Larval ecology of bovine strongylid worms in tropical soils. I.In vitro studies on the longevity of infective strongylid larvae in different soil types

1988 ◽  
Vol 20 (3) ◽  
pp. 190-192 ◽  
Author(s):  
J. R. S. Lyaku ◽  
J. Monrad ◽  
A. A. Kassuku
Keyword(s):  
Tropical Soils ◽  
Soil Types ◽  
Larval Ecology

scholarly journals Silicate fertilization of tropical soils: silicon availability and recovery index of sugarcane

2013 ◽  
Vol 37 (5) ◽  
pp. 1267-1275 ◽  
Author(s):  
Mônica Sartori de Camargo ◽  
Gabriela Rocha ◽  
Gaspar Henrique Korndörfer
Keyword(s):  
Acetic Acid ◽  
Residual Effect ◽  
Tropical Soils ◽  
Soil Types ◽  
Silicon Source ◽  
Recovery Index ◽  
Over Time

Sugarcane is considered a Si-accumulating plant, but in Brazil, where several soil types are used for cultivation, there is little information about silicon (Si) fertilization. The objectives of this study were to evaluate the silicon availability, uptake and recovery index of Si from the applied silicate on tropical soils with and without silicate fertilization, in three crops. The experiments in pots (100 L) were performed with specific Si rates (0, 185, 370 and 555 kg ha-1 Si), three soils (Quartzipsamment-Q, 6 % clay; Rhodic Hapludox-RH, 22 % clay; and Rhodic Acrudox-RA, 68 % clay), with four replications. The silicon source was Ca-Mg silicate. The same Ca and Mg quantities were applied to all pots, with lime and/or MgCl2, when necessary. Sugarcane was harvested in the plant cane and first- and second-ratoon crops. The silicon rates increased soil Si availability and Si uptake by sugarcane and had a strong residual effect. The contents of soluble Si were reduced by harvesting and increased with silicate application in the following decreasing order: Q>RH>RA. The silicate rates promoted an increase in soluble Si-acetic acid at harvest for all crops and in all soils, except RA. The amounts of Si-CaCl2 were not influenced by silicate in the ratoon crops. The plant Si uptake increased according to the Si rates and was highest in RA at all harvests. The recovery index of applied Si (RI) of sugarcane increased over time, and was highest in RA.

scholarly journals Aggregate stability affects carbon sequestration potential of different tropical soils

2018 ◽  
pp. 71-88 ◽  
Author(s):  
Leo Jude Villasica ◽  
Suzette Lina ◽  
Victor Asio
Keyword(s):  
Carbon Sequestration ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Type ◽  
Aggregate Stability ◽  
Tropical Soils ◽  
Soil Types ◽  
Carbon Sequestration Potential ◽  
Sequestration Potential ◽  
Binding Agents

Aggregate stability and carbon (C) sequestration in soils are closely related phenomena. However, high aggregate stability does not always ensure high carbon sequestration to some soil types since other binding agents could dominate other than carbon. Thus, this study aimed to determine the relationship between aggregate stability and carbon sequestration of different tropical soils which basically differ in geology, genesis, and possibly in their dominant aggregating agents. The study selected four representative soil types (Haplic Acrisol, Calcaric Cambisol, Silic Andosol and Haplic Ferralsol) found in Leyte and Samar that were characterized by previous workers. Soil Organic Carbon (SOC) and Aggregate Stability (AS) in dry and wet conditions were quantified using standard procedures. Some pertinent secondary data were also recorded as reference for each soil type. Results revealed that only Silic Andosol showed positive significant correlation (0.93) between aggregate stability and soil organic carbon (SOC). The other soil types showed weak and negative correlation between aggregate stability and SOC; however, their stability revealed a strong positive relationship with inorganic binding agents. Therefore, each soil type reflects a different relationship between aggregate stability in wet condition and SOC and that the variations could be attributed to the differences in the morpho-physical and geochemical nature of the soils. Moreover, SOC is found to greatly influence the aggregate stability in Silic Andosol, thus the soil carbon sequestration potential of this soil type is generally related to its aggregate stability. However, in other soil types like Haplic Acrisol, Calcaric Cambisol, and Haplic Ferralsol, other binding agents like Calcium (Ca) and iron oxides dominate and control the formation and stability of aggregates rather than SOC.

