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Subalpine Loamy Spodosols in Taiwan: Characteristics, Micromorphology, and Genesis
No full textFour subalpine loamy Spodosols with illuvial clay in the spodic horizons were selected for study to understand their characteristics, micromorphology, and genesis. These Spodosols, located in central Taiwan, are covered by coniferous vegetation, receive high levels of precipitation, and occupy gentle slope positions at elevations >2400 m. Soil textures, which range from loam to clay, are finer than those of Spodosols formed in temperate regions. The pedogenic products in the soils of the study area are mainly organo-metallic complexes or illuvial clay mixed with organo-metallic complexes in the spodic horizons. Typical micromorphological features in the spodic horizons of these Spodosols revealed infillings of organo-Fe complexes, argillans, or argiferrans along the irregular voids. The four selected pedons have loose spodic horizons where illuvial clay also has accumulated. The large amounts of spodic materials and illuvial clays in the spodic horizons indicate that podzolization and clay accumulation were the two dominant pedogenic processes. Some of the illuvial clay translocated into the spodic horizons is mixed with organo-Fe (or -Al) complexes along the irregular voids of the spodic horizons. This may also have resulted in a lack of well-oriented clay in these horizons despite the occurrence of large amounts of illuviated clays
Soil characteristics and clay mineralogy of two subalpine forest spodosols with clay accumulation in Taiwan
No full textTwo Spodosols with significant spodic morphological characteristics and clay accumulation were selected from a subalpine forest region where the elevation ranges from 2400 to 2700 meters, with high precipitation and low temperatures, and cool and humid weather conditions prevail. The objectives of this study were to investigate the soil characteristics, weathering patterns of clay mineralogy, and genesis of the two Spodosols with clay accumulation in the Chunta Mountain region of central Taiwan. We have also proposed modification of the description of Spodosols in Soil Taxonomy. Soil characteristics, clay distribution, low soil pH, and very low base saturation percentages caused by strongly leaching processes indicate that podzolization and clay illuviation are the pedogenic processes in the study area. The subsurface horizons of the two Spodosols meet the chemical criteria of the spodic horizon defined in Soil Taxonomy, which suggests that translocation of spodic materials has occurred. The value of organic carbon and Fep/Feo or Alp/Alo ratio reaches a profile maximum in the spodic horizon, which suggests that the spodic horizon was formed predominantly by the illuviation of organo-metallic complexes. Soluble organic matter leached with soil solutions along the soil pores from the upper horizons to the spodic horizon. The spodic horizon is characterized by many black and other dark pellets of organic matter. The clay mineralogy of the A and albic horizons is dominanted by illite, vermiculite and vermiculite-illite interstatified minerals (VI), but the Bhs horizons contain mainly vermiculite and hydroxy-interlayer vermiculite (HIV). The clay mineralogy of the eluvial horizons differs somewhat from that in the illuvial horizons as a result of moderate weathering. The weathering sequence of clay minerals in these two loamy Spodosols is: illite --> vermiculite (or VI) --> HIV. According to the USDA Soil Taxonomy, the two pedons with clay accumulation can be classified as a Typic Haplohumod and a Typic Haplorthod
Removal of 2,4,6-trichlorophenol from a solution by humic acids repeatedly extracted from a peat soil
No full textHumic acid (HA) is one of the major components of soil organic matter. It strongly affects the sorption behavior of organic and inorganic contaminants in soils. To obtain a better understanding of the interactions of contaminants with HA, a repeated extraction technique has been applied to a peat soil to obtain HA fractions with varying aliphaticity and aromaticity, which were subsequently correlated to the sorption properties of 2,4,6-trichlorophenol (TCP). HA fractions were extracted repeatedly using an alkaline solution and each HA fraction was separated into two portions with an air-drying or re-suspending (denoted as RSHAs) process. Solid-state 13C NMR and elemental analysis demonstrated that the aromaticity and polarity of HAs decreased with extractions. Kinetic results indicated that air-dried HAs exhibited two-step first order sorption behavior with a rapid stage followed by a slower stage. The slower