Effects Of Phosphorus Addition Research Articles

Effect of phosphorus addition on the reductive transformation of pentachlorophenol (PCP) and iron reduction with microorganism involvement.

The transformation of phosphorus added to the soil environment has been proven to be influenced by the Fe biochemical process, which thereby may affect the transformation of organic chlorinated contaminants. However, the amount of related literatures regarding this topic is limited. This study aimed to determine the effects of phosphorus addition on pentachlorophenol (PCP) anaerobic transformation, iron reduction, and paddy soil microbial community structure. Results showed that the transformation of phosphorus, iron, and PCP were closely related to the microorganisms. Moreover, phosphorus addition significantly influenced PCP transformation and iron reduction, which promoted and inhibited these processes at low and high concentrations, respectively. Both the maximum reaction rate of PCP transformation and the maximum Fe(II) amount produced were obtained at 1mmol/L phosphorus concentration. Among the various phosphorus species, dissolved P and NaOH-P considerably changed, whereas only slight changes were observed for the remaining phosphorus species. Microbial community structure analysis demonstrated that adding low concentration of phosphorus promoted the growth of Clostridium bowmanii, Clostridium hungatei, and Clostridium intestinale and Pseudomonas veronii. By contrast, high-concentration phosphorus inhibited growth of these microorganisms, similar to the curves of PCP transformation and iron reduction. These observations indicated that Clostridium and P. veronii, especially Clostridium, played a vital role in the transformation of related substances in the system. All these findings may serve as a reference for the complicated reactions among the multiple components of soils.

Effects of phosphorus addition on nitrogen cycle and fluxes of N2O and CH4 in tropical tree plantation soils in Thailand

An incubation experiment was conducted to test the effects of phosphorus (P) addition on nitrous oxide (N2O) emissions and methane (CH4) uptakes, using tropical tree plantation soils in Thailand. Soil samples were taken from five forest stands—Acacia auriculiformis, Acacia mangium, Eucalyptus camaldulensis, Hopea odorata, and Xylia xylocarpa—and incubated at 80% water holding capacity. P addition stimulated N2O emissions only in Xylia xylocarpa soils. Since P addition tended to increase net ammonification rates in Xylia xylocarpa soils, the stimulated N2O emissions were suggested to be due to the stimulated nitrogen (N) cycle by P addition and the higher N supply for nitrification and denitrification. In other soils, P addition had no effects on N2O emissions or soil N properties, except that P addition tended to increase the soil microbial biomass N in Acacia auriculiformis soils. No effects of P addition were observed on CH4 uptakes in any soil. It is suggested that P addition on N2O and CH4 fluxes at the study site were not significant, at least under laboratory conditions.

磷添加对中亚热带米槠和杉木细根分解及其酶活性的影响

磷添加对中亚热带米槠和杉木细根分解及其酶活性的影响

Effects of phosphorus addition with and without nitrogen addition on biological nitrogen fixation in tropical legume and non-legume tree plantations

It is well documented that phosphorus (P) input stimulates biological nitrogen (N) fixation (BNF) in tropical forests with non-legume trees. However, in tropical legume forests with soil N enrichment and P deficiency, the effects of P availability and its combination with N on BNF remain poorly understood. In this study, we measured BNF rate in different compartments, i.e., bulk soil, forest floor, rhizosphere, and nodules, in two tropical plantations with legume trees Acacia auriculiformis (AA) versus non-legume trees Eucalyptus urophylla, (EU) in southern China after 4 years of P addition and combined N and P additions. The objective was to investigate how P addition and its combination with N addition regulate BNF in a tropical legume plantation, and to compare the effects with those in a non-legume plantation. Our results showed that total BNF rates were significantly higher in the P-addition plots than in the control plots by 27.4 ± 4.3 and 23.3 ± 1.7 % in the EU and AA plantations, respectively. Total BNF rates were significantly higher in the NP-addition plots than in the control plots by 27.7 ± 5.0 and 8.5 ± 1.4 % in the EU and AA plantations, respectively, which contrasted to our previous result that total BNF rates were significantly lower in N-addition plots than in the control plots in the AA plantation. These findings suggest that P input can stimulate BNF in tropical forest biome dominated by legume trees, even in consideration of elevated atmospheric N deposition. Thus, our study revealed the important role of P in regulating biological N input, which should be taken into account in the modeling of biogeochemical cycles in the future.

