Physico‐chemical characterization of humic‐metal‐phosphate complexes and their potential application to the manufacture of new types of phosphate‐based fertilizers

Abstract

The aim of this review is to describe the main physicochemical characteristics of diverse types of humic‐metal‐phosphate acid complexes. The effects of these complexes on phosphorus (P) fixation in soils with different pH values and physicochemical features and on plant phosphorus uptake are also discussed. Humic‐metal‐phosphate complexes have apparent stability constants in the same range as those of metal‐humic complexes, in solutions with diverse pH and ionic‐strength values. Likewise, the molecular‐size distribution of humic‐metal‐phosphate complexes as a function of pH is similar to that of potassium or sodium humates and metal‐humic complexes. Humic‐metal‐phosphate complexes are able to decrease phosphate fixation in soils and increase plant growth and phosphate uptake. Phosphorus fertilizers containing humic‐metal‐phosphate complexes proved to be efficient to improve plant growth and P uptake with respect to conventional fertilizers such as single superphosphate. The values of parameters related to plant phosphorus‐utilization efficiency (PUt E) suggest that the regulation of root acquisition of phosphate from these complexes could involve the interregulation of a system for the optimization of metabolic P utilization in the shoot and another system involving stress responses of roots under phosphorus deficiency.

Internal phosphorus loading in Canadian fresh waters: a critical review and data analysis

“…Several recent studies have characterised synthetically produced organic matter -metalphosphate complexes (Kizewski et al 2010;Erro et al 2012) and structurally similar arsenate complexes (Mikutta and Kretzschmar 2011). Interest in such ternary complexes, dubbed "super-phosphates", has been shown from agricultural chemists (e.g., Erro et al 2012;Urrutia et al 2014). The conditions under which humic-metalphosphate complexes dissociate to orthophosphate are not well defined but include ultraviolet radiation and pH decreases (Gerke and Hermann 1992;Jones et al 1993;Hens and Merckx 2001) (Fig.…”

Incorporation of humic-derived active molecules into compound NPK granulated fertilizers: main technical difficulties and potential solutions

“…This fact suggested that RCF were able to trigger the regulation pathways involved in shoot P needs-root P uptake crosstalk (Fig. 10) [50]. As P uptake from RCF implies additional energy, plants tend to optimize P usage in shoots and minimize P uptake in roots [50].…”

“…10) [50]. As P uptake from RCF implies additional energy, plants tend to optimize P usage in shoots and minimize P uptake in roots [50].…”

“…P in RCF is poorly soluble but sensitive to the root exudation associated with root responses to P-limiting conditions, while in CSP is water soluble and the role of root exudates is probably different in some way (improvements in P shoot use efficiency were also observed for CSP) [50].…”

Influência do silício sobre a difusão do fósforo no solo e na eficiência agronômica de fertilizantes fosfatados granulados

“…O autor atribuiu este resultado à possível maior energia dispensada pela planta para absorver o nutriente, justificando em partes o menor ganho de massa vegetal. Pois segundo Urrutia et al (2014) os processos para descomplexação do P do fertilizante envolvem gasto de energia, levando a planta, através de respostas metabólicas a maximizar o aproveitamento do P absorvido, oque pode ainda ocasionar um menor acúmulo de matéria seca das plantas.…”