Effects Of Phosphorus Addition Research Articles

Effects of phosphorus addition on leaf litter decomposition in two tropical tree plantations in Thailand

There is a widespread belief that organic matter decomposition in phosphorus (P)-poor tropical forests is limited by P shortage and stimulated by exogenous P addition. An incubation experiment was performed to test the effect of P addition on decomposition of litter layers taken from two tropical tree plantations. The result was compared with our earlier soil incubation experiment in the same region. Contrary to the traditional view, we found no significant effects of P addition on the litter layer decomposition, which was also in contrast with our previous soil incubation experiment that showed stimulatory effects of P addition on soil microbial respiration. The difference between our two experiments was attributed to the role of added P to release organic matter from the sorption sites on mineral soils, which made the adsorbed organic matter in soil accessible for microbes and easier to be decomposed. Overall, our incubation experiments did not support the P-limitation hypothesis: organic matter decomposition in P-poor tropical forests is limited by P shortage.

Effects of Phosphorus Addition on the Hydrophobicity and Catalytic Performance in Methane Combustion of θ-Al2O3 Supported Pd Catalysts

A series of xPθ-Al2O3 supports modified with different amounts of phosphorus element were prepared and taken as supports of palladium catalysts for methane catalytic combustion. The impacts of phosphorus additives on the hydrophobicity of Pd/xPθ-Al2O3 and its performance of methane catalytic combustion in the absence of and presence of 8% water were systematically studied. It was found that the hydrophobicity of xPθ-Al2O3 changed with the increase of phosphorus content, which had a significant effect on the activity of methane catalytic combustion. The incorporation of phosphorus replaced the hydroxyl groups on the surface of Al2O3 in the form of phosphates, thus changing the density of hydroxyl groups of Al2O3 support. TGA, NH3-TPD, IR, and XPS were employed to illustrate the process of phosphate replacement. xPθ-Al2O3 with less than 1 wt.% phosphorus content had better hydrophobicity than the unmodified θ-Al2O3 and Pd/xPθ-Al2O3, therefore had better performance for methane catalytic combustion, which was attributed to the substitution of hydroxyl groups on the surface of θ-Al2O3 by PO43− and HPO42−. However, when the phosphorus content of Al2O3 was higher than 1 wt.%, the substitution of H2PO4− began to dominate, which would lead to poorer hydrophobicity and catalytic performance. This work will guide the design of methane catalytic combustion catalysts resistant to water inhibition problem.

One-pot Synthesis of Phosphorus-modified ZSM-5 Zeolite by Solid-state Method and its MTO Catalytic Performance.

The traditional hydrothermal synthesis strategy of ZSM-5 zeolite is energy-consumption accompanying by pollution issues. Herein, phosphorus-modified layered ZSM-5 zeolites (PZ) were obtained by one-pot synthesis under solvent-free conditions. The synthesized samples were fully characterized by XRD, SEM, BET, NH3 -TPD and FTIR. The effect of phosphorus addition on the morphology and catalytic activity of ZSM-5 was investigated. The results showed that phosphorus-modified ZSM-5 zeolites exhibited higher light olefin (ethylene and propylene) selectivity (above 50 %) and longer catalytic lifetime (33 h) in methanol to olefin (MTO) reaction when the weight hourly space velocity was 4 h-1 . Phosphorus-modified ZSM-5 zeolite synthesized by in situ solvent-free method, which not only reduced the discharge of sewage but also showed a simple method to realize the introduction of phosphorous species, which provided a new idea for phosphorus modification of ZSM-5 zeolite.

