scholarly journals Relationship between macrofauna, mineralogy and exchangeable calcium and magnesium in Cerrado Oxisols under pasture

2009 ◽  
Vol 44 (8) ◽  
pp. 996-1001 ◽  
Author(s):  
Pedro Rodolfo Siqueira Vendrame ◽  
Robélio Leandro Marchão ◽  
Osmar Rodrigues Brito ◽  
Maria de Fátima Guimarães ◽  
Thierry Becquer

The objective of this work was to assess the relationship between macrofauna, mineralogy and exchangeable calcium and magnesium in Cerrado Oxisols under pasture. Twelve collection points were chosen in the Distrito Federal and in Formosa municipality, Goiás state, Brazil, representing four soil groups with varied levels of calcium + magnesium and kaolinite/(kaolinite + gibbsite) ratios. Soil macrofauna was collected in triplicate at each collection point, and identified at the level of taxonomic groups. Macrofauna density showed correlation with contents of kaolinite, gibbsite and exchangeable Ca + Mg in the soils. Mineralogy and exchangeable Ca + Mg had significant effects on taxonomic groups and relative density of soil macrofauna. The termites (Isoptera) were more abundant in soils with low exchangeable Ca + Mg; earthworms (Oligochaeta), in soils with high levels of kaolinite; and Hemiptera and Coleoptera larvae were more abundant in gibbsitic soils with higher contents of total carbon.

2012 ◽  
Vol 518-523 ◽  
pp. 3150-3154
Author(s):  
Jian She Yang ◽  
Ying Ding

Abstract: Calcium and magnesium contents of sludge composting are measured by using the method of ammonium acetate-EDTA complex metric titration here, through Fermentation accelerant and increased nutrient agent treatments. The results showed as following: 1, exchangeable Ca and Mg contents of sludge single treatment increased more 6.83% and5.12% at the end of composting, than at the beginning of composting. 2, Fermentation accelerant added in sludge from 8% to 40%,,the exchangeable calcium and magnesium are more 4.38% ~ 10.58% and 6.77% ~ 13.78% at the end of composting than at the beginning of composting. The exchangeable Ca increased 19.51% ~ 104.83%, but 6.05% of a decreased trend for exchangeable magnesium, Compared with the sludge single compost. 3, as increasing the amount of nutrient agent from 30% to 50%, the exchangeable calcium and magnesium are more 3.88%~7.75%and 5.24%~9.18% at the end of composting than at the beginning of composting. The exchangeable Ca increased in 11.35%~41.13%,but 49%~-3.96% of a decreased trend for exchangeable magnesium, Compared with the sludge single compost. 4, under the condition added 24% of the Fermentation accelerant agent to the sludge, as the Increased nutrient agents from 8% to 32%, the exchangeable calcium and magnesium measured are increased 2.63%~5.54%and3.6%~4.19% at the end of composting , compared with The beginning of composting. The exchangeable Ca increased in 52.34%~112.04%,but -10.15%~-15.59% for exchangeable magnesium, Compared with the sludge single compost.


Soil Research ◽  
1977 ◽  
Vol 15 (3) ◽  
pp. 255 ◽  
Author(s):  
WW Emerson ◽  
CL Chi

Samples of illites, two extracted from soils, one from a shale, prepared with a range of exchangeable calcium, magnesium, sodium were immersed dry into water. The extent of dispersion with time was estimated visually and also deduced from the O.D. of the suspensions derived from the dispersed clay. The dispersion of wet calcium and magnesium soil illites sheared at a given water content and then immersed in water was also assessed visually. The dispersion of all three illites was enhanced when magnesium was the dominant cation rather than calcium. For the soil clays a lower ESP was required to initiate dispersion of the dry clay when immersed in water. Both calcium and magnesium forms of the shale illite dispersed partially over a period of several days when immersed dry into water, the magnesium to a greater extent than calcium. The magnesium form of the coarser of the two soil illites also dispersed slowly. By comparing the calcium-magnesium and calcium-sodium forms of the last clay, it was deduced that about 10 times the equivalent concentration of exchangeable magnesium as sodium was needed to cause the same degree of dispersion. For the other soil illite the water content for dispersion of the wet, sheared magnesium clay was found to be less than for the calcium clay. The O.D. of suspensions of the clays was found to decrease with increasing ESP and when magnesium was the dominant cation rather than calcium. This is explained in terms of particle aggregation. The ease of dispersion of the illites was correlated with particle size. Possible reasons for this, and the effect of magnesium, as opposed to calcium, on the forces between the clay particles are discussed.


