Superphosphate Research Articles

Phosphate solubilizing bacteria, Pseudomonas aeruginosa, improve the growth and yield of groundnut (Arachis hypogaea L.).

For agricultural safety and sustainability, instead of synthetic fertilizers the eco-friendly and inexpensive biological applications include members of plant-growth-promoting rhizobacteria (PGPR) genera, Pseudomonas spp. will be an excellent alternative option to bioinoculants as they do not threaten the soil biota. The effect of phosphate solubilizing bacteria (PSB) Pseudomonas aeruginosa (MK 764942.1) on groundnuts' growth and yield parameters was studied under field conditions. The strain was combined with a single super phosphate and tested in different combinations for yield improvement. Integration of bacterial strain with P fertilizer gave significantly higher pod yield ranging from 7.36 to 13.18% compared to plots where sole inorganic fertilizers were applied. Similarly, the combined application of PSB and inorganic P fertilizer significantly influenced plant height and number of branches compared to sole. However, a higher influence of phosphorous application (both PSB and P fertilizer) observed both nodule dry weight and number of nodules. Combined with single super phosphate (100% P) topped in providing better yield attributing characters (pod yield, haulm yield, biomass yield, 1000 kernel weight, and shelling percentage) in groundnut. Higher oil content was also recorded with plants treated with Pseudomonas aeruginosa combined with single super phosphate (SSP) (100% P). Nutrients like nitrogen (N), phosphorous (P), and potassium (K) concentrations were positively influenced in shoot and kernel by combined application. In contrast, Ca, Mg, and S were found to be least influenced by variations of Phosphorous. Plants treated with Pseudomonas aeruginosa and lower doses of SSP (75% P) recorded higher shoot and kernel P. We found that co-inoculation with PSB and SSP could be an auspicious substitute for utilizing P fertilizer in enhancing yield and protecting nutrient concentrations in groundnut cultivation. Therefore, PSB can be a good substitute for bio-fertilizers to promote agricultural sustainability.

ZIF-8 metal organic framework, carboxymethylcellulose and polyvinyl alcohol bio-nanocomposite controlled-release phosphorus fertilizer: Improved P management and tomato growth

This study is concerned with the synthesis, characterization, and application of bio-nanocomposite films using a mixture of carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) integrated with zeolitic imidazolate type 8 (ZIF-8) nanoparticles (NPs). The advanced bio-nanocomposites were employed as a coating for triple superphosphate (TSP) fertilizers, and their impact on tomato plant growth was evaluated. The successful integration of ZIF-8 into the composite matrix was determined by distinct changes in Fourier transform infrared (FTIR) spectra, indicating significant structural modifications. Morphological analyses by scanning electron microscopy (SEM) revealed alterations in the surface characteristics of the CMC/PVA films. Furthermore, energy dispersive X-ray (EDX) analysis confirmed the elemental composition of the resulting nanocomposite. The precision-coated TSP fertilizers exhibited a notable enhancement in mechanical strength, as evidenced by their superior resistance to crushing. The coated TSP also exhibited a controlled release of phosphorus over time, prolonging the release of phosphorus for up to 9 days in water and 50 days in soil. In soil, the 0.5 % ZIF-8 NP coating delayed the release of phosphorus, with only 12.29 ± 2.75 % released after five days compared to 96.96 ± 2.03 % for uncoated TSP. The application of coated TSP fertilizers to tomato plants (of the MARIA variety) resulted in a 13.79 % increase in leaf number and a 15.83 % increase in plant height compared to uncoated TSP. This research underscores the pivotal role of advanced coating fertilizers in fostering sustainable and efficient agricultural practices, thereby making a substantial contribution to the advancement of innovative agrochemical solutions.

