Speciation of phosphorus accumulated in fertilized cropland of Aichi prefecture in Japan with different soil properties by sequential chemical extraction and P K-edge XANES

Microscale Heterogeneous Distribution and Speciation of Phosphorus in Soils Amended with Mineral Fertilizer and Cattle Manure Compost

“…Our study found a remarkable increase of Truog-P and Ac-P in NPK + compost and PK + compost plots (Table 3). The proportion of Truog-P and Ac-P to total P (Table 3) corresponded approximately to the proportion of Ca-P determined by LCF of bulk XANES spectra (Figure 1, Supplementary Figure S5), suggesting that, for the soils analyzed here, the use of Truog-P and Ac-P can evaluate soil P associated with Ca [8,16] although quantitative evaluation of the contribution of hydroxyapatite was difficult. The increase of Ca-P by the continuous application of compost (Table 3, Figures 1 and 3) was also observed in the experimental fields with a long-term manure application using bulk XANES spectroscopy [15,49,55].…”

“…The pool size of Ca-P evaluated by the modified Hedley method is larger than those evaluated by XANES [10]. On the other hand, the pool size of Ca-P evaluated by the Sekiya method [8] was consistent with those evaluated by XANES, while those of Al-P and Fe-P were inconsistent with XANES results [16]. Therefore, complementary analyses combining chemical extraction and spectroscopy should enhance the interpretation of soil P speciation analyses with respect to lability by combining sensitivity to minor differences in P extractability with the power of physical techniques that more directly infer P speciation based on local molecular bonding configurations.…”

“…Solid-state 31 P NMR can differentiate P species according to different chemical shifts of P associated with calcium and aluminum (Ca-P and Al-P) or in organic P forms, whereas iron-associated P (Fe-P) is difficult to detect [11]. XANES spectroscopy can distinguish phosphate associated with calcium (Ca-P), iron (Fe-P), and aluminum (Al-P) based on unique spectral features, specifically a post-edge shoulder (Ca-P), a pre-edge peak (Fe-P) and typically an intense white line (Al-P), especially for adsorbed Al-P [12][13][14][15][16], although identification of organic P is difficult [17]. Chemical extraction is more sensitive to small changes in P pools than solid-state spectroscopy.…”

Phosphorus speciation and distribution in a variable‐charge Oxisol under no‐till amended with lime and/or phosphogypsum for 18 years

“…In the native forest samples, the lower available Ca concentrations, the presence of organic ligands and low pH levels disfavoured the presence of Ca-bound P forms (Figure 5). Ando et al (2021) report that soils with high exchangeable Ca and high pH tend to have more Ca-P species, especially with high crystallinity. Ando et al (2021) also suggest that the presence of these forms can be attributed to the continuous application of superphosphate and/or animal manure.…”

“…For example, Gatiboni et al (2021) found a reduction in P forms associated to Fe and an increase in forms associated to Al as the degree of soil P saturation increased. Ando et al (2021), on the other hand, observed that total C and exchangeable Ca are the attributes that exert the most control on Ca P forms. In both studies, the in-situ evaluations were crucial to consolidate the data obtained with chemical fractionations.…”