Struvite as a Sustainable Fertilizer in Mediterranean Soils (original) (raw)
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Agriculture
Struvite (MgNH4PO4 ∙ 6H2O) has been widely studied as an emerging recycled phosphorous fertilizer despite its low solubility. However, there are few studies on the use of this mineral as an N fertilizer. This article evaluates the use of two powder struvite-containing materials from wastewater treatment as an N fertilizer in agricultural soils. A 9-week soil incubation experiment was conducted to compare the effectiveness of this mineral as an N fertilizer in two soils with different pH values (8.2 and 6.7), using two different doses and a control soil. The use of these materials has a positive effect on soil fertility, especially in acidic soils where struvite seems to be more soluble. Thus, struvite can be a potential N fertilizer for agricultural soils and can promote circular economy opportunities for the wastewater industry, especially in acid soils (concentrations of mineral N between 453–339 mg/kg were obtained in the mixtures with acid soil, and values between 408–212 mg/kg ...
Struvite: a slow-release fertiliser for sustainable phosphorus management?
Background and aim Recycled sources of phosphorus (P), such as struvite extracted from wastewater, have potential to substitute for more soluble manufactured fertilisers and help reduce the long-term threat to food security from dwindling finite reserves of phosphate rock (PR). This study aimed to determine whether struvite could be a component of a sustainable P fertiliser management strategy for arable crops. Methods A combination of laboratory experiments, pot trials and mathematical modelling of the root system examined the P release properties of commercial fertiliser-grade struvite and patterns of P uptake from a low-P sandy soil by two different crop types, in comparison to more soluble inorganic P fertilisers (di-ammonium phosphate (DAP) and triple super phosphate (TSP)). Results Struvite had greatly enhanced solubility in the presence of organic acid anions; buckwheat, which exudes a high level of organic acids, was more effective at mobilising struvite P than the low level exuder, spring wheat. Struvite granules placed with the seed did not provide the same rate of P supply as placed DAP granules for early growth of spring wheat, but gave equivalent rates of P uptake, yield and apparent fertiliser recovery at harvest, even though only 26 % of struvite granules completely dissolved. Fertiliser mixes containing struvite and DAP applied to spring wheat have potential to provide both optimal early and late season P uptake and improve overall P use efficiency. Conclusions We conclude that the potential resource savings and potential efficiency benefits of utilising a recycled slow release fertiliser like struvite offers a more sustainable alternative to only using conventional, high solubility, PR-based fertilisers.
Possible use of struvite as an alternative phosphate fertilizer
Journal of soil science and plant nutrition
Struvite, from human urine, is an alternative phosphorus (P) fertilizer. This study evaluated P release from struvite and its effectiveness for maize in Inanda (Ia), Sepane (Se) and Cartref (Cf) soils. Phosphorus sorption isotherms were determined, an incubation study determined the release pattern of P from struvite, and a pot trial compared struvite with single superphosphate (SSP) on maize P uptake. The amount of P at equilibrium (where Q = 0) in the Cf was 1.39 mg L-1 , followed by Ia and Se with values of 0.17 and 0.13 mg L-1 , respectively. Buffer coefficients were in the order Ia > Se > Cf with values of 454, 71 and 50 mg kg-1 /mg L-1 , respectively. The extractable P in all three soils increased with time, with evidence of declining P release after Day 8. Struvite was most effective as a P source in the Cf followed by Se and Ia. Compared to SSP, there was significant improvement in maize grown on the Cf, while the reverse occurred in the Se. Maize grown in the Ia did not respond to either struvite or SSP. It was concluded that the phosphorus sorption was the main limiting factor that governed struvite effectiveness as a P source.
Assessment of Recovered Struvite as a Safe and Sustainable Phosphorous Fertilizer
Environments
Phosphorus (P) is an essential nutrient for crops. Modern agriculture is dependent on P derived from phosphate rock, which is a non-renewable resource that is becoming increasingly scarce and expensive. Therefore, it is necessary to identify alternative sources of P and develop novel technologies for its recovery. Such technologies are increasingly focused on the recovery of struvite (MgNH4PO4·6H2O) (STR) from urban wastewater. A reduction of P in effluents decreases the risk of eutrophication while allowing this mineral to be recovered and reused. Here we applied STR recovered from urban wastewater to three different soils and examined its slow-release properties. We performed a soil column leaching study and compared the results of soil treated with STR with those of soil amended with conventional phosphorous fertilizers, namely NPK, ammonium phosphate (MAP), and superphosphate (SSP). Phosphate leaching capacity followed the order MAP ~ NPK > SSP > STR in the three soils and...
