Cent Of Phosphorus Research Articles

Characterization of Mulberry Stalk Biochar and its Impact on Soil Nutrients Release

An incubation study was conducted with graded levels of biochar to know the soil nutrients release till 120 days after incubation at Department of Soil Science and Agricultural chemistry, University of Agricultural Sciences, GKVK, Bengaluru during 2021. The experiment consisted of 4 treatments replicated five times and was laid out in a completely randomized design. The mulberry stalk biochar was characterized and recorded a pH of 8.53 and Electrical conductivity of 0.39 dS m-1. The physical properties like bulk density (0.32 Mg m-3) and maximum water holding capacity (93.14 %) were measured. Mulberry stalk biochar had 69.37 per cent of total carbon, 0.89 per cent Nitrogen, 0.22 per cent Phosphorus, 0.65 per cent Potassium and secondary nutrients like Calcium of 0.96 per cent, 0.48 per cent Magnesium and 0.18 per cent sulphur and micronutrients like Iron (493 mg kg-1), Zinc (34.59 mg kg-1), Manganese (94.1 mg kg-1), copper (20.55 mg kg-1) and boron (33.5 mg kg-1) were recorded. It was observed that with increased levels of biochar application to soil from 5 to 10 t ha-1 positively influenced the nutrient release pattern in the soil. Higher primary, secondary and micronutrients were recorded with application of biochar @ 10 t ha-1 (T3) at 60, 90 and 120 days after incubation and lower values were recorded in control treatment (T4).

Requirement of phosphorus and its use efficiency by sunflower (Helianthus annuus L.) in high phosphorus soils

Field experiments were conducted during kharif 2008, 2009 and 2010 to find out the phosphorus requirementto sunflower crop grown in a soil with high initial available phosphorus (110-119 kg P2O5/ha). Three years pooled data revealed that application of 100% recommended dose of P2O5(RDP) resulted highest seed yield of 12.18 q/ha. The seed yield increased significantly by about 9.51, 11.75, 12.50 and 13.62 per cent due to application of 25 (11.74 q/ha), 50 (11.98 q/ha), 75 (12.06 q/ha) and 100 (12.18 q/ha) per cent RDP, respectively over control (10.72 q/ha). However, the differences in seed yields observed at 50, 75 and 100% RDP are narrow and imperceptible. The per cent phosphorus derived from fertilizer (% Pdff) and phosphorus-use efficiency decreased significantly from 21.10 to 19.93 per cent and 24.19 to 6.67 per cent, respectively due to increase in P level from 25 to 100% RDP, whereas the fertilizer P uptake and soil P uptake increased from 1.58 to 1.75 kg/ha and 5.93 to 7.03 kg/ha, respectively with increase in P level from 25 to 100% RDP. The extent ofsaving in P fertilizer in these soils is ranged from 75 to 100 per cent depending upon the P build up in the soil.

Towards minimizing wear by improving antiwear additives and surface characteristics using reduced phosphorus plain ZDDP oil under boundary lubrication

Purpose – This study aims to examine the effect of the antiwear resistance of plain zinc-dialkyldithiophosphate (ZDDP) oil in the presence of Titanium-fluoride/iron-fluoride/polytetrafluoroethylene (TiF3/FeF3/PTFE) in the time to tribofilm breakdown and extent of wear under extreme boundary lubrication using a contact load of 317 Newton and a rotational speed of 700 rpm to simulate the cold start of a car engine. The mechanism of tribofilm formation and breakdown was followed carefully by monitoring the friction coefficient for different surface roughnesses over the duration of several reproducible tests that were performed in a ball on cylinder tribometer. Design/methodology/approach – The heating time of the cylinder dipped in the specified lubricant blend then set for one minute before testing and the break in period of 2 minutes to cool the contacting metal to metal surfaces during tribological testing played important roles in minimizing friction and wear, and are directly proportional to the durability and time for breakdown of the tribofilm. This article addresses the improvement of water drop contact angles for different surfaces during heat treatment and the tribological enhancement of antiwear additives when optimum concentration of fluorinated catalysts and PTFE is used in connection with reduced surface roughness and break in period. Findings – Design of Experiment software, scanning electron microscopy, energy dispersive spectroscopy and nanoindentation were used in this study to evaluate the antiwear resistance films when using 0.05 per cent phosphorus ZDDP plain oil with 0.5 weight per cent TiF3 + 0.5 weight per cent FeF3 + 2 weight per cent PTFE and when applying 2 minutes break in time to cool down the contacting bodies when temperature rises. Results indicated that the coated film on the thermally treated surfaces that is reflected as white patches on the SEM images is a function of the antiwear additives contribution; it is also shown to have positive influence on the friction and wear performances during tribological testing. Originality/value – This research involved the study of lubricant and surface interactions with antiwear additives under boundary lubrication and extreme pressure loading. Several researchers studied these effects and submitted articles to the journal. This is the first time that a break in period was used with surface conditions to simulate car stops in heavy traffic conditions.

