Soil phosphorus saturation degree: Review of some indices and their suitability for P management in Québec, Canada

1999 ◽  
Vol 79 (4) ◽  
pp. 615-625 ◽  
Author(s):  
Suzanne Beauchemin ◽  
R. R. Simard

Many agricultural fields contain excessive labile soil P in regard to crop needs. Its environmental fate must be assessed. The concept of P saturation degree is meaningful as it describes the portion of the soil binding sites already covered with P, and indicates the potential desorbability of soil P. The first objective of this study was to review different indices that have been proposed to estimate the degree of soil P saturation and the relationships between soil P saturation degree and P solubility. The second objective is to discuss their suitability as environmental indicators for P management in the province of Québec, Canada. In the Netherlands, the P saturation index is defined as the ratio of P to Al + Fe contents extracted by ammonium oxalate [Pox/( Alox + Feox ) or ( Pox/0.5( Alox + Feox )]. This approach has been mainly used with non-calcareous soils. In Québec, the ratio of Mehlich-III extractable P to Al (M3P/AlM3) is proposed as an alternative, which relies on routine laboratory test. However, the suitability of the M3P/AlM3 ratio has yet to be determined for some specific soil groups (e.g. gleyed soils, soils with Alox content >6 g kg−1) and for subsoil horizons. Regardless of the chosen index, it is suggested that the best way to manage the risk of water contamination by P in Québec (namely, defining critical levels of soil P saturation) may be to form homogeneous soil groups to account for their distinctive behaviour and characteristics. Key words: Phosphorus, saturation, management

1989 ◽  
Vol 61 (2) ◽  
pp. 67-72 ◽  
Author(s):  
Raina Niskanen

Release of P, Al and Fe of five mineral soils in four-hour extraction by 0.1 M NH4F, pH 4.2—8.6, generally increased with decreasing pH of the extractant. Fluoride was a rather selective extractant of Al at pH 6.1—8.6 where the extractability of iron was low. NH4F, pH 4.2, released a great part of P solubilized in fractionation of inorganic soil P, and Al was extracted more than by Tamm’s acid ammonium oxalate. Acid fluoride solutions released OH- ions from soils. The initial pH of fluoride was 4.2—5.2, and it rose in the filtrates of all soils.


2006 ◽  
Vol 86 (5) ◽  
pp. 897-910 ◽  
Author(s):  
Annie Pellerin ◽  
Léon -Étienne Parent ◽  
Catherine Tremblay ◽  
Josée Fortin ◽  
Gilles Tremblay ◽  
...  

Soil phosphorus (P), which is potentially a risk for environmental contamination, is currently interpreted using soil P saturation in North America. Our objective was to assess the ratio of P to aluminum (Al) in the Mehlich-III (M-III) soil test to build P requirement models for corn and soybean. We analyzed 129 corn and 19 soybean P fertilizer trials. For corn, the (P/Al)M-III ratio improved soil fertility classification compared with PM-III alone. The critical PM-III value as determined by the Cate-Nelson procedure was found to be 31.5 mg PM-III kg-1, close to published values. The critical (P/Al)M-III ratios of 0.025 for > 300 g clay kg-1 soils and 0.040 for ≤ 300 g clay kg-1 soils differed significantly between the two soil groups. For (P/Al)M-III ratios above 0.214, there was no positive response to added P for all soils regardless of texture. Using published critical environmental (P/Al)M-III ratios of 0.076 for > 300 g clay kg-1soils and 0.131 for ≤ 300 g clay kg-1 soils as benchmarks values, agri-environmental P requirement models were built using conditional expectations of 50 to 80% of computed optimum P values within a soil class. A validation study supported the low critical (P/Al)M-III ratios and the 50% conditional expectation model except for a high carbon soil which was outside the application range of the models. However, banded P decreased corn yield at four validation sites although the model predicted positive response to P. Soybean did not respond to P except at extremely low fertility levels ((P/Al)M-III ≤ 0.02) and behaved as a P-mining crop even in low-P soils. Corn-soybean rotations can reduce soil P to low (P/Al)M-III ratios with minimal agronomic risk. Key words: Soil phosphorus saturation, Mehlich-III soil extraction method, soil fertility classification, soil texture, fertilizer P requirement model, corn, soybean


Agronomy ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 24
Author(s):  
Jeff D. Nze Memiaghe ◽  
Athyna N. Cambouris ◽  
Noura Ziadi ◽  
Antoine Karam ◽  
Isabelle Perron

Phosphorus (P) is an essential nutrient for grassland production systems. However, continuous applications of P fertilizers result in soil P accumulations, increasing the risk of P losses in runoff and erosion. This study aims to investigate the field-scale variability of soil-test P (STP) in two contrasting grassland fields using descriptive statistics and geostatistics for accurate recommendations on soil sampling strategy and sustainable approaches to P management. A young grassland (YG; 2 years) and an old grassland (OG; 10 years under permanent pasture) were classified as humo-ferric podzol and received organic fertilizers. Soil samples were collected in 16-m by 16-m triangular grids at two depths (0–5 and 5–20 cm). They were analyzed for available P and other soil elements extracted using the Mehlich-3 method (M3). The agri-environmental P saturation index (P/Al)M3 was calculated. Phosphorus accumulation was observed in OG (0–5 cm) as a result of long-term manure applications. Repeated applications of organic fertilizers can impact the long-term buildup of soil P, thus decreasing soil P va-riability and spatial dependence in permanent grasslands. A soil sampling strategy focusing on the 0–5 cm layer should be retained in permanent grasslands for sustainable P recommendations in Eastern Canada.


