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.

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.

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.

scholarly journals Field evaluation of water or citrate soluble phosphorus in modified phosphate rocks for soybean

2001 ◽  
Vol 58 (1) ◽  
pp. 165-170 ◽  
Author(s):  
Luís Ignácio Prochnow ◽  
José Francisco da Cunha ◽  
Ariel Francisco Candiotti Ventimiglia
Keyword(s):  
Field Evaluation ◽  
Water Soluble ◽  
Ammonium Citrate ◽  
Low Grade ◽  
Triple Superphosphate ◽  
Single Superphosphate ◽  
Standard Source ◽  
Extractable P ◽  
P Fertilizers ◽  
P Sources

Ten P fertilizers were collected (commercial fertilizers) or synthesized (experimental sources) in order to obtain single superphosphates varying in water and citrate solubility. A standard source of P was also produced by crystallization of the water-soluble fraction of a triple superphosphate. Eleven P sources were band applied to a medium textured Xanthic Hapludox, in Bahia, Brazil (low content of resin-extractable P) at a rate of 80 kg ha-1 of NAC + H2O (neutral ammonium citrate plus water) soluble P2O5, with soybean as the crop which was grown to maturity. A check plot (control) was included in the study. Three of the P sources [single superphosphate produced from Araxa phosphate rock (PR), low-grade single superphosphate produced from Lagamar PR and the standard source of P] were also applied at rates to provide 40 and 120 kg ha-1 of NAC + H2O soluble P2O5. Yield of soybean was evaluated by analysis of variance with mean comparison performed utilizing LSD lines, considering the P sources applied at a rate of 80 kg ha-1 of P2O5 + control. Regression procedures were used to study the relation between yield of soybean and rates of P2O5. The fertilizers tested performed equally well as a source of P for soybean. The level of water-soluble P did not influence fertilizer performance.

The fate of phosphorus under contrasting border-check irrigation regimes

Soil Research ◽  
2008 ◽  
Vol 46 (4) ◽  
pp. 309 ◽  
Author(s):  
R. W. McDowell ◽  
D. Rowley
Keyword(s):  
Water Quality ◽  
Soil Moisture ◽  
Surface Water ◽  
Surface Water Quality ◽  
Rainfall Simulation ◽  
Pasture Production ◽  
Olsen P ◽  
Grazed Pastures ◽  
P Loss ◽  
P Concentration

Flood-irrigation, to the extent that outwash (runoff from border-check bays) occurs, is a major cause of P loss from grazed pastures and has potential to harm surface water quality. We used a combination of rainfall simulation to produce runoff and field sampling of outwash to investigate processes of P loss from treatments receiving no irrigation and irrigation at 10%, 15%, and 20% soil moisture and every 21 days (3w). Intact soil blocks were removed from each treatment, dung removed, soils wetted to about 32% soil moisture, and runoff produced via rainfall simulation. This indicated that P losses were proportional to soil Olsen P concentrations (29.8–51.4 mg Olsen P/kg; 0.096–0.541 mg dissolved reactive P/L). Olsen P concentration was less in those treatments receiving a greater number of irrigations due to increased pasture production and, presumably, loss via outwash. When soil blocks were allowed to dry, concentrations in runoff more than doubled and were paralleled by a decrease in soil microbial biomass P. However, when outwash was sampled in the field, P loss was greater in more frequently irrigated treatments. This was attributed to increased stocking rates and P-release from dung masking any soil effect. However, differences in P loss in outwash from 2 treatments (without recent grazing) were attributed to different soil moisture before irrigation. Assuming 25% of irrigation is lost as outwash, annual loads were estimated to range from 0.7 kg P/ha in the 10% treatment, irrigated 2.6 times a year, to 12.6 kg P/ha in the 3w treatment, irrigated 6.5 times per year. This suggests that the frequency of irrigation and stocking rate dictate the majority of P lost in this system (not soil P concentration). Hence, mitigation practices should be promoted to minimise outwash in intensively sheep-grazed pastures and potential surface water quality impacts.

Comparing the agronomic performance of soluble and slow release phosphate fertilisers: the experimental basis for RPR recommendations

1991 ◽  
pp. 181-190
Author(s):  
D.C. Edmeades ◽  
J.H. Watkinson ◽  
K.W. Perrott ◽  
A.G. Sinclair ◽  
S.F. Ledcard ◽  
...  
Keyword(s):  
Soil Ph ◽  
Slow Release ◽  
Lag Time ◽  
Production Data ◽  
Agronomic Performance ◽  
Experimental Basis ◽  
Triple Superphosphate ◽  
Agronomic Effectiveness ◽  
Single Superphosphate ◽  
Pasture Production

