Effects of phosphate buffering on the extraction of labile phosphate by plants and by soil tests

Soil Research ◽  
1979 ◽  
Vol 17 (3) ◽  
pp. 511 ◽  
Author(s):  
ICR Holford ◽  
GEG Mattingly
Keyword(s):  
Sodium Bicarbonate ◽  
Phosphate Buffer ◽  
Buffer Capacity ◽  
Phosphorus Uptake ◽  
Calcareous Soils ◽  
Soil Test ◽  
Soil Tests ◽  
Glasshouse Experiment

In a glasshouse experiment on 24 calcareous soils, the uptake of isotopically exchangeable phosphorus by ryegrass was negatively related to the phosphate buffer capacity. The corresponding effect of buffering on the extraction of exchangeable phosphorus by sodium bicarbonate was almost identical. In four different soil tests, the greater the effect of buffering on extraction, the higher was the correlation between the soil test and phosphorus uptake by the ryegrass.

scholarly journals Effects of phosphate buffer capacity on critical levels and relationships between soil tests and labile phosphate in wheat growing soils

Soil Research ◽  
1980 ◽  
Vol 18 (4) ◽  
pp. 405 ◽  
Author(s):  
ICR Holford
Keyword(s):  
Sodium Bicarbonate ◽  
Phosphate Buffer ◽  
Buffer Capacity ◽  
Maximum Yield ◽  
Ammonium Fluoride ◽  
Yield Response ◽  
Soil Test ◽  
Critical Levels ◽  
Soil Tests ◽  
Negative Effect

Thirty-nine soils from northern New South Wales were used to examine the effects of phosphate buffer capacity on (i) the extraction of labile phosphate by four soil tests, (ii) the relationships between the four soil tests, and (iii) the critical level of each soil test required for near-maximum yield of wheat under field conditions. The results confirmed the principle, recently proposed by the author, that the larger the negative effect of buffer capacity on extraction of labile phosphate by a soil test, the higher is the correlation between the soil test and plant yield response to phosphate. The acidic ammonium fluoride extractant of Bray and Kurtz was the most sensitive to buffering in this respect, while the alkaline sodium bicarbonate extractant of Olsen et al. was less sensitive and the modified sodium bicarbonate test of Colwell least sensitive to buffering. Whereas a previous glasshouse study suggested that the ammonium fluoride test was over-sensitive to buffering, and hence underestimated available phosphate in strongly buffered soils, this field study showed that the test is correctly sensitive to buffering. Consequently critical levels for near-maximum wheat yields do not vary for the ammonium fluoride tests, but increase with increasing buffer capacity for the sodium bicarbonate tests. The additional measurement of buffer capacity is therefore required to give precision in the use of the sodium bicarbonate soil test and particularly the Colwell test. The results also suggest that a high correlatiori between two soil tests can only be expected where each test is similarly sensitive to buffering, provided of course that both tests extract phosphate mainly from the labile pool.

Increased P application to lateritic soil in 1976 increased Colwell soil test P for P applied in 2000

Soil Research ◽  
2003 ◽  
Vol 41 (4) ◽  
pp. 645 ◽  
Author(s):  
M. D. A. Bolland ◽  
D. G. Allen
Keyword(s):  
Sodium Bicarbonate ◽  
Sandy Soil ◽  
Buffer Capacity ◽  
Lateritic Soil ◽  
Soil Test ◽  
P Values ◽  
Phosphate Retention ◽  
Subsequent Application ◽  
Soil Test P ◽  
P Application

In a field experiment, 6 amounts of superphosphate [0–800 kg phosphorus (P)/ha] were applied in July 2000 to an acidic lateritic ironstone gravel sandy soil treated 24 years previously (May 1976) with 6 amounts of superphosphate (0–599 kg P/ha). In October 2001, samples of the top 10 cm of soil were collected to measure the capacity of the soil to sorb P by the phosphate retention index (PRI) and P buffer capacity (PBC) methods, and to measure soil test P by the Colwell (sodium bicarbonate) procedure. The capacity of the soil to sorb P, as measured by both PRI and PBC, decreased with increased P application in 1976. For all amounts of P applied in 2000, Colwell soil test P increased with increased P application in 1976. We conclude that increasing amounts of P applied in 1976 decreased the capacity of the soil to sorb the subsequent application of P, thereby increasing soil test P values of soil treated with the subsequent P.

