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.

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.

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.

Effect of P-buffer capacity and P-retention index of soils on soil test-P, soil test P-calibrations and yield response curvature

Soil Research ◽  
1994 ◽  
Vol 32 (3) ◽  
pp. 503 ◽  
Author(s):  
MDA Bolland ◽  
IR Wilson ◽  
DG Allen
Keyword(s):  
Retention Index ◽  
Buffer Capacity ◽  
Linear Equations ◽  
Yield Response ◽  
Soil Test ◽  
Soil P ◽  
Sorption Method ◽  
Mitscherlich Equation ◽  
Soil Test P ◽  
P Retention

Twenty-three virgin Western Australian soils of different buffer capacities (BC) for phosphorus (P) were collected. The effects of BC on the relationships between Colwell soil test P and the level of P applied, yield and soil test P, and yield and the level of P applied were studied. Wheat (Triticum aestivum cv. Reeves), grown for 27 days in a glasshouse, was used. Two methods of measuring P sorption of soils, P buffer capacity (PBC) and P retention index (PRI), were used. The PBC is determined from a multi-point sorption curve. The PRI is a new, diagnostic, one-point, sorption method now widely used for commercial soil P testing in Western Australia. Both PBC and PRI produced similar results. The relationship between soil test P and the level of P applied was adequately described by a linear equation. When the slope coefficient of the linear equations was related to PBC or PRI, there was no relationship. The other two relationships were adequately described by a Mitscherlich equation. When the curvature coefficient of the Mitscherlich equation was related to PBC or PRI, the trend was for the value of the coefficient to decrease with increasing PBC or PRI. Consequently, as the capacity of the soil to sorb P increased the trend was for larger soil test P or higher levels of P application to produce the same yield.

Soil measurements and wheat yield response to superphosphate in Victoria

1975 ◽  
Vol 15 (72) ◽  
pp. 93
Author(s):  
B Palmer ◽  
VF McClelland ◽  
R Jardine
Keyword(s):  
Wheat Yield ◽  
Geographic Location ◽  
Yield Response ◽  
Soil Test ◽  
Soil Tests ◽  
Yield Data ◽  
Chemical Measurements ◽  
Soil Measurements ◽  
Yield Responses ◽  
Available Phosphate

The relationships between soil tests for 'plant available' phosphate and wheat yield response to applied superphosphate were examined and the extent to which these relationships were modified by other soil measurements was determined. Soil samples and wheat yield data were obtained from experiments conducted in the Victorian wheat belt. The sites were grouped into four relatively uniform classes using soil pH measurement and geographic location. The soil test values differed widely and were accountable for by the soil characteristics measured. However, the overall and within group yield responses to applied superphosphate could not be accounted for in terms of either the soil test value or the associated chemical measurements. By inference, yield response was clearly dependent on factors other than those determining the results of soil tests.

An evaluation of several soil tests for predicting wheat yield response to superphosphate in Victoria

1968 ◽  
Vol 8 (30) ◽  
pp. 52
Author(s):  
JV Mullaly ◽  
JKM Skene ◽  
R Jardine
Keyword(s):  
Field Experiments ◽  
Wheat Yield ◽  
Response Variability ◽  
The Other ◽  
Yield Response ◽  
Available Phosphorus ◽  
Soil Test ◽  
Soil Tests ◽  
Using Data ◽  
Soil Groups

The predictability of three different measures of wheat yield response to superphosphate from each of four soil test measures of available phosphorus (0-6 inches) was examined, using data from field experiments over the period 1951 to 1965. The associations were studied separately within the three great soil groups that are dominant over the wheatgrowing areas of Victoria. Whichever measure of yield response was considered, soil bicarbonate P test measurement gave the best basis for prediction. However, at most, only 26 per cent of the yield response variability was predictable, and the other three tests were substantially less successful. Under the general conditions considered, where yield response is subject to a variety of uncorrected environmental deficiencies, it is concluded that the soil tests for P investigated in this paper are of doubtful practical value.

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.