scholarly journals Suitability of Universal Soil Loss Erodibility, Inter-rill and Rill Erodibility Models for Selected Tropical Soils

2017 ◽  
Vol 50 (4) ◽  
pp. 191-198 ◽  
Author(s):  
Suarau Odutola Oshunsanya ◽  
Nkem Joseph Nwosu
Keyword(s):  
Soil Loss ◽  
Tropical Soils ◽  
The United States ◽  
Soil Types ◽  
Soil Erodibility ◽  
Soil Taxonomy ◽  
Southwestern Nigeria ◽  
Perfect Agreement ◽  
Erosion Prediction ◽  
Tropical Environments

AbstractThe universal soil loss equation (USLE) and water erosion prediction project (WEPP) (inter-rill and rill) erodibility factors are important indicators for land degradation assessment all over the world, which were primarily developed for the United States of America (USA). However, information on suitability of USLE and WEPP for tropical environment is scarce. Therefore, studies were carried out to investigate the suitability of USLE and WEPP for selected tropical soils of Southwestern Nigeria. Four pedons classified based on USDA soil taxonomy as Plinthic Petraquept (Adio series), Kanhaplic Haplaustalf (Oyo series), Typic Plinthustalf (Temidire series) and Typic Haplaustalf (Owutu series) were used for the study. Soil erodibility factor was determined using USLE and WEPP models. Origin-Pro. 8.1 software was employed to compare USLE and WEPP models for conformity and suitability. The results showed perfect agreement (R2= 1.0;P< 0.001) between the two WEPP (inter-rill and rill) erodibility models in all the four soil types investigated. In addition, WEPP models (inter-rill and rill erodibility) significantly (R2= 0.82;P< 0.001) related to USLE (El-Swaify and Dangler, 1977) erodibility model. There was a poor relationship (R2= 0.46;P< 0.06) between USLE (Wischmeier and Mannering, 1968) and the WEPP erodibility factors. The WEPP erodibility models with a perfect relationship with soil properties of the four soil types are more suitable than USLE models for predicting soil erodibility of the identified soil types in tropical environments.

scholarly journals Could 137Cs remediation be accomplished with stable cesium (CsCl) on tropical soils?

2019 ◽  
pp. 1777-1785
Author(s):  
Riviane Maria Albuquerque Donha ◽  
Mário Roque ◽  
Antônio Enedi Boaretto ◽  
Elcio Ferreira Santos ◽  
Fernando Giovannetti Macedo ◽  
...  
Keyword(s):  
Contaminated Soils ◽  
Shoot Growth ◽  
Specific Activity ◽  
Cesium Chloride ◽  
Tropical Soils ◽  
Total Activity ◽  
Soil Types ◽  
Stable Cesium ◽  
Randomized Design ◽  
Subtropical Soils

Stable cesium can be considered as the best element for desorption of soil radio-cesium. It is considered an element that slightly absorbed by plants, so that the application of high doses to the soil could increase the absorption of 137Cs, which is desired for the remediation of contaminated soils. There is shortage of knowledge on remediation of tropical and subtropical soils contaminated with 137Cs. The aim of this work was to evaluate the use of 133Cs for the remediation of Brazilian tropical and subtropical soils contaminated with 137Cs. In addition, we investigated the Cs uptake by bean plants (Phaseolus vulgaris L.) grown in Cs contaminated soil. The experiment was carried out in pots under greenhouse conditions. Seven soil types were used in the experiment (Oxisol, Udox, Psamment, Ochrept; Aquoll; Udox and Udult), which received the application of four doses of 133Cs (0, 5, 10 and 20 mg/pot in a completely randomized design arranged in a factorial scheme (7 soil types x 4 doses of 133Cs) with three replicates. An increase in transfer factor values of 137Cs was observed for both shoot growth and grains, as well as in percentage of total activity of 137Cs removed from the soil regarding to addition of stable cesium levels in all soils. The results showed that psamment soil presented higher specific activity of 137Cs in the soil and grains, as well as for the transfer coefficient from soil to shoot growth and grains. The application of stable cesium chloride to soil did not cause any effects on dry matter production of shoot growth and grains. The addition of 133Cs increased the transfer from soil 137Cs to the plant regardless of soil type, proving the efficiency of this practice for the remediation of soils contaminated with radioactive Cs. In addition, the plants of common bean were efficient for use in phytoremediation.

