Factors affecting the change in extractable phosphorus following the application of phosphatic fertiliser on pasture soils in southern Victoria

Soil Research ◽  
2001 ◽  
Vol 39 (4) ◽  
pp. 759 ◽  
Author(s):  
L. L. Burkitt ◽  
C. J. P. Gourley ◽  
P. W. G. Sale ◽  
N. C. Uren ◽  
M. C. Hannah
Keyword(s):  
Soil Properties ◽  
Organic Carbon Content ◽  
Single Superphosphate ◽  
Soil P ◽  
Olsen P ◽  
P Sorption ◽  
P Concentration ◽  
Extractable P ◽  
Fertiliser Application ◽  
High Organic Carbon Content

Nine pasture soils from high rainfall zones of southern Victoria were analysed for a range of chemical and physical properties before receiving a single application of P fertiliser in the form of triple superphosphate (TSP), single superphosphate (SSP), or TSP and lime (5 t/ha) at amounts ranging from 0 to 280 kg P/ha. Soils were analysed for bicarbonate-extractable P concentration, using both the Olsen P and Colwell P methods, 6 and 12 months after fertiliser application. A strong positive linear relationship existed at all sites between the amount of P applied and both the Olsen P and Colwell P concentrations. The slopes of these relationships measured the change in extractable P concentration (Δ EP) per unit of P applied, whilst the inverse of the ΔEP value indicated the amount of P fertiliser required above maintenance to increase the extractable P concentration by 1 mg/kg. These values ranged from 5 to 15 kg P/ha, depending on soil type. The ΔEP measured by the Olsen (Δ EP Olsen ) method was closely related to selected soil properties and P sorption measures, whilst the ΔEPColwell values were also closely related to selected soil properties and P sorption measures, but only when one particular site, an acidic sand, with a high organic carbon content was excluded from the analysis. In general, simple, direct measures of soil P sorption could allow the estimation of ΔEP values on different soil types. The application of P in the form of SSP resulted in a trend for higher ΔEP values than occurred with TSP. This difference was significant on 3 sites (P < 0.05), but depended on the method of extraction and the time after fertiliser application. The application of lime significantly (P < 0.001) increased soil pH (H2 O and CaCl 2 ) and decreased the concentration of exchangeable Al, 6 months after treatments were applied, but generally had little impact on ΔEP values.

Soil phosphorus buffering measures should not be adjusted for current phosphorus fertility

Soil Research ◽  
2008 ◽  
Vol 46 (8) ◽  
pp. 676 ◽  
Author(s):  
L. L. Burkitt ◽  
P. W. G. Sale ◽  
C. J. P. Gourley
Keyword(s):  
Agricultural Soils ◽  
Soil Phosphorus ◽  
Single Point ◽  
Sorption Isotherms ◽  
Phosphorus Sorption ◽  
Soil P ◽  
P Sorption ◽  
P Concentration ◽  
Extractable P ◽  
Fertiliser Application

Soil phosphorus (P) sorption is an important and relatively stable soil property which dictates the equilibrium between sorbed and solution P. Soil P sorption measures are commonly adjusted for the effect of current P fertility on the amount of P a soil sorbs. In the case of highly fertilised agricultural soils, however, this adjustment is likely to be inappropriate as it may mask changes in a soil’s capacity to sorb P, which could affect future P fertiliser applications. A study was undertaken to compare adjusted or unadjusted methods of measuring P sorption using 9 pasture soils sampled from southern Victoria which had previously received P fertiliser and lime. The P sorption assessment methods included: P sorption isotherms, P-buffering capacity (PBC) measures (slope between equilibrium P concentration of 0.25 and 0.35 mg P/L), and single-point P-buffering indices (PBI), with methods either adjusted or unadjusted for current P fertility. A single application of 280 kg P/ha, 6 months before sampling, resulted in a general negative displacement of unadjusted P sorption isotherm curves, indicating reduced P sorption on 8 of the 9 soils. Adding the Colwell extractable P concentration to the amount of P sorbed before calculating the slope (PBC+ColP), tended to negate this fertiliser effect and, in 2 of the 9 soils, resulted in a significant increase in PBC+ColP values. Increasing rates of P fertiliser application (up to 280 kg P/ha) resulted in a consistent trend to decreasing PBI values (unadjusted for Colwell P), which was significant at 4 of the 9 sites after 6 months. However, only minimal changes in PBI values were determined when PBI was adjusted for current P fertility (PBI+ColP). Phosphorus sorption properties appeared reasonably stable over time, although 2 soils, both Ferrosols, indicated significant linear increases in PBI values when these sites remained unfertilised for 30 months. Lime significantly increased both PBI and PBI+ColP values at all sites 6 months after application, but the effect generally diminished after 30 months, suggesting PBI measurements should not be taken immediately after liming. These results demonstrate that unadjusted measures of P sorption are more likely to accurately reflect changes in soil P sorption capacity following P fertiliser applications and suggest that the unadjusted PBI be used in commercial soil testing rather that the currently adjusted PBI+ColP.