Effect of Phosphorus Addition on the Performance of Hierarchical ZSM-11 Catalysts in Methanol to Propene Reaction

Hierarchical ZSM-11 zeolite (SiO2/Al2O3 = 65) was found to be an efficient catalyst in Methanol to Propene (MTP) reaction. The catalytic activity of ZSM-11-based catalysts was studied in MTP reaction, and the effect of phosphorus (P) addition has been comprehensively investigated. XRD, N2 adsorption–desorption, NH3-TPD and Py-FTIR analyses reveal that the addition of P has a remarkable influence on the physicochemical properties of the catalysts. With the incorporation of P, the Bronsted acid sites decrease significantly, but the Lewis acid sites are almost preserved. Reaction results indicate that propene selectivity is obviously improved by P addition, and the highest propene yield (20.35 wt%) is obtained over 0.2ZAlPO catalyst. Based on the characterization and reaction results, it can be concluded that the appropriate concentration and strength of acid sites on 0.2ZAlPO catalyst with maintained MEL structure results in the enhanced propene selectivity and stability.

SYNTHESIS OF PROPYLENE FROM ETHANOL USING PHOSPHORUS-MODIFIED HZSM-5

Effects of phosphorus addition to HZSM-5 on ethanol conversion to propylene were evaluated. Catalysts were characterized by XRF, XRD, nitrogen adsorption, 27Al and 31P MAS NMR, n-propylamine and ammonia TPD. Increasing P content decreased the strength and density of acid total sites. Ethanol dehydration was carried out in a fixed bed reactor operating at atmospheric pressure. Conversion was around 100% for all catalysts. 1.2 wt% of P catalyst showed the highest propylene yield, and was used to evaluate temperature and ethanol partial pressure effects on the product distribution. The highest propylene accumulated productivity was obtained for an ethanol partial pressure of 0.4 atm. Propylene formation was favored in the temperature range 475-500 °C. Significant changes in the product distribution as a function of time on stream were observed at higher temperatures, suggesting stronger catalyst deactivation. The ethylene yield decreased up to 500 °C, rising significantly at 550 °C, possibly due to heavier product cracking reactions.

Effect of phosphorus addition on total and alkaline phosphomonoesterase-harboring bacterial populations in ryegrass rhizosphere microsites

Rhizobacterial communities may play a crucial role in phosphorus (P) nutrition of plants. However, our knowledge of how P fertilization modulates rhizobacterial communities in crops and pastures is still poor. Here, we investigated the effect of P addition (phosphate [PHO] and phytate [PHY]) on the composition of total bacterial communities and alkaline phosphomonoesterases (APase)-harboring bacterial populations in the rhizosphere microsites (root tip [RT] and mature zone [MZ]) of L. perenne. Sizes and diversities of bacterial communities were studied by 454-pyrosequencing of 16S rRNA genes, denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR). Our results suggested that phosphorus addition induces significant changes in the rhizobacterial community composition. Despite that pyrosequence analysis showed that members of the Proteobacteria, Actinobacteria, Chloroflexi, and Acidobacteria were the dominant phyla in all sampled rhizosphere microsites, differences in the relative abundances of some bacterial genera were detected (e.g., Arthrobacter and Acidothermus). Greater richness in rhizosphere microsites of plants supplied with PHY compared with PHO were revealed. With respect to APase-harboring bacterial populations, DGGE (phoD gene) showed significant differences between microsites supplied with PHO, PHY and controls. qPCR (16S rRNA genes, phoD and phoX) showed significantly greater abundances of bacteria and APase genes in RT than in MZ microsites. This study contributes to our understanding of the effect P fertilization on rhizobacterial community compositions of pastures grown in Chilean Andisols.

Fischer-Tropsch synthesis: Anchoring of cobalt particles in phosphorus modified cobalt/silica catalysts

The effect of phosphorus addition on silica-supported cobalt catalyst was investigated for Fischer-Tropsch synthesis (FTS). As shown by STEM images and chemisorption, the addition of phosphorus to cobalt of up to 1wt% increased the dispersion of cobalt. Further addition of phosphorus (e.g., 3 and 5wt.%), as demonstrated by TPR, pulse reoxidation, and XANES, significantly hindered the reduction of cobalt oxides. The cobalt FTS catalysts containing 0.5 and 1.0wt% P exhibited greater stability in comparison with undoped and 3.0wt% P containing cobalt catalysts. Analysis of XANES spectra at the P and Co K-edges, along with DRIFTS results of H2-activated cobalt catalysts, suggest that cobalt particles interact with PO43− ions, indicating a role played by P in anchoring Co particles to the support, thus hindering the cobalt sintering rate. The initial selectivity to methane was slightly higher for 0.5%P-20%Co/SiO2 and 1.0%P-20%Co/SiO2 catalysts compared to the undoped catalyst, but at longer times differences were small. At higher loadings of P (3wt.%), FT activity and selectivity were adversely and irreversibly affected.