Soil phosphorus tests II: A comparison of soil test–crop response relationships for different soil tests and wheat

2013 ◽  
Vol 64 (5) ◽  
pp. 469 ◽  
Author(s):  
Simon D. Speirs ◽  
Brendan J. Scott ◽  
Philip W. Moody ◽  
Sean D. Mason
Keyword(s):  
Grain Yield ◽  
Confidence Intervals ◽  
Buffer Capacity ◽  
Soil Phosphorus ◽  
Soil Test ◽  
Soil Tests ◽  
P Values ◽  
Soil P ◽  
Soil P Test ◽  
R Value

The performance of a wide range of soil phosphorus (P) testing methods that included established (Colwell-P, Olsen-P, BSES-P, and CaCl2-P) and more recently introduced methods (DGT-P and Mehlich 3-P) was evaluated on 164 archived soil samples corresponding to P fertiliser response experiments with wheat (Triticum aestivum) conducted in south-eastern Australia between 1968 and 2008. Soil test calibration relationships were developed for relative grain yield v. soil test using (i) all soils, (ii) Calcarosols, and (iii) all ‘soils other than Calcarosols’. Colwell-P and DGT-P calibration relationships were also derived for Calcarosols and Vertosols containing measureable CaCO3. The effect of soil P buffer capacity (measured as the single-point P buffer index corrected for Colwell-P, PBICol) on critical Colwell-P values was assessed by segregating field sites based on their PBICol class: very very low (15–35), very low (36–70), low (71–140), and moderate (141–280). All soil P tests, except Mehlich 3-P, showed moderate correlations with relative grain yield (R-value ≥0.43, P < 0.001) and DGT-P exhibited the largest R-value (0.55). Where soil test calibrations were derived for Calcarosols, Colwell-P had the smallest R-value (0.36), whereas DGT-P had an R-value of 0.66. For ‘soils other than Calcarosols’, R-values >0.45 decreased in the order: DGT-P (r = 0.55), Colwell-P (r = 0.49), CaCl2-P (r = 0.48), and BSES-P (r = 0.46). These results support the potential of DGT-P as a predictive soil P test, but indicate that Mehlich 3-P has little predictive use in these soils. Colwell-P had tighter critical confidence intervals than any other soil test for all calibrations except for soils classified as Calcarosols. Critical Colwell-P values, and confidence intervals, for the very very low, very low, and low P buffer capacity categories were within the range of other published data that indicate critical Colwell-P value increases as PBICol increases. Colwell-P is the current benchmark soil P test used in Australia and for the field trials in this study. With the exception of Calcarosols, no alternative soil P testing method was shown to provide a statistically superior prediction of response by wheat. Although having slightly lower R-values (i.e. <0.1 difference) for some calibration relationships, Colwell-P yielded tighter confidence intervals than did any of the other soil tests. The apparent advantage of DGT-P over Colwell-P on soils classified as Calcarosols was not due to the effects of calcium carbonate content of the analysed surface soils.

Effects of phosphate buffer capacity on yield response curvature and fertilizer requirements of wheat in relation to soil phosphate tests

Soil Research ◽  
1985 ◽  
Vol 23 (3) ◽  
pp. 417 ◽  
Author(s):  
ICR Holford ◽  
BR Cullis
Keyword(s):  
Phosphate Buffer ◽  
Buffer Capacity ◽  
Field Experiments ◽  
Significant Negative Correlation ◽  
Yield Response ◽  
Alkaline Soils ◽  
Soil Tests ◽  
Soil Phosphate ◽  
Fertilizer Requirement ◽  
Actual Response

Data from 39 fertilizer field experiments in north-western New South Wales were used to examine the effects of phosphate buffer capacity on yield response curvature and fertilizer requirements of wheat in relation to six soil phosphate tests (Bray1, Bray2, BSES, Truog, lactate, and bicarbonate). The soil tests were also evaluated for their accuracy in predicting yield responsiveness in a total of 48 experiments. There was a highly significant negative correlation between buffer capacity and response curvature, accounting for nearly 50% of the variance in curvature. The accuracy of the relationship was highest for moderately and strongly buffered soils. When used to predict curvature and hence fertilizer requirements, buffer capacity increased the variance accounted for by the most effective soil test (lactate) from 32% to 75%, compared with 93% using actual response curvatures. Whether used to predict responsiveness or fertilizer requirement, the lactate test was superior and the bicarbonate test was inferior to other soil tests. The bicarbonate test accounted for only half as much variance in responsiveness as the lactate test, and it accounted for none of the variance in fertilizer requirement. The results confirmed earlier studies showing that the bicarbonate test has several intrinsic properties which make it inferior to other soil tests on moderately acid to alkaline soils.