sorption is attributed to the diffusion of 2,4,6-TCP in the condensed aromatic domains of HAs. Conversely, sorption of 2,4,6-TCP on RSHAs was extremely rapid and could not be fitted with any kinetic model. For air-dried HAs the sorption capacity (Koc) was weakly correlated with the chemical compositions of HAs. However, a positive trend between Koc and aromaticity was observed for RSHAs. Compared with the results of air-dried HAs with their counterparts of RSHAs, it is therefore concluded that air-drying may alter the structure of HAs through artificially creating a more condensed domain in HAs. The structural alternation may result in an incorrect interpretation of the relationship between sorption capacity and chemical composition of HAs and a misjudgment of the transport behavior of 2,4,6-TCP in soils and sediments
The Relationships between Rice Yield Variability with crop Nutrients on Precision Agriculture
No full text以水稻為主要試驗作物，在行政院農業委員會農業試驗所農田進行精準農業之試驗研究，分析與評量試驗農田植體營養狀態之變異與土壤性質變異之相關性，並進一步利用地理統計軟體繪製各試驗田區之植體營養變異分佈圖。根據農場室於水稻收穫後所得之產量與植體分析資料進行協同克利金（co-kringing）分析，以評估植體營養分對產量之最佳關係。發展及應用有效且精確的方法，藉以評量水稻營養分之空間變異，俾建立植體養分變異與作物生長變異之相關性。
Paddy rice is the main crop for the study. The experiment field of precision agriculture is located at Taiwan Agricultural Research Institute Experimental Farm. We have analyzed and evaluated the rice nutrient spatial distribution and the soil variation of the experiment farm. Geo-statistic sofiware and GIS were applied to map detailed plant nutrient distribution map of experiment fields. The rice yields and plant nutrition data were analyzed by co-kringing method to find the best relationship of rice nutrient and crop yields. For precision agriculture, efficient and accurate methods for assessing the spatial variability of rice nutrient, and relating it to yield quantity and quality component, must be developed and utilized in order to build the relationships between plant nutrient and growth variability
Enhanced chlorophenol sorption of soils by rice-straw-ash amendment
No full textRice-straw burning is a common post-harvest practice on rice paddy land, which results in the accumulation of rice-straw ash (RSA) in paddy soil. Because the occurrence of RSA in soil may affect the fate and transport of contaminants, this study investigated the sorption of 3-chlorophenol (3-CP) on RSA and RSA amended soils to evaluate the sorptive properties of RSA in soils. The results showed that the sorption of 3-CP to RSA proceeds through a surface reaction rather than through partitioning and that the neutral form of 3-CP is preferentially sorbed to the surface when compared to the deprotonated anionic form of 3-CP. The addition of RSA to the soils enhanced the overall 3-CP sorption, indicating that RSA amendment may be applied to retard the movement of 3-CP in contaminated soils. As the RSA content in the soils was increased from 0% to 2%, the Langmuir sorption maximum of the soils increased from 18–80 to 256–274 mg kg−1. Thus, RSA contributed more to the total sorption of the soils than other major components in the soils. Nonetheless, the 3-CP sorption of the soils containing RSA was less than the combination of pure RSA and the soils, thereby indicating that the 3-CP sorption of RSA was suppressed. This may be attributed to the competition of organic matter or other soil components for the surface binding sites of RSA
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Adsorptions of Cd(II) and Pb(II) in aqueous solution by rice-straw char
No full textIn this study, a low-cost adsorbent was prepared from rice straw without any activation process and studied for the adsorption capacities and mechanisms of Cd and Pb ions in water. The adsorption of these metal ions on rice-straw char (RSC) was fast and reached equilibrium within 24h. The adsorption isotherms exhibited the L-type and the adsorption capacities of Pb(II) and Cd(II) at pH 4 were determined to be 68 and 26molg(-1), respectively. The difference between the adsorption capacities of these two metal ions implied different adsorption mechanisms. The adsorptions of Pb(II) and Cd(II) both increased with increasing pH. The adsorption of Pb(II) was insensitive to ionic strength, and the adsorption edge was significantly lower than the PZC of RSC. On the contrary, the adsorption of Cd(II) was affected by changing ionic strength, and the adsorption edges was close to the PZC of RSC. Based on these results, the adsorption mechanism of Pb(II) was determined to be inner-sphere complexation, whereas Cd(II) interacted with the RSC surface through electrostatic attraction and formed outer-sphere complexes on RSC
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