Evaluation of soil test procedures for determining rice-available silicon

2001 ◽  
Vol 32 (11-12) ◽  
pp. 1779-1792 ◽  
Author(s):  
Morel P. Barbosa-Filho ◽  
George H. Snyder ◽  
Curtis L. Elliott ◽  
Lawrence E. Datnoff
Keyword(s):  
Soil Test ◽  
Test Procedures

Soil and tissue tests to predict pasture yield responses to applications of potassium fertiliser in high-rainfall areas of south-western Australia

2002 ◽  
Vol 42 (2) ◽  
pp. 149 ◽  
Author(s):  
M. D. A. Bolland ◽  
W. J. Cox ◽  
B. J. Codling
Keyword(s):  
Western Australia ◽  
Field Experiments ◽  
Relative Yield ◽  
Subterranean Clover ◽  
Test Method ◽  
Yield Response ◽  
Soil Test ◽  
Test Procedures ◽  
Pasture Production ◽  
Yield Responses

Dairy and beef pastures in the high (>800 mm annual average) rainfall areas of south-western Australia, based on subterranean clover (Trifolium subterraneum) and annual ryegrass (Lolium rigidum), grow on acidic to neutral deep (>40 cm) sands, up to 40 cm sand over loam or clay, or where loam or clay occur at the surface. Potassium deficiency is common, particularly for the sandy soils, requiring regular applications of fertiliser potassium for profitable pasture production. A large study was undertaken to assess 6 soil-test procedures, and tissue testing of dried herbage, as predictors of when fertiliser potassium was required for these pastures. The 100 field experiments, each conducted for 1 year, measured dried-herbage production separately for clover and ryegrass in response to applied fertiliser potassium (potassium chloride). Significant (P<0.05) increases in yield to applied potassium (yield response) were obtained in 42 experiments for clover and 6 experiments for ryegrass, indicating that grass roots were more able to access potassium from the soil than clover roots. When percentage of the maximum (relative) yield was related to soil-test potassium values for the top 10 cm of soil, the best relationships were obtained for the exchangeable (1 mol/L NH4Cl) and Colwell (0.5 mol/L NaHCO3-extracted) soil-test procedures for potassium. Both procedures accounted for about 42% of the variation for clover, 15% for ryegrass, and 32% for clover + grass. The Colwell procedure for the top 10 cm of soil is now the standard soil-test method for potassium used in Western Australia. No increases in clover yields to applied potassium were obtained for Colwell potassium at >100 mg/kg soil. There was always a clover-yield increase to applied potassium for Colwell potassium at <30 mg/kg soil. Corresponding potassium concentrations for ryegrass were >50 and <30 mg/kg soil. At potassium concentrations 30–100 mg/kg soil for clover and 30–50 mg/kg soil for ryegrass, the Colwell procedure did not reliably predict yield response, because from nil to large yield responses to applied potassium occurred. The Colwell procedure appears to extract the most labile potassium in the soil, including soluble potassium in soil solution and potassium balancing negative charge sites on soil constituents. In some soils, Colwell potassium was low indicating deficiency, yet plant roots may have accessed potassum deeper in the soil profile. Where the Colwell procedure does not reliably predict soil potassium status, tissue testing may help. The relationship between relative yield and tissue-test potassium varied markedly for different harvests in each year of the experiments, and for different experiments. For clover, the concentration of potassium in dried herbage that was related to 90% of the maximum, potassium non-limiting yield (critical potassium) was at the concentration of about 15 g/kg dried herbage for plants up to 8 weeks old, and at <10 g/kg dried herbage for plants older than 10–12 weeks. For ryegrass, there were insufficient data to provide reliable estimates of critical potassium.