Effects of Phosphorus Addition at Budding Stage on Biomass and Material Distribution of Jerusalem Artichoke

Effects of Phosphorus Addition at Budding Stage on Biomass and Material Distribution of Jerusalem Artichoke

Effect of Phosphorus Additions on the Microstructure and Creep Properties of a Wrought Ni-Base Superalloy

Effect of Phosphorus Additions on the Microstructure and Creep Properties of a Wrought Ni-Base Superalloy

Influence of phosphorus on iron-based friction material prepared directly from vanadium-bearing titanomagnetite concentrates

In situ selective carbothermic reactions and vacuum sintering were used to prepare iron-based friction material directly from vanadium-bearing titanomagnetite concentrates. Effects of phosphorus addition (0.05–0.20 wt.%) on the microstructure and properties of iron-based friction material were investigated. The results show that the addition of phosphorus improves the microstructure and properties of the material significantly. When phosphorus addition increases to 0.15 wt.%, the sintering densification is promoted and the number of lamellar pearlites increases. Therefore, the relative density, hardness and tribological properties of the material are greatly enhanced. Particularly, the friction coefficient decreases from 0.58 to 0.43, and the wear rate reduces from 1.829 × 10–7 to 0.694 × 10–7 cm3 J−1. The dominant wear mechanism of the material changes from severe abrasive wear to mild oxidation wear accordingly. However, when phosphorus addition exceeds 0.15 wt.%, the matrix continuity and tribological properties of the material are deteriorated. Comprehensively, the optimal addition of phosphorus in the iron-based friction material is 0.15 wt.%.

Liquid phase hydrodeoxygenation of furfural over laponite supported NiPMoS nanocatalyst: Effect of phosphorus addition and laponite support

Unsupported and laponite supported NiPMoS catalysts were prepared under the hydrothermal method and investigated for liquid-phase hydrodeoxygenation of furfural in a high-pressure batch reactor at 423 ​K − 463 ​K under 20 ​bar H2 pressure. The reaction significantly produced 94% of furfural conversion with 75% yield of 2-MF on NiPMoS catalyst whereas, NiPMoS/Lap catalyst exhibited 28% of 2-MF yield with complete conversion at 463 ​K under 20 ​bar H2 pressure in toluene solvent. The influence of process parameters such as reaction temperature, reactant volume, catalyst compositions, and hydrogen pressure on furfural conversion and product yield was investigated in detail. The high reactivity and synergetic effect of the NiPMoS catalyst are due to added phosphorus, which has a profound influence on the structure of the catalyst, thereby increasing surface acidity, basicity, hydrogen consumption, and a number of MoS2 fringes and the dispersion of MoS2 on the surface of the support. The catalysts were characterized based on HRTEM, H2, CO2, and NH3 TPD, FT–IR, FT–Raman, DRS UV–Vis, XRD, N2–physisorption, and TGA. Recyclability, N2–physisorption, and XRD results confirm the stability and practical applicability of the catalyst for industrial applications.

Electronic Properties of Silicene Films Subjected to Neutron Transmutation Doping

The radiation doping of single-crystal silicon with phosphorus retains the structure of the sample, reduces internal stresses, and increases the lifetime of minority charge carriers. The study is concerned with the effect of phosphorus additives on the electronic properties of silicene. The electron density-of-states spectra of a phosphorus-doped single layer and 2 × 2 bilayer silicene on a graphite substrate are calculated by the quantum-mechanical method. The carbon substrate imparts semiconductor properties to silicene due to p–p hybridization. Doping with phosphorus can retain or modify the metal properties gained by silicene. The position of phosphorus dopant atoms in silicene influences the semiconductor–conductor transition. The theoretical specific capacity of a phosphorus-doped silicene electrode decreases, and the electrode becomes less efficient for application in lithium-ion batteries. However, the increase in the conductivity is favorable for use of this material in solar cells.

Effect of Phosphorus Addition on Microstructure and Mechanical Properties of Sintered Low Alloy Steel

Effect of Phosphorus Addition on Microstructure and Mechanical Properties of Sintered Low Alloy Steel

Электронные свойства пленок силицена, подвергнутых нейтронному легированию

Abstract The radiation doping of single-crystal silicon with phosphorus retains the structure of the sample, reduces internal stresses, and increases the lifetime of minority charge carriers. The study is concerned with the effect of phosphorus additives on the electronic properties of silicene. The electron density-of-states spectra of a phosphorus-doped single layer and 2 × 2 bilayer silicene on a graphite substrate are calculated by the quantum-mechanical method. The carbon substrate imparts semiconductor properties to silicene due to p – p hybridization. Doping with phosphorus can retain or modify the metal properties gained by silicene. The position of phosphorus dopant atoms in silicene influences the semiconductor–conductor transition. The theoretical specific capacity of a phosphorus-doped silicene electrode decreases, and the electrode becomes less efficient for application in lithium-ion batteries. However, the increase in the conductivity is favorable for use of this material in solar cells.