Assessment of Calcium Phosphate Nanoparticles as Safe Mineral Supplement for Broiler Chicken

An experiment was carried out with the objective with assessment on the safety of calcium phosphate nanoparticles as mineral supplement to broiler chicken. With the help of an indigenous laboratory equipment calcium phosphate nanoparticles were prepared by wet chemical method. Calcium phosphate nanoparticles were analyzed for its size and shape using TEM. It was ranged from 20 to 90 nm with spherical shape. The calcium and phosphorous content was estimated. Results show that 30.81 per cent calcium and 15.48 per cent phosphorus. Using the Vero cell line in vitro cytotoxicity study carried out that indicated 10 mg/ml of calcium phosphate nanoparticles did not provoke observable cellular insult. The in vivo assessment was also done using hematological and serum biochemistry parameters in birds fed with calcium phosphate nanoparticles at graded concentration at 50, 60, 70, 80, 90 and 100% of the phosphorus content of coarse particles of dicalcium phosphate in the diet from day old to 28 days. The results indicated that Calcium phosphate nanoparticles did not exert any significant (P<0.05) influence on haemoglobin, Packed cell volume, total erythrocytes count, total leucocytes count, and differential count of WBC compared to control (fed with dicalcium phosphate). The inclusion of calcium phosphate nanoparticles from 50 to 100% did not have any significant negative influence on the serum glucose, total protein, albumin, triglyceride, cholesterol, serum urea, creatinine, serum Aspartate amino Transferase (AST), Alanine amino Transferase (ALT) and Alkaline Phosphatase (ALP). Hence, it was concluded that calcium phosphate nanoparticles are safe to use since an adult bird would consume at a concentration not more than 6.4 mg/ml which is well within the safe level of 10mg/mlas identified by in vitro cytotoxicity test on vero cell line.

Differential response of phosphorus utilization efficiency in rice by tracer technique using phosphorus-32 under phosphorus stress environment

In most soils, soil and fertilizer Phosphorus (P) are easily bound by either soil organic matter or chemicals and thus are unavailable to plants unless hydrolyzed to release inorganic phosphate. Therefore, the development of P-efficient rice varieties that can grow and yield better with low P supply is a key to improve crop production. P efficient plants play a major role in increasing crop yields due to shortage of inorganic P fertilizer resources, limited land and water resources and increasing environmental concerns. Based on the P uptake efficiency, four rice genotypes viz.,TNRH 180, CB08504, CB06732 and ADT 47 were selected from the field experiment and used in pot culture experiment with three levels of P using radio isotope technique to quantify the P acquisition efficiency (PAE) and P use efficiency (PUE) and also to determine the native P supplying power of the soils using 32P in low P soils. Growth and yield parameters, grain and straw yield and major nutrients uptake of rice genotypes were increased with enhanced level of phosphorus application. Among the four genotypes, TNRH 180 recorded the highest grain yield and uptake. Increasing the P application rate from 25 to 50 kg P2O5 ha-1 increased the %Pdff in grain and straw for all the genotypes. The mean per cent phosphorus utilization (PPU) ranged between 18.74 and 23.72. The PPU of the genotypes followed the order TNRH 180 (23.72 %) &gt; CB08504 (23.36 %) &gt; CB06732 (20.54%) &gt; ADT 47 (18.74%). The PPU values were higher at lower level of P application (25 kg P2O5 ha-1) for the genotypes TNRH 180, CB08504 and CB06732. From this study showed that rice genotypes have the ability to utilize the both available and unavailable form of phosphorus by secreting some organic acids in the root portion to solubilize. Hence rice genotypes indicated above have the ability to increase phosphorus utilization efficiency.

