EVALUATION DU PHOSPHORE ASSIMILABLE DES SOLS ACIDES AVEC DIFFERENTES METHODES D’EXTRACTION EN RELATION AVEC LE RENDEMENT DE L’AVOINE ET LES PROPRIETES DU SOL

1985 ◽  
Vol 65 (1) ◽  
pp. 47-60 ◽  
Author(s):  
M. GIROUX ◽  
T. SEN TRAN

The objective of this study was to evaluate different available P extracting methods in relation with soil properties, oat yield and plant P uptake. Six chemical extractants (Bray-1, Bray-2, new Mehlich, North Carolina DA-4, DA-10, and Olsen) and two anion exchange resins (F− and HCO3−) were compared on 42 acid soils. The DA-4, DA-10, new Mehlich, and HCO3− resin methods showed the best correlation with oat yield and plant P uptake. The Bray-1, Bray-2 methods were significantly less correlated than the other methods. The HCO3− resin was better than F− resin to predict plant P uptake and yield. Available P levels as determined by these eight methods were classified poor, medium and rich by the Cate and Nelson procedure. Oxalate extractable Al, pH (NaF), pH (H2O), exchangeable (Ca + Mg), forms of P, maximum P fixation capacity and soil texture have great influence on the plant P uptake. Soil organic matter content and oxalate-extractable Fe had significantly less important an effect. The Bray-1 and Bray-2 methods were the most affected by soil properties especially oxalate-extractable Al. The P-HCl/P-DAF ratio proposed by Mehlich to identify forms of soil P indicated that seven soils contain predominantly Ca-P and 21 soils with predominantly Al-P and Fe-P. This ratio was related with oxalate extractable Al (r = − 0.32*), pH NaF (r = − 0.59**), pH H2O (r = 0.52**) and exchangeable Ca + Mg (r = 0.55**). The maximum P fixation capacity (M) ranged from 150 to 4200 μg P/g soil and was closely related with oxalate-extractable Al (r = 0.81**), pH NaF (r = 0.74**), pH H2O (r = − 0.36*) and Mehlich ratio (r = − 0.33*). The maximum P buffering capacity (Mb) of soils was also measured and showed the best correlation with oxalate-extractable Al (r = 0.84**) and pH NaF (r = 0.53**). Key words: Soil testing, available P, anion exchange resins, P fixation, oxalate-Al, forms of P

1987 ◽  
Vol 67 (1) ◽  
pp. 1-16 ◽  
Author(s):  
T. SEN TRAN ◽  
M. GIROUX

Seven chemical methods (Bray-II, Bray-I, North Carolina DA-4, DA10, Mehlich II, Mehlich III and Olsen) and two anion exchange resins (F− and [Formula: see text] forms) were evaluated on 43 soils with pH varying from 6.4 to 7.88. A greenhouse experiment was carried out with ryegrass receiving two treatments (without P fertilization and 150 mg kg−1 soil) on these soils. The Olsen's method and the two anion resins used as reference ones were effectively the better correlated with P uptakes (r = 0.83**–0.87**) and relative yield (R2 = 69.3–70.2%). The Mehlich II, Mehlich III and to a lesser extent Bray-I methods showed good correlations with these reference methods (r = 0.77**–0.83**) and with plant P uptakes (r = 0.73**–0.79**) or relative yields (R2 = 48.9–55.1%). The Bray-II, DA-4 and DA-10 methods may dissolve some calcium phosphates such as apatites or tricalcium phosphate in some soils and thus overestimated their available P content. The P amounts extracted by these methods were less correlated with P uptakes (r = 0.57*–0.67**) or relative yields (R2 = 14.4–31.4%). On the other hand, the DA-4 extractability was diminished in soils containing more than 3% of carbonates. Although the Ca-P was the predominant form in these soils, the P fixation capacity (M) and maximum P buffer (Mb) capacity were mostly related with Al and Fe-oxalate contents. However, the low Mb values obtained from these soils indicated that the P concentration in soil solution is more favored with respect to adsorbed P. Organic matter and clay contents, pH (H2O), exchangeable Ca and carbonate contents had some effects on the extraction capability of some methods without affecting plant P uptakes. Key words: Available P, soil testing, anion exchange resins, soil properties, P fixation


