MULTIELEMENTAL ANALYSIS BY PIXE OF CHINAMPA SOILS IN MEXICO CITY

2002 ◽  
Vol 12 (03n04) ◽  
pp. 237-243 ◽  
Author(s):  
R. RAMOS ◽  
N. E. GARCÍA ◽  
E. ANDRADE ◽  
C. SOLÍS ◽  
G. MURILLO ◽  
...  

Chinampas are island plots (500-1000 m2) constructed of soil scooped from the bottom of the lake and surrounded by canals. Over 40 agricultural species, including vegetables, cereals, and flowers, are produced on chinampas and consumed by approximately 100,000 people. This agro-ecosystem, once one of the most diverse and productive, at present is at risk of disappearing, mainly as a consequence of the severe pollution of the irrigation water. To evaluate the relationship between the accumulation of metals and physical soil properties, total trace metals Fe , Cu , Mn and Zn and total heavy metals Pb , Ni , and Cr in soils were determined by Particle Induced X-Ray Emission (PIXE). This method provides a very suitable technique for treating a large number of samples because sample preparation is simple and determination of a large number of elements is simultaneous. Three sites were chosen because of their long history of pollution: Xochimilco, San Luis Tlaxialtemalco and Mixquic in Mexico City. Soil properties were determined by conventional analytical methods. Soils were found to be high in organic matter content, high in sodicity and salinity, and with an alkaline pH. The metals present in the samples are in the following order of abundance: Fe > Mn > Cr > Zn > Cu > Pb .

2017 ◽  
Vol 78 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Ewa Błońska ◽  
Jarosław Lasota ◽  
Maciej Zwydak

Abstract The aim of this study was to assess the effects of different types of land use (forest, tillage and pasture) on soil properties, especially enzyme activity. Our investigation was carried out on 53 research plots with 11 plots in broadleaved forest stands, 12 plots in mixed broadleaved stands, 10 plots in mixed coniferous stands, 9 plots on tillage and 11 plots on pasture. The soil samples were collected from a depth of 0–15 cm after removing the organic horizon. Contents of organic carbon and nitrogen, pH and soil texture were investigated. Furthermore, dehydrogenase and urease activity were determined. Significant differences in the enzyme activity between forest and agricultural soils were observed, thus demonstrating that enzyme activity is influenced by the organic matter content of the soil. The highest enzyme activity was recorded in the forest soil within broadleaved stands, whilst the lowest activity was found in tillage soil, because tillage soil contained significantly less organic matter. High enzymatic activity of pasture soils is the combined result of vegetation type and the lack of plowing.


Author(s):  
Trina Stephens

Land‐use change can have a major impact on soil properties, leading to long‐term changes in soilnutrient cycling rates and carbon storage. While a substantial amount of research has been conducted onland‐use change in tropical regions, empirical evidence of long‐term conversion of forested land toagricultural land in North America is lacking. Pervasive deforestation for the sake of agriculturethroughout much of North America is likely to have modified soil properties, with implications for theglobal climate. Here, we examined the response of physical, chemical and biological soil properties toconversion of forest to agricultural land (100 years ago) on Roebuck Farm near Perth, Ontario, Canada.Soil samples were collected at three sites from under forest and agricultural vegetative cover on bothhigh‐ and low‐lying topographic positions (12 locations in total; soil profile sampled to a depth of 40cm).Our results revealed that bulk density, pH, and nitrate concentrations were all higher in soils collectedfrom cultivate sites. In contrast, samples from forested sites exhibited greater water‐holding capacity,porosity, organic matter content, ammonia concentrations and cation exchange capacity. Many of these characteristics are linked to greater organic matter abundance and diversity in soils under forestvegetation as compared with agricultural soils. Microbial activity and Q10 values were also higher in theforest soils. While soil properties in the forest were fairly similar across topographic gradients, low‐lyingpositions under agricultural regions had higher bulk density and organic matter content than upslopepositions, suggesting significant movement of material along topographic gradients. Differences in soilproperties are attributed largely to increased compaction and loss of organic matter inputs in theagricultural system. Our results suggest that the conversion of forested land cover to agriculture landcover reduces soil quality and carbon storage, alters long‐term site productivity, and contributes toincreased atmospheric carbon dioxide concentrations.


