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.

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.

Effect of soil temperature and moisture on soil test P with different extractants

2012 ◽  
Vol 92 (3) ◽  
pp. 537-542 ◽  
Author(s):  
Chunyu Song ◽  
Xingyi Zhang ◽  
Xiaobing Liu ◽  
Yuan Chen
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Test Methods ◽  
Soil Test ◽  
Soil P ◽  
Soil P Test ◽  
Soil Test P ◽  
Fertilization Level ◽  
Bray 1 ◽  
Soil Temperature And Moisture

Song, C., Zhang, X., Liu, X. and Chen, Y. 2012. Effect of soil temperature and moisture on soil test P with different extractants. Can. J. Soil Sci. 92: 537–542. Temperature and moisture are important factors affecting adsorption, transformation and the availability of soil phosphorus (P) to plants. The different temperatures and moisture contents at which soil is sampled might affect the results of soil test P (STP). In order to evaluate the effect of the temperature and moisture, as well as the fertilization level, on the results of soil test P, an incubation study involving three soil temperatures (5, 10, and 20°C), and three soil moisture contents (50, 70, 90% of field water-holding capacity) was conducted with Chinese Mollisols collected from four fertilization treatments in a long-term experiment in northeast China. Four soil P test methods, Mehlich 3, Morgan, Olsen and Bray 1 were used to determine STP after a 42-d incubation. The effect of temperature and moisture on STP varied among soil P tests. Averaged across the four fertilization treatments, the temperature had significant impact on STP, while the responses varied among soil P test methods. Mehlich 3, Morgan and Bray 1 STP decreased and Olsen STP increased with increase in temperature. Effect of soil moisture was only significant for Mehlich 3 P and Olsen P. Soil temperature had greater impact on STP than soil moisture content. The responses of the Olsen method to temperature differed from the other three methods tested. The interaction between soil temperature and soil moisture on soil test P was only significant for Mehlich 3 P. Fertilization level does not affect the STP in as a clear pattern as the temperature and moisture varied for all four methods. Consistent soil sampling conditions, especially the soil temperature, appear to be the first step to achieve a reliable STP for any soil P test.

Factors influencing the soil-test calibration for Colwell P and wheat under winter-dominant rainfall

2020 ◽  
Vol 71 (2) ◽  
pp. 113
Author(s):  
Mark Conyers ◽  
Richard Bell ◽  
Michael Bell
Keyword(s):  
Soil Type ◽  
Wheat Yield ◽  
Sowing Date ◽  
Soil Test ◽  
Soil Tests ◽  
Factors Affecting ◽  
Soil P ◽  
Critical Range ◽  
South Wales ◽  
Dry Conditions

Critical ranges for soil tests are based on results that inevitably involve some broad variance around the fitted relationship. Some of the variation is related to field-based factors affecting crop response to nutrients in the soil and some to the efficiency of the soil-test extractant itself. Most attempts to improve soil tests focus on the extractant, whereas here, we explore the variation that could be accounted for by field-based factors in the soil-test calibration relationship between Colwell phosphorus (P) and wheat yield, using the Australian Better Fertiliser Decisions for Crops database—the biggest dataset available for this relationship. Calibrations developed from this dataset have been criticised, and so we aimed to explore factors accounting for more of the variation in the relationships for the dryland, winter-dominant rainfall region of southern New South Wales. As reported previously, soil type was shown to influence the critical range and r-value for the Colwell P soil-test calibration for P responses by wheat. We also identified a tendency for dry conditions, at sowing or during the season, to lower relative yields for a given soil-test value, indicating increased reliance on fertiliser P over soil P. A similar trend was evident for later sowing date, again suggesting an increased probability of crop P requirements being met from the fertiliser P. However, additional records need to be generated to establish definitively that early sowing or subsurface P reserves minimise response to fertiliser P. In general, factors that influence crop access to soil P will have an impact on response to fertiliser P. Although this analysis shows that it is possible to ‘tighten’ the response curve for Colwell P and wheat by restricting the data for a given soil type to ideal management and seasonal conditions, the ‘outliers’ that are excluded frequently reflect an important subset of environmental conditions encountered by wheat crops in dryland agriculture.

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.