Synergistic effects of microbial inoculation, different forms of iron application, and phosphorus on wheat growth and nutrient uptake in alkaline soil

Iron and phosphorus deficiencies in alkaline soils threaten wheat by limiting nutrient availability due to their antagonistic relationship. This study tested if combining microbial incubation with foliar iron could synergistically improve wheat productivity and nutrition and mitigate deficiencies. A field experiment using a split plot design tested different iron and phosphate fertilization techniques. The main plots consisted of three iron application methods: foliar-applied iron (FL) at 2.5 kg ha−1, soil-applied iron (FS) at 5 kg ha−1, and no iron (F0). The subplots comprised four phosphate fertilizers: PSB + TSP (inoculation with phosphate-solubilizing bacteria + 100 kg ha−1 of triple superphosphate fertilizer), AMF + TSP (inoculation with arbuscular mycorrhizal fungi + triple superphosphate), TSP alone, and no phosphorus (P0). Foliar iron application with AMF + TSP increased seed potassium and root length density by 16.3-17.9% and 22.1-25.8% more than PSB + TSP, respectively. Under FS conditions, AMF + TSP exhibited 28.5-29.1% lower magnesium and 23.9-28.4% higher zinc seed concentrations compared to PSB + TSP, as well as higher levels of soluble proteins and lower concentrations of chlorophyll. There was no difference in grain yield between PSB + TSP and AMF + TSP for any of the iron treatments. Combining AMF + TSP and foliar iron application resulted in the highest grain yield, desirable seed nutrient content (particularly zinc, iron (>100 mg kg−1), and magnesium (>18 mg kg−1), improved root biomass, chlorophyll, and soluble proteins compared to PSB + TSP and TSP alone. This combination of microbial inoculation with foliar iron application is an effective strategy for mitigating the antagonism between iron and phosphorus and improving both crop productivity and nutrition.

Study and mechanism of formation of phosphorus production waste in Kazakhstan

Abstract This article contains information about the accumulated industrial waste from phosphorus production and methods for its recycling and disposal to produce marketable products. Monitoring of cottrel dust’s impact on the environment, namely, ground and surface water, soil, and atmosphere was carried out. The mechanism of formation of cottrel dust was studied. The dispersed, chemical, and phase compositions of the dust in furnace gases during the electrothermal smelting of phosphorites were determined. The sequence of chemical reactions during the formation of cottrel dust was elucidated. The ratios of initial components entering the chemical reaction and the thermodynamic parameters (Gibbs energy) were determined using the Chemistry HSC-6 software package. IR spectral and elemental analyses were carried out for determining cottrel dust’s functional groups and elemental composition. Based on modern instrumental studies, it was found that the total content of phosphorus(v) oxide in cottrel dust was 30.7%. This content of phosphorus(v) oxide is sufficient to use cottrel dust as an initial raw material for producing phosphorus-containing fertilizers. This method was proposed for processing cottrel dust to produce monocalcium phosphate on a production scale. The chemical composition of the resulting monocalcium phosphate was determined and confirmed by analytical methods. The proposed technology for producing monocalcium phosphate from cottrel dust is recommended for use in the agro-industrial complex.

Fertilization efficiency of thirty marketed and experimental recycled phosphorus fertilizers

Recycling phosphorus (P) from waste streams like sewage sludge, animal manures or food industry by-products is required to sustain soil fertility without depleting non-renewable P resources. Several technologies are available for P recovery, leading to fertilizers differing in P solubility and bioavailability. In this study, thirty fertilizers obtained through different technologies were tested to assess if their fertilization efficiency was equivalent to mineral soluble fertilizer applied as triple superphosphate (TSP). The main selection criteria were (1) ensuring a wide chemical diversity, and (2) choosing products already on the market or at a late stage of development, to encompass a representative selection of current and future recycled fertilizers. The products were classified according to their organic carbon content and neutral ammonium citrate (NAC), and the main P species of each fertilizer was determined through K-edge and L2,3-edge X-ray absorption near edge structure spectroscopy (XANES). Three pot experiments with wheat, barley and ryegrass were conducted in three growing substrates with contrasting properties, all within a pH range of 5.8–6.9. Fertilizers containing ammonium magnesium phosphate, monoammonium phosphate, monocalcium phosphate, and dicalcium phosphate type species as dominant P species showed a similar fertilization efficiency to TSP, while fertilizers with hydroxyapatite, tricalcium phosphate, phytic acid or iron phosphates as their main P species had lower fertilization efficiencies. We conclude that while the trend towards high-efficiency, refined inorganic recycled P fertilizers is positive, lower-performing, mostly unrefined fertilizers must be assessed in light of their long-term P supply potential and additional benefits to soil health owing to their content of organic matter and other nutrients.