Effect of different levels and placement of32P labelled single super phosphate on absorption of phosphorus by banana cv. Robusta under high density planting

Absorption of applied 32P by the treated as well as neighbouring banana cv. Robusta plants under high density planting was studied on a sandy clay loam soil using 32P labelled super phosphate with application of three levels of P fertilizers viz., 60, 80, and 100 per cent at 15–35, 35–55 and 55–75 cm distance from pseudostem of the plant. The first, 2nd and 3rd dose of urea, labelled single superphosphate and muriate of potash was applied to banana at early vegetative (8th leaf/65 DAP), late vegetative (16th leaf/115 DAP) and bud differentiation stages (165 DAP). Higher 32P absorption (dpm/g of dry matter) in leaf was observed in the treatments supplied 100 per cent of recommended dose of fertilizers at closer distance of 15 to 35 cm distance from pseudostem during first split application and at middle distance of 35 to 55 cm from pseudostem during second and third split application. The maximum per cent phosphorus derived from fertilizer (% Pdff) was also recorded with the application of 100 per cent recommended dose of P fertilizers in the middle distance of 35–55 cm from the pseudostem of the experimental plant. No significant difference was observed in the leaves of Robusta banana. The study has brought out the differential nature of the absorption pattern in treated plant and border plants with different levels and placement of fertilizers. Radiophosphorus applied to the root zone was absorbed by the treated plant and the neighbouring plants.

Cost-effective strategies to mitigate multiple pollutants in an agricultural catchment in North Central Victoria, Australia

Strategies to reduce phosphorus and sediment yields are identified for two Australian catchments using a nonlinear optimisation model. This provides novel insight into the cost-effective management of dual pollutants of water courses in Australia. A strong degree of complementarity between the two pollutants is highlighted, given the adsorption of phosphorus to sediment that augments the value of gully and streambank management for mitigation. However, the relationship between the two pollutants is asymmetric. A 30 per cent reduction in phosphorus yield achieves a 75 per cent reduction in sediment yield in one catchment, while a 30 per cent reduction in sediment yield achieves only a 12 per cent reduction in phosphorus yield. Sediment abatement costs are low given the efficiency of gully and streambank management. A 30 per cent phosphorus reduction lowers profit by 3–7 per cent, while a 30 per cent sediment reduction lowers profit by around 1 per cent. Land-use optimisation requires spatial heterogeneity in land-use and gully/streambank management responses. Overall, this research demonstrates the need to determine whether one pollutant is more important than another, while recognising the potential that mitigation practices possess for the reduction of multiple emissions during their evaluation.

Composting of Oil Palm Empty Fruit Bunch and Decanter Cake Slurry with the Addition of Palm Oil Mill Effluent

Formation of compost from oil palm empty fruit bunches (EFB) and decanter cake slurry by adding palm oil mill effluent (POME) with regular turning operation was investigated. The addition of decanter cake slurry has hastened the composting process of the EFB. The C/N ratio after 51 days for the mature compost with the decanter cake slurry was 18.65 while for the matured compost without the decanter cake slurry remained high at 28.96. The compost formed from the addition of decanter cake to EFB and POME had 46.4 per cent nitrogen, 17.9 per cent phosphorus, 17.7 per cent potassium and 23.1 per cent calcium more than that without decanter cake. The use of compost produced from EFB, POME and decanter cake slurry could solve more environmental problems and enhance economic benefits in the oil palm industry. Keywords: Empty fruit bunches, palm oil mill decanter cake slurry, palm oil mill effluent, waste management

Valvetrain friction and wear: Influence of surface engineering and lubricants

Customer demand and legislative pressure are continually challenging automotive manufacturers to improve the fuel economy of their vehicles. Several technologies are currently being evaluated to meet this challenge. Tribology can play a significant role in bringing some of these technologies to a more mature state and can also make enhancements to existing technologies to reduce frictional losses in the powertrain. Although the valvetrain contributes only 6-10 per cent of the total frictional loss in an engine, all opportunities are explored to reduce frictional losses further, provided they are cost effective. This paper describes attempts to reduce frictional losses in directacting mechanical bucket tappet type valvetrains through surface finish, surface texture and coatings. It was observed that surface finish and surface texture could reduce frictional losses, but engine oil formulation also plays a significant role. Improvements were observed with non-friction-modified oils, but with friction-modified oils the overall friction was lower but no additional friction benefit could be observed with surface finish or surface texture. This paper also addresses wear concern associated with implementation of proposed GF-4 low-phosphorus engine oils. The wear was measured by a radiotracer technique. It was observed that, if the engine oils are formulated properly, low-phosphorus engine oils provide similar or better wear protection compared with GF-3 oils containing 0.1 per cent phosphorus.

