Phosphorus Fractionation and Sorption in P-enriched Soils of Norway

Abstract

Phosphorus (P) enrichment can lead to imbalance in nutrient availability and pollution of terrestrial and aquatic ecosystems. Hence studies were carried out to investigate fractionation and sorption of P in eleven P-enriched soils collected from different agro-climatic sites in Norway. Different P fractions viz. total, organic, inorganic (easily soluble P, Fe-P, Al-P, Ca-P and occluded P), P w (water extractable), and NH 4 -lactate extractable P (P AL ) at the beginning and after the completion of the experiments varied widely among the soils studied, indicating a wide variability of P supplying capacity of these soils. Soluble P was positively correlated to Ca-P (r = 0.94; P < 0.001), P w (r = 0.87; P < 0.001), pH (r = 0.79; P < 0.01) and P AL (r = 0.79; P < 0.01), whereas it was negatively correlated with ammonium oxalate-extractable Al (Al ox ) (r = À0.68; P < 0.05). Iron-P was only moderately related to Al ox (r = 0.64; P < 0.05) and P ox (r = 0.70; P < 0.05), whereas it was not related to any of the other parameters tested. The a [a = P ox / (Fe ox + Al ox )] was highly correlated with P AL (r = 0.93; P < 0.001), pH (r = 0.87; P < 0.001), inorganic P (r = 0.80; P < 0.01) and P w (r = 0.77; P < 0.01) but moderately to total P (r = 0.71; P < 0.05). Adsorption data fitted well to the Langmuir equation for most soils. The P affinity constant (k), adsorption maximum (b) and thus maximum buffering capacity (mbc) and adsorption isotherm of P were highest in the sandy clay soil from Øsaker, which also contained high amounts of Fe, Al and clay particles and the lowest in sandy soil from Vestra˚len, which contained very high initial P AL and the lowest content of Fe, Al, silt and clay among all the soils studied. The P affinity constant (k) was correlated positively and significantly to clay content (r = 0.66; P < 0.05), whereas mbc was correlated positively and significantly to clay content (r = 0.63; P < 0.05) and ammonium oxalate-extractable Fe (Fe ox ) (r = 0.63; P < 0.05). Phosphorus desorption of the soils varied widely depending on the initial P status and texture of the soils. Phosphorus desorbed by NH 4 -lactate was many fold higher as compared to CaCl 2 in most soils.

Efficiency of a constructed wetland for retention of sediment-associated phosphorus

“…Hydraulic load and Table 4. Amount (based on dry matter) and proportion of organic phosphorus (P) and sequentially extracted inorganic P fractions according to Singh et al (2005) for the accumulated sediment for the entire S. Stene wetland, inlet area and the mean of two shallow vegetated areas (Typha 1 and Typha 2). …”

“…The different P i fractions were separated with a sequential fractionation procedure (for details, see Singh et al (2005)). P i was divided into 1) NH 4 Cl-P = bioavailable P, 2) NH 4 F-P = aluminum-bound P, 3) NaOH-P = P bound to iron-oxides, and 4) H 2 SO 4 -P = calcium-bound P.…”

Phosphorus Sorption Kinetics in Reclaimed Lignite Mine Soils under Different Age Stands ofRobinia pseudoacaciaL. in Northeast Germany

“…Comparable correlations of PSC with Fe ox and Al ox have been reported in the literature [24,27,33,46,54,87,[89][90][91][92]. Numerous studies [22,29,46,89,93] have shown that the most important parameters that determine the P sorption are Fe ox and Al ox . The strong correlations between Fe ox and Al ox as well with the sum of Fe ox + Al ox as noted by Freese et al [22] make it difficult to assess the single importance of one of these fractions for P sorption by means of regression analysis.…”

“…The greater P release from soil at R14 site compared to that under the young plantations may likely be associated with the Fe ox and Al ox phases in the soils. It was previously reported that the desorbable soil P was related to Fe ox and Al ox in sandy soil [27,29,93,103]. Moreover, study of Daly et al [29] and Nafiu [36] indicated that the sum of Fe ox and Al ox was the most important soil properties influencing the rate of P desorption.…”

“…Studies by Borggaard et al [21] on sandy Danish soil confirm that the Fe ox and Al ox significantly influenced P sorption. Moreover, Singh et al [93] and Lair et al [91] observed that P sorption depends on Fe ox and Al ox contents with the highest P sorption for soils containing high amounts of Fe ox and Al ox and the lowest in soils with the lowest content of Fe ox and Al ox . On the other hand, Lookman et al [94] suggest that Al ox might be associated with soil OM.…”