Acidity control in Latosols under long-term pastures in the Cerrado region, Brazil

Soil Research ◽  
2013 ◽  
Vol 51 (4) ◽  
pp. 253 ◽  
Author(s):  
P. R. S. Vendrame ◽  
O. R. Brito ◽  
E. S. Martins ◽  
C. Quantin ◽  
M. F. Guimarães ◽  
...  
Keyword(s):  
Crop Production ◽  
Clay Fraction ◽  
Clay Mineralogy ◽  
Tropical Soils ◽  
Limiting Factors ◽  
Standard Procedures ◽  
Controlling Parameter ◽  
Exchangeable Al ◽  
The Mean

High acidity and aluminium saturation are among the main limiting factors for crop production in tropical soils. The aim of this work was to measure the acidity of Latosols under pastures in the Brazilian Cerrado and to assess the influence of clay mineralogy as a controlling parameter of soil acidity. Topsoils (n = 73, 0–0.2 m depth) of Latosols developed on different parent materials were sampled in two sub-regions of the Cerrado region. The main chemical characteristics were determined by standard procedures, and kaolinite and gibbsite contents were determined by dissolution with sulfuric acid and thermogravimetric analyses. The exchangeable concentrations of calcium (Ca), magnesium (Mg), and potassium (K) varied considerably among soil samples, with ranges of 0–13.9 cmolc kg–1 (mean ± standard deviation 1.77 ± 1.91 cmolc kg–1) for Ca; 0.2–3.2 cmolc kg–1 (1.13 ± 0.68 cmolc kg–1) for Mg; and 0–1.0 cmolc kg–1 (0.24 ± 0.24 cmolc kg–1) for K. The mean concentration of exchangeable aluminium (Al) was 0.55 ± 0.61 cmolc kg–1 (range 0–2.3 cmolc kg–1). The content of kaolinite (282 ± 96 g kg–1) was higher than of gibbsite (106 ± 77 g kg–1). The amount of exchangeable Al and Al saturation rate varied according to the mineralogy of the clay fraction of the soils. The content of exchangeable Al3+ remained low when gibbsite was the predominant mineral, whereas it increased with kaolinite content. The ratio kaolinite/(kaolinite + gibbsite) could be used as a useful indicator of the sensitivity of soils affected by acidity and Al toxicity.

Phosphorus sorption and desorption in oxide-rich Ferralsols of New Caledonia

Soil Research ◽  
2001 ◽  
Vol 39 (2) ◽  
pp. 403 ◽  
Author(s):  
I. G. Dubus ◽  
T. Becquer
Keyword(s):  
Organic Matter ◽  
Crop Production ◽  
Pacific Islands ◽  
New Caledonia ◽  
Clay Fraction ◽  
South Pacific ◽  
Limiting Factors ◽  
P Availability ◽  
P Sorption ◽  
South Pacific Islands

Phosphorus (P) availability in soils is one of the main limiting factors for crop production in Ferralsols that contain high amounts of aluminium and iron oxides. Highly weathered Geric Ferralsols cover large surface areas of south Pacific islands, some of which are required for agricultural development. Sorption and desorption of P in Geric Ferralsols of the island of Maré (New Caledonia) were investigated. The soils contain large quantities of oxides, especially of aluminium. The clay fraction consisted exclusively of fine, discrete oxide particles. Both Freundlich and Langmuir equations provided a good fit to the data for equilibrium P concentrations ranging from 0.05 to 850 mg P/L. The extremely high P sorption capacities of New Caledonian Geric Ferralsols were exemplified by the large Langmuir sorption maxima which ranged from 6400 to 9250 mg P/kg. A strong negative correlation between P sorption and organic matter was noted, resulting in a larger P availability in topsoils. This relationship can be used to provide a first assessment of P sorption capacities of Geric Ferralsols across the island. Management of organic matter is likely to be of major importance in the control of P availability in Geric Ferralsols of south Pacific islands.

