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| Titel |
Total and extractable Phosphorus concentrations at different depths in a soil fertilized with manure |
| VerfasserIn |
Rosane da Silva Días, Cleide Aparecida de Abreu, Roger Manuel Mestas Valero, José Manuel Mirás Avalos, Eva Vidal Vazquez |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250050667
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| Zusammenfassung |
| A number of extraction methods have been proposed to assess soil phosphorus availability.
The aim of this study was to evaluate the phosphorus (P) concentration at several depths in a
soil using different techniques. The research was carried out in Ribadeo (Lugo Province, NW
Spain). The study area was 625 m2. A total of 36 soil samples were taken in 9 points at the
following depths: 0-5; 5-10; 10-20; 20-40 cm. Total P content in soil was determined by
microwave digestion with nitric acid, USEPA method 3051. Extractable P was
measured by Mehlich-3 extraction followed by two different determination techniques
(ICP and colorimetry, M3-ICP and M3-COL, respectively), anion exchange resin
(AER) and Olsen (Ol). Data were compared using Tukey’s test and Pearson’s r
coefficient. Extracted amounts of P (Table 1) were much higher than expected and they
were also relatively high compared to those measured by other researchers in the
same region. Note that thresholds for excess P contents using the Mehlich-3 and
Olsen methods have been reported as 31 and 21 mg kg-1, respectively. The results
obtained in this study exceeded these thresholds in every depth. However, our results
were within the range reported by Sharpley et al. (2004), who observed P values
extracted by Mehlich-3 within a range of 64 to 2822 mg kg-1 and 407 to 2480
mg kg-1 for total P depending on the type of manure used and at a depth of 0-5
cm. Phosphorus accumulation suggests long-term intensive application of organic
manures.
Table 1. Soil P concentrations as a function of depth and extraction method.
Depth (cm) P
Total(mg-kg) P M3(mg-kg) P
AER(mg-kg) P
Ol(mg-kg)
ICP COL
0-5 1793 a 664 a 598 a 583,0 a 154,0 a
5-10 1814 a 669 a 607 a 600,0 a 156,0 a
10-20 1633 ab 652 a 606 a 625,0 a 146,0 a
20-40 1453 b 539 b 538 b 491,0 b 119,0 b
Total: Total P, M3:Mehlich-3 (ICP and COlL: Colorimetry), AER: Resin and Ol: Olsen.
On each column, different letters indicate statistically significant differences according to
Tukey test (P -¤ 0.05).
P values obtained by Mehlich-3 showed significant correlations with those from Olsen
and resin methods (r values between 0.64 and 0.82). In addition, P measured by Olsen and
resin were significantly correlated (r = 0.69). All the methods, except anion exchange resin,
provided highest P concentrations were at the 5-10 cm depth, thought they were not
significantly different than those measured at the 0.5 and 10-20 cm depths. At 20-40 cm
depth, the significantly lower P concentrations were observed independently of the method
used (Table 1). The relatively high concentrations of P at the 20-40 cm depth are thought to
be caused by soil mixing during deep plowing, whereas more superficial tillage
operations would cause maximum values at the 5-10 cm depth. Based on our results it
would be advisable to cease manure additions to the study soil until the P level
decreases.
Sharpley, A.N., R.W. McDowell, and P.J.A. Kleinman. 2004. Amounts, forms, and
solubility of phosphorus in soils receiving manure. Soil Sci. Soc. Am. J. 68:2048–2057. |
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