Soil testing for phosphorus: comparing the Mehlich 3 and Colwell procedures for soils of south-western Australia

Soil Research ◽  
2003 ◽  
Vol 41 (6) ◽  
pp. 1185 ◽  
Author(s):  
M. D. A. Bolland ◽  
D. G. Allen ◽  
K. S. Walton
Keyword(s):  
Western Australia ◽  
Phosphate Rock ◽  
Field Experiments ◽  
Soil Samples ◽  
Soil Test ◽  
P Values ◽  
Plant Yield ◽  
Soil P ◽  
Soil Test P

Soil samples were collected from 14 long-term field experiments in south-western Australia to which several amounts of superphosphate or phosphate rock had been applied in a previous year. The samples were analysed for phosphorus (P) by the Colwell sodium bicarbonate procedure, presently used in Western Australia, and the Mehlich 3 procedure, being assessed as a new multi-element test for the region. For the Mehlich procedure, the concentration of total and inorganic P in the extract solution was measured. The soil test values were related to yields of crops and pasture measured later on in the year in which the soil samples were collected.The Mehlich 3 procedures (Mehlich 3 total and Mehlich 3 inorganic soil test P values) were similar, with the total values mostly being slightly larger. For soil treated with superphosphate, for each year of each experiment: (i) Mehlich 3 values were closely correlated with Colwell values; and (ii) the relationship between plant yield and soil test P (the soil P test calibration) was similar for the Colwell and Mehlich 3 procedures. However, for soil treated with phosphate rock, the Colwell procedure consistently produced lower soil test P values than the Mehlich 3 procedure, and the calibration relating plant yield to soil test P was different for the Colwell and Mehlich 3 procedures, indicating, for soils treated with phosphate rock, separate calibrations are required for the 2 procedures. We conclude that for soils of south-western Australia treated with superphosphate (most of the soils), the Mehlich 3 procedure can be used instead of the Colwell procedure to measure soil test P, providing support for the Mehlich 3 procedure to be developed as the multi-element soil test for the region.

scholarly journals Long-term Response to Phosphorus Banding in Irrigated and Nonirrigated Pecan Production

HortScience ◽  
2019 ◽  
Vol 54 (7) ◽  
pp. 1237-1242 ◽  
Author(s):  
Michael F. Polozola ◽  
Daniel E. Wells ◽  
J. Raymond Kessler ◽  
Wheeler G. Foshee ◽  
Amy N. Wright ◽  
...  
Keyword(s):  
Application Rate ◽  
P Uptake ◽  
Soil Test ◽  
Soil P ◽  
Foliar Concentrations ◽  
Soil Test P ◽  
P Application ◽  
P Movement ◽  
Over Time

An experiment was conducted to determine the effects of banded phosphorus (P) applications at differing rates in irrigated and nonirrigated pecan (Carya illinoinensis) plots on P movement within the soil, P uptake and movement within pecan trees, and the yield and quality of nuts. On 20 Mar. 2015, P applications of 0 kg·ha−1 (0×), 19.6 kg·ha−1 (1×), 39.2 kg·ha−1 (2×), and 78.5 kg·ha−1 (4×) were administered to bands of triple superphosphate to randomly selected trees in nonirrigated and irrigated plots of a ‘Desirable’ orchard bordered by ‘Elliot’ trees. When P was applied at the 2× and 4× rates, the total soil test P decreased linearly by 35% and 54%, respectively, in nonirrigated plots and by 41% and 59%, respectively, in irrigated plots over the course of the experiment. There was no change in soil test P over time at the 0× rate for either irrigation regimen; however, at the 1× rate, soil test P decreased 44% in the irrigated plot but did not change in the nonirrigated plot. The largest linear decrease of the soil test P from the start of the experiment to the end of the experiment occurred in the top 0 to 7.6 cm. In contrast, soil test P at a depth of 15.2 to 22.9 cm decreased linearly by 23% in the nonirrigated plot, but it did not decrease over time in the irrigated plot. Increasing the P application rate increased foliar P quadratically in the nonirrigated plot, but only the 4× application rate increased foliar P compared with the 0× control. In the irrigated plot, foliar P concentrations decreased linearly from 2015 to 2017, and foliar P concentrations were not influenced by the P application rate. No differences in pecan yield or quality were observed in either irrigated or nonirrigated plots. Overall, P banding may not be the most sustainable way to increase foliar concentrations of P quickly or to maintain concentrations of the nutrient in the long term.

