Phosphorus status of the Nigerian coastal plain sands

1979 ◽  
Vol 93 (2) ◽  
pp. 281-289 ◽  
Author(s):  
E. J. Udo ◽  
V. I. Dambo

SUMMARYThe phosphorus status of five Nigerian coastal plain sands was evaluated by determining the relative abundance of the various P forms and the P adsorption capacities of the soils. Total P ranged from 4460 to 1129 mg/kg. Organic P had a range of 23–232 mg/kg and formed below 30% of total P in four of the profiles but above 50% in the hydromorphic Otegbo profile. The relative distribution of the various inorganic forms was in the increasing order of residual P, active P and occluded P, except in the Onne profile in which the residual P was relatively the least abundant. The relative distribution of the active P forms was in the decreasing order of Fe-P, Al-P and Ca-P.The adsorption capacity varied widely among the soils. The amount adsorbed from the addition of 150 mg/100 g of soil ranged from 40–2 to 86–2 mg/100 g and was related to the clay content. The adsorption at 0–3 mg/1 P in equilibrium solution ranged from 19 to 265 mg/kg. The subsoils generally adsorbed more P than the surface soils. The P requirements of the soils estimated from the sorption capacities were in the low and medium ranges.

1982 ◽  
Vol 99 (1) ◽  
pp. 25-33 ◽  
Author(s):  
P. Loganathan ◽  
P. M. N. Dayaratne ◽  
R. T. Shanmuganathan

SUMMARYThe phosphorus status of 58 soil samples representing 15 soil series and four soil Orders (Ultisol, Entisol, Alfisol and Oxisol) in the major coconut-growing regions of Sri Lanka was evaluated by determining the available P extracted by the methods of Olsen, Bray & Kurtz No. 1, Bray & Kurtz No. 2 and NH4OAc (pH 4·8) and the various P forms. Total P in the soils ranged from 37 to 338 mg/kg with organic P and active P constituting only about 20 and 50% of the total P respectively. In general the sandy soils of the Entisols and Oxisols had lower total and organic P but higher active and available P than the rest. The relative abundance of the various inorganic P forms was generally in the decreasing order of inactive P, Fe-P, Al-P and Ca-P. Al-P and Ca-P were positively correlated with percentage sand and negatively correlated with percentage silt and percentage clay whereas total P and organic P had the opposite trend. Available P extracted by the four methods was very low in almost all soils except some of the sandy soils (Entisols) which had marginal to moderate P contents. They were positively correlated with Al-P, Ca-P, percentage sand and negatively correlated with percentages of silt, clay and organic carbon.Phosphorus concentrations (0·074–0·116%) in the 14th leaf of coconut at the soil sites were all lower than the critical leaf-P concentration (0·120%). Leaf-P correlations with Bray & Kurtz No. 2-P and NH40Ac-P were significant (P < 0·05) and with Al-P and Ca-P were close to significant.The study revealed that the coconut-growing soils of Sri Lanka were deficient in total as well as the active and available forms of P except perhaps some of the sandy soils of the Entisol. This was confirmed by coconut leaf P analysis.


Euphytica ◽  
2021 ◽  
Vol 217 (4) ◽  
Author(s):  
Jakob Eifler ◽  
Jürgen Enno Wick ◽  
Bernd Steingrobe ◽  
Christian Möllers

AbstractPhytic acid is the major organic phosphorus storage compound in rapeseed. Following oil extraction, the defatted meal is used in feed mixtures for livestock. However, monogastric pigs and chickens can only poorly metabolize phytate. Hence, their excrements are rich in phosphorus (P), which when applied as manure may lead to eutrophication of surface waters. The aim of the present study was to analyze the genetic variation for total and organic P concentration (i.e. mainly phytate) in rapeseed and to compare the results with soybean. Two sets of rapeseed material were tested in field experiments in different environments with varying soil P levels and harvested seeds were used for seed quality analysis. Results revealed significant genotypic differences in total seed P concentration, which ranged from 0.47 to 0.94%. Depending on the experiment, the heritability for total P concentration ranged from 52 to 93%. The organic P portion of total P concentration was above 90% for current rapeseed hybrids. In both sets, there was a significant positive correlation between seed protein and P concentration. A NIRS calibration for total P concentration in intact seeds showed in cross validation a standard error of 0.05% and a coefficient of determination of R2 = 0.83. Total P concentration of soybean seeds and meal was between 0.55 and 0.65%, and around 1.1% for rapeseed meal. Rapeseed meal had a twofold higher ratio of total P to nitrogen concentration as compared to soybean which could be considered adverse when the meal is used for feeding livestock.


