Journal articles: 'Phosphorus estimation'

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Sawut, Mamat, Xin Hu, Yierxiati Abulaiti, et al. "Estimation of Leaf Phosphorus Content in Cotton Using Fractional Order Differentially Optimized Spectral Indices." Plants 14, no. 10 (2025): 1457. https://doi.org/10.3390/plants14101457.

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The accurate and timely detection of leaf phosphorus content (LPC) is extremely important for the fertilization management of crop growth and yield. This study aimed to establish an estimating model of LPC in cotton based on hyperspectral data. Under field experimental conditions with different phosphorus treatments, the spectral data and LPC were measured. The spectral characteristics of different cotton cultivars and leaves with varying phosphorus content were analyzed. Optimized spectral indices most correlated to phosphorus were calculated with combinations of arbitrary bands using the Fractional Differential Order (FOD) transform. Then, the random forest-based(RF) estimation model for cotton LPC was established. The research results indicated that (1) the spectral changes of 24 cotton cultivars were basically consistent, and spectral differences between the cultivars became more obvious within the 760–960 nm spectral region; (2) in the visible region, the reflectance of cotton under different phosphorus treatments did not show obvious regularity, while in NIR, the reflectance of cotton increased with the increase in phosphorus content, showing a certain difference in phosphorus; (3) the RF model using a difference spectral index (DSI) had the best performance for LPC estimations in calibration (R2 = 0.78) and validation (R2 = 0.85), which was superior to the other models based on two spectral indices (the NDSI and RSI). This study provides technical support for the hyperspectral estimation of LPC in cotton.

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LOUVANDINI, H., and D. M. S. S. VITTI. "PHOSPHORUS METABOLISM AND ESTIMATION OF PHOSPHORUS REQUIREMENTS FOR SHEEP." Scientia Agricola 53, no. 1 (1996): 184–89. http://dx.doi.org/10.1590/s0103-90161996000100027.

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The main objective of the present work was to determine the effects of different dietary phosphorus (P) levels on endogenous faecal loss and to estimate the minimum daily requirement of P for sheep. The study was conducted with 24 Suffolk sheep which received a basic diet consisting of hay-concentrate mixture. The treatments consisted of different amounts of bone meal, added to the basic diet, so as to obtain supplementary P levels of 0, 1, 2 and 3g/day. Twenty-one days after the introduction of the experimental diet, 7.4 MBq radioactive P (32P) was injected into the left jugular vein of each sheep and blood, faeces and urine samples were collected daily for 8 days at 24-hour intervals. The samples were analysed for inorganic P and for radioactive specific activities. Mean endogenous faecal losses of P were 19.00, 31.79, 39.35, and 38.06mg/kg live weight (LW) per day in sheep supplemented with 0, 1, 2, and 3g, respectively. A positive linear relationship was observed between endogenous faecal loss and consumed P, indicating that this loss was linked to dietary P. Total P excretion in the faeces, as well as P absorption, retention, urinary excretion and salivary secretion were also directly related to P intake, as part of the mechanism of homeostatic control of organism animal. The minimum endogenous faecal loss for zero P intake, calculated by interpolation, was 8.27mg/kg LW per day, and for zero balance, the calculated phosphorus consumption was 21.36mg/kg LW per day.

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Slović, Z. M., D. Bradarić, Karlo Raić, and J. Z. Slović. "Estimation of phosphorus distribution ratio at the end of blowing in BOF." Metallurgical and Materials Engineering 27, no. 4 (2021): 425–36. http://dx.doi.org/10.30544/646.

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In integrated steel plants, the removal of phosphorous normally takes place during the primary basic oxygen furnace (BOF) steelmaking process. Phosphorous is usually introduced to the integrated steelmaking process through blast furnace additions, such as iron ore, coke, sinter, and fluxes. Among the others parameters such as optimizing the charging system, oxygen supply system, oxygen lance parameters of the converter, the flux quality in combination with temperature process control can improve the BOF efficiency of Dephosphorization. Phosphorus partition ratio (LP) is usually used to evaluate the thermodynamic efficiency of the dephosphorization of slags with different compositions in steelmaking processes. However, this parameter is only useful in equilibrium conditions, and it is not accurate when used to evaluate slag efficiency in industrial processes. Because of this, the aim of this work was to study the phosphorus partition ratio estimated from the experimental results in real plant conditions of two different BOF steel plants and compare them with well-known published models. In the present study, data from two steel plants (further Plant A and Plant B) were evaluated applying Healy’s, Suito and Inoui’s, Zhang’s as well as Assis’s equations. The calculated values were compared against measured values.