Increases in Soil Aggregation Following Phosphorus Additions in a Tropical Premontane Forest are Not Driven by Root and Arbuscular Mycorrhizal Fungal Abundances

Tropical ecosystems have an important role in global change scenarios, in part because they serve as a large terrestrial carbon pool. Carbon protection is mediated by soil aggregation processes, whereby biotic and abiotic factors influence the formation and stability of aggregates. Nutrient additions may affect soil structure indirectly by simultaneous shifts in biotic factors, mainly roots and fungal hyphae, but also via impacts on abiotic soil properties. Here, we tested the hypothesis that soil aggregation will be affected by nutrient additions primarily via changes in arbuscular mycorrhizal fungal (AMF) hyphae and root length in a pristine tropical forest system. Therefore, the percentage of water-stable macroaggregates (> 250µm) (WSA) and the soil mean weight diameter (MWD) was analyzed, as well as nutrient contents, pH, root length and AMF abundance. Phosphorus additions significantly increased the amount of WSA, which was consistent across two different sampling times. Despite a positive effect of phosphorus additions on extraradical AMF biomass, no relationship between WSA and extra-radical AMF nor roots was revealed by regression analyses, contrary to the proposed hypothesis. These findings emphasize the importance of analyzing soil structure in understudied tropical systems, since it might be affected by increasing nutrient deposition expected in the future.

Effects of Phosphorus Addition on the Corrosion Resistance of Sn–0.7Cu Lead-Free Solder Alloy

The corrosion behavior of Sn–0.7Cu–xP (x = 0, 0.1, 0.3, 0.5) solder alloy in the aggressive environment was investigated by potentiodynamic polarization and weight loss method. Scanning electron microscope (SEM) was used to observe the morphology of Sn–0.7Cu–xP solder alloys and X-ray diffraction (XRD) was applied to characterize the phases formed on the surface after corrosion. The results indicate that phosphorus (P) can enhance the corrosion resistance of Sn–0.7Cu solder alloy whether in acidic or in alkaline solution, and its corrosion resistance increases with increasing P. The corrosion resistance of the solder alloy is better in alkaline solution compared to that in acidic solution. The morphology observation also shows that the incorporation of P into Sn–0.7Cu alloy can obviously decrease the damage extent of the solder alloys. XRD analysis reveals that the corrosion products both in acidic and alkaline solution are Sn oxides.

Effects of phosphorus addition on N<sub>2</sub>O emissions from an <i>Acacia mangium</i> soil in relatively aerobic condition

Effects of phosphorus addition on N<sub>2</sub>O emissions from an <i>Acacia mangium</i> soil in relatively aerobic condition

The effects of phosphorus addition on phytoavailability of zinc by diffusive gradientsin thin films (DGT)

Diffusive gradients in thin films (DGT) have been used for the assessment of Zn phytoavailability. Phosphorus is of particular interest in soils having Zn toxicity because of the Zn-P interaction. A greenhouse study was carried out to assess the influence of different P rates on the Zn phytoavailability to sorghum-Sudan grass (Sorghum vulgare var. Sudanese) in soil systems by DGT. Soil was amended with ZnSO4 at 0, 150, 300, 600, and 1200 mg Zn kg-1 in order to create various levels of Zn phytoavailability. Phosphorus was applied to soil at 0, 100, and 200 mg P kg-1 as KH2PO4. Plant nutrients were added as Hoagland's solution. In general, plant tissue Zn concentrations were elevated by increasing Zn concentration in soils, and they decreased by increasing P concentrations. However, this reduction was not found in C-DGT results. In other words, DGT did not predict the effects of P additions compared to Zn. P application decreased plant Zn concentrations and increased plant biomass yields. The highest relative yield in shoot tissue was with P200 × Zn150 treatment, while the lowest one was with P0 × Zn1200 treatment. In general, increasing P concentrations in the soil increased shoot yields relative to control, while increasing Zn concentrations decreased the relative shoot yields where no P was added. P addition might be an alternative strategy for remediation of Zn contaminated soil, since addition of P decreased Zn phytoavailability and enhanced plant growth.

