was inherited from primary volcanic ash rather than formed during pedogenesis.  相似文献   

19.
Volcanic ash soils along the western edge of the Omiya tableland, Japan, are covered with thick anthropogenic soil horizons. The formation of anthropogenic soil horizons occurs because of the soil dressing practice known as “Dorotsuke,” where alluvial soil materials are deposited on fields and mixed with volcanic ash topsoil by tillage over the years. To clarify the chronology of this anthropedogenesis, carbon-14 (14C) age profiles were estimated using humic acid fractions from three pedons: an anthropogenic soil, an undressed Andosol, and a Fluvisol. Soil charcoal fragments were also dated to estimate maximum burial age. Charcoal fragments displayed vertically random age distributions, indicating that the fragments may have had multiple origins. However, the age of charcoal in the lower part of the anthropogenic soil horizons indicated that the initiation of anthropedogenesis occurred later than the late 13th century. The 14C age profile of humic acid in the Andosol exhibited little variation in age with depth in the subsoil. The 14C age profile of humic acid in the Fluvisol suggested that the humic acid fraction included allochthonous old carbon (C), although the soil itself had been formed from recent sediments. The 14C age profile of humic acid in the anthropogenic soil showed features of its two component soils. The 14C ages in the volcanic ash subsoil matched with those in the Andosol, whereas the ages increased in the anthropogenic soil horizons because of supplementation with old C from alluvial soil materials. However, the peak 14C ages occurred in the lower part of the anthropogenic horizons, whereas the middle part on the peak position displayed a gradual age-depth gradient. This feature was interpreted as a sign of 14C activity equilibrium throughout anthropedogenesis. On the basis of this postulated 14C activity equilibrium, the linear age-depth gradient at the peak position was derived from differences in burial time, and burial ages were calculated by estimating steady-state 14C. The calculated ages were lower than the charcoal ages. These age estimates suggest that anthropedogenesis was initiated in the Middle Ages and reached an intermediate stage before or during the first half of the Edo period.  相似文献   

20.
In Japan, most of the paddy fields are laid out on alluvial plain while other land crop fields are developed on plateau. The greater part of the latter ccnsists of volcanic ash soils.  相似文献   

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