Bioavailability of phosphorus from composts and struvite in acid soils

Abstract

A B S T R A C TThe objective of this study was to assess the type and fractions of phosphorus (P) forms in composts and struvite and how these P forms affect the bioavailability of P in the soil. P fertilization was performed with compost from sewage sludge (CSS), compost from poultry litter (CPL) and struvite (SV) and compared with single superphosphate (SSP). P forms were quantified through a sequential fractionation scheme. The first extraction was performed with H 2 O, the second with 0.5 M NaHCO 3 , the third with 0.1 M NaOH and the fourth with 1 M HCl. The release of P over time, after soil P fertilization, was assessed by incubating the fertilizers with a low-P acid soil. P bioavailability was assessed through a micro-pot experiment with the incubated soils in a growth chamber using rye plants (Secale cereale L.). Inorganic P forms in the first two fractions represented ~50% (composts), 32% (SV) and 86% (SSP) of the total P; and in the HCl fraction, ~40% (composts), 26% (SV) and 13% (SSP) of the total P. Despite the variability of the P form fractions in the composts and struvite, the P release and bioavailability were similar among the fertilized treatments. The acidic nature of the soil, which improve solubility of Ca-P forms, and the high efficiency of rye, which favors P uptake, were factors that contributed to these results.Biodisponibilidade do fósforo em compostos e struvite aplicados em solos ácidos R E S U M O O trabalho teve como objetivo caracterizar as formas de fósforo (P) presentes em compostos e em struvite e avaliar a influência dessas formas na biodisponibilidade do P. A fertilização fosfatada efetuou-se com composto obtido de lodos de tratamento de águas residuais (CSS), composto a partir de estrume de galinha (CP) ou struvite (SV) utilizando-se o adubo comercial superfosfato simples (SSP) como controle. Realizou-se um fracionamento sequencial das formas de P dos fertilizantes: a primeira extração efetuou-se com H 2 O, a segunda com NaHCO 3 0,5 M, a terceira com NaOH 0,1 M e a quarta com HCl 1 M. Realizou-se um ensaio de incubação após aplicação de cada fertilizante a um solo ácido e pobre em P para avaliação do efeito do tempo na libertação do P. A biodisponibilidade de P foi avaliada num ensaio em vasos com os solos incubados usando como planta teste o centeio (Secale cereale L.). Os compostos apresentaram ~50% do P inorgânico nas duas primeiras frações, a SV 32% e o SSP 86%. A fração de P inorgânico em HCl representou ~40% nos compostos, 26% na SV e 13% no SSP. Apesar da variabilidade nas formas de P todos os fertilizantes mostraram semelhante taxa de libertação e biodisponibilidade em P. A acidez do solo, favorecendo a solubilização de formas de P, em conjunto com a elevada eficiência do centeio em absorver o P, foram fatores que contribuíram para este resultado. Key words:Olsen P phosphorus fractionation phosphorus sustainability phosphorus use efficiency Palavras-chave: Olsen P fracionamento do fósforo sustentabilidade do fósforo uso eficiente do fósforo

Recycling nutrients contained in human excreta to agriculture: Pathways, processes, and products

“…These products are useful as combined soil amendments and fertilizers (Grigatti et al, 2014;Sangare et al, 2015;Kathijotes et al, 2016;Horta, 2017;Liu et al, 2018). When treatment takes place in a closed system, the product can contain N both in the form of inorganic and organic N. Treatment in open systems, however, is prone to N losses through volatilization and/or leaching.…”

Options for Improved Phosphorus Cycling and Use in Agriculture at the Field and Regional Scales

“…Several authors noted that the effect of struvite on crops is not well predicted by its chemical characteristics, especially as determined by solubility assessments or sequential fractionation (Cabeza et al, 2011; Horta, 2017; Vogel et al, 2017a; Wollmann et al, 2018). Thus, different approaches to determining the agronomic value of struvite and other sparingly soluble fertilizers are needed.…”

“…For example, as discussed above, increased STP concentration due to soluble P fertilizer application has been linked to a reduction in the colonization of crop roots by AMF. Struvite application is expected to increase water‐extractable P and STP to a lesser degree than soluble fertilizers (Horta, 2017), but may still have an impact on these labile P pools (Vogel et al, 2017a) and thus on AMF proliferation. Soil fauna including nematodes, mites, termites, and earthworms are known to influence P availability in ecosystems; thus, any indirect effects of P additions on these organisms may in turn affect P dynamics in soil and also affect plant uptake (Faucon et al, 2015; Hallama et al, 2018).…”

“…Individual studies on the fertilizer value of struvite have yielded varying results. Many studies reported similar crop response relative to soluble fertilizers (Antonini et al, 2012;Achat et al, 2014;Katanda et al, 2016;Horta, 2017;Robles-Aguilar et al, 2018) whereas others reported poorer crop response to struvite (Ackerman et al, 2013;Mehta et al, 2018). Some authors suggested than an integrated approach, combining soluble fertilizers with struvite, may improve overall crop performance by providing both readily available and slow-release P sources (Ackerman et al, 2013;Talboys et al, 2016).…”

In Vivo Toxicity and In Vitro Solubility Assessment of Pre-Treated Struvite as a Potential Alternative Phosphorus Source in Animal Feed

“…Currently, the application of struvite has only been limited to arable lands as fertilizer and reported to be non-toxic to plants [13]. Moreover, P bioavailability from struvite has shown similar performance as the chemical fertilizers in crop trials [14]. Furthermore, to our knowledge, none of the studies focused on exploring the feasibility of struvite application in animal feed as an alternative P source.…”