1986 ◽  
Vol 66 (1) ◽  
pp. 105-119 ◽  
Author(s):  
B. I. WAGAR ◽  
J. W. B. STEWART ◽  
J. O. MOIR

A sequential phosphorus (P) fractionation procedure was used to measure the changes in the labile and stable forms of inorganic and organic P following single broadcast P applications to Canadian Chernozemic soils under cereal cropping. Approximately half of the fertilizer residues remained in plant-available forms (resin, NaHCO3). In a Black Waskada clay loam 8 yr after the application of 200 and 400 kg P ha−1, residual fertilizer P consisted of resin-P, 30–40%; HCl-P, 25–30%; residue-P, 10–15%; NaOH-P, 10–15%, NaHCO3-P, 10%; and aggregate protected P, 3%. The residues in a Dark Brown Sutherland clay 5 yr after the application of 160 kg P ha−1 were: resin-P, 35%; NaOH-P, 30–40%; NaHCO3-P, 15%; HCl-P, 0–5%; H2SO4-P, 5%; and aggregate protected P, 5%. The soils differed in the quantity of fertilizer recovered in inorganic HCl-extractable forms. In the Sutherland soil the change from wheat-fallow to continuous wheat cropping produced a build-up of organic P which occurred with and without the addition of P fertilizer. Key words: Residual P, P transformations, Labile Pi; labile Po, stable Pi stable Po


2015 ◽  
Vol 12 (21) ◽  
pp. 6443-6452 ◽  
Author(s):  
X. Jiang ◽  
R. Bol ◽  
S. Willbold ◽  
H. Vereecken ◽  
E. Klumpp

Abstract. To maximize crop productivity fertilizer P is generally applied to arable soils, a significant proportion of which becomes stabilized by mineral components and in part subsequently becomes unavailable to plants. However, little is known about the relative contributions of the different organic and inorganic P bound to Fe/Al oxides in the smaller soil particles. Alkaline (NaOH–Na2EDTA) extraction with solution 31P-nuclear magnetic resonance (31P-NMR) spectroscopy is considered a reliable method for extracting and quantifying organic P and (some) inorganic P. However, any so-called residual P after the alkaline extraction has remained unidentified. Therefore, in the present study, the amorphous (a) and crystalline (c) Fe/Al oxide minerals and related P in soil aggregate-sized fractions (> 20, 2–20, 0.45–2 and < 0.45 μm) were specifically extracted by oxalate (a-Fe/Al oxides) and dithionite–citrate–bicarbonate (DCB, both a- and c-Fe/Al oxides). These soil aggregate-sized fractions with and without the oxalate and DCB pre-treatments were then sequentially extracted by alkaline extraction prior to solution 31P-NMR spectroscopy. This was done to quantify the P associated with a- and c-Fe/Al oxides in both alkaline extraction and the residual P of different soil aggregate-sized fractions. The results showed that overall P contents increased with decreasing size of the soil aggregate-sized fractions. However, the relative distribution and speciation of varying P forms were found to be independent of soil aggregate-size. The majority of alkaline-extractable P was in the a-Fe/Al oxide fraction (42–47 % of total P), most of which was ortho-phosphate (36–41 % of total P). Furthermore, still significant amounts of particularly monoester P were bound to these oxides. Intriguingly, however, Fe/Al oxides were not the main bonding sites for pyrophosphate. Residual P contained similar amounts of total P associated with both a- (11–15 % of total P) and c-Fe oxides (7–13 % of total P) in various aggregate-sized fractions, suggesting that it was likely occluded within the a- and c-Fe oxides in soil. This implies that, with the dissolution of Fe oxides, this P may be released and thus available for plants and microbial communities.


2009 ◽  
Vol 60 (7) ◽  
pp. 619 ◽  
Author(s):  
Richard W. McDowell

Land use can influence stream sediment composition and water quality, whereas moisture status affects sediment phosphorus (P) bioavailability to algae. Declining upland surface-water quality in South Otago, New Zealand, may reflect land-use changes from sheep- to dairy-farming. I sampled sediment (0–20 cm) from streams draining 12 dairy- and 12 sheep-farmed catchments in spring (wet) and autumn (dry). 31P nuclear magnetic resonance (NMR) spectroscopy and the EDTA-fractionation scheme were used to determine different P forms and infer P bioavailability. Significantly more P was present in the sediment of streams draining dairy- than sheep-farmed catchments. Total P did not differ with the moisture regime; however, changes occurred in the following P fractions: acid-soluble organic P, NaOH-P, CaCO3≈P, Fe(OOH)≈P and residual organic P. Extraction for 31P NMR analysis removed 78–85% of sediment total P and isolated five P classes. More bioavailable P such as orthophosphate (23–40% of P extracted) and diesters (2–6% of P extracted) was present in dry than in wet sediments, and in sediments draining dairy streams than in those from sheep-farmed catchments. This indicates substantial reserves of bioavailable P in sediment from these catchments, especially from dairy-farmed catchments, sustaining in-stream P concentrations for many years even without additional P input from land.


