Solubility and Efficiency of Rock Phosphate Fertilizers Partially Acidulated with Zeolite and Pillared Clay as Additives

Abstract

<jats:p>Soluble phosphates are the most common sources currently used in crop production in tropical soils; however, they present low efficiency and are more expensive than natural rock phosphates. The objective was to develop new phosphate fertilizers with slow solubility through the partial acidification of rock phosphates (RPs), incorporating materials with adsorption characteristics to favor slow dissolution and prevent phosphorus (P) fixation in the soil. Three rock phosphates, Araxá (ARP), Bayovar (BRP) and Morocco (MRP), were evaluated at two acidulation levels (25 and 50% Ac.) and two additives; pillared clays (PILC) and zeolites (Zeo), plus triple superphosphate (TSP) and a control (nil-P). The soil diffusion was evaluated in concentric rings in Petri dishes. Solubility was evaluated in leaching columns and sampled in layers from surface for P forms in the soil profile. The relative agronomic efficiency (RAE) was evaluated in maize. Greater diffusion was provided by TSP, followed by BRP and MRP both with 50% Ac. + Zeo, and MRP with 50% Ac. + PILC. Percolated P was more pronounced under TSP, followed by RPs (BRP and MRP) with 50% Ac. + Zeo. BRP and MRP + 50% Ac. were the most promising sources with RAE above 74% compared to TSP.</jats:p>

Struvite-based composites for slow-release fertilization: a case study in sand

“…As an acidified and highly soluble phosphate source, TSP probably achieved complete dissolution within 8 days, after which the P zone radius stabilized. Despite phosphate’s tendency to retrograde to P-Ca precipitates, the result suggests this effect was minimum 40 . The sand’s high permeability and low sorption capacity allowed a high P mobility to P-unsaturated zones.…”

A Circular Economy Model to Improve Phosphate Rock Fertiliser Using Agro-Food By-Products

“…On the other hand, PR lost about 24% of its initial total phosphorus over 30 days, thus suggesting a good performance of all the mixtures in increasing the solubility of phosphate rock. Relatedly, several studies have documented the adoption of different strategies or practices for increasing phosphate rock solubility, such as the addition of zeolite and pillared clay [31], nanoparticles [32], a combination with acid mine waste [29], co-composting [22], a combination with green waste [23], co-application with manure [24] or other amendments [25], and enrichment with microorganisms [27,28]. The effects of all these strategies were directly or indirectly ascribable to acidifying effects.…”

“…In this context, numerous co-application techniques have been proposed in the literature, such as the addition of biomasses [22][23][24][25], microorganisms [26][27][28], and inorganic substances to agricultural soils [29][30][31][32]. However, many of the proposed solutions are complex and expensive, limiting their practical application at the field level.…”

Improving the quality of media and Robusta coffee seedlings with mycorrhizal (AMF) and rock phosphate

“…Therefore, increasing the efficiency of P fertilization can be done by the application of rock phosphate. Rock phosphate has several advantages, including its slow release so that the residue can be used for the next growing season and contains Ca, Mg, and micronutrients making it suitable for acid soils [12] [13]. However, the problem is that this fertilizer contains lower levels of nutrients and relatively slower levels of solubility available [14].…”