2007 ◽  
Vol 36 (4) ◽  
pp. 975-982 ◽  
Author(s):  
Julie Guérin ◽  
Léon-Étienne Parent ◽  
Rahima Abdelhafid

2021 ◽  
Vol 3 ◽  
pp. e3
Author(s):  
Xin Jin ◽  
Changlu Hu ◽  
Asif Khan ◽  
Shulan Zhang ◽  
Xueyun Yang ◽  
...  

Background Diverse phosphorus (P) fractionation procedures presented varying soil P fractions, which directly affected P contents and forms, and their biological availability. Purpose To facilitate the selection of phosphorus (P) fractionation techniques, we compared two procedures based on a long-term experiment on a calcareous soil. Methods The soils containing a gradient P levels were sampled from seven treatments predictor under various long-term fertilizations. The P fractions were then separated independently with both fractionation procedures modified by Tiessen-Moir and Jiang-Gu. Results The results showed that the labile P in Jiang-Gu is significantly lower than that in Tiessen-Moir. The iron and aluminium-bounded P were greater in Jiang-Gu by a maximum of 46 mg kg−1 than Tiessen-Moir. Jiang-Gu fractionation gave similar Ca bounded P to that Tiessen-Moir did at low P level but greater contents at high P level. The two methods extracted much comparable total inorganic P. However, Tiessen-Moir method accounted less total organic P than ignition or Jiang-Gu method (the organic P (Po) estimated by subtract the total inorganic P (Pi) in Jiang-Gu fractionation from the total). P uptake by winter wheat was significantly and positively correlated with all phosphorus fractions in Jiang-Gu; Resin-P, NaHCO3-Pi, D. HCl-P, C. HCl-Pi, NaOH-Po, total-Po in Tiessen-Moir; P fraction categories of Ca-P, Fe & Al-P and total-Pi in both fractionations. Path coefficients indicated that Ca2-P in Jiang-Gu, NaHCO3-Pi and D. HCl-P in Tiessen-Moir had the higher and more significant direct contributions to P uptake among P fractions measured. Conclusions Our results suggested that Jiang-Gu procedure is a better predictor in soil P fractionation in calcareous soils, although it gives no results on organic P fractions.


2021 ◽  
Vol 9 ◽  
Author(s):  
Krystal S. Li ◽  
Van Zeghbroeck J. ◽  
Qingchun Liu ◽  
Shouan Zhang

Many soils including urban soils have high legacy soil phosphorus (P) due to repeated applications of P fertilizers, but a large portion legacy soil P is fixed by calcium in the calcareous soils. Phosphorus solubilizing bacteria (PSB) have the ability to transfer fixed (non-labile) soil P into bioavailable P. The aim of this study was to isolate P solubilizing bacteria from the rhizospheres of four local native plants [broomsedge bluestem (Andropogon virginicus), giant sword ferns (Nephrolepis biserrata), sawgrass (Cladium jamaicense), and sea ox-eye daisy (Borrichia frutescens)] grown in low bioavailable P calcareous soils and to determine their ability to solubilize P. A total of 44 strains of PSB were isolated with 15 of them being identified by sequencing the 16S rRNA genes as Bacillus flexus, Beijerinckia fluminensis, Enterobacter ludwigii, Enterobacter sp., and Pantoea cypripedii. After a 7-day incubation, these strains reduced pH to <4.27 and increased water-soluble P up to 588 mg L−1. Enterobacter ludwigii showed superior P solubilizing ability amount PSB isolated. Therefore, the isolated strains from the local native environment have the potential to thrive in local calcareous soils and possess strong ability to transform non-labile P into bioavailable forms for plants to uptake.


2019 ◽  
Vol 103 (1) ◽  
pp. 43-45 ◽  
Author(s):  
Carlos Crusciol ◽  
João Rigon ◽  
Juliano Calonego ◽  
Rogério Soratto

Some crop species could be used inside a cropping system as part of a strategy to increase soil P availability due to their capacity to recycle P and shift the equilibrium between soil P fractions to benefit the main crop. The release of P by crop residue decomposition, and mobilization and uptake of otherwise recalcitrant P are important mechanisms capable of increasing P availability and crop yields.


Biology ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 158
Author(s):  
Jiang Tian ◽  
Fei Ge ◽  
Dayi Zhang ◽  
Songqiang Deng ◽  
Xingwang Liu

Phosphorus (P) is a vital element in biological molecules, and one of the main limiting elements for biomass production as plant-available P represents only a small fraction of total soil P. Increasing global food demand and modern agricultural consumption of P fertilizers could lead to excessive inputs of inorganic P in intensively managed croplands, consequently rising P losses and ongoing eutrophication of surface waters. Despite phosphate solubilizing microorganisms (PSMs) are widely accepted as eco-friendly P fertilizers for increasing agricultural productivity, a comprehensive and deeper understanding of the role of PSMs in P geochemical processes for managing P deficiency has received inadequate attention. In this review, we summarize the basic P forms and their geochemical and biological cycles in soil systems, how PSMs mediate soil P biogeochemical cycles, and the metabolic and enzymatic mechanisms behind these processes. We also highlight the important roles of PSMs in the biogeochemical P cycle and provide perspectives on several environmental issues to prioritize in future PSM applications.


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