Forms of phosphorus in virgin and fertilised calcareous soils of Western Australia

Soil Research ◽  
1998 ◽  
Vol 36 (4) ◽  
pp. 585 ◽  
Author(s):  
Abbas Samadi ◽  
R. J. Gilkes

Total phosphorus (P), inorganic P (Pi), organic P, and several Pi fractions were determined for 8 fertilised calcareous soils under agriculture and their virgin analogues under natural bush to ascertain changes due to agricultural development. The relationships between soil properties and forms of P were also determined. In general, agricultural development of soils resulted in increases in total P (average 105% increase), Pi (154%), organic P (49%), Olsen P (200%), Colwell P (100%), and all Pi fractions compared with their virgin analogues. For the virgin soils, the abundance of the Pi fractions was in the order: Al-P>O-P (occluded P)>Fe-P>Ca10-P = Ca2-P>Ca8-P, which changed to Al-P>Ca8-P>Ca2-P>Ca10-P>Fe-P>O-P for fertilised soils. The average contribution of each fraction to the increase in total Pi was Al-P (29%), Ca8-P (26%), Ca2-P (18%), Fe-P (13%), Ca10-P (13%), and O-P (4%). The change in Ca8-P was closely correlated with the content of the active fraction of calcite in the soil (ACCE). The increase in Fe-P associated with agriculture was highly correlated with citrate-dithionite-bicarbonate (CDB) extractable Fe (Fed) and acid-ammonium oxalate extractable Fe (Feo). The increase in Al-P was correlated with the ratio of acid-ammonium oxalate extractable Al (Alo) to Feo. Both Olsen and Colwell NaHCO3-extractable P were highly correlated with Ca2-, Al-, Fe-, and Ca10-P, and total P values. Multiple regression analysis indicated that Ca2-P and Ca10-P were major contributors to available P as determined by the Olsen and Colwell soil tests.

Soil Research ◽  
1997 ◽  
Vol 35 (2) ◽  
pp. 327 ◽  
Author(s):  
R. C. Dalal

Vertisols originally carrying brigalow vegetation (Acacia harpophylla F. Muell. ex Benth.) and cultivated for cereal cropping for up to 45 years were examined for trends in available phosphorus (P) [sodium bicarbonate extractable P (bicarb. P) and dilute acid extractable P (acid P)], organic P, inorganic P, and total P. The soils (0-0 · 1 m depth) in their virgin state contained 60 mg/kg of bicarb. P, 168 mg/kg of acid P, 239 mg/kg of organic P, and 330 mg/kg of inorganic P. All fractions of soil P declined following first-order decay with the period of cereal cropping; the rates of bicarb. P and acid P (available P) decline were 0 · 047 and 0 · 08/year. The organic P, inorganic P, and total P declined more slowly than available P; the respective rates were 0 · 026, 0 · 019, and 0 · 021/year. The rates of loss of total P and inorganic P were much higher from the clay-size fraction than the silt-size or sand-size fraction, with the t½ value of inorganic P in the sand-size fraction being almost 20 times greater than any other fraction. On the other hand, organic P loss from the clay-size fraction was much less; presumably, clay provides physical protection to soil organic matter and hence to organic P from decomposition. On average, bicarb. P and acid P declined at the rate of 1 · 3±0 · 3 and 4 · 6±1 · 4 mg P/kg soil · year. The declines in organic P and inorganic P were 3 · 0±0.4 and 4 · 1±1 · 2 mg P/kg soil · year, with a loss in total P of 7 · 2±1 · 3 mg P/kg soil · year. There was no significant shift in the ratio organic P: total P (38±7%) with the period of cultivation and cereal cropping. Organic P was closely correlated with organic C and total N in these soils. The mean amounts of P contained in the grain and the dry matter of each cereal crop from 1981 and 1984 were 7 · 6±1 · 8 and 8 · 3±2 · 4 kg P/ha, respectively. Thus, most of the soil total P loss could be accounted for by crop removal, of which organic P contributed about 40%. However, the continuous decline in available P, especially below 15 mg P/kg soil, warrants remedial measures to arrest the decline in the yields of crops grown on these Vertisols.