A comparison of some surface soil phosphorus tests that could be used to assess P export potential

Soil Research ◽  
2007 ◽  
Vol 45 (5) ◽  
pp. 397 ◽  
Author(s):  
David Nash ◽  
Murray Hannah ◽  
Kirsten Barlow ◽  
Fiona Robertson ◽  
Nicole Mathers ◽  
...  
Keyword(s):  
Organic P ◽  
Soil Tests ◽  
Soil P ◽  
Olsen P ◽  
P Sorption ◽  
P Loss ◽  
Extractable P ◽  
Soil P Tests ◽  
Total P ◽  
Water Extractable

Phosphorus (P) exports from agricultural land are a problem world-wide and soil tests are often used to identify high risk areas. A recent study investigated changes in soil (0–20 mm), soil water and overland flow in 4 recently laser-graded (<1 year) and 4 established (laser-graded >10 years) irrigated pastures in south-eastern Australia before and after 3 years of irrigated dairy production. We use the results from that study to briefly examine the relationships between a series of ‘agronomic’ (Olsen P, Colwell P), environmental (water-extractable P, calcium chloride extractable P, P sorption saturation, and P sorption), and other (total P, organic P) soil P tests. Of the 2 ‘agronomic’ soil P tests, Colwell P explained 91% of the variation in Olsen P, and Colwell P was better correlated with the other soil tests. With the exception of P sorption, all soil P tests explained 57% or more of the total variation in Colwell P, while they explained 61% or less of Olsen P possibly due to the importance of organic P in this soil. Variations in total P were best explained by the organic P (85%), Calcium chloride extractable P (83%), water-extractable P (78%), and P sorption saturation (76%). None of the tests adequately predicted the variation in P sorption at 5 mg P/L equilibrating solution concentration. The results of this limited study highlight the variability between soil P tests that may be used to estimate P loss potential. Moreover, these results suggest that empirical relationships between specific soil P tests and P export potential will have limited resolution where different soil tests are used, as the errors in the relationship between soil test P and P loss potential are compounded by between test variation. We conclude that broader study is needed to determine the relationships between soil P tests for Australian soils, and based on that study a standard protocol for assessing the potential for P loss should be developed.

Changes in bicarbonate-extractable phosphorus over time when P fertiliser was withheld or reapplied to pasture soils

Soil Research ◽  
2002 ◽  
Vol 40 (7) ◽  
pp. 1213 ◽  
Author(s):  
L. L. Burkitt ◽  
C. J. P. Gourley ◽  
P. W. G. Sale
Keyword(s):  
Field Studies ◽  
Triple Superphosphate ◽  
Single Application ◽  
Single Superphosphate ◽  
Pasture Production ◽  
Olsen P ◽  
P Concentration ◽  
Extractable P ◽  
Rate Of Decline ◽  
Linear Regressions