Impacts of phosphorus amendments on legacy soil contamination from lead-based paint on a California, USA university campus

Lead (Pb) is one of the most common heavy metal urban soil contaminants with well-known toxicity to humans. This incubation study (2–159 d) compared the ability of bone meal (BM), potassium hydrogen phosphate (KP), and triple superphosphate (TSP), at phosphorus:lead (P:Pb) molar ratios of 7.5:1, 15:1, and 22.5:1, to reduce bioaccessible Pb in soil contaminated by Pb-based paint relative to control soil to which no P amendment was added. Soil pH and Mehlich 3 bioaccessible Pb and P were measured as a function of incubation time and amount and type of P amendment. XAS assessed Pb speciation after 30 and 159 d of incubation. The greatest reductions in bioaccessible Pb at 159 d were measured for TSP at the 7.5:1 and 15:1 P:Pb molar ratios. The 7.5:1 KP treatment was the only other treatment with significant reductions in bioaccessible Pb compared to the control soil. It is unclear why greater reductions of bioaccessible Pb occurred with lower P additions, but it strongly suggests that the amount of P added was not a controlling factor in reducing bioaccessible Pb. This was further supported because Pb-phosphates were not detected in any samples using XAS. The most notable difference in the effect of TSP versus other amendments was the reduction in pH. However, the relationship between increasing TSP additions, resulting in decreasing pH and decreasing Pb bioaccessibility was not consistent. The 22.5:1 P:Pb TSP treatment had the lowest pH but did not significantly reduce bioaccessible Pb compared to the control soil. The 7.5:1 and 15:1 P:Pb TSP treatments significantly reduced bioaccessible Pb relative to the control and had significantly higher pH than the 22.5:1 P:Pb treatment. Clearly, impacts of P additions and soil pH on Pb bioaccessibility require further investigation to decipher mechanisms governing Pb speciation in Pb-based paint contaminated soils.

Influence of Current Duty Cycle and Voltage of Micro-Arc Oxidation on the Microstructure and Composition of Calcium Phosphate Coating

The micro-arc oxidation (MAO) technique was employed to produce calcium phosphate coatings on titanium surfaces using an electrolyte composed of hydroxyapatite and calcium carbonate in an aqueous solution of orthophosphoric acid. The coatings’ morphology and composition were regulated by adjusting electrical parameters, specifically the duty cycle and voltage. This study examined the effects of the duty cycle and voltage during the MAO process on the microstructure and composition of calcium phosphate coatings on VT1–0 titanium substrates. Scanning electron microscopy (SEM) was utilized to analyze the microstructure and thickness of the coatings, while X-ray diffraction (XRD) was employed to determine their phase composition. The findings reveal that the surface morphology of the calcium phosphate coatings transitions from a porous, sponge-like structure to flower-like formations as the duty cycle and voltage increase. A linear increase in the voltage within the applied duty cycles led to a rise in the size of the forming particles of amorphous/crystalline structures containing phases of monetite (CaPO3(OH)), monocalcium phosphate monohydrate (Ca(H2PO4)2·H2O), and calcium pyrophosphate (γ–Ca2P2O7).

Study on synergistic and antagonistic interactions of P and Zn fertilization on sweet pepper

The present study was carried out to investigate the synergistic and antagonistic interactions of combined application of Phosphorus and Zinc fertilizers on sweet pepper in net house conditions. Pot experiment consists of thirteen treatments combinations set up in a completely randomized design. The treatment combinations comprising of four levels of phosphorus (0, 237.5, 355.5 and 475 kg Single Super Phosphate ha−1) and three levels of Zn (5, 7.5 and 10 kg Zinc Sulfate ha−1) including one control (100% NPK). The available macro and micronutrients content in potting mixture was confirmed in medium range before conducting the experiment. The results clearly demonstrate the treatment comprising 475 kg SSP ha−1 with 10 kg ZnSO4 ha−1 (T13) showed synergistic effects on vegetative characteristics, above and below ground nutrient content as well as nutrient uptake. When balanced phosphatic and zinc fertilizers (T13) are applied to soil, there is a low possibility of an antagonistic reaction. Antagonism problems arise most frequently when the soil’s Zn content is extremely low in combination with excess application of P fertilizer limiting their availability to plants. To avoid P-Zn antagonism in the soil system, utilization of appropriate fertilizer methods, supplies, and rates was done. As a result, the present study confirms that recommended fertilizer doses combined with phosphorus @ 475 kg SSP ha−1 and zinc @ 10 kg ZnSO4 ha−1, is the best nutrient combination for improving plant growth parameters; however, in terms of soil parameters, P and Zn fertilizers affected micronutrient content in soil, which further interacted antagonistically.