1985 ◽  
Vol 65 (3) ◽  
pp. 467-473 ◽  
Author(s):  
V. K. BHATNAGAR ◽  
M. H. MILLER

A series of laboratory experiments was conducted to determine the mechanism(s) responsible for a previously reported observation that addition of liquid manure to soil increased the NaHCO3-extractable P (Ext-P) of large aggregates (> 2 mm) more than that of smaller aggregates whereas addition of an inorganic P solution did not. Application of liquid poultry manure increased the total P, Ext-P and total C concentrations in large aggregates (> 2 mm) much more (> 2.5 ×) than that in small aggregates (< 1 mm). Addition of inorganic P solution or of supernatant liquid from a centrifuged manure slurry increased the P content of the large aggregates only slightly (1.2 ×). A greater increase in Ext-P in large aggregates was observed even when the smaller aggregates were purposely layered on top of the larger ones prior to addition of the liquid manure. A similar but less pronounced effect of aggregate size on increase in P or C concentration was observed when different sized aggregates were left in contact with an effectively infinite source of liquid manure for 24 h. It is concluded that the larger aggregates absorbed more of the bulk manure slurry than smaller aggregates. A partial sealing of small aggregates by particulates is suggested as a possible mechanism. Key words: Carbon, phosphorus, liquid manure, soil aggregates


Soil Research ◽  
2007 ◽  
Vol 45 (4) ◽  
pp. 255 ◽  
Author(s):  
Ebrahim Adhami ◽  
Hamid Reza Memarian ◽  
Farzad Rassaei ◽  
Ehsan Mahdavi ◽  
Manouchehr Maftoun ◽  
...  

Inorganic phosphorus (P) sequential fractionation schemes are applicable techniques to interpret soil P status. The present study was initiated to determine the origin of various P fractions in highly calcareous soils. Inorganic P forms were determined by a sequential fractionation procedure extracting with NaOH (NaOH-P), Na citrate-bicarbonate (CB-P), Na citrate 2 times (C1-P and C2-P), Na citrate-ascorbate (CAs-P), Na citrate-bicarbonate-dithionite (CBD-P), Na acetate (NaAc-P), and HCl (HCl-P). Results showed that NaOH-P was negatively correlated with active iron oxides. CB-P was positively correlated with silt content and negatively related to citrate-bicarbonate-dithionite extractable Fe (Fed). This result illustrates the weathering effect on Ca-P, with Ca-P content declining as a consequence of weathering. A negative correlation was observed between C1-P and citrate ascorbate extractable Fe (FeCAs). Second citrate extractable P (C2-P) was negatively related to calcium carbonate equivalent and positively related to hydroxylamine-hydrochloride and neutral ammonium acetate-hydroquinone extractable Mn (Mnh and Mnq). Fine silt (Fsilt) was the most influential factor affecting CAs-P. It seemed citrate-dithionite-bicarbonate extractable Al (Ald), Mnh, and Mnq have been sinks for CBD-P, while free iron oxide compounds (Feo, Fec, and FeCAs) were a major contributing factor for the formation of NaAc-P. Stable P compounds (HCl-P) of highly calcareous soils originated from coarse silt (Csilt) and hydroxylamine-hydrochloride extractable Mn (Mnh).


2016 ◽  
Vol 51 (9) ◽  
pp. 1088-1098 ◽  
Author(s):  
Leandro Bortolon ◽  
Paulo Roberto Ernani ◽  
Elisandra Solange Oliveira Bortolon ◽  
Clesio Gianello ◽  
Rodrigo Gabriel Oliveira de Almeida ◽  
...  

Abstract The objective of this work was to assess the risk of phosphorus losses by runoff through an index based on the degree of P saturation (DPS), in cropland soils of Southern Brazil. Sixty-five highly representative cropland soils from the region were evaluated. Three labile P forms were measured (Mehlich-1, Mehlich-3, and ammonium oxalate), and four P sorption indexes were tested (phosphorus single sorption point and Fe+Al determined with the three extractors). Water-extractable P (WEP) was used as an index of P susceptibility to losses by surface runoff. The DPS was determined from the ratio between labile P and each sorption index. DPS values obtained from the ratio between Mehlich-1 P and the single P sorption point ranged from 1 to 25%, whereas those from Mehlich-1 P and Fe+Al (ammonium oxalate) ranged from 1 to 55%. All DPS types were highly correlated with WEP. From a practical stand point, the DPS obtained with both P and Fe+Al extracted with Mehlich-1 can be used to estimate the risk of P losses by runoff in soils of Southern Brazil.