Clay mineralogy effects on sodium fluoride pH of non-allophanic tropical soils

Soil Research ◽  
2004 ◽  
Vol 42 (8) ◽  
pp. 865 ◽  
Author(s):  
M. E. Alves ◽  
A. Lavorenti
Keyword(s):  
Agricultural Soils ◽  
Ammonium Oxalate ◽  
Clay Fraction ◽  
Chemical Properties ◽  
Clay Mineralogy ◽  
Clay Content ◽  
Soil Classification ◽  
Tropical Soils ◽  
Oh Groups ◽  
Soil Weathering

Soil pH measured in 1 m NaF (pHNaF) can be a useful tool for soil classification and to provide better advice on the chemical management of agricultural soils in the tropics. In this study, we verified the effects of clay mineralogy on pHNaF values of non-allophanic soils of São Paulo State, Brazil. Fourteen subsurface soil samples were characterised for chemical properties, clay content, clay mineralogy, and for pHNaF values, which were measured in the whole soil and in both natural and deferrified (dithionite-treated) clay fractions. Regression and correlation analyses showed that both ammonium-oxalate-extractable Al (Alo) and gibbsite contents have positive relationships with both clay and soil pHNaF values. On the other hand, kaolinite is inversely related to the pHNaF measured in the clay and has nonsignificant effect on soil pHNaF. X-ray diffraction patterns of dithionite-treated clays did not show disruption of kaolinite or gibbsite after the treatment with 1 m NaF, suggesting that the displacement of surface OH groups by F– seems to be the main mechanism associated with the pH increase verified in the NaF solution after its contact with the deferrified clay fraction. The smaller influence of hematite on pHNaF seems to be due to its correlation to Alo. Goethite and ammonium-oxalate-extractable Fe (Feo) exert no effect on pHNaF. Finally, the relationships observed in the present study strongly suggest that pHNaF values <10.3 measured in non-allophanic kaolinitic soils with low levels of non-humified organic matter are essentially due to their smaller Alo and gibbsite contents, which agrees with the direct correlation verified between pHNaF and soil weathering degree.

Soil acidification as influenced by crop rotations, stubble management, and application of nitrogenous fertiliser, Tarlee, South Australia

Soil Research ◽  
2002 ◽  
Vol 40 (3) ◽  
pp. 483 ◽  
Author(s):  
R. K. Xu ◽  
D. R. Coventry ◽  
A. Farhoodi ◽  
J. E. Schultz
Keyword(s):  
Soil Acidification ◽  
Surface Soil ◽  
South Australia ◽  
Base Cations ◽  
Crop Rotations ◽  
Stubble Retention ◽  
Exchangeable Al ◽  
The Mean ◽  
Fertiliser Application

Soil acidification, as influenced by N fertiliser, stubble management, and crop rotations, was investigated using soil samples from a long-term rotation trial at Tarlee, South Australia. With the effects of combination of treatment inputs (wheat–lupin, stubble retention and N-fertiliser application), the pHCa (0–10 cm depth) declined from the starting value of 6.12 to 4.50 after a 14-year period. All of the treatments caused the soil pH to decrease. The mean acidification rates for the period 1978–1992 varied from 0.5 to 2.22 kmol H+/ha.year for different treatments. Although the rainfall at Tarlee (483 mm) is not sufficient to cause regular drainage events, it is likely that downward movement of NO3– in the soil profile has caused acidification in the surface soil. Also the retention of stubble caused more acidification than where there was regular stubble burning or removal. The acidification resulted in an increase in soil exchangeable Al and Mn and extractable Al and Mn, and the decrease in soil exchangeable base cations. The values for soluble Al (extracted in CaCl2) in 1992 were 1.58 and 2.45 mg/kg (0–10 cm depth) for the wheat–bean and wheat–lupin rotations, but the percentage of Al in the ECEC was low. It is not known whether this acidity has any impact on yields of field crops at this stage. But with soluble Al and the percentage of Al in ECEC increasing, it is possible that Al toxicity may occur in the high input-output cropping soils in South Australia. acidity, pH, aluminium, manganese.

scholarly journals Hillslope curvature, clay mineralogy, and phosphorus adsorption in an Alfisol cultivated with sugarcane

2009 ◽  
Vol 66 (6) ◽  
pp. 819-826 ◽  
Author(s):  
Diogo Mazza Barbieri ◽  
José Marques Júnior ◽  
Luis Reynaldo Ferracciú Alleoni ◽  
Fernando José Garbuio ◽  
Livia Arantes Camargo
Keyword(s):  
Clay Fraction ◽  
Clay Mineralogy ◽  
Geostatistical Analysis ◽  
Limiting Factors ◽  
Available Phosphorus ◽  
Maximum Adsorption Capacity ◽  
Phosphorus Adsorption ◽  
Management Zones ◽  
P Adsorption ◽  
Area Data