Effects of phosphorus addition on selectivity and stability of Pd model catalysts during cyclohexene dehydrogenation

P addition to Pd increases dehydrogenation selectivity and increases catalyst stability.

Species‐specific effects of phosphorus addition on tropical tree seedling response to elevated CO2

Abstract Tropical forest productivity is often thought to be limited by soil phosphorus (P) availability. Phosphorus availability might therefore constrain potential increases in growth as the atmospheric CO2 concentration increases, yet there is little experimental evidence with which to evaluate this hypothesis. We hypothesized that while all species would respond more strongly to elevated CO2 when supplied with extra P, the responses of individual species would also depend on their habitat associations with either high‐ or low‐P soils. We further hypothesized that this effect would be exacerbated by a reduction in transpiration rate under elevated CO2, as transpiration may aid in P acquisition. We used a pot experiment to test the effects of P addition on the physiological and growth response to elevated CO2 of eight tropical tree species with contrasting distributions across a soil P gradient in Panamanian lowland forests. Seedlings were grown in an ambient (400 ppm) or elevated (800 ppm) CO2‐controlled glasshouse in either a high‐ or low‐P treatment to quantify the effects of P limitation on relative growth rate (RGR), transpiration, maximum photosynthetic rate and foliar nutrients. We found evidence of limitation by P and CO2 on growth, photosynthesis, foliar nutrients and transpiration. However, the affinity of a species for P, defined as the species distribution relative to P availability, was not correlated with RGR or transpiration responses to elevated CO2 in either the low‐P or high‐P treatments. Transpiration rates decreased under elevated CO2, but foliar P was greater for some species under elevated CO2, suggesting a greater capacity for upregulation of P acquisition in species associated with low‐P soils. Our results show that tropical forest responses to elevated CO2 will be species‐specific and not necessarily explained by P affinities based on distribution, which poses challenges for predictions of community‐wide responses. A free Plain Language Summary can be found within the Supporting Information of this article.

Effect of Phosphorus Addition on N2O Emissions from Rice-Rapeseed Rotation Soils

The red soils in southern China are generally classified as phosphorus-deficient, and therefore planting crops in these regions usually requires high applications of phosphate fertilizer. However, the effect of phosphorus addition on N2O emissions in rice-rapeseed rotation soils is not clear. We carried out an incubation experiment with the rice-rapeseed rotation soil from Qianjiang and Xianning to explore the effect of different concentrations of phosphorus (0, 15, and 30 mg·kg-1) and different concentrations of nitrogen (0 and 100 mg·kg-1) on N2O emission. Studies have shown that the addition of phosphorus has a significant effect on soil N2O emissions, but the pathways of impact are varied:in the case of low nitrogen soil, the addition of phosphorus promotes the fixation of nitrogen in the soil by microorganisms and thus reduces N2O emissions; in case of sufficient nitrogen content in soil, adding less phosphorus promotes the activity of nitrifies and thereby promotes the emission of N2O, while adding more phosphorus also promotes fixation by microorganisms in the soil; when there is a high content of available phosphorus in the soil, whether the nitrogen is sufficient or not, the addition of phosphorus will inhibit the emission of N2O.

Effect of Phosphorus Addition on the Abundance of Autotrophic CO2-Fixation Microorganisms in Rhizospheric Soil from a Phosphorus-Limited Paddy Field