Soil Research ◽  
1999 ◽  
Vol 37 (6) ◽  
pp. 1095 ◽  
Author(s):  
R. A. Falkiner ◽  
P. J. Polglase

We examined the fate of applied phosphorus (P) in a young Pinus radiata plantation in south-eastern Australia, spray-irrigated with secondary-treated municipal effluent. Measurements included changes (before irrigation, and after 5 years) in total P, total organic P, total inorganic P, labile P, and sorption and desorption characteristics. During the first 5 years a total of 363 kg/ha of P was applied at an average concentration of 5.4 mg/L. Irrigation changed the forms and distribution of P throughout the profile (0–1 m). Increases in labile inorganic P (membrane-exchangeable, bicarbonate-extractable, and in soil solution) were confined mostly to the 0–0.5 m horizon, and wholly within the 0–0.7 m horizon. In addition, large amounts of organic P (204 kg/ha) were mineralised within the surface 0.7 m, due to stimulation of decomposer activity by increased soil water. Mineralisation, therefore, provided a significant and additional input of inorganic P to soil. Irrigation and P additions changed both the placement and curvature of soil sorption isotherms. Retention capacity (0–0.5 m), calculated from P sorption isotherms, decreased by 180 kg/ha. Desorbable P, determined by sequential extraction with dilute acid, increased by 184 kg/ha. Thus, these 2 independent methods of measuring the changes in exchangeable P gave the same result. Of the total inorganic P added to the soil (in effluent and mineralised), 25% remained in the exchangeable form; the rest was retained unavailable for short-term exchange and migration through soil. After 5 years, fluxes (kg/ha) of P in the 0–0.7 m horizon were: input in effluent less storage in vegetation (323), change in total organic P (–204), change in total inorganic P (517), net change in total P (313). Thus, 97% of the net amount of P added in effluent was recovered in the surface 0.7 m. Results have implications for the way in which P retention capacity is calculated under effluent irrigation.


Soil Research ◽  
2007 ◽  
Vol 45 (5) ◽  
pp. 397 ◽  
Author(s):  
David Nash ◽  
Murray Hannah ◽  
Kirsten Barlow ◽  
Fiona Robertson ◽  
Nicole Mathers ◽  
...  

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.


1975 ◽  
Vol 55 (4) ◽  
pp. 457-466 ◽  
Author(s):  
L. B. CAMPBELL ◽  
G. J. RACZ

Greater amounts of 0.5 M NaHCO3 and water-extractable P were found in soil beneath a cattle feedlot located on an alkaline sandy soil than in soil in an adjacent non-manured field. The 0.5 M NaHCO3-extractable P contents of the feedlot soil samples were greater than for the adjacent field to a depth of 120–150 cm, suggesting that P from the manure had moved to this depth. Water extracted very little P from all field samples and the feedlot samples obtained below 120 cm. Concentration of total P in the feedlot soil was usually greater than in the corresponding field soil. The field soil contained more organic P than the feedlot soil at depths of 0–90 cm. Organic P concentrations at the 0 to 15-cm depths were 268 and 56 ppm for the field and feedlot sites, respectively. The organic C:N:P ratios for the 0 to 15-cm feedlot and field samples were 214:18:1 and 132:8.7:1, respectively. Mineralization of organic P in laboratory experiments was greater in flooded soils than in soils maintained at field capacity. Rates of mineralization were greater for manured than for non-manured samples. Organic and inorganic P moved at about equal rates in soil treated with manure extract. Rates of movement of both decreased with increasing sample depth in the feedlot soil. The feedlot soil below 30 cm and the field soils exhibited a high potential for inorganic and organic P fixation. Organic and inorganic P applied as manure extract moved faster than an equivalent concentration of P as KH2PO4.