Yield sustainability and phosphorus utilization in soybean–wheat system on Vertisols in response to integrated use of manure and fertilizer phosphorus

Low native soil phosphorus (P) availability coupled with poor utilization efficiency of added P is a major constraint limiting the productivity of soybean–wheat system on Vertisols in Indian semi-arid tropics. The use of fertilizer P is limited by its high cost, while organic inputs generally cannot provide sufficient P for optimum crop growth due to their low P concentration. We, therefore, evaluated in a 5-year field experiment (1992–1997) the effects of integrated use of manure and fertilizer P on crop yield sustainability, P utilization and soil P fertility under soybean–wheat system on a Typic Haplustert. The treatments consisted four rates each of manure (applied only to soybean) and fertilizer P (applied to both soybean and wheat) arranged in a split-plot design with four replications. Both soybean and wheat crops responded significantly to the application of manure and fertilizer P. For the same level of P input, the yield increases were greater with manure P than with fertilizer P. Further, integrated use of fertilizer P and manure was better than their sole application in increasing and sustaining the productivity of soybean–wheat system. The P uptake by the crops increased with increasing rates of manure and fertilizer P and was relatively larger in soybean than in wheat. The per cent phosphorus recovery by the crops from fertilizer P decreased with increasing fertilizer P rate, while it was improved in the presence of manure. Though the extent of fertilizer P recovery was more or less similar in both the crops, soybean was more efficient than wheat in extracting the soil and manure P. The available P status of the soil showed a significant build-up during successive cropping seasons due to fertilizer P and the increase was strikingly greater when fertilizer P was applied in combination with manure. The integrated use of manure and fertilizer P is a promising strategy to improve soil P fertility status and to obtain higher and sustained productivity of the soybean-wheat cropping system on Vertisols of the semi-arid tropics.

EFFECT OF COMBINED INOCULATION OF Rhizobium sp AND PHOSPHOBACTERIA AT DIFFERENT LEVELS OF PHOSPHORUS IN GROUNDNUT

A field trial was conducted at the Agricultural Research Station, to study the effect of combined inoculation of Rhizobium strain T19 with a phosphobacterium. Bacillus megaterium var. Phos phaticum (PB 1) at different levels of phosphorus in groundnut (Co 1). Maxiumum crop growth, nodulation, plant dry weight and yield were obtained in treatments which received hundred per cent chemical fertilizer. The combined inoculation of Rhizobium and phosphobacteria at 50 per cent gave a comparable yield to 100 per cent phosphorus level with no bacterial inoculation indicating a saving of 50 per cent chemical fertilizer.

USE OF PHOSPHATE SORPTION ISOTHERMS FOR ASSESSING P NEEDS OF MAIZE (Zea mays) IN SOME SOIL TYPES OF KARNATAKA

Study of phosphorus sorption isotherms of vertisol (Hanchinal), alfisol (Gubbi), oxisol (Ankola) and inceptisol (Kudalasangum) to predict the P needs of Deccan 101 maize (Zea mays L.) revealed that an equilibrium P solution concentration of 0.2 ppm would be optimum to get maximum dry matter yield. Per cent phosphorus content of maize was also maximum in all the soil types at an equilibrium P concentration of 0.2 ppm. Near maximum uptake of P by maize in all soil types except oxisol was observed at an equilibrium concentration of 0.2 ppm.

Variation in the major element content of red spruce foliage with season, crown position, tree and tissue age

Abstract Three different age classes of red spruce were sampled and analysed to determine the variability in the major element content with seasonal and sampling part changes. Results show a definite seasonal pattern for each element. Variations in nutrient content occur with changes in the sample crown position, tree and tissue age. Regeneration stands have statistically higher nitrogen contents, while the more mature stands are significantly higher in the other elements. Upper crown samples have higher contents of nitrogen, phosphorus and magnesium while the lower crowns have higher ash, calcium and potassium contents. Nutrient levels are low and the mean values for regeneration, immature and mature stands range between 0.95–1.19 per cent nitrogen; 0.089–0.143 per cent phosphorus; 0.46–0.59 per cent potassium; 0.18–0.31 per cent calcium; 0.056–0.100 per cent magnesium and 2.12–2.76 per cent ash.