Effects of phosphorus addition on soil microbial biomass and community composition in a subalpine spruce plantation

Phosphorus (P) availability is expected to affect soil microbial community. However, our knowledge about the responses of soil microbial biomass and community composition to P availability is still limited. In this study, we established field plots with addition of 0, 5 (LP), 15 (MP) and 30 (HP) g P m−2 yr−1 in a subalpine spruce plantation and investigated the responses of soil microbes. Chloroform fumigation-extraction and phospholipid fatty acids (PLFA) analysis were used to determine soil microbial biomass and community composition, respectively. After two growing seasons of P addition, the HP treatment significantly increased soil microbial biomass carbon, nitrogen and P. The P addition exerted the specific influences on soil microbial community composition. The abundance of most groups of soil microbial community (bacteria, fungi, and arbuscular mycorrhizal fungi) increased in the HP treatment and the ratio of fungi to bacteria decreased in the LP and MP treatment, whereas the nonmetric multidimensional scaling ordination revealed no significant difference in the PLFA pattern between the P treatments and the control. Although soil P availability increased in all P treatments compared to the control, the dissolved organic carbon, indicative of soil carbon availability, was promoted only by the HP treatment. Besides, soil microbial biomass was positively correlated to soil carbon availability and pH. These results indicate that soil microbes are insensitive to the elevated P availability in this spruce plantation and P addition increases soil microbial biomass mainly through improving carbon availability and pH.

磷肥输入对稻田土壤剖面胶体磷含量的影响

磷肥输入对稻田土壤剖面胶体磷含量的影响

Effects of experimental nitrogen and/or phosphorus additions on soil nematode communities in a secondary tropical forest

In tropical forest ecosystems, highly weathered soils are often considered as relatively nitrogen-rich but phosphorus-poor. Nutrient availability greatly regulates ecosystem processes and functions of tropical forests. However, little is known about how nitrogen and/or phosphorus additions affect the conditions of soil food web which is an important component of belowground ecosystems. In the present study, soil nematode communities were monitored and served as indicators of soil food web conditions under experimental nitrogen and phosphorus additions in a secondary forest in tropical China. The principal response curves of soil nematode community structure revealed same tendency of changes under nitrogen and/or phosphorus additions compared with control, in terms of nematode functional guild compositions: apparent successions from communities dominated by He3 and Ba1 to communities dominated by Ba2 and Fu2 occurred after nitrogen and/or phosphorus additions. The diversity of soil nematode genera was not sensitive to either nitrogen or phosphorus addition. Phosphorus addition significantly suppressed total nematode density, density of omnivore-predators, and four nematode faunal indices (i.e. MI25, EI, SI, and SFI), but increased two faunal indices (i.e. CI and BaI). However, nitrogen addition did not induce remarkable changes of these variables in the present study. Our results suggest that nitrogen and/or phosphorus additions suppress soil nematodes in tropical secondary forests, which was inconsistent with our expectation that nitrogen addition was detrimental to and phosphorus addition was conducive to soil nematodes in this nitrogen-rich but phosphorus-poor soil. Furthermore, the effects of phosphorus addition are more powerful than the effects of nitrogen addition. Moreover, phosphorus addition degrades the structure and trophic links of the soil food web, reduces the carbon utilization of soil nematodes, and leads to a more fungal dominated decomposition pathway. The alterations of soil food web conditions might result in altered ecosystem functioning. Our findings could provide a better understanding of the responses of soil food web to nitrogen and phosphorus additions in nitrogen-rich but phosphorus-poor soils.

Sintering and Properties of Pb0.98Ca0.02 [(Zr0.52Ti0.48)0,98(Cr3+0.5, Ta5+0.5)0,02] O3 Ferroelectric Ceramics Doped with P2O5

The effect of phosphorus additions on the structure, microstructure and dielectrics properties of the Pb0.98Ca0.02[(Zr0.52Ti0.48)0,98(Cr3+0.5, Ta5+0.5)0,02]1-xPx O3 (x ranged from 0.01 to 0.12) ceramics have been investigated. All of the samples were prepared by a high-temperature solid-state reaction technique. AFM analysis of the compounds suggests that the average grain size increases with increasing sintering temperature which is characteristic of a ceramic material. Until that it reaches maximum values for the simple doped with 4 Wt. % of P2O5 at a sintering temperature of 1050°C. Dielectric studies of the compounds as a function of frequency (from 1 to 200 KHz) sintered at different sintering temperatures (1000, 1050, 1100, 1150 and 1180° C) show that the compounds undergo a phase transition of diffuse type. The transition temperature shifts towards higher side with increase in frequency a typical characteristic of a relaxor material.