A new phosphorus fertilizer blend enhances grain legume yield and profitability in northern part of Ghana

Low concentrations of phosphorus limit grain legumes’ yield in the northern part of Ghana. Smallholder farmers could benefit from P-fertilizer blends to improve yield. This study evaluated the responses of soybean, cowpea and groundnut to P-fertilizer blends and their profitability in researcher-managed and farmer-managed trials in Northern, Upper West, and Upper East regions. The experiment was set up in a cross-factorial arranged in randomized complete block design with four replications. The treatments were two types of P-fertilizer blends (triple superphosphate and new yaraLegume applied at 30 kg P ha−1), a control and three varieties each of soybean (TGX 1835-10E, TGX 1789-8E and TGX 1834-5E), cowpea (Padituya, Wang-Kae and Kirkhouse), and groundnut (Samnut 23, Samnut 22 and Yenyawwaso). P-fertilizer blends increased grain yield of grain legumes in researcher-managed trials. In the researcher-managed trials, P-fertilizer blends doubled the nodulation of soybean varieties but did not influence the nodulation of cowpea and groundnut. P-fertilizer blends increased P-agronomic efficiency over control; however, the different P-fertilizer blends had similar P-use efficiencies. In farmer-managed trials, only the yield of groundnuts varied with the different P-fertilizer blends in the Upper West region, suggesting that P utilization may be location-specific for groundnuts. P-fertilizer blends increased the grain yield of soybean and cowpea varieties in the Northern and Upper West regions but not the Upper East region. The interaction between soybean and cowpea varieties and P-fertilizer blends was not significant. P-fertilizer blends recorded a higher value cost ratios (VCRs) that can offset uncertainties in price fluctuations. The high VCRs indicated that P-fertilizer blends were profitable and could be used to improve the livelihoods of smallholder grain legume farmers. The study demonstrated that grain legumes responded to P-fertilizer blends and are profitable. However, the non-responsive nature of the Upper East soils needs to be investigated to make P-fertilizer blends profitable in the region.

Soil profile distribution of nutrients in contrasting soils amended with struvite and other conventional phosphorus fertilizers

AbstractPhosphorus (P) can be recovered from wastewater and used as an alternative fertilizer, namely, struvite [MgNH4PO4·6(H2O)]. However, the soil mobility of wastewater‐derived P and other nutrients needs to be evaluated. The objective of this study was to compare the vertical distribution of water‐soluble (WS) soil P and other nutrients from a synthetic‐wastewater‐derived electrochemically precipitated struvite (ECST) to that from a chemically precipitated struvite (CPST), triple superphosphate (TSP), monoammonium phosphate (MAP), and a control in six soils from Arkansas (AR; loam [L] and silt loam [SiL]), Missouri (MO; SiL 1 and SiL 2), and Nebraska (NE; sandy loam [SL] and SiL). A column‐leaching experiment was conducted with the six soils and five fertilizer‐P treatments. Water‐soluble (WS) P from the two struvite materials generally did not differ (p > 0.05) and was similar to that of MAP in the depths of 0–3, 3–6, and 6–10 cm, but was greater than that of TSP in the top 6 cm in four of the six soils. WS P from CPST in the MO‐SiL 2 and NE‐SL soils (6.6 and 12.7 mg kg−1, respectively) was larger than that from ECST, MAP, and TSP. In the AR‐L and MO‐SiL 1 soils, TSP was the only fertilizer‐P source that had increased WS P concentrations in the top 6 cm relative to the other fertilizer‐P sources. Results showed that ECST‐derived, WS P had similar soil profile distributions in the top 10 cm, suggesting that ECST will be equally protective of environmental health and leachate quality across multiple soil textures as other common fertilizer‐P sources.