Author(s):  
Juliana Vantellingen ◽  
Sean C. Thomas

Log landings are areas within managed forests used to process and store felled trees prior to transport. Through their construction and use soil is removed or redistributed, compacted, and organic matter contents may be increased by incorporation of wood fragments. The effects of these changes to soil properties on methane (CH<sub>4</sub>) flux is unclear and unstudied. We quantified CH<sub>4</sub> flux rates from year-old landings in Ontario, Canada, and examined spatial variability and relationships to soil properties within these sites. Landings emitted CH<sub>4</sub> throughout the growing season; the average CH<sub>4</sub> emission rate from log landings was 69.2 ± 12.8 nmol m<sup>-2</sup> s<sup>-1</sup> (26.2 ± 4.8 g CH<sub>4</sub> C m<sup>-2</sup> y<sup>-1</sup>), a rate comparable to CH<sub>4</sub>-emitting wetlands. Emission rates were correlated to soil pH, organic matter content and quantities of buried woody debris. These properties led to strong CH<sub>4</sub> emissions, or “hotspots”, in certain areas of landings, particularly where processing of logs occurred and incorporated woody debris into the soil. At the forest level, emissions from landings were estimated to offset ~12% of CH<sub>4</sub> consumption from soils within the harvest area, although making up only ~0.5% of the harvest area. Management practices to avoid or remediate these emissions should be developed as a priority measure in “climate-smart” forestry.


1987 ◽  
Vol 35 (3) ◽  
pp. 407-415 ◽  
Author(s):  
A. Kamphorst

A small rainfall simulator is described, which can be used in the field as well as in the laboratory for the determination of infiltration and erosion characterisitcs of soils. It is particularly suitable for soil conservation surveys, as it is light to carry and easy to handle in the field. A description is given of a standard procedure for the determination of topsoil erodibilities in the field and some results are presented. The method appears to be highly sensitive to soil properties influencing soil erodibility, such as clay content, organic matter content and soil pH. (Abstract retrieved from CAB Abstracts by CABI’s permission)


2021 ◽  
Vol 30 (1) ◽  
pp. 145-152
Author(s):  
Vyacheslav S. Savchuk ◽  
Vasyl F. Prykhodchenko ◽  
Dmytro V. Prykhodchenko ◽  
Valeriia V. Tykhonenko

Taking into consideration the whole history of geological development of the Western Donbas, data on composition and grade of С12 series coal involved information about the geotectonic development of the Basin. To satisfy the objectives, a system of research methods, covering petrographic, computational, statistical, chronological, comparative and other methods, has been applied. In the process of identification of the petrographic composition and grade of series С12coal on the territory of the Prydniprovia Block, and determination of lateral regularities of their change as well as change in stratigraphic section of the Lower Carboniferous, data of petrographic as well as chemical and technological indices of the coal seam c1 were generalized along with data of all seams of С13 series. The activities helped define genetic features of series С12coal as well as stratigraphic and lateral regularities of changes in the coal composition. The differences in the petrographic composition as well as in the chemical and technological characteristics of series С12 and С13 are indicative of dissimilar conditions of formation of their peat depositions. It has been determined that compared with С13 series coal, the coal of С12 series contains more humidity and fewer mineral impurities. It is characterized by higher values of sulfur content, volatile-matter content, and combustion heat. The ultimate composition of coal seams of С12series is characterized by smaller values of carbon and oxygen contents as well as greater hydrogen content. The conclusions on common features and differences in the petrographic composition as well as chemical and technological features of coal seams of С12and С13 series, and regularities of their changes over the area of the seam occurrence was assessed.


