Search

Copyright of Ecologia Austral is the property of Asociacion Argentina de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Principia (2790-377X) is the property of Universidad Monteavila and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ecologia Austral is the property of Asociacion Argentina de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soils in Patagonian Andean Region are developed mainly from volcanic ashes and they have distinct properties. We aimed to develop models in order to estimate Field capacity (FC) and Permanent Wilting Point (PWP) in volcanic soils, using easily measured variables: soil textural class and Fieldes test, which allows detecting non-crystalline aluminosilicates. Data were analyzed with second order regression models, considering textural class as ordinal independent variable (x) and FC and PWP as dependent variables. The following regression models were developed: For soils with negative Fieldes test (i.e., without non-crystalline aluminosilicates) (N = 132): FC = 47,18 - 4,09 * x + 0,13 * x² (R² = 0,52) PWP = 30,46 - 3,52 * x + 0,13 * x² (R² = 0,53) For soils with positive Fieldes test (i.e., with non-crystalline aluminosilicates) (N = 211): FC = 35,50 + 1,26 * x - 0,23 * x² (R² = 0,25) PWP = 21,53 + 0,29 * x - 0,13 * x² (R² = 0,37) x = code for textural class: 1 = clay; 2 = silty clay; 3 = silty clay loam; 4 = sandy clay; 5 = clay loam; 6 = silt; 7 = silt loam; 8 = sandy clay loam; 9 = loam; 10 = sandy loam; 11 = loamy sand; 12 = sand. These models showed significant fit, and are a useful tool based on readily available field data. [ABSTRACT FROM AUTHOR]

Copyright of Medicina (Buenos Aires) is the property of Medicina (Buenos Aires) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Grain-size analysis is a key analysis in soil studies, so accurate determinations are needed for this variable. However, different analytical methods could show different results, even more in volcanic soils with high organic matter contents. The aim of this study was to compare the granulometric fractions of non-allophanic volcanic soils of the Andean Region of Argentina, applying different methods for particle size analysis (hydrometer, pipette and laser diffraction), following pretreatments and protocols commonly used for each technique. Feasibility of applying ignition as pretreatment for removing organic matter was also evaluated. The hydrometer method (HM) tended to overestimate sand fraction and underestimate silt fraction, respect to the pipette method (PM). However, HM and PM were highly correlated for sand and silt fraction, but not for clay fraction: SandPM = 0,94 SandHM - 3,99 (r²=0,83); SiltPM = 1,07 SiltHM + 8,49 (r²=0,79); ClayPM = 0,62 ClayHM + 1,79 (r²=0,54) HM and laser diffraction method (LM) showed similar values for sand and silt fractions and differed in clay fraction, which showed higher values by HM. Both methods were highly correlated for sand and silt fractions, and not for clay fraction: SandLM = 1,32 SandHM - 17,72 (r²=0,78); SiltLM = 1,30 SiltHM - 7,20 (r²=0,77); ClayLM = 0,83 ClayHM - 2,32 (r²=0,27) Results were influenced not only by the technique followed for grain-size determination, but also by the pretreatment applied in each case. The removal of organic matter by ignition was not appropriate. High temperature (430 °C) modified the different grain size fractions. [ABSTRACT FROM AUTHOR]

Austrocedrus chilensis forests suffer a widespread mortality locally known as «mal del cipré controversial. Previous studies suggested Phytophthora austrocedrae as the biotic cause; how studied since there are affected areas not connected with Phytophthora. The soil was prov disease. The purpose of this article was to study soil chemical properties related to A. chi chilensis dense forests developed on different types of soils were selected in the 16 de Oct In each of them, pairs of plots that differed in disease symptoms were established. Each pa of disease (diseased plot) and another that did not exhibit symptoms (asymptomatic plot forests, where the disease was totally absent. In each plot, a soil sample from the A horizon study showed high soil chemical fertility in all the forest soils, with high contents of organic m high cation exchange capacity. Differences between diseased forests and control forests we of bases, base saturation, calcium, pH NaF and phosphorus. These differences could be associ also be associated to the presence of Phytophthora. [ABSTRACT FROM AUTHOR]

Copyright of Latin American Archives of Animal Production / Archivos Latinoamericanos de Producción Animal / Arquivos Latino-Americanos de Produção Animal is the property of Asociacion Latinoamericana de Produccion Animal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aimed to characterize the surface soil chemical fertility nine months after the occurrence of fires in two Andean Patagonian forests: Nothofagus antarctica and Austrocedrus chilensis. The study focused on an area of volcanic ash soils affected by the wildfire locally known as La Colisión (Chubut, Argentina, February 2008) and later covered by volcanic ash from the Chaitén volcano (May 2008). Soil samples were collected at two depths (0-5 cm and 5-10 cm) from stands of N. antarctica and A. chilensis, considering three fire levels (unburned control, low fire damage and high fire damage). As a result from fire, 0-5 cm soil samples from burned forests showed significant increase in pH and electrical conductivity, and decrease in organic matter content, total nitrogen, CEC and sodium than those from control sites. Samples at 5-10 cm from burned forests showed significantly lower organic matter content and total nitrogen, and higher sulfur content compared with control sites. The higher sulfur content in burned soils and the observed higher phosphorus content in allophanic soils with low degree of fire damage could improve vegetation recovery. [ABSTRACT FROM AUTHOR]

