Some Physico-chemical characteristics of soils influenced by Taal Volcano in reference to soil productivity

Soils of the northwestern part of the Taal Volcano in the Philippines representing four geomorphological units (upper, middle, and lower slopes and alluvial plains) were investigated and related to soil productivity. Results revealed that the soils on the upper and middle slopes contained higher amounts of organic matter and available P and displayed a low P retention together with more favorable physical properties such as loamy soil texture, loose and friable and well-drained soils compared to those on the lower slopes and in the alluvial plains. Due to these favorable soil characteristics, sustained agricultural production was higher at the upper elevations than at the lower elevations. Year-round multistorey / mixed cropping systems of cultivation in the upper and middle landscapes were also made possible because the higher precipitation was evenly distributed coupled with cooler temperatures compared the conditions on the lower slopes and in the alluvial plains. On the other hand, the soils on the lower slopes and in the alluvial plains had a clayey texture and contained a lower amount of organic matter and available P, in addition to the lower precipitation, resulting in reduced land utilization, as indicated by the limited types of crops grown and lower yield of crops.     

Characteristics of the induration of tephra-derived soils in Kyushu,Japan

The physical, chemical, and mineralogical properties as well as the micromorphology of five indurated volcanic ash soils in Kyushu, Japan were investigated. The indurated soils were divided into two types based on the physical and chemical properties. Type 1 was not indurated in its moist state, but shrank and became very hard by air-drying. Type 1 included the buried volcanic ash soils whose physical and chemical properties were similar to those of other buried volcanic ash soils except for the property of induration by air-drying. The mechanism of the induration is still unknown, although it is considered to have occurred during the long period after the deposition of tephra under the influence of soil formation processes. Type 2 included the tephra layers that were indurated in both moist and air-dried states. The carbon and clay contents of type 2 were remarkably lower than those of type 1. Type 2 had not been affected by the soil formation process but had undergone induration soon after the deposition of the tephra. Neither type 1 nor type 2 could be classified into any indurated horizons that are defined in the present soil classification system. For the improvement of soil productivity, type 1 should be harrowed thoroughly soon after its exposure to the surface, and type 2 should be harrowed or removed using farm machinery.     

Characteristics of bacteria in the forest soils under natural vegetation

Characteristics of the predominant bacteria isolated in November and May from the forest soils of both dry and wet types under natural vegetation were studied.

Although Gram-negative rods were the most abundant bacteria in both soil types and in both seasons, their contents were less and other bacteria especially spore-forming ones increased in May.

Among Gram-negative rods in the soil of the dry type in November, the most predominant was those with nonchromogenic rods motile with polar flagella which grew in a simple synthetic media containing glucose or p-hydroxybenzoate and ammonium as the sole carbon and nitrogen sources. In May, the ratio of the bacteria which require amino nitrogen or those with more chomplex nutritional requirement increased. In the soil of moderately wet type, the difference in kinds of bacteria between the two seasons was not so clear as that in the dry type.

Most of Bacillus species obtained in these soils were those requiring amino acids or other growth factors among which B. cereus was most abundant.     

Influence of applied p on the cation exchange capacity of volcanic ash soils

Abstract

The CEC of volcanic ash derived soils in Guatemala was measured following equilibration with 1.5 and 6.0 me P/100 g soil supplied through KH₂PO₄ solutions. An increase in CEC resulted due to P reaction and the increase was substantial after removal of soluble Al from P reacted soils. The average ratios of increase in CEC to P retained were 0.49 and 1.63 in the former and later, respectively. P apparently neutralized positive charges on the surface of amorphous component and those internally in the soil particles resulting in a net increase in negative charge (CEC).     

Effect of sulfate on nitrate transport in volcanic ash soils sampled from the A and the B horizons

Intensive cultivation of crop fields using agricultural chemicals and fertilizers has led to changes in ecological systems, resulting in a high possibility of environmental pollution by contamination, or occasional reactions not only in the soil but also in the water and the atmosphere. Some substances are known to be very toxic to human beings at low concentrations. For example, nitrosamines are believed to be carcinogenic and mutagenic.     