Recent results from field trials comparing the agronomic effectiveness of water soluble fertilisers (single superphosphate (SSP), triple superphosphate (TSP)) and fertilisers of low water solubility ('slow release', reactivephosphaterock (RPR) fertilisers) are reviewed. It is shown that the pasture production data from the 'National Series' of trials are consistent with, and can be described by, a model for the dissolution of RPR in soil. Applying both the pasture production data and the dissolution model the term 'lag time' associated with 'slow release' RPR is defined and quantified for New Zealand conditions. Results show that on average the rate of release of P from RPR is about 30% within the year of application, 23% in year 2 and progressively less in subsequent years. It follows that when RPR is applied annually, the amount of Preleased annually, from the current application and from the residues of previous annual applications, is 30,53,70,82, 9 1,96% as a fraction of the total P applied annually. Consequently about 3.5 times the amount of RPRP is required to achieve the same yield as soluble P in year 1, about 2 times in year 2 and 1.5 in year 3. The lag time is defined as the time required to accumulate sufficient RPR residues in the soil from applications such that the annual amount of P dissolved from RPR each year is equal to or greater than 90% of the amount of total RPR-P applied annually. The lag time associated with RPR use is about 4-6 years depending on the site. The agronomic performance of RPR based on the National Series data was not associated with soil pH (5.1 to 6.3), annual rainfall (700 to 1800 mm) or soil phosphate retention (13-98%). This probably reflects the narrow range and confounding effects of the soil and climate factors. The experimental basis for the current soil pH and rainfall boundary conditions are briefly discussed. Available evidence suggests that the P dissolved from RPR has the same agronomic effectiveness as P from soluble fertiliscrs. The agronomic implications of these results on P fertilisers of intermediate solubility (i.e. PAPR and Longlife) are discussed in relation to field results. Keywords agronomy, comparison, dissolution, fertilisers, Longlife, PAPR,phosphorus, RPR, slow release, soluble P, single superphosphate, triple superphosphate

Low rates of phosphorus fertiliser applied strategically throughout the growing season under rain-fed conditions did not affect dry matter production of perennial ryegrass (Lolium perenne L.)

2010 ◽  
Vol 61 (5) ◽  
pp. 353 ◽  
Author(s):  
L. L. Burkitt ◽  
D. J. Donaghy ◽  
P. J. Smethurst
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Dry Matter ◽  
Growing Season ◽  
Dry Matter Production ◽  
Pasture Production ◽  
Lolium Perenne L ◽  
Matter Production ◽  
Extractable P ◽  
Intensively Managed

Pasture is the cheapest source of feed for dairy cows, therefore, dairy pastures in Australia are intensively managed to maximise milk production and profits. Although soil testing commonly suggests that soils used for dairy pasture production have adequate supplies of phosphorus (P), many Australian dairy farmers still apply fertiliser P, often by applying smaller rates more frequently throughout the year. This study was designed to test the hypotheses that more frequent, but lower rates of P fertiliser applied strategically throughout the growing season have no effect on dry matter production and P concentration in perennial ryegrass (Lolium perenne L.), when soil extractable P concentrations are above the critical value reported in the literature. Three field sites were established on rain-fed dairy pasture soils ranging in P sorption capacity and with adequate soil P concentrations for maximising pasture production. Results showed that applied P fertiliser had no effect on pasture production across the 3 sites (P > 0.05), regardless of rate or the season in which the P was applied, confirming that no P fertiliser is required when soil extractable P concentrations are adequate. This finding challenges the viability of the current industry practice. In addition, applying P fertiliser as a single annual application in summer did not compromise pasture production at any of the 3 sites (P > 0.05), which supports the current environmental recommendations of applying P during drier conditions, when the risk of surface P runoff is generally lower. The current results also demonstrate that the short-term cessation of P fertiliser application may be a viable management option, as a minimal reduction in pasture production was measured over the experimental period.

Leaching of dissolved phosphorus from tile-drained agricultural areas

2016 ◽  
Vol 73 (12) ◽  
pp. 2953-2958 ◽  
Author(s):  
H. E. Andersen ◽  
J. Windolf ◽  
B. Kronvang
Keyword(s):  
Soil Layer ◽  
High Concentration ◽  
Measured Concentration ◽  
Leaching Potential ◽  
Dissolved Phosphorus ◽  
Olsen P ◽  
P Loss ◽  
Tile Drains ◽  
Extractable P ◽  
Water Extractable

Abstract We investigated leaching of dissolved phosphorus (P) from 45 tile-drains representing animal husbandry farms in all regions of Denmark. Leaching of P via tile-drains exhibits a high degree of spatial heterogeneity with a low concentration in the majority of tile-drains and few tile-drains (15% in our investigation) having high to very high concentration of dissolved P. The share of dissolved organic P (DOP) was high (up to 96%). Leaching of DOP has hitherto been a somewhat overlooked P loss pathway in Danish soils and the mechanisms of mobilization and transport of DOP needs more investigation. We found a high correlation between Olsen-P and water extractable P. Water extractable P is regarded as an indicator of risk of loss of dissolved P. Our findings indicate that Olsen-P, which is measured routinely in Danish agricultural soils, may be a useful proxy for the P leaching potential of soils. However, we found no straight-forward correlation between leaching potential of the top soil layer (expressed as either degree of P saturation, Olsen-P or water extractable P) and the measured concentration of dissolved P in the tile-drain. This underlines that not only the source of P but also the P loss pathway must be taken into account when evaluating the risk of P loss.