Novel artificial tricalcium phosphate and magnesium composite graft facilitates angiogenesis in bone healing

BackgroundBone grafting is the standard treatment for critical bone defects, but autologous grafts have limitations like donor site morbidity and limited availability, while commercial artificial grafts may have poor integration with surrounding bone tissue, leading to delayed healing. Magnesium deficiency negatively impacts angiogenesis and bone repair. Therefore, incorporating magnesium into a synthetic biomaterial could provide an excellent bone substitute. This study aims to evaluate the morphological, mechanical, and biological properties of a calcium phosphate cement (CPC) sponge composed of tetracalcium phosphate (TTCP) and monocalcium phosphate monohydrate (MCPM), which could serve as an excellent bone substitute by incorporating magnesium. MethodsThis study aims to develop biomedical materials composed mainly of TTCP and MCPM powder, magnesium powder, and collagen. The materials were prepared using a wet-stirred mill and freeze-dryer methods. The particle size, composition, and microstructure of the materials were investigated. Finally, the biological properties of these materials, including 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay for biocompatibility, effects on bone cell differentiation by alkaline phosphatase (ALP) activity assay and tartrate-resistant acid phosphatase (TRAP) activity assay, and endothelial cell tube formation assay for angiogenesis, were evaluated as well. ResultsThe data showed that the sub-micron CPC powder, composed of TTCP/MCPM in a 3.5:1 ratio, had a setting time shorter than 15 minutes and a compressive strength of 4.39±0.96 MPa. This reveals that the sub-micron CPC powder had an adequate setting time and mechanical strength. We found that the sub-micron CPC sponge containing magnesium had better biocompatibility, including increased proliferation and osteogenic induction effects without cytotoxicity. The CPC sponge containing magnesium also promoted angiogenesis. ConclusionIn summary, we introduced a novel CPC sponge, which had a similar property to human bone promoted the biological functions of bone cells, and could serve as a promising material used in bone regeneration for critical bone defects.

Preparation of Injectable Dicalcium Phosphate Bone Cement for Potential Orthopedic Applications

Various natural wastes can be promising for mining more valuable compounds if some specialized extraction techniques are adopted. Hydroxyapatite (HA) is a significant biomaterial that can be extracted from waste bovine bones by heating them at 700 °C and 900 °C. Based on this idea, we made a novel dicalcium phosphate (DCP) bone cement (BC) by extracting HA via the reaction with monocalcium phosphate monohydrate (MCPM) and trisodium citrate. The setting time, injectability, and compressive strength (CS) of this DCPBC were examined using various analytical techniques, such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) attached with energy-dispersive X-ray (EDX) spectroscopy, and Fourier-transformed infrared spectroscopy (FTIR). The phase composition, surface morphology, and chemical compositions of HA and DCP were evaluated. A Gillmore needle apparatus was used to measure the initial and final setting times of the specimens. The CS values of the prepared specimens were determined using INSTRON Series IX. The in vitro dissolution behavior of all samples was evaluated by immersing them in simulated body fluid (SBF) over 7 days at 37 °C. The final setting times of samples 3, 4, and 5 were 20, 24, and 18 min, respectively. In addition, the CS value of sample 1 before immersion in SBF was much lower (1.23 MPa) compared to sample 5 (21.79 MPa) after 7 days of immersion. The CS of the DCP after 3 days of immersion was increased to 33.75 MPa. The in vitro results for the dissolution and bioactivity of HA showed the highest degradation rate after 1 day of immersion and then decreased with the increase in the immersion duration. The HA layer thickness was considerably improved with longer incubation times. The proposed injectable DCP bone cement may have potential in future orthopedic applications.

Effect of triple superphosphate fertilizer and spraying with licorice root extract In the growth and production of tomato Lycopersicon esculentum Mill

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PFAS fate using lysimeters during degraded soil reclamation using biosolids.