1985 ◽  
Vol 65 (1) ◽  
pp. 35-46 ◽  
Author(s):  
T. SEN TRAN ◽  
M. GIROUX

The objective of this study was to compare different available-P extracting methods on 83 Québec soils. The alkaline Olsen’s method and five acid chemical extractants (Bray-1, Bray-2, new Mehlich, North Carolina double acid DA-4 and DA-10) were compared with each other and with two anion-exchange resin methods. The ratio of P-HCl/P-DAF of Mehlich was used to identify the group of soils with predominant P-Ca forms [Formula: see text]. Within this soil group, the Bray-2, DA-4 and DA-10 methods extracted more P and they were less correlated with all the other methods (r = 0.01 to 0.48*). The Bray-1 and Mehlich methods showed good relationships with Olsen, F−- and HCO3−-form resin methods (r = 0.80** to 0.89**) for this soil group, with the exception that Bray-1 solution was more affected by the presence of free carbonates. In the soil group containing more than 0.6% oxalate-Al, the Bray-1, Bray-2 and DA-10 methods extracted more P than the Mehlich, DA-4 or Olsen methods. The F−-form exchange resin extracted more P than that in the HCO3− form. The depressing effect of free iron oxides on the DA-4 method was also observed with the soil group containing more than 0.6% oxalate-Fe. The contents of DA-4-P were less correlated with those of other methods (r = 0.74** to 0.88**) in this soil group. On the other hand, the Olsen, F− and HCO3− resins extracted more of the P-Fe forms from these soils. The DA-4 method was further influenced by the soil organic matter (OM) contents. The relationships between P-Olsen, P-HCO3−-resin with the other chemical methods were also improved by taking into account the contribution of OM contents. Soil texture influenced mostly Bray-2, Bray-1, DA-4 and DA-10 extractable P. The Mehlich, Olsen and F−-resin extractable P was less affected by clay contents while the HCO3−-resin was the most consistant over a wide range of soil textures. Key words: Available-P, anion-exchange resins, new Mehlich extractant, P-forms, soil testing


2008 ◽  
Vol 43 (7) ◽  
pp. 893-901 ◽  
Author(s):  
Sidney Netto Parentoni ◽  
Claudio Lopes de Souza Júnior

The objective of this work was to determine the relative importance of phosphorus acquisition efficiency (PAE - plant P uptake per soil available P), and phosphorus internal utilization efficiency (PUTIL - grain yield per P uptake) in the P use efficiency (PUE - grain yield per soil available P), on 28 tropical maize genotypes evaluated at three low P and two high P environments. PAE was almost two times more important than PUTIL to explain the variability observed in PUE, at low P environments, and three times more important at high P environments. These results indicate that maize breeding programs, to increase PUE in these environments, should use selection index with higher weights for PAE than for PUTIL. The correlation between these two traits showed no significance at low or at high P environments, which indicates that selection in one of these traits would not affect the other. The main component of PUTIL was P quotient of utilization (grain yield per grain P) and not the P harvest index (grain P per P uptake). Selection to reduce grain P concentration should increase the quotient of utilization and consequently increase PUTIL.


2013 ◽  
Vol 373 (1-2) ◽  
pp. 711-722 ◽  
Author(s):  
Sean D. Mason ◽  
Mike J. McLaughlin ◽  
Caroline Johnston ◽  
Ann McNeill

2003 ◽  
Vol 83 (4) ◽  
pp. 737-744 ◽  
Author(s):  
A. Liu ◽  
C. Hamel ◽  
A. A. Elmi ◽  
T. Zhang ◽  
D. L. Smith

Arbuscular mycorrhizal fungi (AMF) have a large enhancing effect on the P uptake capacity of host plants, which could make possible the production of high crop yields on soil with reduced level of available P, or could help reduce the P level in rich soils, thereby reducing the risk of P loss to the environment. A field experiment was conducted in Ste-Anne-de-Bellevue, Quebec, Canada, on a loamy sand in 1997 and a fine sandy loam in 1998 to assess the impact of indigenous AMF-maize hybrid combinations on soil available P level. The experiment had three factors organized in a split-split plot design. There were two soil fumigation levels (fumigated and non-fumigated) randomized in the main plots, three P fertilizer rates (0, 60, and 120 kg ha-1) randomized in the sub-plots and three maize (Zea mays L.) hybrids with contrasting genotypes [two newly developed leafy hybrids, Leafy normal stature (LNS) and Leafy reduced stature (LRS), and a commercial hybrid, Pioneer 3979 (P3979)], which were randomized in the sub-sub-plots. Soil extractable P, plant P content, plant dry mass, root colonization with AMF and extraradical hyphae were determined at the 6-leaf, 10-leaf, tasselling and silking stages of maize, and grain yield and total P in maize were determined at harvest. Soil fumigation to reduce AMF and P fertilization reduced the amount of indigenous mycorrhizal development in maize hybrids. The growth of LNS, the most mycorrhizae-dependent hybrid, was more supressed by fumigation than the growth of the other two hybrids. When the soil P level was low, plant dry mass, grain yield and total P content of LNS were higher in the non-fumigated plots than in the fumigated plots. Fumigation had a significant but smaller influence on soil extractable P level than on plant P uptake and growth. Soil extractable P was lower in non-fumigated plots than in fumigated plots from silking to the end of the growing season in 1997, only in non-fertilized plots growing LNS. Extraradical hyphae density was positively correlated with maize P uptake and negatively correlated with soil extractable P. This suggested that soil extractable P can be reduced through AMF-enhanced plant P uptake when soil available P conditions and host plant genotype are favourable to mycorrhizal development, and when P uptake enhancement is large. Key words: Arbuscular mycorrhizal fungi, maize hybrids, soil extractable P, P uptake, extraradical hyphae, root colonization, mycorrhizal dependency