Tubular and spheroidal halloysite in pyroclastic deposits in the area of the Roccamonfina volcano (Southern Italy)

Halloysite-bearing weathered pyroclastic deposits of the Roccamonfina volcanic area (Southern Italy), consisting generally of light grey clay masses richer in slightly weathered pumice grains, mottled patches of whitish clayey material and yellowish-brown veins along vertical root channels, were characterised by chemical analysis, X-ray diffraction (XRD), infrared spectroscopy (FT-IR), optical (OM), scanning (SEM) and transmission (TEM) microscopy, electron diffraction (ED) and energy dispersive X-ray analysis (EDXRA). Both tubular and spheroidal forms of halloysite were observed, different parts of the deposits being characterised by a particular morphology. No consistent differences in terms of the chemical and mineralogical composition of the deposit materials were found. However, the chemical composition of the different particle-size clay fractions indicated that less silica, with concomitant relative enrichment in aluminium, and loss of bases characterised the <0.5 μm compared with the 0.5–2.0 μm fraction reflecting their differences in the content of primary minerals. The amounts of Fe, Al and Si extracted by dithionite–citrate–bicarbonate (DCB) and oxalate reagents suggested the presence of short-range-order aluminosilicates but this could not be proved by other physical techniques. X-ray analysis revealed the presence of hydrated (1 nm) and dehydrated (0.7 nm) halloysite, mica, sanidine and plagioclase minerals. TEM/EDXRA analysis of the <0.5 μm clay fraction revealed an amorphous Si-rich phase in the sample containing spheroidal halloysite. The differential X-ray diffraction analysis (DXRD) from untreated and DCB treated yellowish-brown material along with the electron diffraction (ED) of the <0.5 μm clay fraction showed the presence of goethite and ferrihydrite. The various weathered pyroclastic materials showed a major difference in terms of their physical characteristics, particularly in terms of their compactness and porosity/permeability as revealed by microscopic and sub microscopic observations. It is suggested that the different morphological forms of halloysite may result from conditions of growth in the different microenvironments related to variability in physical conditions.     

Characteristics and fertility constraints of degraded soils in Leyte,Philippines

Knowledge of the characteristics and fertility status of degraded soil is fundamental to planning suitable soil management strategies for crop production purposes. Such knowledge can be obtained through quantitative appraisal of soil properties and assessment of soil fertility status. Sixty soil samples were collected from five locations at Ormoc, Baybay, Bontoc, Bato and Matalom on the western side of Leyte island, Philippines. An important physical constraint in most of the soils is the high clay content, particularly in the soils of Baybay and Bato where it is a problem for cultivation. The strongly acidic and strongly alkaline pH, low available P and, in some cases, low exchangeable K are the chemical constraints. Variation in the physical and chemical constraints of these degraded soils is directly or indirectly related to the nature of the parent material, geomorphic position and anthropogenic effect. Soil fertility characteristics are distinct within similar soil types, primarily because they are related to the dominant soil-forming processes. Consideration of the soil physical and chemical constraints is essential for the long-term planning of soil management strategies that will lead to sustainable utilization of these problematic soils.     

Monitoring of matrix flow and bypass flow through the subsoil in a volcanic ash soil

Daily matrix flow at 1-m depth in a volcanic ash soil was calculated during a period of one year using Darcy's law. Unsaturated hydraulic conductivity of undisturbed core samples could be expressed as a unique function of the soil water content. Hydraulic gradient obtained from soil water suction by a tensiometer installed at 90- and 110-cm depths, and hydraulic conductivity converted from the soil water content by time domain reflectometry (TDR) were monitored every 30 min throughout a year in a maize (Zea mays L.) Chinese cabbage (Brassica pekinensis Rupr.) field. The matrix flow obtained by this method was substituted for the water balance equation to estimate the bypass flow, and monthly and annual evapotranspiration. Annual rainfall in 1997 was 989 mm and evapotranspiration was estimated to be 730 mm. Net matrix flow at 1-m depth was 164 mm downward even though upward matrix flow occurred during half of the year. Downward flow determined by the water balance method exceeded the downward matrix flow during two heavy rain events in the year and the difference between the two flows was 63 mm, which was considered to correspond to a bypass flow. The bypass flow accounted for only 6.4% of the annual rainfall. Matrix flow was well monitored by the application of unsaturated Darcy's law in a field, and monthly evapotranspiration and bypass flow could be quantified by the introduction of the water balance equation.     