scholarly journals Trends in cause-specific readmissions in heart failure with preserved versus reduced and mid-range ejection fraction

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
X.T Cui ◽  
E Thunstrom ◽  
U Dahlstrom ◽  
J.M Zhou ◽  
J.B Ge ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ejection Fraction ◽  
Temporal Trend ◽  
Funding Source ◽  
Preserved Ejection Fraction ◽  
Readmission Rates ◽  
P Values ◽  
National Board ◽  
Over Time

Abstract Background It remains unclear whether the readmission of heart failure (HF) patients has decreased over time and how it differs among HF with preserved ejection fraction (EF) (HFpEF) versus reduced EF (HFrEF) and mid-range EF (HFmrEF). Methods We evaluated HF patients index hospitalized from January 2004 to December 2011 in the Swedish Heart Failure Registry with 1-year follow-up. Outcome measures were the first occurring all-cause, cardiovascular (CV) and HF readmissions. Results Totally 20,877 HF patients (11,064 HFrEF, 4,215 HFmrEF, 5,562 HFpEF) were included in the study. All-cause readmission was highest in patients with HFpEF, whereas CV and HF readmissions were highest in HFrEF. From 2004 to 2011, HF readmission rates within 6 months (from 22.3% to 17.3%, P=0.003) and 1 year (from 27.7% to 23.4%, P=0.019) in HFpEF declined, and the risk for 1-year HF readmission in HFpEF was reduced by 7% after adjusting for age and sex (P=0.022). Likewise, risk factors for HF readmission in HFpEF changed. However, no significant changes in cause-specific readmissions were observed in HFrEF. Time to the first readmission did not change significantly from 2004 to 2011, regardless of EF subgroup (all P-values&gt;0.05). Conclusions Although the burden of all-cause readmission remained highest in HFpEF versus HFrEF and HFmrEF, a declining temporal trend in 6-month and 1-year HF readmission rates was found in patients with HFpEF, suggesting that non-HF-related readmission represents a big challenge for clinical practice. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): The SwedeHF was funded by the Swedish National Board of Health and Welfare, the Swedish Association of Local Authorities and Regions.

Agronomic and environmental soil test phosphorus in manured and non-manured Manitoba soils

2007 ◽  
Vol 87 (1) ◽  
pp. 73-83 ◽  
Author(s):  
D. Kimaragamage ◽  
O O Akinremi ◽  
D. Flaten ◽  
J. Heard
Keyword(s):  
Iron Oxide ◽  
Surface Soil ◽  
Single Equation ◽  
Soil Samples ◽  
Soil Test ◽  
Regression Equations ◽  
Soil P ◽  
Soil Test Phosphorus ◽  
Bray 1 ◽  
Water Extractable

Quantitative relationships between soil test phosphorus (STP) methods are needed to guide P management especially in manured soils with high P. Our objectives were: (i) to compare amounts of P extracted by different methods; (ii) to develop and verify regression equations to convert results among methods; and (iii) to establish environmental P thresholds for different methods, in manured and non-manured soils of Manitoba. We analyzed 214 surface soil samples (0–15 cm), of which 51 had previous manure application. Agronomic STP methods were Olsen (O-P), Mehlich-3 (M3-P), Kelowna-1 (original; K1-P), Kelowna-2 (modified; K2-P), Kelowna-3 (modified; K3-P), Bray-1 (B1-P) and Miller and Axley (MA-P), while environmental STP methods were water extractable (W-P), Ca Cl2 extractable (Ca-P) and iron oxide impregnated filter paper (FeO-P) methods. The different methods extracted different amounts of P, but were linearly correlated. For an O-P range of 0–30 mg kg-1, relationships between O-P and other STP were similar for manured and nonmanured soils, but the relationships diverged at higher O-P levels, indicating that one STP cannot be reliably converted to another using a single equation for manured and non-manured soils at environmentally critical P levels (0–100 mg kg-1 O-P). Suggested environmental soil P threshold ranges, in mg P kg-1, were 88–118 for O-P, 138–184 for K1-P, 108–143 for K2-P, 103–137 for K3-P, 96–128 for B1-P, 84–111 for MA-P, 15–20 for W-P, 5–8 for Ca-P and 85–111 for FeO-P. Key words: Phosphorus, soil test phosphorus, manured soils, non-manured soils, environmental threshold

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

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