Carbon- and nutrient-rich biosolids are used in agriculture and land reclamation. However, per- and polyfluoroalkyl substances (PFAS) typically present in biosolids raise concerns of PFAS leaching to groundwater and plant uptake. Here, we investigated PFAS persistence and leaching from biosolids applied to a site constructed artificially to mimic degraded soils. Treatments included biosolids and biosolids blended with mulch applied at different rates to attain either one and five times the agronomic N rate for vegetable crops and a control treatment with synthetic urea and triple superphosphate fertilizer. Leachates were collected for a 2-year period from 15-cm depth zero-tension drainage lysimeters. Soils were analyzed post biosolids application. PFAS were quantified using isotope-dilution, solid-phase extraction and liquid chromatography tandem mass spectrometry. Leachate profiles exemplified an initial high total PFAS concentration, followed by a sharp decline and subsequent small fluctuations attributed to pre-existing soil conditions and rainfall patterns. Quantifiable PFAS in leachate were proportional to biosolids application rates. Short-chain perfluoroalkyl acids (CF2<6) were dominant in leachate, while the percentage of longer chains homologues was higher in soils. A 43% biosolids blend with mulch resulted in 21% lower PFAS leachate concentrations even with the blend application rate being 1.5 times higher than biosolids due to the blend's lower N-content. The blending effect was more pronounced for long-chain perfluoroalkyl sulfonic acids that have a greater retention by soils and the air-water interface. Biosolids blending as a pragmatic strategy for reducing PFAS leachate concentrations may aid in the sustainable beneficial reuse of biosolids.

Rock Phosphate and Biochar Effects on Greenhouse Gas Emissions and Soil Fertility in Southern Alberta Potato Field

The application of biochar soil amendment and rock phosphate fertilizer to the soil could lead to achieving net zero emissions and food security; however, the effectiveness of using biochar and rock phosphate in southern Alberta brown chernozemic soil is not yet assessed. In the first trial of this study, varying levels of urea (N), with varying levels of biochar (B) were applied. The same level of rock phosphate (RP) and triple super phosphate (TSP) were applied to compare efficiency of the two fertilizers. The second trial involved applying the same nutrients, but with higher levels than the first trial. The results indicated that the fertilizer application rates did not affect the growth and yield of potatoes because of the application rates of the fertilizer and fertility status of the soil, whereas in the second trial, TSP and RP treatments had the same growth and yield. Furthermore, the high application rate of nitrogen fertilizer and RP with or without biochar in the potato plot emitted high nitrous oxide gas emissions while the low application rate of nitrogen fertilizer and RP kept the carbon dioxide in the soil. Nevertheless, in the second experiment, the application of biochar and rock phosphate reduced nitrous oxide and carbon dioxide emissions. We observed high residual nitrogen and manganese nutrients after harvest in the plot treated to rock phosphate and biochar. Therefore, rock phosphate and biochar have the potential to increase food production and mitigate climate change.

Influence of mixing uniformity between stabilisation materials and contaminated soil on the stabilisation efficiency of heavy metals

This study investigates the impact of degree of mixing of stabilisation materials and soil under physical mixing on the efficiency of stabilisation remediation. Experiments were designed in terms of the type of stabilisation material, dosage of agent and the number of physical mixing times. Monocalcium phosphate (abbr. MCP), which represents chemical precipitation, and Zeolite, which is physically adsorbed, were used to stabilise and remediate industrial Cd-contaminated soils, and A measurement method for the degree of mixing based on the bivariate coefficient of variation (BCV) was constructed to analyse the influence of mixing uniformity on stabilisation efficiency. The results indicated that (1) comparing the rate of change of BCV (coefficient b), zeolite (0.19–0.31) was larger than MCP (0.07–0.14). (2) At the same dosage, the amount of mixing required to achieve 100% mixing uniformity between MCP and contaminated soil was lower than that required with zeolite. (3) Incubation treatment could increase the stabilisation efficiency of MCP by over five times, but could not significantly improve the stabilisation efficiency of zeolite. After a comprehensive consideration of the restoration cost, the suitable number of times the two types of stabilisation materials should be mixed was determined to be limited to two times. This experiment is not enough for the study of the specific principle of action, the next step should be from the stabilisation materials and mechanisms, soil properties, and further discuss the effect of the mixing uniformity of materials and soil on the stabilisation of the restoration.