Overwinter changes in Olsen phosphorus in a 24-year crop rotation study in southwestern Saskatchewan

1993 ◽  
Vol 73 (1) ◽  
pp. 123-128 ◽  
Author(s):  
C. A. Campbell ◽  
R. P. Zentner
Keyword(s):  
Cropping Systems ◽  
Soil Testing ◽  
Available Phosphorus ◽  
Canadian Prairie ◽  
Olsen P ◽  
Extractable P ◽  
P Fertilizer ◽  
Soil Test P ◽  
Nutrient Analyses ◽  
Rotation Study

In the Canadian prairie, producers generally sample soils in the autumn for nutrient analyses, whereas calibration of crop responses has been made based on soils sampled in the spring prior to seeding. A recent report suggests that available phosphorus (P) in soil increases between autumn and spring. At Swift Current, Saskatchewan, we have monitored bicarbonate-extractable P (Olsen P) every autumn and spring for the past 24 years, in four cropping systems: continuous wheat (Cont W), fallow-wheat (F-W), and two fallow-wheat-wheat (F-W-W) rotations. The first three systems received nitrogen (N) and P each crop year, with one F-W-W rotation receiving only N. These data were analyzed to test the authenticity of the aforementioned observations. We found that although there were some apparent overwinter increases in Olsen P there were also some decreases. Further, because of the considerable variability in Olsen P, relatively few of the overwinter changes were significant (P = 0.10). Efforts to correlate the changes in Olsen P to overwinter temperature or precipitation were unsuccessful. We concluded that Saskatchewan soil testing laboratories need not make adjustments to P fertilizer recommendations to account for changes in overwinter soil test P levels. Key words: Soil testing, bicarbonate-extractable P, crop rotations, available P

A laboratory study of phosphorus mobilisation from commercial fertilisers

Soil Research ◽  
2003 ◽  
Vol 41 (6) ◽  
pp. 1201 ◽  
Author(s):  
D. Nash ◽  
M. Hannah ◽  
L. Clemow ◽  
D. Halliwell ◽  
B. Webb ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Total Variation ◽  
Laboratory Study ◽  
High Moisture ◽  
Single Superphosphate ◽  
South Eastern ◽  
Extractable P ◽  
Eastern Australia ◽  
Water Extractable ◽  
South Eastern Australia

Phosphorus (P) exported from pastures following fertiliser application contributes to the nutrients and associated problems in the streams and rivers of south-eastern Australia. This laboratory study examined whether attributes of P fertilisers may affect P exports soon after their application to field soils; 3 commercial fertilisers [diammonium phosphate (DAP), single superphosphate (SSP), and sulfur-coated single superphosphate (CSSP)] were applied to 2 repacked soils (Arawata and Ellinbank) at 5 moisture contents.Soil type was the most important factor affecting water-extractable P (expressed as a percentage of the P added as fertiliser), accounting for 30% of the total variation. The majority of this variation is explained by the water-extractable P concentrations in the Arawata low moisture treatments. These treatments [7, 6, and 6% soil moisture when equilibrated at 99, 95, and 86.5% relative humidity (RH), respectively] contained water-extractable P concentrations c. 3 times higher than the high moisture (c. 20 and 25% soil moisture) or the Ellinbank treatments. This result probably reflects differences in soil properties including the extent of water repellency and P adsorption.Fertiliser type explained only 6.9% (P < 0.001) of the total variation in water-extractable P, partially as a result of the 86.5% RH (a low moisture) Arawata treatment. In this Arawata low moisture treatment, the mean extractable P was similar for both DAP and SSP, 13.1% [least significant interval (l.s.i.) 16.7–10.3] and 11.3% (l.s.i. 14.3–8.9), respectively, but for SSP, water-extractable P increased over time unlike any other treatment. Water-extractable P from DAP was approximately double that from SSP for the Ellinbank and high moisture treatments. The higher water-extractable P following DAP application is explained in terms of its chemical properties and reaction products. Sulfur coating the SSP granules (CSSP) increased water-extractable P, as did higher soil moisture.This study suggests that under conditions present in most pastures in south-eastern Australia and depending on soil hydrology, water-extractable P and P export from fertilisers may increase in the order DAP > CSSP > SSP if overland flow occurs soon after their application.

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