Influence of phosphorous doping on silicon nanocrystal formation in silicon-rich silicon nitride films

Phosphorus-doped silicon nanocrystals (Si-NCs) embedded in a silicon nitride matrix were fabricated by post-annealing of silicon-rich silicon nitride (SRN) films deposited by electron cyclotron resonance chemical vapour deposition. The effects of phosphorus addition on the Si crystallization behaviour in SRN films were investigated. From the experimental results, the existence of phosphorus enhances phase separation in SRN and thus Si crystallization rate. As the phosphorus content increases, the Si-NC size increases under the same annealing conditions. The x-ray photoelectron spectroscopy P 2p signal attributed to Si–P or P–P bonds indicates that the phosphorus may exist inside Si-NCs. It was also found that the crystallization temperature decreases when phosphorus concentration is increased, and could be as low as 800 °C.

Effects of Phosphorus Addition on Piezoelectric and Mechanical Properties of Pb0.98Ca0.02[(Zr0.52Ti0.48)0.98(Cr3+0.5, Ta5+0.5)0.02]O3

In this paper, we report the effect of P5+ addition on the Piezoelectric and mechanical Properties and crystallographic characteristics of PZT-CCT ceramics. The samples chosen for this stud were prepared using the conventional mixed-oxide route. Structural analysis (XRD) and measurement of Piezoelectric and mechanical were carried out. The results show that addition of P2O5 significantly improved the sinterability of PZT-CCT ceramics and could decrease the sintering temperature from 1180 to 1050°C. The 4wt.% P2O5 added PZT-CCT ceramics sintered at 1050°C exhibited the favorable piezoelectric and mechanical properties, which were listed as follows: d31 = 10.3436×10-11C/N, Kp =0.73, g31=25×10-3 mV/N, Qm =263 and E=1.2794×10+11 The obtained properties make this composition to be a good candidate for high power piezoelectric devices.

Effects of phosphorus addition with and without ammonium, nitrate, or glucose on N2O and NO emissions from soil sampled under Acacia mangium plantation and incubated at 100 % of the water-filled pore space

An incubation experiment was conducted to examine the effects of phosphorus (P) addition with and without ammonium, nitrate, or glucose on N2O and NO emissions from soil taken under Acacia mangium plantation and incubated at 100 % water-filled pore space (WFPS). Additions of NO 3 − stimulated the N2O and NO emissions while NH 4 + did not, showing that denitrification was the main process of N2O and NO production in the study condition. When NO 3 − was added with P significantly (P < 0.05) increased N2O emissions regardless of the ratio of the added nitrogen and carbon, suggesting that P addition stimulated denitrification activity. The activation of denitrification by P addition is possibly attributed to two mechanisms: (1) the added-P stimulated denitrification by relieving P shortage for denitrifying bacteria and (2) the added-P stimulated activity of heterotrophic soil microflora with increased O2 consumption promoting the development of anaerobic conditions with stimulation of denitrification.

Effect of phosphorus additions on the sintering and transport properties of proton conducting BaZr0.85Y0.15O3−δ

The influence of phosphorous additions on the sintering and electrical transport properties of the proton-conducting perovskite BaZr0.85Y0.15O3−δ (BZY) has been studied with a view to the use of phosphates as typical dispersants for the formation of stabilised solid suspensions or as possible sintering aids. P2O5 additions, (1−x)BZY·xP2O5, monotonously promote densification in the intermediate compositional range 0.04≤x≤0.08. Nonetheless, BZY reacts with phosphorous forming the phase Ba3(PO4)2 at temperatures as low as 600°C. The associated loss of Ba from the perovskite, leads to a decrease in the perovskite lattice parameter, the formation of yttria-based impurity phases and impaired grain growth. Such reaction has an extremely detrimental effect on bulk and grain boundary conductivities. It is, therefore, vital that the current results are taken into account by the protonics community when attempting to prepare the stabilised solid suspensions of BZY nanopowders required for thin ceramic applications. Alternative dispersants to phosphate esters must be found.