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

Abstract

Struvite (St) recovered from wastewaters is a sustainable option for phosphorus (P) recovery and fertilization, whose solubility is low in water and high in environments characterized by a low pH, such as acidic soils. To broaden the use of struvite in the field, its application as granules is recommended, and thus the way of application should be optimized to control the solubility. In this study struvite slow-release fertilizers were designed by dispersing St particles (25, 50, and 75 wt%) in a biodegradable and hydrophilic matrix of thermoplastic starch (TPS). It was shown that, in citric acid solution (pH = 2), TPS promoted a steadier P-release from St compared to the pure St pattern. In a pH neutral sand, P-diffusion from St-TPS fertilizers was slower than from the positive control of triple superphosphate (TSP). Nevertheless, St-TPS featured comparable maize growth (i.e. plant height, leaf area, and biomass) and similar available P as TSP in sand after 42 days of cultivation. These results indicated that St-TPS slow P release could provide enough P for maize in sand, achieving a desirable agronomic efficiency while also reducing P runoff losses in highly permeable soils.

Struvite-phosphorus effects on greenhouse gas emissions and plant and soil response in a furrow-irrigated rice production system in eastern Arkansas

“…Measured CH 4 flux differences and similarities could have been related to the low VWC during the first half of the growing season that may have affected fertilizer solubilization (Chien et al, 2011). Low soil VWC conditions could have enhanced the activity of organic acids produced by the roots, acting as solubilizing agents for struvite that is acid soluble, suggesting the struvite could constitute a more efficient fertilizer-P source in more aerobic conditions (Moussa et al, 2006;Valle et al, 2022). A significant, positive correlation (r = 0.41) between extractable soil P and CH 4 fluxes was reported by Della Lunga et al (2021a) in a study conducted in the same furrow-irrigated rice field in 2018 and 2019.…”

Production of Nano Hydroxyapatite and Mg-Whitlockite from Biowaste-Derived products via Continuous Flow Hydrothermal Synthesis: A Step towards Circular Economy

“…Thus, non-treated wastewater does not only lead to water pollution but also contributes to the loss of potentially useful resources such as N and P. Therefore, recovering phosphorus from wastewater streams would be beneficial for waste management strategies, which could potentially be done through the precipitation of struvite (magnesium ammonium phosphate; MAP/MgNH 4 PO 4 6H 2 O) [ 67 , 69 , 71 , 73 ]. Struvite contains 39% phosphate [ 74 ] and thus has great potential for use as a natural P source [ 75 ].…”

Unveiling the Role of Polysulfide Matrices in Phosphate Diffusion for Controlled Release Fertilizers

“…Choosing a proper matrix is an important step for developing CRF, and recently, our research group has been studying polysulfides (PSs) as multifunctional candidates for dispersing P fertilizers . PSs were first demonstrated as suitable CRF vehicles for highly soluble NPK fertilizers by Mann et al Further studies proved the material is especially convenient due to its acidifying character and its role as a sulfur fertilizer, adding agronomic value to the final composite. ,− The present work aims to better understand the controlled-release mechanism of the PS matrix for struvite (ST) ,− and BR and the factors that influence this process. Hence, we studied the polymer characteristics and permeability, as well as phosphate diffusion from the composite systems.…”