Author(s):  
J.S. Rowarth ◽  
A.G. Gillingham

A large-scale phosphate (P) fertiliser grazing trial was carried out at Whatawhata Research Centre between 1980 and 1984. The effect of 5 fertiliser rates (10, 20 30, 50 or 100 kg P/ha) on pasture production, plant P uptake, dung P distribution, dung decomposition and Olsen P concentration were monitored on 4 slope groups (campsites, O-10"; easy, 1 I-20"; moderate, 21-30" and steep, 31" +). Soils collected from each slope and fertiliser treatment were used in a pot trial to investigate the size of the plant available P pool. Results can be used to interpret data from field trials where fertiliser has been withheld. Initially, pasture production or Olsen P will change little because the most productive areas of the paddock receive large amounts of dung P which buffer the effect of fertiliser withdrawal. On these areas P is cycled more rapidly than on steep slopes, further buffering the system against P deficiency. Small changes in Olsen P do not reflect the more rapid changes in inorganic P or plant-available P. As inorganic P becomes depleted, plant P uptake decreases. The associated decrease in dung P return and the slower rate of dung decomposition contribute to a slowing of the P cycle. The net effect is less feed and slower regrowth after grazing. Recovering from this state will require not only P fertiliser but also time for high producing pasture species to regenerate. Keywords phosphate cycling, topdressing, fertiliser, pasture production, hill country, dung


1983 ◽  
Vol 55 (2) ◽  
pp. 109-117
Author(s):  
Raili Jokinen

A total of 430 topsoil samples were collected from ten fields of the Viikki Experimental Farm, University of Helsinki. Particle size distribution, organic carbon content, pH(CaCl2), exchangeable Ca, Mg, K contents, plant available P (Bray 1), 1 M KCI extractable (Al+H) content and effective cation exhange capacity of the soils were determined. The coefficient of variation was used as indicator of the variability of soil properties with in each field. The lowest coefficients of variation were observed for pH(CaCl2) and the highest for exchangeable Mg 1 M KCI extractable (Al+H) and effective cation exchange capasity. The results indicate that from 1 (pH(CaCl2)) to 33 (exchangeable Mg) samples per hectare are needed from individual fields for strict level of accuracy in estimation of the soil properties. For determination of soil type (according to clay content) and organic carbon content on average 8 samples, and for the plant available P (Bray 1) and exchangeable Mg and K contents 10 to 16 samples per hectare appear sufficient. Four samples suffice for a less stringent, lax accurate determination of all properties. The variability of soil properties is discussed from the viewpoint of agricultural advisory work and field experiments for agricultural research.


2019 ◽  
Vol 16 (21) ◽  
pp. 4293-4306 ◽  
Author(s):  
Heyong Liu ◽  
Ruzhen Wang ◽  
Hongyi Wang ◽  
Yanzhuo Cao ◽  
Feike A. Dijkstra ◽  
...  