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.


1989 ◽  
Vol 69 (1) ◽  
pp. 111-117 ◽  
Author(s):  
N. B. COMERFORD ◽  
M. F. SKINNER

A highly weathered, clayey soil was sampled 14 yr after a Pinus radiata stand was broadcast fertilized with 0, 50 and 200 kg P ha−1 as ordinary superphosphate. Incremental loadings of oxalate and citrate anions from 10 to 100 μmol of anion g−1 soil were evaluated for increased soluble, reactive P (SRP) and soluble, nonreactive (SNP) P. Sorption isotherms were compared to evaluate the effect of the previous fertilization on P sorption by the soil material sampled, and also to measure SNP displacement by orthophosphate-P. A portion of the SNP pool was more readily released than SRP and orthophosphate displaced a significant amount of SNP. After 14 yr the effect of fertilization was still obvious in the sampled soil material. Much of the organic anion-soluble P was in the SRP form. Key words: Citrate, organic P, orthophosphate, oxalate, Pinus radiata, residual P


2017 ◽  
Vol 29 (2) ◽  
pp. 123-131
Author(s):  
Reshma Akter ◽  
Md Jamal Uddin ◽  
Md Faruque Hossain ◽  
Zakia Parveen

A study was carried out to evaluate the effects of brick manufacturing on phosphorus (P) and sulfur (S) concentrations in soil and plant collected from different distances of brick kilns in four AEZs of Bangladesh. Forty eight composite soil samples (0 - 15 cm depth) were collected from 48 points in 12 different sites at 0 m, 300 m, 800 m and 1500 m from brick kilns, where most (site 2, site 3, site 5, site 6, site 7, site 9 and site 10) of the brick kilns used coal for brick burning purposes. Plant samples (rice straw and different vegetables) were also collected from the respective fields except 0 m distances. Significantly (p ? 0.05) lower organic matter, cation exchange capacity, clay content and soil pH were found at 0 m distances compared to other distances. Highest concentration of total P in soil were recorded at 0 m distances and these concentrations decreased with increasing distances from the brick kilns in most of the sites; whereas available P is significantly lower at 0 m distances than that of other distances. Total and available concentration of S in soil followed the trend 0 m>300 m>800 m>1500 m. Maximum accumulation of P (69.15 mg kg-1) and S (0.14%) in plant was found at 800 m away from the brick kiln.Bangladesh J. Sci. Res. 29(2): 123-131, December-2016


1980 ◽  
Vol 95 (1) ◽  
pp. 191-198 ◽  
Author(s):  
E. J. Udo

SummaryTotal, dithionite-extractable (‘free’) and oxalate-extractable (amorphous) Fe as Fe2O3 forms were determined in eight Nigerian soil profiles selected to include four major parent materials and different drainage conditions.Total Fe ranged from 1·98 to 15·01 % Fe2O3, the average contents being 4·40, 8·62, 12·59 and 13·49 Fe2O3 for soils derived from the coastal plain sands, basement complex rocks, shale and basalt, respectively. ‘Free’ Fe ranged from 0·08 to 12·28% Fe2O3, the basaltic soils having the highest content, and those on shale the least. Generally the poorly drained soils had low contents, the free Fe oxide constituting about 61 % of total Fe in well-drained soils, and only about 9% in poorly drained soils.The oxalate-extractable or non-crystalline Fe oxide ranged from 0·04 to 1·21% Fe2O3. The proportion of amorphous iron oxide, indicated by the ‘active’ ratio ‘oxalate-Fe/DCB-Fe’, was higher in poorly drained than in well-drained soils.The clay/DBC-Fe ratio remained constant in the well-drained soils but increased with depth in the poorly drained profiles, indicating a co-migration of free Fe oxide and clay in the former but not in the latter soils.In general, the relative distribution of the different Fe forms appeared influenced by both the parent materials and the drainage of the soils.


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