Agronomy
Phosphorus (P) is an essential growth-limiting nutrient that cannot be synthetically produced. Mineral P fertilisers are typically applied to crops to sustain modern farming practice and food production. These fertilisers are generally derived from finite phosphate ore, for which there is much concern over long-term sustainability. To address these concerns, various technologies have been developed to recover P from municipal wastewater treatment plants. One product recovered from these processes is struvite, which is a precipitate formed of magnesium, ammonium, and phosphate. To analyse the fertilisation value of the recovered struvite, field trials were conducted on perennial ryegrass (Lolium perenne) over three growing seasons, analysing the dry matter yield of recovered struvite fertiliser. The trial was based on a three-crop silage system designed to mimic typical Irish agricultural practice. This research highlights that recovered struvite as a fertiliser provides additional b...
Fertilizer Potential of Struvite as Affected by Nitrogen Form in the Rhizosphere
Sustainability, 2020
Struvite is increasingly considered a promising alternative to mined phosphorus (P) fertilizer. However, its solubility is very low under neutral to alkaline pH while it increases with acidification. Here, we investigated whether supplying ammonium to stimulate rhizosphere acidification might improve struvite solubility at the vicinity of roots and, ultimately, enhance P uptake by plants. Using a RHIZOtest design, we studied changes in soil pH, P availability and P uptake by ryegrass in the rhizosphere and bulk soil supplied with either ammonium or nitrate under three P treatments: no-P, triple super phosphate and struvite. We found that supplying ammonium decreased rhizosphere pH by more than three units, which in turn increased soluble P concentrations by three times compared with nitrate treatments. However, there was no difference between P treatments, which was attributed to the increase of soluble Al concentration in the rhizosphere, which subsequently controlled P availabilit...
Horticulturae
The global rise in population highlights the need for a greater production of quality food. In this regard, intensification of the agricultural sector and an increased use of fertilizers are key. Phosphorus (P), together with nitrogen (N) and potassium (K), is one of the essential elements for plant growth. Modern agriculture is dependent on P derived from phosphate rock, which is a non-renewable resource whose high-quality reserves are becoming increasingly scarce and expensive. In this context, alternative sources of P and the development of new recovery technologies are required. Such technologies are increasingly focused on struvite (MgNH4PO4·6H2O) (STR) from urban or livestock wastewater, whose accessibility is guaranteed. In this study, the medium–long term efficiency of STR from urban wastewater as a fertilizer was evaluated in three successive lettuce crops using a 25 kg pot trial. To this end, STR application was compared with the use of other conventional P fertilizers (NP...
Plant and Soil, 2016
Aims Struvite (MgNH 4 PO 4 .6H 2 O) recovered from wastewater can be used as fertilizer. The agronomic effectiveness of struvite has mostly been evaluated using ground fertilizer mixed through soil. However, fertilizers are most commonly applied in granular form in the field. In this study, we assessed the dissolution and effectiveness of different struvites when applied in granular or powdered form. Methods Phosphorus (P) diffusion in soil, determined using a visualization technique and chemical analyses, and P uptake by 6-week old wheat was compared for soluble fertilizer (monoammonium phosphate, MAP), a commercial struvite and three synthesized struvites with different excess MgO, in both granular and ground form. Results Ground struvite mixed through soil quickly dissolved and its agronomic effectiveness was similar to that of MAP. For pure granular struvite, the granule dissolution rate ranged from circa 0.03 mg d −1 in alkaline soil to 0.43 mg d −1 in acidic soil. Excess base in the struvite fertilizer reduced its dissolution rate. The P uptake by wheat followed the order MAP > > struvite ≥ control (no P), with no significant difference between the control and the struvite treatment in alkaline soil. Conclusions Both fertilizer characteristics (particle size, excess base) and soil pH strongly affect the dissolution rate of struvite and hence its agronomic effectiveness.
Science of The Total Environment, 2021
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