1992 ◽  
Vol 119 (1) ◽  
pp. 79-82 ◽  
Author(s):  
E. P. Papanicolaou ◽  
C. G. Apostolakis ◽  
V. Skarlou ◽  
C. Nobeli ◽  
P. Kritidis

SummaryThe relationship between values of 85Sr concentration ratios (CRs) and exchangeable bases, expressed in absolute (mmol/kg) or relative (percentage of cation exchange capacity (CEC)) terms, was considered using the results of a glasshouse pot experiment conducted in 1989, for soils and crops of Greece. Exchangeable calcium, expressed in mmol/kg, presented, in most instances, a significant (P = 0·05–0·01) or highly significant (P < 0·01) negative correlation with the CRs of various crops or plant parts, while exchangeable calcium plus magnesium or total exchangeable bases (expressed also in mmol/kg) showed an even better correlation (higher values of r, lower variability). Expression of the amounts of exchangeable bases in relative terms further improved the correlation coefficient in each comparison. The correlations between the percentage of exchangeable (Ca + Mg) or exchangeable bases and CRs, which were always negative, were significant or highly significant for all tested crops or plant parts. The correlation between CRs and soil properties was greatest for exchangeable (Ca + Mg) expressed as a percentage of CEC (r = -0·92) and followed the order: Exchangeable (Ca + Mg) as % of CEC ≈ exchangeable bases as % of CEC ≈ exchangeable (Ca + Mg) in mmol/kg ≈ exchangeable bases in mmol/kg > exchangeable Ca as % of CEC > exchangeable Ca in mmol/kg.Quantitative relationships between CRs of the tested crops or plant parts and exchangeable calcium plus magnesium (% of CEC) of soils are also presented.


2001 ◽  
Vol 44 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Mário Miyazawa ◽  
Marcos A. Pavan ◽  
Cláudio O. Ziglio ◽  
Júlio C. Franchini

A laboratory study was conducted with soil samples and synthetic solutions to investigate possible mechanisms related with reduction in KCl exchangeable Ca and Mg with increasing pH. Increasing soil pH over 5.3 with CaCO3 added to the soil and with NaOH solution added to soil/KCl suspension increased adsorptions of Ca and Mg. The reduction of Mg was greater than Ca and was related to the concentration of soil exchangeable Al. The decreases of soluble Ca and Mg following addition of Al in synthetic solution were at pH > 7.5. The isomorphic coprecipitation reaction with Al compounds may be the most possible mechanism responsible for the decrease of exchangeable Ca and Mg with increasing pH. Possible chemical reactions are presented.


Soil Research ◽  
1973 ◽  
Vol 11 (2) ◽  
pp. 143 ◽  
Author(s):  
AC Bakker ◽  
WW Emerson ◽  
JM Oades

The susceptibility to waterlogging of red-brown earth subsoils is discussed. One of these, Shepparton, has been leached with chloride solutions of given SAR, in the range 0-7, the last solution being 1 mM in calcium or magnesium. The soil was then extracted with neutral lM ammonium chloride and the displaced cations measured. The exchange of sodium for both calcium and magnesium was similar, following the Gapon equation except at very low SAR values. Some potassium and sodium was extracted from calcium and magnesium soils. Shepparton soil of known SAR was remoulded over a range of water contents and synthetic aggregates formed. The percentage of the clay fraction which dispersed from the aggregates was measured. The water content for perceptible dispersion of magnesium soil was only about half that of calcium soil, the water contents being near the 15 bar and 0.1 bar values respectively for unsheared soil. The water content for dispersion decreased sharply with increasing SAR of the soil. Calcium-sodium soil with an ESP of 3.5 dispersed at the same water content as magnesium soil. Possible reasons for the enhanced dispersion of sheared, wet magnesium soil compared with similar calcium soil are discussed.


Author(s):  
Usha Choudhary ◽  
Meenaxi Sareen ◽  
Anil Moolchandani

The present study was carried out to evaluate the variations in serum minerals ( viz. calcium, magnesium and phosphorus) and transaminases in ketotic buffaloes. Results of blood analysis revealed a significant (P<0.05) reduction in serum phosphorus in ketotic buffaloes whereas nonsignificant (P>0.05) difference occur in serum calcium and magnesium in ketotic buffaloes as compared to control. At the same time significant increase in transaminases GPT, GOT and GGT have been observed .


1936 ◽  
Vol 2 (5) ◽  
pp. 473-475
Author(s):  
W. A. Riddell

Determinations of the Ca, Mg, Na, K, P and Cl content were made and the ratios of calcium, magnesium and phosphorus oxides suggest the presence of calcium and magnesium metaphosphates in the ash of the flesh, calcium metaphosphate in that from the skin and tribasic calcium orthophosphate in that from the bone.