Hillslope curvatures are associated with specific environments that correlate to chemical and mineralogical attributes of soil, so determining specific management zones. Phosphorus is one of the main limiting factors to the development and longevity of sugarcane. The type and the mineralogical constitution of the clay fraction play an important role in the phosphorus (P) adsorption of soil. High proportion of gibbsite (Gb) in soil may be the major responsible for P adsorption. The relationships among spatial variability as a function of hillslope curvature, the proportion of kaolinite (Kt) and Gb, and phosphorus adsorption were evaluated in an Alfisol cultivated with sugarcane. Two plots of 1 ha of a concave and a convex hillslope area were selected and 121 samples were collected in each area. The maximum P adsorption was determined in six samples taken randomly in each area. Data were submitted to descriptive statistical and geostatistical analysis. The lowest average values of available phosphorus were found in the convex area. In this area, the proportion of gibbsite, expressed by the values of the ratio [Gb/(Gb + Ct)] and the values of maximum adsorption capacity of phosphorus were higher than in the concave area.

Acute and Chronic Changes in Platelet Volume and Count After Cardiopulmonary Bypass Induced Thrombocytopenia in Man

1987 ◽  
Vol 57 (01) ◽  
pp. 55-58 ◽  
Author(s):  
J F Martin ◽  
T D Daniel ◽  
E A Trowbridge
Keyword(s):  
Platelet Count ◽  
Mean Platelet Volume ◽  
Artery Bypass ◽  
Bypass Graft ◽  
Control Group ◽  
Artery Bypass Graft ◽  
Platelet Volume ◽  
Young Males ◽  
The Mean

SummaryPatients undergoing surgery for coronary artery bypass graft or heart valve replacement had their platelet count and mean volume measured pre-operatively, immediately post-operatively and serially for up to 48 days after the surgical procedure. The mean pre-operative platelet count of 1.95 ± 0.11 × 1011/1 (n = 26) fell significantly to 1.35 ± 0.09 × 1011/1 immediately post-operatively (p <0.001) (n = 22), without a significant alteration in the mean platelet volume. The average platelet count rose to a maximum of 5.07 ± 0.66 × 1011/1 between days 14 and 17 after surgery while the average mean platelet volume fell from preparative and post-operative values of 7.25 ± 0.14 and 7.20 ± 0.14 fl respectively to a minimum of 6.16 ± 0.16 fl by day 20. Seven patients were followed for 32 days or longer after the operation. By this time they had achieved steady state thrombopoiesis and their average platelet count was 2.44 ± 0.33 × 1011/1, significantly higher than the pre-operative value (p <0.05), while their average mean platelet volume was 6.63 ± 0.21 fl, significantly lower than before surgery (p <0.001). The pre-operative values for the platelet volume and counts of these patients were significantly different from a control group of 32 young males, while the chronic post-operative values were not. These long term changes in platelet volume and count may reflect changes in the thrombopoietic control system secondary to the corrective surgery.

Multi-Center Calibration of the Second Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149R

1991 ◽  
Vol 65 (03) ◽  
pp. 263-267 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Reference Material ◽  
Standard Error ◽  
Standard Errors ◽  
Sensitivity Index ◽  
Long Term Stability ◽  
Significant Bias ◽  
The Mean ◽  
The Relationship ◽  
International Sensitivity Index

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.

Comparative Study of effectiveness of mobilization with movement (MWM) and End range mobilization (ERM) techniques in frozen shoulder

2018 ◽  
Vol 4 (4) ◽  
pp. 519-522
Author(s):  
Jeyakumar S ◽  
Jagatheesan Alagesan ◽  
T.S. Muthukumar
Keyword(s):  
Range Of Motion ◽  
Frozen Shoulder ◽  
Type I ◽  
Mean Values ◽  
Functional Activities ◽  
Group A ◽  
The Mean ◽  
Group B

Background: Frozen shoulder is disorder of the connective tissue that limits the normal Range of motion of the shoulder in diabetes, frozen shoulder is thought to be caused by changes to the collagen in the shoulder joint as a result of long term Hypoglycemia. Mobilization is a therapeutic movement of the joint. The goal is to restore normal joint motion and rhythm. The use of mobilization with movement for peripheral joints was developed by mulligan. This technique combines a sustained application of manual technique “gliding” force to the joint with concurrent physiologic motion of joint, either actively or passively. This study aims to find out the effects of mobilization with movement and end range mobilization in frozen shoulder in Type I diabetics. Materials and Methods: 30 subjects both male and female, suffering with shoulder pain and clinically diagnosed with frozen shoulder was recruited for the study and divided into two groups with 15 patients each based on convenient sampling method. Group A patients received mobilization with movement and Group B patients received end range mobilization for three weeks. The outcome measurements were SPADI, Functional hand to back scale, abduction range of motion using goniometer and VAS. Results: The mean values of all parameters showed significant differences in group A as compared to group B in terms of decreased pain, increased abduction range and other outcome measures. Conclusion: Based on the results it has been concluded that treating the type 1 diabetic patient with frozen shoulder, mobilization with movement exercise shows better results than end range mobilization in reducing pain and increase functional activities and mobility in frozen shoulder.