Ultrastructure of the basal body apparatus in epidermal cells of a sponge larva (Aplysilla SP: Demospongiae)

1992 ◽  
Vol 50 (1) ◽  
pp. 928-929
Author(s):  
R.L. Pinto ◽  
R.M. Woollacott
Keyword(s):  
Sodium Bicarbonate ◽  
Epoxy Resin ◽  
Basal Body ◽  
Phosphate Buffer ◽  
Similar Data ◽  
Basal Apparatus ◽  
Striated Rootlet ◽  
The Common ◽  
Basal Foot ◽  
Sexually Mature

The basal body and its associated rootlet are the organelles responsible for anchoring the flagellum or cilium in the cytoplasm. Structurally, the common denominators of the basal apparatus are the basal body, a basal foot from which microtubules or microfilaments emanate, and a striated rootlet. A study of the basal apparatus from cells of the epidermis of a sponge larva was initiated to provide a comparison with similar data on adult sponges.Sexually mature colonies of Aplysillasp were collected from Keehi Lagoon Marina, Honolulu, Hawaii. Larvae were fixed in 2.5% glutaraldehyde and 0.14 M NaCl in 0.2 M Millonig’s phosphate buffer (pH 7.4). Specimens were postfixed in 1% OsO4 in 1.25% sodium bicarbonate (pH 7.2) and embedded in epoxy resin. The larva ofAplysilla sp was previously described (as Dendrilla cactus) based on live observations and SEM by Woollacott and Hadfield.

scholarly journals Prediction of zinc deficiency in navy beans (Phaseolus vulgaris) by soil and plant analyses

1990 ◽  
Vol 30 (4) ◽  
pp. 557 ◽  
Author(s):  
JD Armour ◽  
AD Robson ◽  
GSP Ritchie
Keyword(s):  
Phaseolus Vulgaris ◽  
Soil Solution ◽  
Relative Yield ◽  
Fresh Weight ◽  
Soil Tests ◽  
Plant Parts ◽  
Zn Concentration ◽  
Navy Beans ◽  
Glasshouse Experiment ◽  
Zn Status

Navy beans (Phaseolus vulgaris cv. Gallaroy) were grown with 7 rates of zinc (Zn) in a Zn-deficient gravelly sandy loam in a glasshouse experiment. The plant shoots were harvested 31 days after sowing and the Zn concentration in each of 4 plant parts (YL, young leaf; YOL, young open leaf; YFEL, youngest fully expanded leaf; and whole shoots) was related to the fresh weight of the shoots. The critical Zn concentrations (mgtkg) in the plant parts determined by the 2 intersecting straight lines model were 21.1 for YL (r2 = 0.66), 17.1 for YOL (r2 = 0.83), 10.6 for YFEL (r2 = 0.91) and 12.5 for the whole tops (r2 = 0.88). The YFEL was selected as an appropriate diagnostic tissue because it is readily identifiable in the field and had the highest 1.2 with fresh weight. In a second glasshouse experiment, the critical Zn concentration in the YFEL and 5 soil tests were evaluated for their ability to predict the Zn status of navy beans. There were 13 soils from sands to clays with a wide range of chemical properties. The soil tests were 0.1 mol/L HCl, DTPA, EDTA, dilute CaCl2 and soil solution Zn. The concentration of Zn in the YFEL correctly predicted Zn deficiency or adequacy in about 77% of samples. The results from both experiments showed that a critical Zn concentration of 10-11 mg/kg in the YFEL can be used to diagnose the Zn status of Gallaroy navy beans. It was not possible to recommend a single soil test for prediction of the relative yield of navy beans. A combination of quantity (HCl, EDTA, DTPA) and intensity (soil solution, 0.002 mol/L CaCl2, 0.01 mol/L CaCl2) parameters were able to explain most of the variation in the Zn concentration of the YFEL, a more sensitive measure of nutrient availability than relative yield. EDTA-Zn in combination with 0.01 mol/L CaCl2-Zn explained 90% of the variation in the Zn concentration in the YFEL, while HCl- or DTPA-Zn and 0.01 mol/L CaCl2 explained about 80% of the variation. As soil solution Zn was significantly correlated with 0.002 and 0.01 mol/L CaCl2-Zn (r = 0.75, P<0.01; r = 0.62, P<0.05, respectively), CaCl2-Zn may be used as a more convenient measure of Zn intensity than soil solution Zn.

Correction of manganese deficiency in barley crops on calcareous soils. 2. Comparison of mixed and compound fertilizers

1973 ◽  
Vol 13 (63) ◽  
pp. 440 ◽  
Author(s):  
DJ Reuter ◽  
TG Heard ◽  
AM Alston
Keyword(s):  
Particle Size ◽  
Field Experiments ◽  
Phosphorus Uptake ◽  
Calcareous Soils ◽  
Nutrient Content ◽  
Manganese Deficiency ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Foliar Sprays ◽  
Compound Fertilizer