A rice pot experiment was conducted to investigate the effect of phosphorus addition on the abundance of autotrophic CO2-fixation microorganisms using phosphorus-limited paddy soil from the Changsha Observation and Research Station for the Agricultural Environment. Rice seedlings were transplanted in the paddy soil with or without phosphorus addition, corresponding to P-treated-pot (P) or control pot (CK), respectively. Rhizosphere soils were collected from the P and CK treatments during the tillering and shooting stages. The physical and chemical soil properties were measured and the abundance of autotrophic CO2-fixation microorganisms was quantified with a real-time PCR technique based on four functional genes (cbbL, cbbM, accA, and aclB) involved in three CO2-fixation pathways (CBB cycle, rTCA cycle, and 3-hydroxypropionate/4-hydroxybutyrate cycle). The results show that phosphorus addition improves the concentrations of DOC and Olsen-P and the pH value, whereas negative effects on the MBC and NH4+-N concentrations are revealed during the tillering stage. The effect of phosphorus addition on the NO3--N concentration in the tillering and shooting stages differs. Phosphorus addition significantly increases the abundances of the cbbL, cbbM, accA, and aclB genes, which are 156%, 99%, 110%, and 193% higher than those of the CK treatment in the tillering stage. However, this positive effect is not notable for the cbbL, accA, and aclB genes during the shooting stage. Redundancy analysis (RDA) shows that Olsen-P is the environmental factor that most significantly affects the abundance of autotrophic CO2-fixation microorganisms.

Seasonal shifts in the importance of bottom–up and top–down factors on stream periphyton community structure

We examined the importance of temporal variability in top–down and bottom–up effects on the accumulation of stream periphyton, which are complex associations of autotrophic and heterotrophic microorganisms. Periphyton contributes to primary production and nutrient cycling and serves as a food resource for herbivores (grazers). Periphyton growth is often limited by the availability of nitrogen and phosphorus, and biomass can be controlled by grazers. In this study we experimentally manipulated nutrients and grazers simultaneously to determine the relative contribution of bottom–up and top–down controls on periphyton over time. We used nutrient diffusing substrates to regulate nutrient concentrations and an underwater electric field to exclude grazing insects in three sequential 16–17 day experiments from August to October in montane Colorado, USA. We measured algal biomass, periphyton organic mass, and algal community composition in each experiment and determined densities of streambed insect species, including grazers. Phosphorus was the primary limiting nutrient for algal biomass, but it did not influence periphyton organic mass across all experiments. Effects of nutrient additions on algal biomass and community composition decreased between August and October. Grazed substrates supported reduced periphyton biomass only in the first experiment, corresponding to high benthic abundances of a dominant mayfly grazer (Rhithrogena spp.). Grazed substrates in the first experiment also showed altered algal community composition with reduced diatom relative abundances, presumably in response to selective grazing. We showed that top–down grazing effects were strongest in late summer when grazers were abundant. The effects of phosphorus additions on algal biomass likely decreased over time because temperature became more limiting to growth than nutrients, and because reduced current velocity decreased nutrient uptake rates. These results suggest that investigators should proceed with caution when extending findings based on short‐term experiments. Furthermore, these results support the need for additional seasonal‐scale field research in stream ecology.

The effect of phosphorus addition, soil moisture, and plant type on soil nematode abundance and community composition

Environmental variables such as soil moisture and phosphorus (P) might influence above- and below-ground biodiversity. In this study, we investigated the rarely reported individual and interactive multifactor effects of soil moisture and phosphorus addition with the type of above-ground tree species (biological interactions) on the soil nematode community structure. We established a completely randomized experimental design with two plant types (N2-fixer and non-nitrogen fixer) and different combinations of water treatments and P additions (i.e., water with P addition, water only, drought with P addition, and drought only) in a greenhouse and investigated their effects on the soil chemical properties and nematode community. Soil samples were collected at the end of the experiment and were analyzed for soil moisture content (SM), available phosphorus (aP), nitrate nitrogen (NO3−–N), ammonium nitrogen (NH4+–N), dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and nematode community. The following trophic groups were assigned to the nematodes: bacterivores (Ba), fungivores (Fu), omnivores–predators (Op), and plant parasites (PP). The channel index (CI), enrichment index (EI), maturity index (MI), genus richness (GR), and Simpson dominance (Ig) were adopted to indicate the indices of the nematode food web. Phosphorus addition and its interaction with water treatments had no statistically significant effects on the soil nematode community, but there were significant decreasing (p < 0.05) effects of P addition on the total density of nematodes of the N2-fixing tree under optimum water treatment. There were no significant interactive effects of P addition and water treatments on all the trophic groups, but plant type, water treatments, and their interactions significantly affected the density of most nematode trophic groups. The total nematode abundances of bacterivores, plant parasitic, omnivores, and enrichment index were significantly higher in the N2-fixers than in the non-nitrogen-fixing tree. Soil nematode abundance and community composition were more affected by the plant type than by the P addition and its interaction with water treatments. Drought exerted adverse effects on the total density of soil nematodes, the dominant genera, and the trophic groups. This study demonstrated that the rate of drought impact hinges more on the type of tree and that N2-fixing tree could still maintain the soil food web structure irrespective of the environmental changes.