Influence of Volcanic Ash Deposition on the Classification,Fertility, and Suitability of Some Soils of West Sarawak,Malaysia

Abstract

A study was conducted to determine the influence of the volcanic ash deposition on the physicochemical characteristics of some soils of West Sarawak and to evaluate their suitability for some common crops. A total of seven common soil series of different geology and locations from West Sarawak were collected and analyzed for their physicochemical and dissolution analysis. For comparison, similar analytical procedures were conducted on selected volcanic ash soils of Indonesia and the Philippines. The Sarawak soils were classified as Inceptisol, Ultisol, and Oxisol. The soils were acidic and had relatively low CEC and exchangeable bases. The other laboratory analysis, however, were not conclusive in the results. The soils were evaluated for crops such as rubber, oil palm, rice, pepper, banana and tapioca. Most of these soils were rated as moderate (S₂) to marginally suitable (S₃), indicating insignificant contribution of volcanic ash into the fertility status of soils of west Sarawak regions.     

Genesis and micromorphology of loess-derived soils from central Kansas

The genesis and micromorphology of three Harney soils from different precipitation regions (from 540 mm to 715 mm) (fine, smectitic, mesic Typic Argiustolls) in the Smoky Hills of central Kansas were investigated. The objectives were to (1) examine the morphological, chemical, physical and mineralogical characteristics of Harney soils formed in loess; (2) determine the clay mineral distribution with depth and the origin of the clay minerals present; and (3) investigate the relationship between the clay mineralogy and other soil properties such as soil plasmic fabric, COLE values and fine clay/total clay ratios. Mineralogical and micromorphological techniques were used to evaluate the characteristics of the loess-derived soils. The first pedon was formed in 88 cm of Bignell loess over Peoria loess and the other two pedons were formed from Peoria loess. The chemical properties were similar for the pedons studied. Differences were observed in physical properties, especially in particle size distribution, oven-dry bulk density and coefficient of linear extensibility values. Although the soils were mapped in the same soil series, the geomorphic positions of the pedons and the nature of the parent material affected the characteristics of the soils. Smectite was the predominant clay mineral, especially in the fine clay fraction, regardless of the location in the precipitation gradient. The dominance of smectite increased in the C-horizons. This implies a detrital source of smectite in the B-horizons formed in both Bignell and Peoria loess units. The presence of randomly interstratified mica-smectite and the micromorphological observations of weathering biotite indicate that weathering also plays an important role in the mineralogy of Harney soils. The high content of clay mica in the surface horizons was caused by dust fall in the study area. Thick and continuous argillans were observed when FC/TC and COLE values were low and crystalline smectite was present. In the lower part of the soil profiles, the plasmic fabric was mostly ma-skelsepic (granostriated b-fabric) and smectite was more crystalline as indicated by sharper X-ray diffraction peaks.     

Mineral Composition of Clay Fractions and Oxygen Vacancies in Silt-Sized Quartz in Soils on the Ka-Etsu Plateau, Fukui, Central Japan—Possibility of Eolian Dust Brought from Northern Asia as Parent Material of Soils

Fine- to medium-textured soils are distributed on the Early Pliocene rocks and Pleistocene sandy sediments in the Ka-Etsu plateau. The Jingaoka (JIN) soil was classified into Aluandic Andosols by WRB, and Low-humic Non-allophanic Kuroboku soils by the Fourth Committee for Soil Classification and Nomenclature of the Japanese Society of Pedology, although it was similar morphologically to Yellow-Brown Forest soils. On the other hand, the Tomitsu (TMI) and Yamamuro (YAM) soils were classified into Hyperdystri-Chromic Cambisols by WRB, and Typic Yellow-Brown Forest soils by the Fourth Committee for Soil Classification and Nomenclature based on the morphological, physical and chemical properties. These soils were influenced considerably by the Akahoya tephra, especially the JIN soil. Based on the results of clay-mineralogical analysis and the measurement of the ESR-signal intensity associated with the oxygen vacancies in fine quartz, a large part of parent materials in the soils distributed on the Ka-Etsu plateau was derived from the eolian dust which was brought with the NW winter monsoon from the Precambrian sediments in the northern part of the Asian continent during MIS 2 (24–11 thousand years ago) at the Last Glacial Maximum. The parent materials of the fine-textured JIN soil located on the highest terrace near the rocky coastline were mostly composed of eolian dust, although the influenced of the Akahoya tephra was recognized. The parent materials of the TMI soil were admixed with a small amount of autochthonous materials from the sandy coast located windward. In the YAM soil which was located on the side of a hilly area distant from the coastline, the ESR-signal intensity in fine quartz was considerably low, and the admixture of autochthonous materials was also considered since the texture of this soil was coarser than that of the JIN and TMI soils.     