PITUITARY-ADRENAL RECOVERY FOLLOWING LONG-TERM CORTICOSTEROID THERAPY

1966 ◽  
Vol 51 (1) ◽  
pp. 63-70 ◽  
Author(s):  
P. F. Roe ◽  
D. M. Mitchell ◽  
G. W. Pennington
Keyword(s):  
Corticosteroid Therapy ◽  
Adrenocortical Function ◽  
Endocrine Disorders ◽  
Marked Rise ◽  
Underlying Condition ◽  
Normal Limits ◽  
Small Rise ◽  
The Mean ◽  
Corticosteroid Drugs

ABSTRACT Adrenocortical function was assessed in 20 patients receiving long-term corticosteroid drugs for a variety of non-endocrine disorders. In all cases plasma 17-hydroxycorticosteroids (17-OHCS) levels were within or above normal limits 48 hours after abruptly stopping their drugs and a further marked rise occurred in 7 patients given metyrapone for 24 h. Urinary 17-OHCS excretion did not show a parallel rise. Taking the group as a whole, a small rise in the mean output occurred 48 hours after stopping therapy, and a further slightly greater rise followed metyrapone. 3 patients had a relapse of their underlying condition during the test in spite of normal plasma and urinary 17-OHCS levels.

Impact of long-term trials on crop production research and education

2010 ◽  
Vol 58 (Supplement 1) ◽  
pp. 1-5 ◽  
Author(s):  
M. Jolánkai ◽  
F. Nyárai ◽  
K. Kassai
Keyword(s):  
Crop Production ◽  
Life Sciences ◽  
Ecological Models ◽  
Dynamic Databases ◽  
Production Research ◽  
Research And Education

Long-term trials have a twofold role in life sciences, acting as both live laboratories and public collections. Long-term trials are not simply scientific curios or the honoured relics of a museum, but highly valuable live ecological models that can never be replaced or restarted if once terminated or suspended. These trials provide valuable and dynamic databases for solving scientific problems. The present paper is intended to give a brief summary of the crop production aspects of long-term trials.

Influence of NPK fertilization on weed flora in maize field

2014 ◽  
Vol 63 (1) ◽  
pp. 139-148 ◽  
Author(s):  
Éva Lehoczky ◽  
M. Kamuti ◽  
N. Mazsu ◽  
J. Tamás ◽  
D. Sáringer-Kenyeres ◽  
...  
Keyword(s):  
Plant Nutrition ◽  
Crop Production ◽  
N Availability ◽  
Weed Species ◽  
Negative Effects ◽  
Production Factors ◽  
Maize Field ◽  
Weed Flora ◽  
Npk Fertilization

Plant nutrition is one of the most important intensification factors of crop production. The utilization of nutrients, however, may be modified by a number of production factors, including weed presence. Thus, the knowledge of occurring weed species, their abundance, nutrient and water uptake is extremely important to establish an appropriate basis for the evaluation of their risks or negative effects on crops. That is why investigations were carried out in a long-term fertilization experiment on the influence of different nutrient supplies (Ø, PK, NK, NPK) on weed flora in maize field.The weed surveys recorded similar diversity on the experimental area: the species of A. artemisiifolia, S. halepense and D. stramonium were dominant, but C. album and C. hybridum were also common. These species and H. annuus were the most abundant weeds.Based on the totalized and average data of all treatments, density followed the same tendency in the experimental years. It was the highest in the PK treated and untreated plots, and significantly exceeded the values of NK fertilized areas. Presumably the better N availability promoted the development of nitrophilic weeds, while the mortality of other small species increased.Winter wheat and maize forecrops had no visible influence on the diversity and the intensity of weediness. On the contrary, there were consistent differences in the density of certain weed species in accordance to the applied nutrients. A. artemisiifolia was present in the largest number in the untreated control and PK fertilized plots. The density of S. halepense and H. annuus was also significantly higher in the control areas. The number of their individuals was smaller in those plots where N containing fertilizers were used. Contrary to them, the density of D. stramonium, C. album and C. hybridum was the highest in the NPK treatments.

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