The purpose of this work was to characterize the soil chemical fertility of Austrocedrus chilensis soils developed from different parent materials. Five sampling sites with A. chilensis dense forests were selected in 16 de Octubre Valley and Los Alerces National Park (Chubut province, Argentine). In each of them three to six plots were installed. In each plot a clod from the A horizon was collected for chemical analyzes. All the soils showed high soil chemical fertility, with high organic matter content and nitrogen. The soils developed from glacifluvial deposits showed higher content of exchangeable cations, cation exchange capacity and phosphorous than volcanic soils. Volcanic soils properties varied according to the granulometry of the parent material. Soils developed from volcanic ash tended to present higher cation exchange capacity and exchangeable cations than soils originated from pumicite. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Filosofía UIS is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The determination of organic matter (OM) content is key for the knowledge of agricultural and forestry soil productivity. This study evaluated the relationship between OM content determined by weight loss-on ignition (OMWLOI) and Walkley-Black wet oxidation method (OMWO) in soils of the Patagonian Andean Region. The relation was evaluated for volcanic soils with and without amorphous components and with different vegetation types: Pinus ponderosa plantations, herbaceous steppe, shrubly steppe, shrubs and Austrocedrus chilensis forests. One hundred sampling sites were selected and composed samples were obtained from horizon A. Data were analyzed by means of analysis of variance and simple regressions. OMWO was always lower than OMWLOI. This is expectable since OMWLOI includes the total OM, whereas MOWO discriminates the strongly condensed carbon forms. Although differences in the relationship between the analytical methods for soils with and without amorphous components were not detected, a great relationship between these components and organic matter content was found. The relationship between the analytical methods varied according to the vegetation type. Soils with herbaceous steppe and pine plantations presented the greatest differences between the analytical methods. OMWO was in average 37% lower than OMWLOI for these types of vegetation, being significantly greater than soils with srhubs (26%). Soils with Austrocedrus chilensis forests and shrubly steppe presented intermediate values (30% and 35% respectively). Pinus ponderosa plantations (first rotation, average age 21 years) were located in areas with herbaceous steppe. The similarities found between both soils could be associated to the characteristics of OM in the herbaceous steppe environment and soil type, which did not change because of the little time passed since the implantation. Two linear regression models were generated that show the relationship between OMWO and OMWLOI for different vegetation types: Pinus ponderosa plantation and herbaceous steppe OMWLOI (%) = 1.37 x OMWO (%) + 0.81 (R² = 0.86; n = 40) Shrubs, shrubly steppe and Austrocedrus chilensis forest OMWLOI (%) = 1.19 x OMWO (%) + 1.58 (R² = 0.93; n = 60) These equations allow the comparison of MO content data generated by different analytical methods. [ABSTRACT FROM AUTHOR]

In the Spanish Ports a project has been developed that it allows to define "Systems of Quality of Service", very useful according to ISO Standards 9000:2001, more centered in the administration of the own entity that in results or commitments of services guided to the port operation. The present article details the stages developed for the proposal and validation of a Quality. System of the ports and Maritime Services. [ABSTRACT FROM AUTHOR]

Most Patagonian Andean soils were developed from volcanic ashes, showing high forest aptitude. In 2008, Chaitén volcano (Chile) eruption affected Chubut province in Argentina and left a recognizable ash layer on the soils. The objective of this study was to estimate the capacity of different vegetation systems for entrapping particles transported by the wind, using as indicators the recent volcanic ash and the overlying mineral material (i.e., ash and other sediments re-transported and deposited after the eruption). Near Esquel town, Chubut, entrapping capacity was evaluated in ponderosa pine plantations and in adjacent rangelands, located in flat sites. Variables associated with entrapping capacity (soil cover, dasometric characteristics) were also analysed. Plantations showed a continuous organic layer which favoured particle retention. Thus, entrapping capacity was higher in plantations than in rangelands (24,13 ± 8,16 vs. 1,70 ± 0,44 m3ha-1 for recent ash and 2,29 ± 1,08 vs. 1,34 ± 1,08 m3ha-1 for mineral material). Dasometric variables positively correlated with this capacity were: age, number of trees per hectare, basal area, height, and crown projection area. Just seven years after the eruption, most of the plantations showed a quantifiable deposit of mineral material over the recent ash, representing a soil growth rate of 0,98 ± 0,46 m3ha-1year-1. These results highlight plantations ability for entrapping and retaining particles transported by the wind, emphasizing not only their influence on erosion mitigation, but also on soil genesis. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Filosofía UIS is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)