1985 ◽  
Vol 65 (4) ◽  
pp. 651-665 ◽  
Author(s):  
T. L. ROBERTS ◽  
J. W. B. STEWART ◽  
J. R. BETTANY

A sequential extraction procedure was used to determine phosphorus fractions (resin, bicarbonate, hydroxide, sonicated hydroxide, acid and acid-peroxide digest with separate organic and inorganic P determinations) in surface and subsurface horizons taken from the upper, mid- and lower slope positions of four catenas (representing Brown, Dark Brown and Black Chernozemic soils, and a Luvisolic soil) which encompass a narrow environmental gradient of climate (annual precipitation: 300–475 mm) and vegetation. Trends in the local distribution of organic and inorganic soil P between upper and lower slope positions in any one catena were similar to the regional distribution patterns across all soil zones. Concentration of organic P, in both the surface and subsurface horizons, increased from the upper to the lower slope positions and from the Brown to the Black soils, while inorganic P decreased. The largest single organic fraction (hydroxide extractable) accounted for up to 22 and 17% of the total P (surface and subsurface horizons, respectively). Acid extractable P dominated the inorganic fractions, accounting for 40–63% of the total P (surface and subsurface horizons, respectively). The distribution of organic P along the catenas and among the soil zones was related to the transformations of inorganic P caused by differences in weathering intensity between slope positions and across the Province. Key words: Catena, climo-toposequence, sequential P extraction


2021 ◽  
pp. 104063872110258
Author(s):  
Carlos O. Schild ◽  
Fabiana M. Boabaid ◽  
Luiz G.S. Olivera ◽  
Mizael Machado ◽  
Ana Vildoza ◽  
...  

We investigated 2 outbreaks of osteomalacia as a result of phosphorus (P) deficiency in herds of lactating beef cows grazing subtropical native pastures in Uruguay. Cows exhibited pica, difficulty to stand and walk, rib fractures, and body weight loss even with adequate forage availability. Osteopenia and severe osteomalacia were observed on gross and histologic examination. The concentrations of bicarbonate-extractable P in soil (4.0, 4.1 mg P/kg), total P in pasture (0.9, 1.1 g P/kg), inorganic P in serum (1.0, 0.71 mmol P/L), and P in bone (73 mg P/mL) were all low. Although injectable and mineral salt supplements provided additional P in both outbreaks, these supplementary amounts were insufficient to prevent P deficiency. The P ingested by the cows from the pasture and supplements would have provided 20–55% of their daily P requirements of ~21 g P/d. Osteomalacia occurred in cattle at the 2 ranches as a result of severe P deficiency in the soil and forage, and inadequate P supplementation. Following diagnosis, control of P deficiency in beef cattle requires estimation of the amount of pasture P ingested and provision of sufficient additional supplementary P to meet the animals’ requirements.


1974 ◽  
Vol 54 (4) ◽  
pp. 379-385 ◽  
Author(s):  
T. G. ALEXANDER ◽  
J. A. ROBERTSON

Soil samples from virgin profiles of Solonetzic and geographically associated Chernozemic series along with Ap horizons of Solonetzic and Chernozemic soils were taken. Soil pH, organic C, oxalate-extractable Al and Fe, inorganic P forms, organic and total P, and extractable P by NH4F + H3SO4 and NaHCO3 methods were determined. On the average, Solonetzic sola had higher contents of oxalate-extractable Al and Fe, Fe-P, and lower levels of Ca-P than do their associated Chernozemic sola. There was not a clear difference in Al-P contents between the sola of the two Orders. Ap samples from Solonetzic soils had twice the amount of NH4F + H2SO4- and NaHCO3-extractable P found in the Chernozemic ones. The higher levels of extractable P in the Solonetzic than in the Chernozemic Ap samples could be explained by the higher contents of Al-P and Fe-P in the former. The high acidity in the upper sola of Solonetzic soils, indicative of intense weathering conditions, apparently has resulted in relatively high contents of oxalate-extractable Al and Fe, and these probably account for the higher levels of Al-P and Fe-P and lower levels of Ca-P in the Solonetzic than in the Chernozemic soils.


Sign in / Sign up

Export Citation Format

Share Document