Observations on the phosphorus requirement of cattle for growth

Weaner cattle were fed ad libitum a diet of Stylosanthes humilis (Townsville stylo) containing 1.80 per cent nitrogen and 0.12 per cent phosphorus in the dry matter, with or without a supplement of phosphorus at the rate of 5 g/day. The feed was consumed in amounts sufficient to support gains in weight of over 0.5 kg/day during the experiment, and the supplement had no influence on voluntary feed intake, live weight gain or phosphorus concentration in samples of rib bone obtained by biopsy at the end of the experiment. It is suggested that the recomendations of the Agricultural Research Council and the National Research Council for the intake of phosphorus by young growing cattle overestimate requirements by approximately 35 per cent.

Isolation of a low molecular weight glycoprotein inhibitor of calcium phosphate precipitation from the extra-parotid saliva of macaque monkeys

A low molecular weight (9600) glycoprotein was isolated from monkey ( Macaca arctoides) extra-parotid saliva by gel filtration on Sephadex G-200 and Sephadex G-50. Criteria of purity included immunodiffusion, immunoelectrophoresis and polyacrylamide gel electrophoresis. The molecule contained 76 per cent protein, 23.4 per cent carbohydrate and 0.6 per cent phosphorus. The glycoprotein was a potent inhibitor of calcium phosphate precipitation.

Effect on soil and plant mineral levels following application of manures of different copper contents

Manure from finishing pigs fed diets with and without a growth stimulating level of added copper (250 ppm in 1972, 370 ppm in 1973 and 300 ppm in 1974) was incorporated into a Groseclose silt loam at the rate of 15.5, 12.9 and 15.7 metric tons of dry matter per hectare, respectively, for 1972, 1973 and 1974. A third treatment was no manure. The manure was applied between rows when corn was about 10 cm tall and worked into the surface 10 cm of the soil with a rotary tiller. The average composition of the manure for the three years on a dry basis was 3.6 per cent nitrogen, 2.87 per cent calcium, 0.93 per cent magnesium, 2.22 per cent phosphorus, 1.30 per cent potassium, 648 ppm zinc, 2191 ppm iron. The copper content was 73 ppm for control manure and 1719 ppm for high copper manure. The copper content in the upper 10 cm of the soil was significantly increased each year when high copper manure was applied. During one growing season, copper did not appear to move down, however, plowing after the first year increased the copper level in the 10–20 cm depth with a small increase in the 20–30 cm depth. Potassium, zinc, phosphorus, calcium and magnesium levels of the soil were increased when manure was applied. There was a small increase in the copper content of the maize ear leaf (average of one ppm per year) when manure from pigs fed diets containing high copper was applied. Copper in the washed roots of the mature maize plants was doubled (5.6 vs 11.2 ppm) when the high copper manure was added. The copper content of grain from plants grown on soil receiving high copper manure was not different from that of grain from soil receiving no manure. The zinc, potassium and phosphorus contents of the maize ear leaf were increased a small amount when both control and high copper manure were applied with the effect of potassium and phosphorus carrying over to the grain. The iron and calcium contents of the ear leaf were not affected by application of manure, but there was a decrease in calcium content of the grain from the application of control and high copper manure. re]19750305

Influence of phosphorus content on feed intake and weight gain in sheep

In two experiments penned sheep were fed the dry residues from subterranean clover based pastures. Phosphorus levels in the pelleted residues, produced by varying the rate of superphosphate application, ranged from 0.07 to 0.23 per cent. In addition, a high phosphorus ration was produced by the addition of inorganic phosphate salts. This supplement raised the phosphorus concentration from 0.07 to 0.30 per cent of dry matter. In both experiments, increasing the concentration of phosphorus in the dry feed by higher fertilizer rates resulted in: increased dry matter intake; increased percentage of dry matter digested (at least in one experiment) ; more phosphorus retained by the sheep (although on feed containing 0.1 1 per cent phosphorus or less, losses still exceeded gains) ; and increased body weight gains. Increasing the phosphorus content of the feed by use of an inorganic supplement gave: a smaller increase in dry matter intake; decreased digestibility; positive phosphorus balances; and an increase in body weight gain of about half that given by unsupplemented feed high in phosphorus. The results indicate that for maximum animal production, phosphorus concentrations needed in the dry feed are higher than those produced by fertilizing legume-based pastures at the lowest rate that gives maximum dry matter production. Near linear responses in body weight gains were obtained up to phosphate fertilizer rates of about three times those needed for maximum pasture yield.