Field studies were established on 9 different soil types used for pasture production in the high rainfall zones of southern Victoria. Sites were selected to represent a range of phosphorus (P) buffering capacities (PBC) and were analysed for a series of chemical and physical properties before receiving P fertiliser treatments. A single application of P fertiliser in the form of triple superphosphate (TSP), single superphosphate (SSP), or TSP and lime (5 t/ha) was applied at amounts ranging from 0 to 280 kg P/ha at the start of the experiment, whilst treatments of 35 and 70 kg P/ha were reapplied at 6-monthly intervals. Soils were analysed for bicarbonate-extractable P concentration, using both the Olsen P and Colwell P methods, 6, 12, 18, 24, and 30 months after P fertiliser was applied. A strong positive linear relationship existed at all sites and time periods between the amounts of P applied as a single application and both the Olsen P and Colwell P concentrations. The slopes of these relationships measured the change in extractable P concentration per unit of P applied (ΔEP) and the rate of decline in ΔEP values represented the decline in the effectiveness of the P fertiliser with increasing time from application. The decline in these ΔEP values varied with soil type. The ΔEP values of some low to moderate P buffered soils remained 2–3 times higher compared with the most highly buffered soils, after 30 months. Despite this, the decline in ΔEP values between 6 and 30 months was difficult to predict using a single soil property. Multiple linear regressions involving a measure of PBC and either organic carbon or exchangeable hydrogen were useful methods of predicting the decline in ΔEP values across the 9 field sites examined in this study. In general, the reapplication of P fertiliser every 6 months resulted in significantly higher extractable P concentrations compared with the same rates applied in a single application, across all sites and rates of P applied. The application of SSP, TSP, and TSP and lime had little impact on ΔEP values 18–30 months after treatments were applied.

scholarly journals Kinetics of phosphorus sorption in soils in the state of Paraíba¹

2011 ◽  
Vol 35 (4) ◽  
pp. 1301-1310 ◽  
Author(s):  
Hemmannuella Costa Santos ◽  
Fábio Henrique Tavares de Oliveira ◽  
Ignácio Hernan Salcedo ◽  
Adailson Pereira de Souza ◽  
Valério Damásio da Mota Silva
Keyword(s):  
Soil Properties ◽  
Clay Content ◽  
The State ◽  
Phosphorus Sorption ◽  
P Adsorption ◽  
Soil P ◽  
P Sorption ◽  
P Concentration ◽  
Elovich Equation ◽  
Kinetics Of

The soil P sorption capacity has been studied for many years, but little attention has been paid to the rate of this process, which is relevant in the planning of phosphate fertilization. The purpose of this experiment was to assess kinetics of P sorption in 12 representative soil profiles of the State of Paraíba (Brazil), select the best data fitting among four equations and relate these coefficients to the soil properties. Samples of 12 soils with wide diversity of physical, chemical and mineralogical properties were agitated in a horizontal shaker, with 10 mmo L-1 CaCl2 solution containing 6 and 60 mg L-1 P, for periods of 5, 15, 30, 45, 60, 90, 120, 420, 720, 1,020, and 1,440 min. After each shaking period, the P concentration in the equilibrium solution was measured and three equations were fitted based on the Freundlich equation and one based on the Elovich equation, to determine which soil had the highest sorption rate (kinetics) and which soil properties correlated to this rate. The kinetics of P sorption in soils with high maximum P adsorption capacity (MPAC) was fast for 30 min at the lower initial P concentration (6 mg L-1). No difference was observed between soils at the higher initial P concentration (60 mg L-1). The P adsorption kinetics were positively correlated with clay content, MPAC and the amount of Al extracted with dithionite-citrate-bicarbonate. The data fitted well to Freundlich-based equations equation, whose coefficients can be used to predict P adsorption rates in soils.

