Investigation of Soil Legacy Phosphorus Transformation in Long-Term Agricultural Fields Using Sequential Fractionation, P K-edge XANES and Solution P NMR Spectroscopy

Abstract

Understanding legacy phosphorus (P) build-up and draw-down from long-term fertilization is essential for effective P management. Using replicated plots from Saskatchewan, Canada, with P fertilization from 1967 to 1995 followed by either P fertilization or P cessation (1995-2010), soil P was characterized in surface and subsurface layers using sequential fractionation, P K-edge X-ray absorption near-edge structure (XANES) and solution (31)P nuclear magnetic resonance (P NMR) spectroscopy. Legacy P from a 28-year build-up was sufficient for 15 years of wheat cultivation, resulting in no significant differences in crop yield in 2010. In surface soils, soil test (Olsen) P decreased significantly in unfertilized plots compared with 1995, which was reflected in declining aluminum (hydr)oxide-associated inorganic P by fractionation and XANES. Furthermore, XANES analysis revealed a decrease of calcium-associated P in 2010-unfertilized soils at both depths and an increase of Fe (hydr)oxides-associated P in the 2010-fertilized and -unfertilized surface soils relative to the 1995 soils. Increased total organic P and orthophosphate diesters by P NMR and accumulated inositol hexaphosphate by XANES were observed in surface soils with P fertilization cessation. In subsurface soils, few legacy P transformations were detected. These results provide important information about legacy P to improve agricultural sustainability while mitigating water quality deterioration.

Characteristics of phosphorus components in the sediments of main rivers into the Bohai Sea

“…Generally, the P components were analyzed by solution 31 P NMR including phosphonates, orthophosphate, orthophosphate monoesters, orthophosphate diesters, pyrophosphate and polyphosphate, and the orthophosphate monoesters include some of components, such as phytate, Glucose-6-phosphate (Cade-Menun, 2005;CadeMenun and Preston, 1996;Turner et al, 2005). This method has been successfully applied for analyzed the soil, sediment (river, lake and marine) and manure (Vincent et al, 2013;Liu et al, 2015;McDowell et al, 2006;Cade-Menun et al, 2002;Ding et al, 2013;Zhang et al, 2016;Li et al, 2015).…”

Characterizing phosphorus forms in cropland soils with solution 31P-NMR: past studies and future research needs

“…Three of these studies identified only broad compound classes [10,58,59], one identified the majority of peaks [60] and three identified peaks in detail [61][62][63]. In North America, there was one study from Mexico [22], five from Canada [23,32,33,64,65] and five from the USA [31,[66][67][68][69]. The early studies identified only broad peaks [22,23,64,66].…”

“…Of the 44 studies listed in Table 1, many do not even include measures of soil test P (STP), and only nine include information on yield or P balances [48, 54, 55, 59-61, 65, 70, 75]. Of these nine, only six identified peaks in enough detail (M or D) to identify trends in P forms other than orthophosphate [48,54,60,61,65,75]. I will focus on these studies in more detail, and they are summarized in Table 2.…”

“…The studies that included detailed peak identifications and yield information were studies of rice in Madagascar [48], greenhouse-grown tomatoes in China [54], wheatbased crop rotations in Sweden [60] and Switzerland [61], continuous wheat monoculture in Canada [65], and summer rotations [including corn, soybean (Glycine max (L.) Merrill), common bean (Phaseolus vulgaris L.)] with a grazed winter wheat cover crop in Brazil [75]. One had only CF [65], one had CF plus grazing of winter cover crops [75], two were fertilized with CF and AM [54,60], one had fertilization with CF, AM, and compost [48], and one studied fertilization with CF, AM, compost and sewage sludge [61].…”

Mineral nutrient calibration for Cassava (Manihot esculenta Crantz) grown in dry-tropical North-Eastern Queensland, Australia: with a focus on Phosphorus and Boron

“…The plot had recently been used to produce a cycle of cassava crop after land preparation in 2013. This one cycle of cassava production could have generated legacy effects originating from the fertilizer residues (particularly with immobile elements) (Liu et al, 2015;Sharpley et al, 2013). In view of this, soil testing was carried out prior to establishing the field trial to ensure these effects were taken into consideration.…”