Electron microprobe analysis of iron content of incisor enamel in some species of rodentia

Enamel from maxillary incisors of six species was analysed. In those species where pigmentation was observed in the outermost layer of enamel, a corresponding iron-rich zone was demonstrated by elemental analysis. The enamel of squirrel and beaver contained about 10 per cent of iron close to the enamel surface and the concentration gradually decreased to less than 0.1 per cent within 20–30 μm from the surface. Through the same zone, the calcium and phosphorus concentration profile lines showed a gradual increase until a plateau was reached (about 36 per cent calcium and 17 per cent phosphorus) at the point where iron had decreased below a detectable level. This inverse relationship between iron on one hand and calcium and phosphorus on the other was clearly seen in incisor enamel of hamster and mouse which contained a maximum of 5–6 per cent iron near the enamel surface, but was not observed in the lemming (maximum 3 per cent iron). In the non-pigmented enamel of the guinea-pig, iron was not detected at the 0.1 per cent level, and the calcium and phosphorus profile lines followed a horizontal course through the entire width of the enamel. The sum of iron, calcium and phosphorus was approximately equal in all analysed areas. The results indicate that a clear relationship exists between pigmentation and iron content of rodent incisor.

Effects of soils, fertilizers and stocking rates on pastures and beef production on the Wallum of south-eastern Queensland. 3. Relation of liveweight changes to chemical composition of blood and pasture

During the concluding phase of a six-year grazing trial a study was made of the steers and the pasture material from paddocks annually fertilized with 125 kg ha-1and 250 kg ha-1of superphosphate. Plucked pasture samples from the low and high superphosphate treatments contained 0.11 and 0.15 per cent phosphorus, 0.83 and 0.91 per cent nitrogen and 0.12 and 0.12 per cent sulphur, respectively. The N: S ratio of these samples were 6.8 and 7.6 and the in vitro digestibilities were 41.6 and 44.9 per cent. There were marked seasonal patterns in the concentrations of all components with minimum values in the winter months when liveweight gain was lowest. Greater superphosphate application increased mean liveweight gain (0.29 to 0.41 kg head-1day-1), mean plasma concentrations of both urea-nitrogen (6.3 vs 5.0 mg 100 ml-1) and of inorganic phosphorus (6.7 vs 6.3 mg 100 ml-1). The mean blood sulphate-sulphur concentration of 28 �g ml-I was not influenced by treatment. Comparisons of the levels of nutrients in pasture and blood with published requirements indicated that neither sulphur nor phosphorus were deficient in either treatment. However, the between treatment differences in both nitrogen and phosphorus levels could not be ignored as possible reasons for the difference in animal production between the two levels of superphosphate application. Improved animal performance associated with increased application of superphosphate was probably influenced more by the induced changes in the organic components rather than the mineral levels of the pasture material.

Liquid encapsulated growth of GaP from non-stoichiometric melts

Crystals of GaP have been grown by the liquid encapsulation Czochralski (LEC) technique from non-stoichiometric melts at temperatures between 1430°C and 1200°C. Using melt compositions of 36 atom per cent phosphorus (36 at% P) and 30 at% P, satisfactory growth was obtained at 0.5-0.3 in./hr. These crystals which had a maximum diameter of 0.6 in. and weighed up to 25 g were free of second phase and contained lower dislocation densities (104 cm−2 and 102 cm−2 respectively) than GaP grown from stoichiometric melts. Crystals grown at rates between 0.3-0.1 in./hr from solutions containing 20 at% P and 10 at% P exhibited some cellular growth morphology and generally contained excess gallium. Correlated with decreasing growth temperature is a large increase in the red photoluminescence quantum efficiency reaching 0.8% for a crystal grown from a 10 at% P solution.