Decrease in phosphorus concentrations when P fertiliser application is reduced or omitted from grazed pasture soils

Soil Research ◽  
2014 ◽  
Vol 52 (3) ◽  
pp. 282 ◽  
Author(s):  
Jessica Coad ◽  
Lucy Burkitt ◽  
Warwick Dougherty ◽  
Leigh Sparrow
Keyword(s):  
Environmental Sustainability ◽  
Soil P ◽  
Grazed Pasture ◽  
Extractable P ◽  
Grazing Systems ◽  
Intensively Managed ◽  
Fertiliser Application ◽  
Changes Over Time ◽  
Proportional Decrease ◽  
Extractable Soil

Many intensively managed soils contain phosphorus (P) concentrations greater than required for optimum production. Soils with P concentrations in excess of the agronomic optimum can have unnecessary losses of P that can adversely affect water bodies. Reducing excessive soil-P concentrations is important for the economic and environmental sustainability of intensive agriculture, such as the Australian dairy industry. However, little is known of decreases in extractable soil-P concentrations when P fertiliser applications are reduced or omitted from soils with P concentrations and properties representative of intensive pasture grazing systems. Decreases in extractable P (calcium chloride (CaCl2), Olsen and Colwell) were monitored for up to 4.5 years for six Australian grazed pasture soils (Red Ferrosol, Brown Kurosol, Grey Dermosol, Brown Dermosol, Podosol and Hydrosol) with contrasting textures and P-buffering indices (PBI). Sixteen treatments consisting of four initial extractable-P concentrations (Pinit) paired with four ongoing P fertiliser rates (Pfert) were established for each of the six soils, except on an extremely low-PBI Podosol, where a range of Pinit concentrations could not be established. The resultant decreases in P were larger with higher Pinit concentration and lower rate of ongoing Pfert, except in the extremely low PBI Podosol where decreases in initially high CaCl2-P concentrations were large irrespective of ongoing Pfert. There was a greater proportional decrease in the environmentally extractable P compared with agronomically extractable P, with mean decreases in CaCl2-P of 57%, Olsen-P of 25%, and Colwell-P of 12%. The Pinit concentrations, which were well above agronomic optimum, remained above this target. This study advances scientific knowledge of extractable soil-P concentrations when P fertiliser inputs are withheld or reduced from grazed pasture soils, and aids land and catchment managers in estimating likely changes over time.

Residues from a buckwheat (Fagopyrum esculentum) green manure crop grown with phosphate rock influence bioavailability of soil phosphorus

2010 ◽  
Vol 90 (2) ◽  
pp. 257-266 ◽  
Author(s):  
M M Arcand ◽  
D H Lynch ◽  
R P Voroney ◽  
P. van Straaten
Keyword(s):  
Microbial Biomass ◽  
Green Manure ◽  
Phosphate Rock ◽  
Fagopyrum Esculentum ◽  
Soil P ◽  
Olsen P ◽  
P Concentration ◽  
Microbial Biomass P ◽  
P Supply

Low soil test phosphorus (P) concentrations are common in organically managed soils in Canada. This field study examined the effect of residues from a buckwheat (Fagopyrum esculentum) green manure (GM) crop grown with an igneous and a sedimentary source of phosphate rock (PR) on in situ soil P supply, Olsen P, and soil microbial biomass P on an organic farm in Ontario, Canada. Phosphate rock application did not increase GM dry matter production, but did increase above-ground tissue P concentration with applications of the sedimentary PR (Calphos). In the following spring, in situ soil P supply and Olsen P were increased in GM residue-applied soils and in soils containing the Calphos PR, while microbial biomass P was largely unaffected. Release of P was detected when GM P concentration was greater than 2.9 g P kg-1. The results suggest the quality of the GM residues had more influence on P availability than the quantity applied to the soil; however, the low changes in available P (P supply and Olsen P) were not agronomically significant. Key words: Phosphate rock, soil phosphate supply, Olsen P, organic agriculture, green manure

scholarly journals Soil Phosphorus Fractions as Influenced by Different Cropping Systems: Direct and Indirect Effects of Soil properties on Different P Pools of Nitisols of Wolayta, Ethiopia

2016 ◽  
Vol 3 (1) ◽  
pp. 17-24
Author(s):  
Shiferaw Boke ◽  
Sheleme Beyene ◽  
Heluf Gebrekidan
Keyword(s):  
Path Analysis ◽  
Soil Properties ◽  
Direct Effect ◽  
Indirect Effect ◽  
Cropping Systems ◽  
Available P ◽  
Analysis Model ◽  
Soil P ◽  
Olsen P ◽  
P Pools