Mineral nutrition of soybeans grown in the South Burnett region of south eastern Queensland. 2. Prediction of grain yield response to phosphorus with soil tests

1983 ◽  
Vol 23 (120) ◽  
pp. 38 ◽  
Author(s):  
PW Moody ◽  
GF Haydon ◽  
T Dickson
Keyword(s):  
Grain Yield ◽  
Buffer Capacity ◽  
Soil Phosphorus ◽  
Maximum Yield ◽  
Relative Yield ◽  
Yield Response ◽  
Phosphorus Concentration ◽  
The South ◽  
Equilibrium Phosphorus Concentration ◽  
Highly Correlated

Grain yield response of soybean (Glycine max cv. Bragg) to applied phosphorus was measured at 19 experimental sites in the South Burnett region. The soil phosphorus supply factors of quantity, intensity, buffer capacity and rate were estimated by various soil chemical tests, and relative yield [(yield at nil applied phosphorus/maximum yield) x 100] regressed against these tests. The equilibrium phosphorus concentration-the intensity measure-accounted for the greatest percentage variation in relative yield (80%) and at 90% maximum yield was 0.014 �g P/ml. Phosphorus extracted by 0.01 M CaCl2 was highly correlated with the equilibrium phosphorus concentration (r2=0.93) and accounted for 73% of the variation in relative yield. Soil levels of calcium chloride-extractable phosphorus were interpreted as follows: < 0.044 �g P/g, response to phosphorus probable; 0.044 �g P/g to 0.058 �g P/g, response uncertain; > 0.058 �g P/g, response unlikely

Effect of phosphorus fertiliser on the yield of potato tubers (Solanum tuberosum L.) and the prediction of tuber yield response by soil analysis

1989 ◽  
Vol 29 (3) ◽  
pp. 419 ◽  
Author(s):  
NA Maier ◽  
KA Potocky-Pacay ◽  
JM Jacka ◽  
CMJ Williams
Keyword(s):  
Total Phosphorus ◽  
Tuber Yield ◽  
Soil Phosphorus ◽  
Total Yield ◽  
Maximum Yield ◽  
Critical Values ◽  
Yield Response ◽  
Soil Test ◽  
Phosphorus Extraction ◽  
Bray 1

Field experiments were conducted over 6 years at 33 sites throughout the main potato growing areas of South Australia to examine the effects of applied phosphorus (banded at planting), at rates up to 300 kg/ha, on the total yield and size distribution of tubers and to calibrate, in terms of total yield, 8 soil phosphorus extraction procedures (Colwell, Olsen, Bray 1, Bray 2, Mehlich no. 1, lactate, fluoride and total). Phosphorus application significantly (P< 0.05) increased total tuber yield at 16 sites. The mean relative yield for these responsive sites was 69.7% (range 37.4- 91.2%) compared with 97.5% (range 88.0-102.5%) for the non-responsive sites. Tuber size distributions were determined at 13 sites and, depending on site and cultivar, the yield of 80-450 g tubers for the highest yielding treatments represented from 64.2 to 93.7% of the total yield of tubers for those treatments. For each soil phosphorus extraction procedure the Mitscherlich and Smith-Dolby bent-hyperbola models and the Cate-Nelson separation were used to investigate the correlations between yield response and extractable and total phosphorus in the surface (0- 15 cm) soil samples and to calculate critical values. For loamy sand to sandy clay loam surface soils, the order of efficacy of soil tests based on the coefficients of determination (r2) calculated using the Mitscherlich and Smith-Dolby bent-hyperbola models was Bray 1 and Bray 2 > Olsen > lactate, Mehlich no. 1, fluoride and Colwell. The coefficients of determination ranged from 0.88 (Bray 1) to 0.64 (Colwell) for the Smith-Dolby bent-hyperbola model and from 0.86 (Bray 1) to 0.65 (fluoride) for the Mitscherlich model. Yield response was not correlated with total phosphorus concentration. Using the Smith-Dolby benthyperbola model the critical phosphorus values (s.e. in parentheses) were: 25.8(1.8), 40.9(2.6), l6.8(1.4), 13.9(1.0), 38.4(3.1), 24.2(2.9) and 35.1(3.0) mg/kg for the Bray 1, Bray 2, Olsen, lactate, fluoride, Mehlich no. 1 and Colwell methods, respectively. Yield deficits >20% were associated with phosphorus soil test values t 2 0 mg/kg (Bray 1 method) and P-sorption values >240 mg/kg. Rates of 48-73 kg P/ha banded at planting were required for 95% of maximum yield at the deficient sites. For acid coarse-grain sand surface soils, significant Cate-Nelson separations were obtained for the Colwell, Bray 1, Bray 2, Mehlich no. 1 and fluoride methods, the critical phosphorus values were 7.5, 7.0, 5.5, 6.5 and 8.0 mg/kg, respectively. The order of efficacy of the soil tests was Bray 2 (r2 = 0.66) >Bray 1, Colwell, Mehlich no. 1 and fluoride (all r2 = 0.55). Yield deficits >10% were associated with soil test values t 6 mg/kg (Bray 1 method). Rates of 27-59 kg P/ha banded at planting were required for 95% of maximum yield at the deficient sites. Data are presented which suggest that for similar soil types and extraction procedures critical values or critical concentration ranges may apply across a range of growing conditions, planting times and cultivars.