scholarly journals Glauconitic Siltstone as a Source of Potassium, Silicon and Manganese for Flooded Rice

2020 ◽  
Vol 12 (9) ◽  
pp. 96
Author(s):  
Rafael Gómez Arrieta ◽  
Camila de Andrade Carvalho Gualberto ◽  
Thiago Siqueira Prudente ◽  
Gustavo Alves Santos ◽  
Luiz Henrique Silveira ◽  
...  
Keyword(s):  
Dry Matter ◽  
Tropical Soils ◽  
Soil Samples ◽  
Soil Types ◽  
Manganese Sulfate ◽  
Nutrient Source ◽  
Rice Plants ◽  
Flooded Rice ◽  
Gradual Release ◽  
Different Doses

The objective of this study was to evaluate the efficiency of glauconitic siltstone as a multi-nutrient source for flooded rice. Two experiments were carried out under greenhouse conditions, one using a Ferralsol and the another an Arenosol. Glauconitic siltstone was applied in different doses (0, 5, 20, 40, and 80 mg dm-3 K2O) and potassium chloride, wollastonite, and manganese sulfate were respectively used as standard sources, at doses of 80 mg dm-3 K2O, 270 mg dm-3 Si, and 2 mg dm-3 Mn. The sources were incubated for 90 days on the two soil types and, after the incubation period, rice plants were sown, and two consecutive rice growths were performed. The application of glauconitic siltstone in tropical soils promotes increases in the plant and grain dry matter of rice plants, as well as K, Si and Mn contents in soil samples and accumulated in plants. Greater effects following the application of glauconitic siltstone are obtained after the second rice growth due to its gradual release.

Sorption behaviour of pentachlorophenol in sub-Saharan tropical soils: soil types sorption dynamics

2016 ◽  
Vol 75 (24) ◽  
Author(s):  
Bamidele I. Olu-Owolabi ◽  
Paul N. Diagboya ◽  
Chukwunonso P. Okoli ◽  
Kayode O. Adebowale
Keyword(s):  
Tropical Soils ◽  
Soil Types ◽  
Sorption Behaviour ◽  
Sorption Dynamics ◽  
Sub Saharan

The assessment of structure in tropical soils

1955 ◽  
Vol 45 (4) ◽  
pp. 401-410 ◽  
Author(s):  
H. C. Pereira
Keyword(s):  
Field Experiments ◽  
Clay Soil ◽  
Pore Space ◽  
Field Capacity ◽  
Tropical Soils ◽  
Soil Types ◽  
Acceptance Test ◽  
Volcanic Origin ◽  
Lateritic Clay ◽  
Wet Sieving

A comparison of methods of measuring the structural condition of cultivated surface soil was made for two important East African soil types.The soil samples were drawn from two field experiments: (i) a tillage trial in coffee on a porous red lateritic clay soil of recent volcanic origin; (ii) a rotation trial for cotton, on a red sandy lateritic loam of granitic origin.Of the measurements on soil cores, total porespace and field capacity (⅓ atmosphere) showed little change, while percolation rates, free-draining pore-space and a new rainfall acceptance test all reflected the observed field behaviour of the soils, and showed fairly close and highly significant correlation. Field sieving of dry clods gave highly significant differences in the lateritic clay, the stronger clods indicating the poorer soil condition. Drysieving for ½ mm. crumb was ineffective, as was wet-sieving after wetting under vacuum. Wetting by immersion gave some differences between treatments, but higher variability and no significant correlation with free-draining pore-space. Wetting by rainfall impact on dry crumbs gave the best wet-sieving tests on the clay soil. Different sieving techniques gave inconsistent results on the sandy soil. Crumb structure measurements are not efficient indications of structural conditions on these soil types, which are of wide occurrence in tropical countries.

