Phosphorus speciation in a prairie soil amended with MBM and DDG ash: Sequential chemical extraction and synchrotron-based XANES spectroscopy investigations

Abstract

Sequential chemical extraction and synchrotron-based XANES spectroscopy techniques were used to identify P species in two ashes before and after addition to a prairie soil. The used ashes were: meat and bone meal ash (MBMA) and dried distillers grains ash (DDGA) plus mineral P fertilizer (MP) for comparison. Soil treated with MP contained higher content of resin-Pi and NaHCO 3 -Pi followed by DDGA and MBMA. The MBMA amended soil had the highest (47%) proportion of the soil P contained in recalcitrant HCl extractable fraction, reflecting more Ca-bound P present and being formed in soil after application. Analysis of both ashes with XANES spectroscopy before application to soil revealed that MBMA had strong spectral features consistent with hydroxyapatite (Ca 5 (PO 4 ) 3 (OH)). DDGA exhibited spectral features consistent with a mixture of several Mg and K phosphate salts rather than a single mineral species. The distinctive features in the XANES spectra of both ashes largely disappeared after amendment to the soil, suggesting transformation to different P forms in the soil after application. It is also possible that the added amount of P to the studied soil via DDGS or MBMA was small enough so that P speciation is not different from the background P level.Phosphorus is an essential element for plants, and its supply in soil is critical in maximizing crop production and improving food and feed quality. The global demand for phosphorus fertilizer is projected to increase by 50-100% by 2050 to enable sustained food production for a growing world population 1 . Complete reliance on phosphorus fertilizer manufactured from mined phosphate rock may not be a good strategy for sustained crop yields, stimulating the need to find alternative phosphorus sources and recycle more effectively the P that is contained in agricultural by-products. One option is the utilization of ash generated from organic materials via the gasification process, a thermal breakdown of organic materials under high temperature (800-900 °C) in presence of oxygen 2 . Application of this combustion technology to meat and bone meal (MBM) and dried distillers grains (DDG) as a means of providing additional nutrient and energy recovery has gained interest 3-5 . The gasification of MBM and DDG produces ash byproduct that was noted to have high content of total P, and with potential as P fertilizer source 6 . However, the P forms in the ash and ash amended soil were not examined in this study. In general, ashes derived from various feedstocks, such as poultry litter, turkey manure and crop residues have a positive impact on crop yield and soil properties when added to soil [7][8][9] . However, the effects on P availability and mobility will depend on the P forms produced in the amended soil, and may vary depending on feedstock and gasification conditions. Furthermore, P in ash may exist in different forms and availability levels, and when added to soil, it is anticipated to interact/associate with soil constituents and reside in different forms as well. Ther...

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

“…Our results suggest the use of more than one analytical method to investigate phenomena related to P chemistry in soils, in line with Alotaibi et al (2018), Liu et al (2013) and Luo et al (2017). The Hedley fractionation provides operationally defined P fractions that are not specific to one particular chemical species (Hunger et al, 2005).…”

Molecular Understanding of Humic Acid-Limited Phosphate Precipitation and Transformation

“…8 Similarly, the dissolution of goethite (010) cleavage surfaces in phosphate-bearing solutions leads to simultaneous nucleation of iron phosphate (Fe−P) nanoparticles and subsequent aggregation to form layered precipitates under acid soil solution conditions; 9 in the presence of Al 3+ ions, Alsubstituted cacoxenite (Fe 3+ 24 Al(PO 4 ) 17 O 6 (OH) 12 •17H 2 O) and wavellite (Al 3 (PO 4 ) 2 (OH) 3 •5H 2 O) also forms on goethite. 9 Moreover, a legacy of excess fertilizer use has caused soil P to accumulate, 10,11 and for those past P deposits, Ca(H 2 PO 4 ) 2 was identified as a reserve of labile P and hydroxyapatite (HAP) was detected after long-term cropping, 12,13 suggesting that Ca-P phase transformation occurs in soils. 14 Soil organic matter (SOM) is a continuum of progressively decomposing organic compounds as relatively simple biomolecules 15,16 supported by the functional group chemistry of the extracted humic substances 17 and plays a major role in determining long-term stability of phosphorus 18 and contributes to soil fertility 19 by retaining plant-available nutrients.…”

“…Similarly, the dissolution of goethite (010) cleavage surfaces in phosphate-bearing solutions leads to simultaneous nucleation of iron phosphate (Fe–P) nanoparticles and subsequent aggregation to form layered precipitates under acid soil solution conditions; in the presence of Al 3+ ions, Al-substituted cacoxenite (Fe 3+ 24 Al­(PO 4 ) 17 O 6 (OH) 12 ·17H 2 O) and wavellite (Al 3 (PO 4 ) 2 (OH) 3 ·5H 2 O) also forms on goethite . Moreover, a legacy of excess fertilizer use has caused soil P to accumulate, , and for those past P deposits, Ca­(H 2 PO 4 ) 2 was identified as a reserve of labile P and hydroxyapatite (HAP) was detected after long-term cropping, , suggesting that Ca-P phase transformation occurs in soils …”

Molecular Scale Studies of Phosphorus Speciation and Transformation in Manure Amended and Microdose Fertilized Indigenous Vegetable Production Systems of Nigeria and Republic of Benin

“…Therefore, understanding how the applied manure and nitrogen fertilizer influences the forms and plant availability of P is important in minimizing its negative effects on the environment [29] in any agricultural system. X-ray absorption near-edge structure (XANES) spectroscopy has been used by many researchers in studying the speciation of P in soils [26,[30][31][32][33][34][35][36][37]. This direct speciation technique is preferred because it is element specific and non-destructive [38] and it avoids bias in distinguishing different P species that can arise from chemical fractionation methods [39,40].…”