Recycled Iron Phosphates: A New Phosphorus Fertilizer for Paddy Rice.

The potential of recycled iron phosphates (FePs), e.g., vivianites (Fe3(PO4)2·8H2O) and Fe(III)-rich phosphorus (P) adsorbent materials, as phosphorus fertilizer is limited by the strong interaction between Fe and P. In this study, the efficiency of FePs as P fertilizer was explored by applying them as granules or powder in flooded strongly P-fixing soils (acid and calcareous), thereby taking advantage of increased P release induced by reductive dissolution of P-bearing Fe(III) minerals. First, no P diffusion from granular FeP fertilizers into flooded soils was detectable by the diffusive gradient in thin films (DGT) technique and microfocused X-ray fluorescence (μ-XRF) analysis of thin soil sections, in contrast to detectable P diffusion away from granules of soluble triple superphosphate (TSP) fertilizer. On the contrary, powdered FePs demonstrated an excellent increase in extractable P (1 mM CaCl2) in a 120-day incubation experiment in flooded soils. Second, a pot experiment was performed with rice (Oryza sativa) grown in flooded acid and calcareous soils. The fertilizer value of FePs was remarkable when dosed as powder, as it was even up to 3-fold higher than TSP in the acid soil and similar to TSP in the calcareous soil. The beneficial effect of FeP over TSP in the acid soil is attributed to the slow release of P from FePs, which allows to partly overcome P fixation. The promising results of FePs as P fertilizer applied as powders in flooded soils debunk the generally accepted idea that FePs are poor sources of P while demonstrating the importance of the timing of FeP fertilizer application.

258 Nutritional strategies allowing inorganic phosphates reduction in maintaining maximum growth performance and bone mineralization in piglets

Abstract Phosphorus (P) is an essential component for optimal maintenance of growth and bone mineralization but its inclusion in animal feed is a core concern for economic and environmental concerns in ensuring sustainability of this resource. This study aimed to test impacts of different nutritional strategies such as dietary calcium (Ca) reduction and phytase superdosing for piglets fed without inorganic phosphate. A total of 147 piglets Piétrain*(Large White*Landrace) were divided among 5 experimental diets. Three levels of digestible P were tested (0.21%, 0.27%, 0.33%) by adding monocalcium phosphate (MCP) from 1) a negative control diet (NC) without MCP, 2) a diet with 0.3 % MCP (NC+0.3 % MCP), or 3) a diet with 0.6 % MCP (NC+0.6 % MCP). Those three diets contained 250 FTU/kg of phytase and a minimum amount of phytate set at 0.27%. All dietary treatments were formulated following a constant Ca:digestible P ratio at 2.1. The other two diets were formulated with two phytase’ doses added on top of the NC diet 4) 2,000 FTU/kg (NC+2000 phy) or 5) 3,000 FTU/kg (NC+3000 phy). Piglets were weighed individually at 42, 55 and 69 d of age, and feed intake per phase was recorded per pen. Average daily gain (ADG), daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated. At the end of the experiment, right metacarpal was removed from 12 animals per treatment to analyze bone mineralization. Data were submitted to an ANOVA including effects of dietary treatments and body weight at start of the trial using JMP 16.2.0. Differences among means were separated by a Student’s test and significance accepted at P &amp;lt; 0.05. Liveability % was not different between treatments. The reduction of Ca and digestible P in NC did not affect growth performance (P &amp;gt; 0.05) but reduced bone ash % compared with PC (P &amp;lt; 0.05, 30.4 % vs 34.6 %, respectively). Phytase supplementation at 2,000 and 3,000 FTU/kg improved body weight gain (28.8 kg for animals fed NC vs 30.0 kg for NC+2000 phy vs 30.2k g for NC+3000 phy, P &amp;lt; 0.05), feed efficiency (1.60 vs 1.50 for NC and NC + 3000 phy, respectively; P &amp;lt; 0.05) and bone mineralization (P &amp;lt; 0.05). This experiment confirms the benefit of reducing the Ca and concomitantly P levels in piglet feed without impairing growth performance by optimal use of phytase that also provides the ability to overcome dependence on inorganic phosphates.