Assessment of the phosphorus and sulphur status of subterranean clover pastures. 2. Soil tests

1969 ◽  
Vol 9 (38) ◽  
pp. 320 ◽  
Author(s):  
K Spencer ◽  
D Bouma ◽  
DV Moye
Keyword(s):  
New South ◽  
Subterranean Clover ◽  
Soil Samples ◽  
Soil Test ◽  
Soil Tests ◽  
Test Procedures ◽  
Pasture Production ◽  
South Wales ◽  
Extractable P ◽  
Yield Responses

Values obtained by a number of established soil test procedures for phosphorus and sulphur were correlated with yield responses to addition of the relevant nutrient, by subterranean clover-based pastures at 21 sites in south-eastern New South Wales. Colwell's bicarbonate-soluble P and Bray's P, phosphorus values showed sufficiently close associations with response to added phosphorus to be useful for predictive purposes ; Bray's P, values generally gave smaller coefficients. In general, the pasture on soils testing less than 25 p.p.m. bicarbonate-extractable P in the surface three inches responded appreciably to applied phosphorus (relative yields were <85 per cent). The corresponding value for the Bray P, procedure was 10 p.p.m. P. Soil samples from 0-1, 0-3, and 3-6 inch depths gave similar correlations with response. The time of soil sampling did not affect the relationships but winter pasture production was not as closely related to soil test values as was spring production. By contrast, soil tests for sulphur were not reliable but some discrimination between soils could be made with a 500 p.p.m. phosphate extraction. Values from soil samples collected in the winter were less closely related to response than were values from samples collected in the autumn.

Effects of soil composition on the relationships between soil test values for phosphorus fertilizer requirements

Soil Research ◽  
1971 ◽  
Vol 9 (1) ◽  
pp. 43 ◽  
Author(s):  
JD Colwell ◽  
JD Donnelly
Keyword(s):  
Soil Test ◽  
Soil Composition ◽  
Phosphorus Fertilizer ◽  
Test Procedures ◽  
Reactive Iron ◽  
Standard Procedures ◽  
P Fertilizer ◽  
Calibration Equations

The correlations between the P test values obtained by a series of standard procedures were found to be improved by allowing for the effects of soil composition, particularly with respect to reactive iron, aluminium, magnesium, and calcium. The high correlations thus obtained suggest that most of the P test procedures will be of about equal value for estimating P fertilizer requirements if allowance is made for the effects of variations in soil composition. They also suggest that P test calibration equations should include variables representing soil Fe, Al, Mg, or Ca, as well as the actual P test.

Predicting the response of wheat (Triticum aestivum L.) to liquid and granular phosphorus fertilisers in Australian soils

Soil Research ◽  
2007 ◽  
Vol 45 (6) ◽  
pp. 448 ◽  
Author(s):  
T. M. McBeath ◽  
M. J. McLaughlin ◽  
R. D. Armstrong ◽  
M. Bell ◽  
M. D. A. Bolland ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Calcium Carbonate ◽  
Dry Matter ◽  
Calcareous Soils ◽  
Triticum Aestivum L ◽  
Soil Test ◽  
Alkaline Soils ◽  
Test Procedures ◽  
Soil P ◽  
Yield Responses

Liquid forms of phosphorus (P) have been shown to be more effective than granular P for promoting cereal growth in alkaline soils with high levels of free calcium carbonate on Eyre Peninsula, South Australia. However, the advantage of liquid over granular P forms of fertiliser has not been fully investigated across the wide range of soils used for grain production in Australia. A glasshouse pot experiment tested if liquid P fertilisers were more effective for growing spring wheat (Triticum aestivum L.) than granular P (monoammonium phosphate) in 28 soils from all over Australia with soil pH (H2O) ranging from 5.2 to 8.9. Application of liquid P resulted in greater shoot biomass, as measured after 4 weeks’ growth (mid to late tillering, Feeks growth stage 2–3), than granular P in 3 of the acidic to neutral soils and in 3 alkaline soils. Shoot dry matter responses of spring wheat to applied liquid or granular P were related to soil properties to determine if any of the properties predicted superior yield responses to liquid P. The calcium carbonate content of soil was the only soil property that significantly contributed to predicting when liquid P was more effective than granular P. Five soil P test procedures (Bray, Colwell, resin, isotopically exchangeable P, and diffusive gradients in thin films (DGT)) were assessed to determine their ability to measure soil test P on subsamples of soil collected before the experiment started. These soil test values were then related to the dry matter shoot yields to assess their ability to predict wheat yield responses to P applied as liquid or granular P. All 5 soil test procedures provided a reasonable prediction of dry matter responses to applied P as either liquid or granular P, with the resin P test having a slightly greater predictive capacity on the range of soils tested. The findings of this investigation suggest that liquid P fertilisers do have some potential applications in non-calcareous soils and confirm current recommendations for use of liquid P fertiliser to grow cereal crops in highly calcareous soils. Soil P testing procedures require local calibration for response to the P source that is going to be used to amend P deficiency.

scholarly journals How Closely Is Potassium Mass Balance Related to Soil Test Changes?

