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.

The systematic effect of soil P buffer capacity on Colwell soil P test v. plant response calibration exists only when field experiments are adjacent

Soil Research ◽  
2004 ◽  
Vol 42 (7) ◽  
pp. 763 ◽  
Author(s):  
M. D. A. Bolland ◽  
R. J. Gilkes
Keyword(s):  
Buffer Capacity ◽  
Field Experiments ◽  
Soil Phosphorus ◽  
Triticum Aestivum L ◽  
Systematic Effect ◽  
Calibration Data ◽  
P Values ◽  
Soil P ◽  
Soil P Test ◽  
The Relationship

Thirteen field experiments distributed throughout south-western Australia examined the relationship between percentage of maximum grain yield of wheat (Triticum aestivum L. cv. Aroona) and Colwell soil phosphorus (P) values. These calibration data were fitted to a linear equation, and the slope values for the 13 sites were compared with the P buffer capacity (PBC) of the soils. There was no systematic relationship between these variables except for 3 adjacent sites at Badgingarra and for 3 adjacent sites at Newdegate. We conclude that differences in climate and site conditions have a greater effect than PBC on Colwell soil P test calibration when widely separated sites are compared.

Interpretation of a single-point P buffering index for adjusting critical levels of the Colwell soil P test

Soil Research ◽  
2007 ◽  
Vol 45 (1) ◽  
pp. 55 ◽  
Author(s):  
P. W. Moody
Keyword(s):  
Buffer Capacity ◽  
Soil Phosphorus ◽  
Single Point ◽  
Maximum Yield ◽  
P Value ◽  
P Availability ◽  
Soil P ◽  
P Concentration ◽  
Soil P Test ◽  
Rate Of Increase

Soil phosphorus (P) buffer capacity is the change in the quantity of sorbed P required per unit change in solution P concentration. Because P availability to crops is mainly determined by solution P concentration, as P buffer capacity increases, so does the quantity of P required to maintain a solution P concentration that is adequate for crop demand. Bicarbonate-extractable P using the Colwell method is the most common soil P test used in Australia, and Colwell-P can be considered to estimate P quantity. Therefore, as P buffer capacity increases, the Colwell-P concentration required for maximum yield also increases. Data from several published and unpublished studies are used to derive relationships between the ‘critical’ Colwell-P value (Colwell-P at 90% maximum yield) and the single-point P buffer index (PBI) for annual medics, soybean, potato, wheat, and temperate pasture. The rate of increase in critical Colwell-P with increasing PBI increases in the order: temperate pasture < medics < wheat < potato. Indicative critical Colwell-P values are given for the 5 crops at each of the PBI categories used to describe soil P buffer capacity as it increases from extremely low to very high.

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

Correlation of soil phosphorus tests with the response of irrigated perennial pasture to phosphorus fertilizer

1978 ◽  
Vol 18 (91) ◽  
pp. 243 ◽  
Author(s):  
AJ Montgomery ◽  
G Rubenis
Keyword(s):  
Soil Phosphorus ◽  
Maximum Yield ◽  
Correlation Coefficients ◽  
Response Functions ◽  
Phosphorus Fertilizer ◽  
Soil Tests ◽  
Yield Data ◽  
P Values ◽  
Olsen P ◽  
Pasture Yield

The level of soil phosphorus and the response of irrigated perennial pasture to phosphorus fertilizer were measured on 33 sites in the Goulburn Valley of northern Victoria. Eleven of the 33 sites were found to have Olsen P values above 10 p.p.m. and Colwell P values above 30 p.p.m. Of these 11, 9 did not give a pasture response to superphosphate and 2 gave a relatively small response. Functions of the form Y = a - be-CX (where Y = total pasture yield over 12 months (t ha-1), X = rate of superphosphate application (t ha-1), and a, b and c are constants respectively denoting maximum yield, maximum response, and the rate at which maximum yield is approached) were fitted to the yield data from those sites at which a response did occur. b was found to be correlated with a number of soil tests, the highest correlation coefficient being -0.74 for Colwell P. a was significantly correlated with some tests (P < 0.01) but was generally less predictable, and c gave very low correlation coefficients with all soil tests.

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.

Temporal variation in the results of soil phosphate analyses

1985 ◽  
Vol 25 (4) ◽  
pp. 881 ◽  
Author(s):  
DR Kemp ◽  
WJ McDonald ◽  
RD Murison
Keyword(s):  
Soil Moisture ◽  
Soil Type ◽  
Soil Test ◽  
General Estimate ◽  
P Values ◽  
Thermal Index ◽  
Soil P ◽  
Soil Phosphate ◽  
Improved Pasture ◽  
Over Time

Soil phosphate (P) values were determined for 49 improved pasture sites on 11 occasions over a 3-year period. Each sample was taken from under an improved pasture on the Central Tablelands of New South Wales and analysed using the Bray No. 1 and Colwell (modified Olsen) tests. Variations in soil P values between samplings over time were significant (P<0.05). For individual sites, the 95% confidence limit, as a percentage of the mean, averaged � 19% for Bray P values and � 13% for Colwell P values. The pattern of variation in P values over time was not significantly (P<0.05) affected by soil P level, soil type or soil test. Variation in P values over time with both tests was significantly (P<0.05) correlated with a general estimate of soil moisture and thermal index for the sampling month. Both Colwell P and Bray P values showed negative correlations with increasing soil moisture or increasing thermal index. The correlation between Colwell P and Bray P values on any one soil type was not reliable enough to allow prediction of one soil-test P value from the other.