Data from 12 surface soils (0 – 15 cm depth)of three cropping systems (enset, maize and grazing land) and path analysis was used to evaluate effects of soil properties: pH, texture (Clay, silt and sand) , organic carbon (OC) cation exchange capacity (CEC),citrate-dithionite-bicarbonate (CDB) extractable Fe and Al (Fed and Ald) on total phosphorous (Pt), organic phosphorous (Po), Olsen P (Available P) and Chang and Jackson (1957) inorganic phosphorous (Pi) fractions. Correlation analysis was performed to study the relationships between soil properties and different soil P pools while path analysis model was used to evaluate direct and indirect effect of these soil properties on the P pools. Only soil properties that significantly contribute to the fit of the model were used. High significant values of coefficient of determination (R2) and low values of uncorrelated residual (U) values indicate the path analysis model explains most of the variations in soil Pt, Po, Olsen-P, Saloid-P, Ca-P, Al-P, and Fe-P pools. Soil pH had significantly high and positive direct effect (D = 0.618*) on Pt, (D = 1.044***) on saloid P, and (D = 1.109***) on Fe-P with modest and negative indirect effect (D= -0.478 and -0.405) on saloid P and Fe-P, respectively, through OC. The direct effect of clay on Ca-P, Al-P and Fe-P (readily available P forms) was significant and negative with a relatively higher indirect effect on Fe-P through pH suggesting that clay is dominant soil property that influences readily available P pools in Nitisols of the study area. Fed had significant and negative direct effect (D = -0.430*) on Olsen available P with low negative indirect effect ( D = -0.154) through pH results in significant and negative correlation (r = -0.657*). The significant and negative direct effect of Fed on Olsen P indicates that crystalline iron is the sink for available P. Relative influence of the soil properties on the soil P pools was in the order: pH > clay > Fed > OC.  These results show that most of P pools of Nitisols of Wolayita are best predicted from pH, clay (texture), Fed and OC. On the other hand, our data also show that the inclusion of other soil variables is needed to fully predict Ca-P and stable P pools.

Phosphorus sorption-desorption by some sediments of the Johnstone Rivers catchment, northern Queensland

1992 ◽  
Vol 43 (6) ◽  
pp. 1535 ◽  
Author(s):  
C Pailles ◽  
PW Moody
Keyword(s):  
Equilibrium Solution ◽  
Buffer Capacity ◽  
Sea Water ◽  
Phosphorus Sorption ◽  
Constant Amount ◽  
Inorganic P ◽  
P Sorption ◽  
P Concentration ◽  
Extractable P ◽  
Water Columns

Phosphorus (P) sorption-desorption characteristics were determined for 11 sediments from the Johnstone Rivers catchment, northern Queensland. Sediments were selected to cover a range in values of Bray extractable P from 0.1 to 10.4 mg P kg-1. P sorption curves were determined by using 0.01 M NaCl to simulate fluvial water conditions and, on a restricted number of sediments, 0.5 M NaCl to simulate sea water. The amounts of P released in 10 successive extractions for 30 min with 0.01 M CaCl2 were determined for each sediment. The amounts of P desorbed either declined to nondetectable levels or declined to a constant amount. These desorption curves were used to delineate 'rapidly desorbable' P from 'slowly desorbable' P. Bray extractable P and adsorption characteristics (equilibrium solution P concentration and P buffer capacity) were poorly correlated with 'rapidly desorbable' P. Most sediments in the suite would act as P sinks in both fluvial and marine environments because their equilibrium P concentrations are lower than the dissolved inorganic P concentrations of their respective water columns. For those sediments acting as potential sources (5 from 11 in 0.01 M NaC1, 2 from 6 in 0.5 M NaCl), amounts of P that could potentially be desorbed into the fluvial water column ranged from 0.1 to 3.9 mg P kg-1 sediment.