2021 ◽  
Author(s):  
Bárbara Moguel ◽  
Liseth Pérez ◽  
Luis David Alcaraz ◽  
Socorro Lozano-García ◽  
Luis Herrera-Estrella ◽  
...  

&lt;p&gt;For decades, paleoecological studies in lake sediments have focused on reconstructing the environments of the past and explaining phenomena linked to climatic variations. Recent advances in high-throughput DNA sequencing have allowed access to environmental DNA (eDNA) and ancient sedimentary DNA (sedaDNA) as a new and efficient proxy for past and present biodiversity. The basin of Mexico (BM) is located in the central part of the Trans-Mexican Volcanic Belt at 2,200 m a.s.l.; with the southern portion harboring the Chalco sub-basin. Lake Chalco is one of the last remaining natural aquatic ecosystems within the ever-expanding urban area surrounding Mexico City. The paleoenvironmental history of this lake has been previously characterized using sedimentological and geochemical proxies, as well as preserved microfossils (diatoms, pollen) with a temporal framework based on multiple radiocarbon dates. However, information for the remaining taxonomic groups and metabolic pathways remained unexplored. Here, we present the first metagenomics-based study for the Holocene in a high-altitude lake in Central Mexico &amp;#8211;Lake Chalco. We explored the relationship between the lake&amp;#8217;s paleoenvironmental condition and estimations of taxonomic and metabolic profiles across the sedimentary sequence (2.5 meters long). Multiple biological and abiotic variables revealed three main environmental phases: 1) a cool freshwater lake (FW1: 11,500-11,000 cal years BP), 2) a warm hyposaline lake (HS2: 11,000-6,000 cal years BP), and 3) a temperate, subsaline lake (SS3, &lt;6,000 cal years BP). We describe the structure of the microbiota community and taxonomy richness turnover in the three Holocene paleoenvironmental phases. During the past 12 000 years BP the most abundant domains in Lake Chalco sediments were Bacteria, followed by Archaea, and Eukarya (36,722 genera). The analysis of functional proteins showed high biodiversity with a total of 27,636,243 proteins identified, but it was only possible to annotate 3,227,398 of them. Also, we identified several genes associated with some relevant pathways, such as methanogenesis. Altogether, this study allowed us to reconstruct the natural history of lake Chalco and its surroundings.&lt;/p&gt;


1993 ◽  
Vol 27 (6) ◽  
pp. 455-462 ◽  
Author(s):  
Anete S. Grumach ◽  
Solange E.I. Jerônimo ◽  
Marcia Hage ◽  
Magda M.S. Carneiro-Sampaio

The composition of breast milk from brazilian mothers delivering low birthweight infants and its adequacy as a source of nutrients for this group has not yet been fully elucidated. A total of 209 milk samples from 66 women were analysed. The mothers were divided into three groups: G1, mothers delivering term babies of low birthweight (TSGA, n=16); G2, mothers delivering preterm babies of appropriate birthweight (PTAGA, n=20); G3, mothers delivering term babies of appropriate birthweight (TAGA, n=30). The following factors were analysed: osmolarity, total proteins and protein fractions, creamatocrit, sodium, potassium, calcium and magnesium. Milk samples were collected 48 h and 7, 15, 30 and 60 days after delivery. The groups did not differ significantly in terms of osmolarity, total proteins and fractions, creamatocrit, calcium, magnesium or potassium throughout the study period. Sodium levels were higher in all samples from mothers of TSGA infants and in samples from mothers of PTAGA infants on the 7th, 15th and 30th days than in milk from the TAGA group. The authors consider the needs of the low birthweight and TAGA infants and that these high sodium levels may be necessary for growth of low birthweight infants.


1981 ◽  
Vol 8 (2) ◽  
pp. 155 ◽  
Author(s):  
IB Ferguson ◽  
CB Watkins

Leakage of calcium, magnesium and potassium from discs of cortical apple fruit tissue was followed through fruit development and ripening. Leakage of potassium always exceeded that of calcium and magnesium and was little affected by the external presence of the divalent ions. Calcium and magnesium leakage was markedly increased by the external presence of either ion. In tissue from both freshly picked fruit and that taken from storage, potassium and magnesium leakage increased when the fruit was in an advanced state of senescence, but calcium leakage decreased. During fruit development, leakage of all cations was closely related to availability as expressed in tissue concentration. There was a marked increase in potassium leakage in association with the respiratory climacteric.


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