70 Determination of phosphorus release of Microtech phytase in nursery pig diets

Abstract A total of 320 barrows (DNA 241 × 600; initially 10.7 ± 0.21 kg) were used in a 21-d growth trial to determine the available P (aP) release curve for Microtech phytase (Guangdong VTR Bio-Tech Co, Ltd. Zhuhai, Guangdong, China). At approximately 21 d of age, pigs were weaned and randomly allocated to pens and fed a common diet for 18 d and then fed a P depletion diet (0.11% aP) for 3 d. On d 21 post-weaning, considered d 0 of the study, pigs were blocked by average pen body weight (BW) and randomly allotted to 1 of 8 dietary treatments with 5 pigs per pen and 8 pens per treatment. Dietary treatments were derived from a single basal diet and ingredients including phytase, monocalcium P, limestone, and sand were added to create the treatment diets. Treatments include 3 diets with increasing aP (0.11, 0.19 and 0.27%) using monocalcium phosphate that were used to develop the standard curve and 5 diets with 0.11% aP and increasing phytase (250, 500, 1,000, 1,500 and 2,000 FTU/kg) that were used to develop the aP release curve. Pigs were weighed weekly and feed disappearance was recorded per pen for the calculation of average daily gain (ADG), average daily feed intake (ADFI) and gain to feed ratio (G:F). At the conclusion of the experiment, 1 pig, closest to the mean weight of each pen, was euthanized for bone analysis. The right fibula, rib, and metacarpal were collected for the determination of bone density, bone ash weight, and bone ash percentage. Pigs fed diets with increasing aP from inorganic P had improved (quadratic, P ≤ 0.05) final BW, ADG, and G:F (Table). Pigs fed diets with increasing phytase had linearly increased (P &amp;lt; 0.01) final BW and ADFI and quadratically increased (P ≤ 0.04) ADG and G:F. Bone density, bone ash weight, and bone ash percentage increased linearly (P &amp;lt; 0.01) with increasing aP from inorganic P and increasing phytase. Results were used to determine release values for Microtech phytase for each response criteria as shown in the table. The aP release quadratically increased (P ≤ 0.02) with increasing phytase when growth performance was used as response criteria and linearly increased (P &amp;lt; 0.01) when bone characteristics were used as response criteria. The available P release curve developed for Microtech phytase for percentage bone ash using combined data generated from all three bones is: aP = (0.868 × FTU/kg) ÷ (9,599.511 + FTU/kg).

Apparent total tract digestibility of calcium and phosphorus from partially defatted Hermetia illucens larvae meal in pigs

Abstract Insect meals, which have emerged as a sustainable protein source in animal nutrition, are also rich in calcium and phosphorus and thus might be a valuable source for supplying these minerals in farm animals. The aim of the present study was to determine the apparent total tract digestibility (ATTD) of these minerals from commercially available partially defatted meals of Hermetia illucens (HI) larvae in growing pigs. According to a difference approach, twenty male growing pigs with an average body weight of around 30 kg were divided into five groups of four pigs each and fed either a basal diet or the basal diet blended with one of three HI meals or monocalcium phosphate (MCP, as a positive control) for 14 days. Calcium and phosphorus ATTD were determined, by using the indicator method with acid-insoluble ash as an indigestible marker. Calcium ATTD on average of the three HI meals was 71.2%, ranging from 60.7% to 77.0%, and the ATTD of phosphorus was 80.6%, with a range of 70.8% to 88.9%. Calcium and phosphorus ATTD of MCP were 95.0% and 82.8%, respectively. The study shows that calcium and phosphorus from HI meals exhibit a relatively high ATTD in pigs, similar to that observed from inorganic mineral sources. Thus, HI meal could substantially contribute to the supply of calcium and phosphorus to pigs, thus opening the possibility to conserve scarce minerals resources such as phosphate-rich rocks for pig nutrition.