Depletion, accumulation and availability of soil phosphorus in the Askov long-term field experiment

Soil Research ◽  
2020 ◽  
Vol 58 (2) ◽  
pp. 117 ◽  
Author(s):  
Musibau O. Azeez ◽  
Gitte Holton Rubæk ◽  
Ingeborg Frøsig Pedersen ◽  
Bent T. Christensen
Keyword(s):  
Rock Phosphate ◽  
Soil Phosphorus ◽  
Available P ◽  
Soil P ◽  
Olsen P ◽  
Extractable P ◽  
P Application ◽  
Plant Available P ◽  
Water Extractable

Soil phosphorus (P) reserves, built up over decades of intensive agriculture, may account for most of the crop P uptake, provided adequate supply of other plant nutrients. Whether crops grown on soils with reduced supply of other nutrients obtain similar use-efficiency of soil P reserves remains unclear. In treatments of the Askov Long-Term Experiment (initiated in 1894 on light sandy loam), we quantified changes in soil total P and in plant-available P (Olsen P, water extractable P and P offtake in wheat grains) when P-depleted soil started receiving P in rock phosphate and when P application to soil with moderate P levels ceased during 1997–2017. Additionally we studied treatments with soil kept unfertilised for &gt;100 years and with soil first being P depleted and then exposed to surplus dressings of P, nitrogen (N) and potassium in cattle manure. For soil kept unfertilised for &gt;100 years, average grain P offtake was 6 kg ha–1 and Olsen P averaged 4.6 mg kg–1, representing the lower asymptotic level of plant-available P. Adding igneous rock phosphate to severely P-depleted soil with no N fertilisation had little effect on Olsen P, water extractable P (Pw), grain yields and P offtake. For soils with moderate levels of available P, withholding P application for 20 years reduced contents of Olsen P by 56% (from 16 to 7 mg P kg–1) and of Pw by 63% (from 4.5 to 1.7 mg P kg–1). However, the level of plant-available P was still above that of unfertilised soil. Application of animal manure to P-depleted soil gradually raised soil P availability, grain yield and P offtake, but it took 20 years to restore levels of plant-available P. Our study suggests symmetry between rates of depletion and accumulation of plant-available P in soil.

Changes in soil phosphorus availability and potential phosphorus loss following cessation of phosphorus fertiliser inputs

Soil Research ◽  
2013 ◽  
Vol 51 (5) ◽  
pp. 427 ◽  
Author(s):  
R. J. Dodd ◽  
R. W. McDowell ◽  
L. M. Condron
Keyword(s):  
Agricultural Soils ◽  
Soil Phosphorus ◽  
Pasture Production ◽  
Soil P ◽  
Olsen P ◽  
P Loss ◽  
P Concentration ◽  
Rate Of Decline ◽  
P Retention

Long-term application of phosphorus (P) fertilisers to agricultural soils can lead to in the accumulation of P in soil. Determining the rate of decline in soil P following the cessation of P fertiliser inputs is critical to evaluating the potential for reducing P loss to surface waters. The aim of this study was to use isotope exchange kinetics to investigate the rate of decline in soil P pools and the distribution of P within these pools in grazed grassland soils following a halt to P fertiliser application. Soils were sourced from three long-term grassland trials in New Zealand, two of which were managed as sheep-grazed pasture and one where the grass was regularly cut and removed. There was no significant change in total soil P over the duration of each trial between any of the treatments, although there was a significant decrease in total inorganic P on two of the sites accompanied by an increase in the organic P pool, suggesting that over time P was becoming occluded within organic matter, reducing the plant availability. An equation was generated using the soil-P concentration exchangeable within 1 min (E1 min) and P retention of the soil to predict the time it would take for the water-extractable P (WEP) concentration to decline to a target value protective of water quality. This was compared with a similar equation generated in the previous study, which used the initial Olsen-P concentration and P retention as a predictor. The use of E1 min in place of Olsen-P did not greatly improve the fit of the model, and we suggest that the use of Olsen-P is sufficient to predict the rate of decline in WEP. Conversely, pasture production data, available for one of the trial sites, suggest that E1 min may be a better predictor of dry matter yield than Olsen-P.

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