Abstract. Here we investigated the effects of P compounds (KH2PO4 and Ca(H2PO4)2) with different addition rates of 0, 20, 40, 60, 80, and 100 kg P ha−1 yr−1 and NH4NO3 addition (0 and 100 kg N ha−1 yr−1) on soil labile inorganic phosphorus (IP) (dicalcium phosphate, Ca2-P), moderate-cycling IP, and recalcitrant IP fractions in a calcareous grassland of northeastern China. Soil moderate-cycling IP fractions, not readily available to plants but transforming into soil-available P quickly, include variscite (Al-P), strengite (Fe-P) and octacalcium phosphate (Ca8-P); recalcitrant IP fractions include hydroxylapatite (Ca10-P) and occluded P (O-P). Soil labile and moderate-cycling IP fractions and total P significantly increased with increasing P addition rates, with higher concentrations detected for KH2PO4 than for Ca(H2PO4)2 addition. Combined N and P treatments showed lower soil labile IP and moderate-cycling IP fractions compared to ambient N conditions, due to enhanced plant productivity. Moderate-cycling IP was mainly regulated by P addition and plant P uptake to further enhance labile IP and total P concentrations with KH2PO4 and Ca(H2PO4)2 addition. Soil labile IP was also directly and negatively affected by soil pH and plant P uptake with Ca(H2PO4)2 addition. Ca(H2PO4)2 addition significantly increased the soil recalcitrant IP (Ca10-P) fraction, while KH2PO4 addition showed no impact on it. A significant positive correlation was detected between soil labile IP, moderate-cycling IP fractions and soil Olsen-P which illustrated that labile IP and moderate-cycling IP fractions were important sources for soil-available P. Our results suggest that moderate-cycling IP fractions are essential for grassland P biogeochemical cycling and the chemical form of P fertilizer should be considered during fertilization management for maintaining soil-available P.


Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1818
Author(s):  
Mohsin Mahmood ◽  
Yi Tian ◽  
Qingxia Ma ◽  
Waqas Ahmed ◽  
Sajid Mehmood ◽  
...  

Excessive phosphorus (P) application can alter soil P availability and limit plant growth by compacting soil and fixation of P into different organic and inorganic forms. However, it remains uncertain whether these changes happen after limited fertilization or an excessive rate applied under the winter wheat cropping system. The current study aimed to identify the transformation of P into different organic (Po) and inorganic (Pi) fractions, and their role in the plant P uptake and winter wheat (Triticum aestivum L.) production. A long-term study (12 years) was conducted to assess the changes in soil Pi and Po fractions in response to different P rates (0, 50, 100, 150, and 200 kg P2O5 ha−1) applied to winter wheat. Phosphorus fractions were determined using the Hedley modified Tiessen and Moir fractionation scheme. Our findings demonstrated that different P rates significantly increased the available P, particularly NaHCO3-Pi, in the inorganic P fractions compared to P0 treatment. NaHCO3-Pi showed a strong relationship with grain yield (R2 = 0.91) and P uptake (R2 = 0.80). Grain yield was significantly higher in the P100 treatment, but no significant difference was observed between P100 and P200 treatments. The P200 treatment had a maximum grain P content and plant P uptake. Compared with the P0 treatment, all organic fractions yielded the highest Po with the P rate increase, ranging from 27.3 to 75.6 mg kg−1, 27.2 to 35.6 mg kg−1, and 58.8 to 124 mg kg−1 for NaHCO3-Po, NaOH-Po, and HCl-Po, respectively. Among all Pi fractions, the maximum fraction, known as apatite (HClD-Pi), was found in the P200 treatment with the range of 165 to 245.9 mg kg−1. HClD-Pi accounted for 32% of total P, which can be transformed into the available P form with the passage of time. An increase of 78% in residual P was found under the treatment of P200. The residual P fraction was positively correlated with grain yield, P uptake, and other inorganic fractions. It can be concluded that application of P increases P availability and grain yield with an increase in its application rate, but too much use of P can cause soil pollution and higher fixation of P. Consequently, a balanced application of fertilizer is recommended to reduce its fixation and increase its availability for higher crop yield.


2002 ◽  
Vol 82 (2) ◽  
pp. 239-247 ◽  
Author(s):  
J A Lamb ◽  
G W Rehm

The spatial and temporal stability of soil test values is important to the use of soil testing for site-specific soil fertility management. A study was conducted to evaluate the spatial and temporal stability of soil test phosphorus (P). Five sites ranging in size from 3.7 to 4.4 ha were soil sampled in the same locations in a 18.3 × 18.3-m grid either three or four times over a 2-yr period. Bray 1-P values were similar or decreased over time, while Olsen-P values at two of five sites decreased. One site showed no pattern and two sites had cyclic patterns where the spring sample values were greater than the fall. The spatial pattern of soil test values during a 2 yr rotation for Bray 1-P and Olsen-P was very stable. The changes in distribution in soil test P categories over a 2-yr period resulted in a shift to lower soil test categories. The decreases in soil test P were probably caused by plant P uptake in combination with no application of P fertilizer during the study. Key words: Soil test phosphorus, spatial stability, pH, temporal stability


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