2020 ◽  
pp. 263-282
Author(s):  
David W. Franzen ◽  
Keith Goulding ◽  
Antonio P. Mallarino ◽  
Michael J. Bell
Keyword(s):  
Mass Balance ◽  
Cropping Systems ◽  
Soil Test ◽  
Test Procedures ◽  
Exchangeable K ◽  
Layer Silicates ◽  
Crop Uptake ◽  
Exchangeable Fraction ◽  
Secondary Layer ◽  
Soil Test K

AbstractThe exchangeable fraction of soil potassium (K) has been viewed as the most important source of plant-available K, with other sources playing smaller roles that do not influence the predictive value of a soil test. Thus, as K mass balance changes, the soil test should change correspondingly to be associated with greater or reduced plant availability. However, soil test changes and the availability of K to plants are influenced by many other factors. This chapter reviews research on soil test K changes and the relation to crop uptake and yield. A mass-balance relationship is rarely achieved from the measurement of exchangeable K because of the potential for buffering of K removal from structural K in feldspars and from interlayer K in primary and secondary layer silicates. Similarly, surplus K additions can be fixed in interlayer positions in secondary layer silicates, or potentially sequestered in sparingly soluble neoformed secondary minerals, neither of which is measured as exchangeable K. In addition, soil moisture, temporal differences in exchangeable K with K uptake by crops, K leaching from residues, clay type, organic matter contribution to the soil CEC, and type of K amendment confound attempts to relate K additions and losses with an exchangeable K soil test. Research is needed to create regionally specific K soil test procedures that can predict crop response for a subset of clays and K-bearing minerals within specific cropping systems.

General considerations for skin test procedures in the diagnosis of drug hypersensitivity

Allergy ◽  
2002 ◽  
Vol 57 (1) ◽  
pp. 45-51 ◽  
Author(s):  
K. Brockow ◽  
A. Romano ◽  
M. Blanca ◽  
J. Ring ◽  
W. Pichler ◽  
...  
Keyword(s):  
Skin Test ◽  
Drug Hypersensitivity ◽  
Test Procedures

Reliability of Laboratory Tests for the Control of Oral Anticoagulation

1974 ◽  
Vol 32 (02/03) ◽  
pp. 483-491
Author(s):  
E. A Loeliger ◽  
M. J Boekhout-Mussert ◽  
L. P van Halem-Visser ◽  
J. D. E Habbema ◽  
H de Jonge
Keyword(s):  
Human Brain ◽  
Laboratory Tests ◽  
Test Procedure ◽  
Rabbit Brain ◽  
Normal Range ◽  
Test Procedures ◽  
Discrimination Power ◽  
Power Of The Test ◽  
Assay Procedure ◽  
Low Sensitivity

SummaryThe present study concerned the reproducibility of the so-called prothrombin time as assessed with a series of more commonly used modifications of the Quick’s onestage assay procedure, i.e. the British comparative reagent, homemade human brain thromboplastin, Simplastin, Simplastin A, and Thrombotest. All five procedures were tested manually on pooled lyophilized normal and patients’ plasmas. In addition, Simplastin A and Thrombotest were investigated semiautomatically on individual freshly prepared patients’ plasmas. From the results obtained, the following conclusions may be drawn :The reproducibility of results obtained with manual reading on lyophilized plasmas is satisfactory for all five test procedures. For Simplastin, the reproducibility of values in the range of insufficient anticoagulation is relatively low due to the low discrimination power of the test procedure in the near-normal range (so-called low sensitivity of rabbit brain thromboplastins). The reproducibility of Thrombotest excels as a consequence of its particularly easily discerned coagulation endpoint.The reproducibility of Thrombotest, when tested on freshly prepared plasmas using Schnitger’s semiautomatic coagulometer (a fibrinometer-liJce apparatus), is no longer superior to that of Simplastin A.The constant of proportionality between the coagulation times formed with Simplastin A and Thrombotest was estimated at 0.64.Reconstituted Thrombotest is stable for 24 hours when stored at 4° C, whereas reconstituted Simplastin A is not.The Simplastin A method and Thrombotest seem to be equally sensitive to “activation” of blood coagulation upon storage.

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