Aluminum concentrations in sclerotia from a buried humic horizon of volcanic ash soils in Mt. Myoko,Central Japan

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.     

Characteristics of phosphorus fractions in the soils derived from sedimentary and serpentinite rocks in lowland tropical rain forests,Borneo

ABSTRACT

Soil organic phosphorus (P) is an important P source for biota especially in P-limited forests. Organic P has various chemical formations which differ in bioavailability and these organic P can be degraded by phosphatase enzymes. Here, we report soil P fractions inferred from solution ³¹P-NMR spectroscopy and soil phosphatase activities of two tropical rain forests on contrasting parent materials; sedimentary and ultramafic igneous (serpentinite) rocks. Compared to the sedimentary soils　and previous studies, P fractions of the serpentinite soils have distinctly high proportions of pyrophosphate and scyllo-inositol hexakisphosphate (scyllo-IP₆). The accumulation of pyrophosphate and scyllo-IP₆ may be related to strong sorptive capacity of iron oxides present in the serpentinite soils, which implies a consequent low P availability in the serpentinite soils. Mean value of soil phosphatase activities was higher in the serpentinite soils than in the sedimentary soils, suggesting that biota in these serpentinite forests depend more on soil organic P as a P source.     

起源于暗棕壤和红壤的水稻土有机质特性研究

土壤有机质是土壤的重要组成部分,其不仅对土壤的理化性质、肥力水平具有深刻影响,而且所包含的有机碳库动态与全球气候变化关系密切。农业土壤受人类活动的高强度干扰,其持有的碳库是全球碳库中最活跃的部分,对于维持全球碳平衡具有不可忽视的贡献[1]。水稻土是我国重要的农业土壤资源,地域分布广泛,其有机质含量是我国耕作土类中最高的,且固碳潜力显著大于旱地土壤[2]。在不同土壤类型和有机碳库的背景下,引起农业土壤碳库变化的关键因素不同[3]。我国地域广阔,南北气候和稻田耕作制度差异很大,不同区域水稻土的起源土壤存在明显的地带性。不同区域水稻土既具有长期人为利用下形成的一系列共性,又由于不同生物气候、母土、耕     

Porosity and soil water properties of Caribbean volcanic ash soils

Abstract. Volcanic ash soils are generally recognized as soils with excellent and stable physical properties. Here we characterized the porosity and water properties of volcanic ash Andosols and Nitisols from Guadeloupe in contrasting banana systems: (1) perennial crop without mechanization, (2) mechanized and regularly replanted crop. Desiccation from 1 kPa to 1550 kPa moisture tension leads to significant shrinkage in the Andosol, representing a 50% reduction of the void space. The clayey Nitisol exhibited limited shrinkage. Soil clods from the mechanized plots had a significantly smaller macroporosity than that from perennial plots. The soil hydraulic conductivity was also drastically reduced in the compacted layers of the mechanized plots. However, Nitisols appeared to be less affected than Andosols. Laboratory compression tests showed that both soils were susceptible to compaction at soil moisture close to field capacity. The shrinkage properties of the Andosol were due to microaggregation of non-crystalline components upon drying. The relative stability of the macroporosity in the Nitisol was probably related to the presence of stable microaggregates made of halloysite and iron oxide. Two major processes promote soil structure degradation in the Andosol under mechanized banana cropping, surface desiccation and soil compaction. They are both induced by repeated tillage after clearing.     