2021 ◽  
Vol 1 (42) ◽  
pp. 109-115
Author(s):  
Binh Phan Khanh Huynh ◽  
Tho Van Nguyen ◽  
Vien My Tran

This study aimed to use charcoal derived from the bamboo and melaleuca produced by traditional kiln applied to sandy soil growing mustard green (Brassica juncea L.). The charcoals were applied at three ratio (1%,2%, and 3%, which correspond to 10, 20, and 30 g charcoal/kg soil in pots) and the control treatment without charcoal. Soil properties were investigated including bulk density, pH, electrical conductivity (EC), cation exchange capacity (CEC), organic matter content, total nitrogen, and total phosphorous. The results showed that bulk density decreased in charcoal-treated soils. pH and EC were in the suitable range for plants.Nutrients and CEC of the soil in the charcoal treatment were significantly higher compared with the control (CEC increase 6.8% to 16%; TC increase 80% to 115%; TN increase 37.5 to 75%). Green mustard growing on charcoalamended soil had greater height (higher 3% to 21%), bigger leaves, and higher yield (increase18% to 81%) than those of plants groomed in the control treatment. This study showed the potential of using charcoal as supplying nutrient to the poor soil. Moreover, the abundant of raw material and easy to produce, it is suitable for applying in the Mekong Delta, Viet Nam, and other countries with similar conditions and infrastructure. 


2008 ◽  
Vol 53 (No. 5) ◽  
pp. 225-238 ◽  
Author(s):  
N. Finžgar ◽  
P. Tlustoš ◽  
D. Leštan

Sequential extractions, metal uptake by <i>Taraxacum officinale</i>, Ruby&rsquo;s physiologically based extraction test (PBET) and toxicity characteristic leaching procedure (TCLP), were used to assess the risk of Pb and Zn in contaminated soils, and to determine relationships among soil characteristics, heavy metals soil fractionation, bioavailability and leachability. Regression analysis using linear and 2nd order polynomial models indicated relationships between Pb and Zn contamination and soil properties, although of small significance (<i>P</i> < 0.05). Statistically highly significant correlations (<i>P</i> < 0.001) were obtained using multiple regression analysis. A correlation between soil cation exchange capacity (CEC) and soil organic matter and clay content was expected. The proportion of Pb in the PBET intestinal phase correlated with total soil Pb and Pb bound to soil oxides and the organic matter fraction. The leachable Pb, extracted with TCLP, correlated with the Pb bound to carbonates and soil organic matter content (<i>R</i><sup>2</sup> = 69%). No highly significant correlations (<i>P</i> < 0.001) for Zn with soil properties or Zn fractionation were obtained using multiple regression.


1973 ◽  
Vol 24 (6) ◽  
pp. 889 ◽  
Author(s):  
RF Thornton ◽  
DJ Minson

Eight grasses and six legumes were fed ad libitum at hourly intervals to wethers fitted with large rumen fistulas to determine voluntary intake, apparent digestibility, and the apparent retention time of organic matter in the rumen, as well as the quantity of rumen digesta and the organic matter content of the rumen digesta. The voluntary intake of legumes was 28% higher than that of equally digestible grasses. This difference was caused by a shorter retention time (17%) and a higher amount of organic matter (14%) in the rumen digesta from legume diets than from grass diets. The weight of wet digesta in the rumen of sheep fed on legumes was 7% lower than from those fed on grass. Neither the quantity of digesta nor the quantity of organic matter in the rumen was related to the voluntary intake, digestibility, or retention time of organic matter in the rumen. Number of jaw movements each day and rate of cotton thread digestion were not related to the retention time of the diets either. Daily intake of digestible organic matter (DOMI, g/day) was closely correlated with retention time (RTOM, hr) for the feeds in this study (r = –0.93) and the same relation applied to both temperate and tropical feeds, viz. DOMI = 1276–50.7 RTOM (r=0.96) Differences in voluntary intake between grasses and legumes were attributed to differences in retention time and the density to which the food was packed in the rumen.


Sign in / Sign up

Export Citation Format

Share Document