Effect of Phosphorus Addition on Dry Sliding Behavior of Fe–P Alloys Prepared by Powder Metallurgy

Iron–phosphorus powder metallurgy (P/M) alloys having 0, 0.35 and 0.65 wt.% P have been prepared by hot-forging technique. Hot forging consists of heating encapsulated powder at a temperature of 1050 °C in the atmosphere of hydrogen gas followed by hot forging. These hot-forged specimens have been subjected to dry sliding adhesive wear test at a normal load of 19.6, 29.4, and 39.2 N, at a constant sliding speed of 2.2 m/s and for a sliding distance of 4000 m using a pin-on-disk wear testing machine. Archard wear coefficient has been found to decrease from 2.5 × 10−7 to 1.4 × 10−7 with increasing phosphorus content in the alloys. The average coefficient of friction has also been found to decrease more or less linearly with increasing load as well as with increasing phosphorus content in the alloy. The mechanism of wear is primarily oxidative in nature, which has been confirmed by SEM–EDS analysis of the worn surfaces.

Effect of Phosphorus Additions and Arbuscular Mycorrhizal Fungal Inoculation on the Growth, Physiology, and Phosphorus Uptake of Wheat Under Two Water Regimes

ABSTRACTDrought stress greatly affected the growth and development of wheat in the world, while wheat growth could benefit through improvement of water status and nutrient uptake by mycorrhizal symbiosis or addition of phosphorus (P). Experimental treatments were (a) phosphorus addition (0 and 90 kg/ha), (b) soil water condition (40% field capacity and 95% field capacity), and (c) arbuscular mycorrhizal fungi (AMF, Glomus intraradices) (noninoculation and inoculation) which were conducted in a growth chamber. The results showed that addition of phosphorus and AMF inoculation significantly increased the relative water content and specific leaf area of flag leaves especially under 40% field capacity (water deficit (WD)). The leaf gas exchange parameters were all decreased under WD. The water use efficiency (WUE) and instantaneous WUE (WUEi) was enhanced by WD, AMF inoculation, and phosphorus addition. AMF inoculation and WD significantly decreased the carbon isotope discrimination (CID) of leaf. The P concentrations in stem, grain, and leaf were significantly increased by phosphorus addition, WD, and AMF inoculation. Significant correlations were found between WUE and grain P, stem P, and leaf P concentrations. Leaf CID was significantly negatively correlated with WUE and stem P concentrations. Inoculation of AMF or phosphorus addition could improve the growth, physiology, and phosphorus uptake in spring wheat under drought conditions.

Effect of phosphorus addition on onion plants grown in 13 soils of varying degree of weathering

ABSTRACTPhosphorus (P) phytoavailability decreases with soil weathering, however P dynamics in high-P soils with relatively narrow differences in weathering and further addition of P is not known. In the present study, P dynamics and availability in soils varying in their chemical properties and P availability were examined. Onion plants were grown in 13 high-P soils at two P levels [Ρ0 and Ρ1]. Extractable P was assessed with Olsen, Mechlich-3, ammonium oxalate, and water soluble methods, as well as plant tissues P content and morphological features. Despite the initial high P content, all the measured parameters, including soil P, plant morphology, and P content, further increased at P1 compared to P0. Moreover, water soluble P, bulb weight, and plant P content exhibited greater differences between P0 and P1 in Alfisols. In conclusion, for high-P soils, P application could increase traits, such as onion bulb weight, especially for soils with higher weathering.

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.