Land use dynamics derived from colluvial deposits and bogs in the Black Forest,Germany

The Black Forest is considered to be a rather unfavorable area, having a short vegetation period, low mean annual temperatures, high precipitation, and a pronounced relief. These conditions do not favor agricultural land use and thus it is widely accepted that people only began using the land intensively during the Middle Ages. In this integrated study 17 soil profiles, two peat bogs and a database of archaeological finds were used to reconstruct past land use impacts on the environment. AMS–¹⁴C datings of charcoals, luminescence datings of colluvial deposits, archaeological finds and pollen records indicate land use already during the Neolithic. This pre‐medieval land use might be related to seasonal settlements dominated by pastoralism and the use of wood or bedrock to build settlements and infrastructure or as energy supply. There is new evidence of human activity dating back to the Bronze and Iron Age, which is a discrepancy to the absence of archaeological finds in the direct vicinity of the studied sites. With the beginning of the Middle Ages land use practices changed, most likely with the expansion and intensification of agricultural land use, which coincides with the increasing use of natural resources in the Black Forest. Hence, the main phases of colluvial deposition date to the Middle Ages and Modern Times. Increased contents of As, Cr, Cu, Pb, or Zn in medieval colluvial deposits might indicate smelting or mining, even though there are no known archeological sites pointing to such activities nearby. Whereas the pattern of colluvial deposition in the southeastern Black Forest points to distinct, but local land use in pre‐medieval times and to intensified and widespread land use since the Middle Ages, thick and multi‐layered colluvial deposits indicate intensive land use in the neighboring Baar region since the Neolithic. The different land use patterns of these two regions originate from the rather favorable conditions for agriculture in terms of soils, climate, and topography in the Baar region compared to the unfavorable conditions in the Black Forest.     

Physico-chemical characteristics of the soils developed from alluvial deposits on Chongming Island in Shanghai,China

The effects of the water extracts of rapeseed cakes undergoing decomposition under different conditions on plant growth were evaluated using Lemna paucicostata 6746 for the bioassays. Half-strength Hutner’s medium was used as the basal medium, to which aliquots of concentrated water extracts were added in the ratio of 1/1,000, and the number of reproduced fronds were counted after 7 days as an index of the growth.

Aerobic decomposition of rapeseed cake (1:1 ratio of rapeseed cake to water, w/w) showed a strong inhibitory effect on the growth of L. paucicostata 1 to 4 weeks after the start of the decomposition. In the submerged decomposition (1 : 10 ratio of rapeseed cake to water, w/w), no inhibition was detected in the first weeks, but a strong inhibition appeared after 8 weeks and increased thereafter. The water extracts of the rapeseed cake undergoing decomposition under the submerged condition contained large amounts of fatty acids (acetic, propionic, and butyric acid), which were considered to be the main phytotoxins inhibiting the growth of L. paucicostata. In the aerobic decomposition, the concentrations of both ammonium nitrogen and lower fatty acids were too low to inhibit plant growth, suggesting that other decomposed products were concerned with the inhibition.

As the bioassay with L. paucicostata showed similar results to those previously obtained by germination tests, it is considered that the use of L. paucicostata could be generalized to other crop plants.     

Genesis and characteristics of brown forest soils derived from serpentine in Kyushu,Japan

Recently, micropedological investigations have become an important means to explain some pedogenetical processes. The micromorphological features of Brown Forest soils and Mountain Brown Forest soils have been reported by several investigators(12, 14–15), Braunerde can be distinguished from Braunlehm by the presence of a spongy structure, immobility of peptizable iron hydroxides, or by the absence of any fluidal structure in its (B) horizon. In his review on micropedology, osmond(16) has stated that Brown Earths do not show any evidence of illuviation of ferruginous compounds or clay formed by oxidative weathering. As a result of micromorphological investigations on soils derived from serpentine in Greece, Krause(12) has described that the dominant soil of the hillsides is rubefied Braunlehm (Rotlehm), whereas the soil developed on valley terraces is Braunerde which appears as a transformation product of Rotlehm and has a spongy fabric in the A horizon.