Indicator of risk of water contamination by phosphorus from Canadian agricultural land

2006 ◽  
Vol 53 (2) ◽  
pp. 303-310 ◽  
Author(s):  
E. van Bochove ◽  
G. Thériault ◽  
F. Dechmi ◽  
A.N. Rousseau ◽  
R. Quilbé ◽  
...  
Keyword(s):  
Water Contamination ◽  
Crop Residue ◽  
Management Practices ◽  
Agricultural Land ◽  
Soil Phosphorus ◽  
Soil Test ◽  
Soil P ◽  
Soil Test P ◽  
P Balance ◽  
Balance Factor

The indicator of risk of water contamination by phosphorus (IROWC_P) is designed to estimate where the risk of water P contamination by agriculture is high, and how this risk is changing over time based on the five-year period of data Census frequency. Firstly developed for the province of Quebec (2000), this paper presents an improved version of IROWC_P (intended to be released in 2008), which will be extended to all watersheds and Soil Landscape of Canada (SLC) polygons (scale 1:1, 000, 000) with more than 5% of agriculture. There are three objectives: (i) create a soil phosphorus saturation database for dominant and subdominant soil series of SLC polygons – the soil P saturation values are estimated by the ratio of soil test P to soil P sorption capacity; (ii) calculate an annual P balance considering crop residue P, manure P, and inorganic fertilizer P – agricultural and manure management practices will also be considered; and (iii) develop a transport-hydrology component including P transport estimation by runoff mechanisms (water balance factor, topographic index) and soil erosion, and the area connectivity to water (artificial drainage, soil macropores, and surface water bodies).

scholarly journals Preliminary Critical P-limit Values of 0.01 M CaCl2 Soil Test Procedure

2001 ◽  
pp. 18-21 ◽  
Author(s):  
István Jászberényi ◽  
Jakab Loch
Keyword(s):  
Test Procedure ◽  
Extraction Procedure ◽  
Soil Characteristics ◽  
Soil Test ◽  
Joint Research ◽  
Limit Values ◽  
P Values ◽  
Soil P ◽  
Research Activities ◽  
P Supply

In the last decade, the 0.01 M CaCl2 extraction procedure was tested as a multi-nutrient extractant. In 1995-97, international joint research activities were carried out within the COPERNICUS project. Detailed calibration of conventional and the 0.01 M CaCl2 extraction procedures for pH, Mg and K were published.The amount of phosphorus extracted using a 0.01 M CaCl2 solution is very low and reflects the intensity parameter of phosphorus bio-availability. As a readily desorbed P fraction of soils can reflect the soil P-supply and the CaCl2-P values are in close correlation with P-fertiliser rates and P balance. However, the effects of various soil characteristics on CaCl2-P values are different and their interpretation is difficult.Relatively poor correlations were found between amounts of P extracted by conventional and CaCl2 soil test methods and, therefore, P limit values could not be calculated directly. To characterise the soil P supply at different sites, the CaCl2 desorbed P and the adsorbed P in a modified Baker Soil Test were also applied.Soil test results of Hungarian long-term fertiliser experiments and recommended CaCl2-P limit values, calculated on yield effects and soil characteristics, are discussed.

scholarly journals Correlations Among Different P-Test Methods Studied in a Network of Hungarian P Fertilization Long-term Field Trials

2002 ◽  
Vol 51 (1-2) ◽  
pp. 167-176 ◽  
Author(s):  
Marianna Magyar ◽  
P. Csathó ◽  
K. Debreczeni ◽  
Keyword(s):  
Field Trials ◽  
Test Methods ◽  
P Fertilization ◽  
P Values ◽  
Soil P ◽  
Soil Group ◽  
Soil P Test ◽  
Plant P Uptake ◽  
Term Field

Five soil P-test methods were compared on the soils of the network of unified Hungarian P fertilization long-term field trials. The effect of P application on the soil P-test values was significant on the different P levels and sites. The average effect of the sites varied between 1.5-fold (H 2 O method) and 3.7- fold (AL-method). The amounts of extracted P increased in the order of H 2 O-P < Olsen-P < Pi-P < AERM-P < AL-P < Corrected AL-P. For studying the relationships between the P values extracted by the different methods, acidic, calcareous and all soils groups were taken into account as a basis. A good correlation was found between the Pi- and AERM-methods in each soil group. Within the acidic soil group, pH has a much less expressed effect on AL-P values, presumably this was the reason why the strongest correlation in this soil group was found between the AL- and the Corr. AL-P methods  The next step in our research will be to calibrate these soil-P tests with plant P uptake and yield responses.

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