Abrasive wear of polymer/steel gear drives

2008 ◽  
Vol 4 (1) ◽  
pp. 1-26
Author(s):  
Gábor Kalácska
Keyword(s):  
Wear Resistance ◽  
Abrasive Wear ◽  
Material Selection ◽  
Solid Particles ◽  
Soil Types ◽  
General View ◽  
Modern Engineering ◽  
Clean Environment ◽  
Engineering Polymers ◽  
Plastic Gears

Research was performed on the friction, wear and efficiency of plastic gears made of modern engineering polymers and their composites both in a clean environment (adhesive sliding surfaces) and in an environment contaminated with solid particles and dust (abrasive), with no lubrication at all. The purpose is to give a general view about the results of abrasive wear tests including seven soil types as abrasive media. At the first stage of the research silicious sand was applied between the meshing gears and the wear of plastic and steel gears was evaluated and analyzed from the point of different material properties (elongation at break, hardness, yield stress, modulus of elasticity) and its combinations. The different correlations between the experienced wear and material features are also introduced. At the second stage of the project the abrasive sand was replaced with different physical soil types. The abrasive wear of gears is plotted in the function of soil types. The results highlight on the considerable role of physical soil types on abrasive wear resistance and the conclusions contain the detailed wear resistance. The results offer a new tribology database for the operation and maintenance of agricultural machines with the opportunity of a better material selection according to the dominant soil type. This can finally result longer lifetime and higher reliability of wearing plastic/steel parts.

Effects of heavy metals on soil invertase enzyme activity in different soil types

2010 ◽  
Vol 18 (2) ◽  
pp. 175-180
Author(s):  
Rajesh K. Verma ◽  
Dharam Veer Yadav ◽  
Chandra Pal Singh ◽  
Archna Suman ◽  
Asha Gaur
Keyword(s):  
Heavy Metals ◽  
Enzyme Activity ◽  
Soil Types

Compressive response of some agricultural soils influenced by the mineralogy and moisture

2013 ◽  
Vol 27 (3) ◽  
pp. 239-246 ◽  
Author(s):  
A.E. Ajayi ◽  
M.S. Dias Junior ◽  
N. Curi ◽  
I. Oladipo
Keyword(s):  
Agricultural Soils ◽  
Tropical Soils ◽  
Homogeneity Test ◽  
Confined Compression ◽  
Moisture Retention ◽  
Soil Mineralogy ◽  
Undisturbed Soil ◽  
Statistical Homogeneity ◽  
Compressive Response ◽  
Fine Clay

Abstract This study aimed to investigate the mineralogy, moisture retention, and the compressive response of two agricultural soils from South West Nigeria. Undisturbed soil cores at the A and B horizons were collected and used in chemical and hydrophysical characterization and confined compression test. X-ray diffractograms of oriented fine clay fractions were also obtained. Our results indicate the prevalence of kaolinite minerals relating to the weathering process in these tropical soils. Moisture retention by the core samples was typically low with pre-compression stress values ranging from50 to 300 kPa at both sites. Analyses of the shape of the compression curves highlight the influence of soil moisture in shifts from the bi-linear to S-shaped models. Statistical homogeneity test of the load bearing capacity parameters showed that the soil mineralogy influences the response to loading by these soils. These observations provide a physical basis for the previous classification series of the soils in the studied area. We showed that the internal strength attributes of the soil could be inferred from the mineralogical properties and stress history. This could assist in decisions on sustainable mechanization in a datapoor environment.

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