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.

Using soil testing and petiole analysis to determine phosphorus fertiliser requirements of potatoes (Solanum tuberosum L. cv. Delaware) in the Manjimup-Pemberton region of Western Australia

2000 ◽  
Vol 40 (1) ◽  
pp. 107 ◽  
Author(s):  
M. A. Hegney ◽  
I. R. McPharlin ◽  
R. C. Jeffery
Keyword(s):  
Solanum Tuberosum ◽  
Tuber Yield ◽  
Solanum Tuberosum L ◽  
Maximum Yield ◽  
Soil Testing ◽  
Yield Response ◽  
Soil Test ◽  
Versus Level ◽  
Soil Test P ◽  
The Relationship

Field experiments were conducted over 3 years at 21 sites of varying phosphorus (P) fertiliser histories (Colwell P range: 9–170 g/g) in the Manjimup–Pemberton region of Western Australia to examine the effects of freshly applied (current) and previously applied (residual or soil test ) P on the yield of potatoes (Solanum tuberosum L. cv. Delaware). Phosphorus was placed (banded) at planting, 5 cm either side of and below seed planted at 20 cm depth, at levels up to 800 kg P/ha. Exponential [y = a – b exp (–cx)] regressions were fitted to the relationship between tuber yield and level of applied P at all sites. Weighted (according to the variance) exponential regressions were fitted to the relationship between yield responsiveness (b/a, from the yield versus level of applied P relationship) and Colwell P, and two P sorption indices—phosphate adsorption (P-adsorb) and a modified phosphate retention index (PRI(100)). A weighted exponential regression was also fitted to the relationship between the level of applied P required for 95% of maximum yield (Popt; also from yield versus level of applied P) and P-adsorb and PRI(100). A weighted linear regression best described the relationship between Popt and Colwell P. Phosphorus application significantly (P<0.10; from the regression analysis) increased total tuber yield at all but 4 sites. Marketable tuber yield response paralleled total tuber yield response at all sites and averaged 85% of total yields (range 63–94%). Colwell P gave a good prediction of the likely yield response of potatoes across all sites. For example, the yield responsiveness (b/a) of potatoes in relation to Colwell P decreased exponentially from 1.07 at 0 g/g to 0, or no yield response, at 157 g/g Colwell P (R2 = 0.96) i.e. the critical Colwell P for 95% of maximum yield of potatoes on soils in the Manjimup–Pemberton region. Similarly, no yield response (b/a = 0) would be expected at a P-adsorb of 180 g/g (R2 = 0.69) or a PRI(100) of 46 (R2 = 0.61). The level of applied P required for 95% of maximum yield (Popt) decreased linearly from 124 kg/ha on infertile sites (<5 g/g Colwell P) to 0 kg P/ha at 160 g/g Colwell P (R2 = 0.66). However, a more accurate prediction of Popt was possible using either P-adsorb or PRI(100). For example, Popt increased exponentially from 0 kg/ha at <181 g/g P-adsorb (high P soils) to 153 kg/ha at a P-adsorb of 950 g/g (low P soils) (R2 = 0.75) and exponentially from 0 kg/ha at a PRI(100) of <48 (high P soils) to 147 kg/ha at a PRI(100) of 750 (low P soils) (R2 = 0.80). PRI(100) is preferred as a soil test to predict Popt for potatoes in the Manjimup–Pemberton region because of its superior accuracy to the Colwell test. It is also preferred to P-adsorb because of both superior accuracy and lower cost as it is a simpler and less time consuming procedure — features which are important for adoption by commercial soil testing services. A multiple regression including Colwell P, P-adsorb and PRI(100) only improved the prediction of Popt slightly (R2 = 0.89) over PRI(100) alone. When tubers were 10 mm long, the total P in petioles of youngest fully expanded leaves which corresponded with 95% of maximum yield was 0.41% (dry weight basis). These results show that, while the Colwell soil P test is a useful predictor of the responsiveness of potato yield to applied P across a range of soils in the Manjimup–Pemberton region, consideration of both the soil test P value and the P sorption capacity of the soil, as determined here by PRI(100), is required for accurate predictions of the level of P fertiliser required to achieve maximum yields on individual sites.

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