Mixed and compound fertilizers made from superphosphate and manganous sulphate were compared in field experiments as sources of manganese for barley on the calcareous soils of southern Yorke Peninsula, South Australia. The compound fertilizers were made by blending manganous sulphate with 'den-fresh' superphosphate before the granulation process: mixed fertilizers were made by mixing the components after manufacture. The fertilizers were applied at sowing at rates of 19 kg haw1P and 16 kg haelMn in one experiment and 28 kg ha-1 P and 6 kg ha-1 Mn in a second experiment. In the latter, up to three foliar sprays of manganous sulphate (1.3 kg ha-1 Mn per spray) were applied in addition. The rate at which the fertilizers reacted with the soil was studied in an incubation experiment, and the nutrient content of particle-size fractions of the fertilizers was also determined. Plant dry weight, manganese and phosphorus uptake, and grain yield were increased to a greater extent by application of the compound fertilizer than by the mixed fertilizer. Application of compound fertilizers at sowing also delayed the appearance of manganese deficiency symptoms in crops by two weeks compared with mixed fertilizers. Neither fertilizer prevented the occurrence of manganese deficiency and further yield increases were obtained by subsequent foliar sprays of manganous sulphate. Fertilizer manganese was rapidly immobilized in the soil. After 167 hours' incubation, approximately three quarters of that added in manganous sulphate, and in the mixed and compound fertilizers was not extractable in divalent form. The variation in nutrient content of particle size fractions of a compound fertilizer was much less than that in a mixed fertilizer.

Relationship of soil phosphorus fractions to phosphorus soil tests and fertilizer response

2003 ◽  
Vol 83 (4) ◽  
pp. 443-449 ◽  
Author(s):  
R. H. McKenzie ◽  
E. Bremer
Keyword(s):  
Available P ◽  
Soil Test ◽  
Strongly Correlated ◽  
P Fractions ◽  
Soil Tests ◽  
Fertilizer Response ◽  
Inorganic P ◽  
Soil P ◽  
P Fertilizer ◽  
Soil Test P

Soil tests for available P may not be accurate because they do not measure the appropriate P fraction in soil. A sequential extraction technique (modified Hedley method) was used to determine if soil test P methods were accurately assessing available pools and if predictions of fertilizer response could be improved by the inclusion of other soil P fractions. A total of 145 soils were analyzed from field P fertilizer experiments conducted across Alberta from 1991 to 1993. Inorganic P (Pi) removed by extraction with an anion-exchange resin (resin P) was highly correlated with the Olsen and Kelowna-type soil test P methods and had a similar relationship with P fertilizer response. No appreciable improvement in the fit of available P with P fertilizer response was achieved by including any of the less available P fractions in the regression of P fertilizer response with available P. Little Pi was extractable in alkaline solutions (bicarbonate and NaOH), particularly in soils from the Brown and Dark Brown soil zones. Alkaline fractions were the most closely related to resin P, but the relationship depended on soil zone. Inorganic P extractable in dilute HCl was most strongly correlated with soil pH, reflecting accumulation in calcareous soils, while Pi extractable in concentrated acids (HCl and H2SO4) was most strongly correlated with clay concentration. A positive but weak relationship as observed between these fractions and resin P. Complete fractionation of soil P confirmed that soil test P methods were assessing exchangeable, plant-available P. Key words: Hedley phosphorus fractionation, resin, Olsen, Kelowna

scholarly journals Phosphorus Supply of Typical Hungarian Soils

2006 ◽  
Vol 55 (1) ◽  
pp. 117-126 ◽  
Author(s):  
György Füleky
Keyword(s):  
Soil Properties ◽  
Inorganic Phosphate ◽  
Phosphorus Uptake ◽  
Calcareous Soils ◽  
Hot Water ◽  
Percolation Method ◽  
Water Percolation ◽  
Phosphorus Source ◽  
Fraction I ◽  
Test Plants

The new hot water percolation (HWP) method was introduced to determine the phosphorus supply of soils from the Soil Bank of 36 Hungarian soils. The present work aimed to explain the availability of phosphorus by determining the inorganic phosphate fractions and using ryegrass test plants. Four inorganic phosphate fractions were distinguished: Fraction I, the sorbed phosphates; Fraction II, the easily soluble Ca phosphates and the Al bound phosphates; Fraction III, the Fe phosphates; and Fraction IV, the hardly soluble Ca phosphates. Fraction II, in which the easily soluble Ca phosphates and Al phosphates accumulate, was the main phosphorus source for the test plants on both calcareous and non-calcareous soils. Fraction III (the iron phosphates) plays a greater role in non-calcareous soils, while Fraction IV (the hardly soluble Ca phosphates) in calcareous soils. Both fractions are closely connected with soil development, and with soil properties such as pH and CaCO 3 content. The hot water percolation method reflects the phosphorus supply of soil as well as that measured with ryegrass plants and with the AL method. This new HWP method is in good correlation with the main source of phosphate, with fraction II. For routine purposes the first collected HWP fraction can possibly be used to determine the phosphorus supply of soil correlating well with the phosphorus uptake of test plants.

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