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M. Hasan and N. P. S. Sirohi. "Irrigation and Fertigation Scheduling for Peach and Citrus Crops." Journal of Agricultural Engineering (India) 43, no. 4 (2006): 43–46. http://dx.doi.org/10.52151/jae2006434.1215.

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A completely automatic drip irrigation system used in fertigation for peach and citrus was designed and installed at the IARI farm. A separate fertigation control unit was made for operation and control of fertigation of fruit crops in the orchard. Fertigation scheduling comprised two important components i.e. estimation of crop water and nutrient requirement and their application in correct dosage at appropriate stage. The water requirement varied in different months and at various stages of the crop. Hydraulic fertilizer pumps were used for the fertigation through solenoid operated hydraulic valves. The most suitable dose of nitrogen, phosphorus and potassium was found to be 30, 15 & 30 ppm in peach and 60, 30 & 60 ppm in citrus during the initial stages of growth and fruiting. The annual consumption of major nutrients per tree was found to be 354 gm for nitrogen, 160gm for phosphorus and 345 gm for potassium. Water soluble fertilizers viz., Potassium nitrate, Ammonium nitrate and Phosphoric acid were used for fertigation. Potassium nitrate was the only source of potassium while nitrogen was found in both potassium and ammonium nitrate. Phosphoric acid served the twin purpose of phosphorous source as well as cleaning of lateral pipes of drip irrigation, whenever so required.

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Tarasova, Natalia P., Anna S. Makarova, Evgeniya G. Vasileva, and Diana D. Savelova. "Estimation of the phosphorus loading with consideration for the planetary boundaries (for the Russian Federation as an example)." Pure and Applied Chemistry 89, no. 3 (2017): 287–92. http://dx.doi.org/10.1515/pac-2016-0904.

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AbstractSome scientists believe today that problems related to phosphorus entry into fresh-water bodies may be more important for setting the planetary boundary. Excessive entry of biogenic elements (especially phosphorus) into water bodies and water streams causes their eutrophication. This process may cause a decrease in the light transmittance of surface water layers and other consequences for ecosystem and humans. In this paper the results of model application for the estimation of the phosphorus content in fresh waters of the Russian Federation regions are presented. The method for the estimation of the phosphorus amount in fresh water was developed on the basis of the dynamic model. Phosphorus loading is most characteristic of regions that have developed types of agriculture which cause increases the rate of mineral phosphorus entry into erodible soil.

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Pererva, Yehor, Charles D. Miler, and Ronald C. Sims. "Sulfur, Phosphorus and Metals in the Stoichiometric Estimation of Biomethane and Biohydrogen Yields." Processes 8, no. 6 (2020): 714. http://dx.doi.org/10.3390/pr8060714.

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The estimation of biomethane or biohydrogen yield is used to evaluate energy recovery during the process of the anaerobic treatment of waste and wastewater. Mathematically calculated theoretical values can also be used in biomethane or biohydrogen potential tests as reference points to calculate which fraction of substrate is decomposed, when the substrate degradation stopped and when the sample’s self-digestion begins. This study suggests expanded forms of equations for anaerobic processes leading to either biomethane or biohydrogen. The traditional equations describing the conversion of a substrate with known carbon, hydrogen, oxygen and nitrogen composition were expanded to account for the composition of sulfur (for biohydrogen yields) and phosphorus (both biohydrogen and biomethane yields). As an optional part, one metal cation was also incorporated into the chemical formula of the evaluated wastewater composition in case the compound of biodegradable interest exists as a salt. The equations derived here can be useful for researchers estimating energy recovery based on the elemental analysis of samples, such as algal biomass harvested during harmful algal blooms (HABs). Examples of biomethane and biohydrogen yield estimations from sulfur- and phosphorus-containing compounds are also provided.

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Samar A. Yako and Payman A. A. Zibari. "ESTIMATION VARIABILITY AND SOME GENETIC PARAMETERS FOR YIELD AND ITS COMPONENTS IN PEA GENOTYPES UNDER DIFFERENT PHOSPHOROUS LEVELS." IRAQI JOURNAL OF AGRICULTURAL SCIENCES 56, no. 2 (2025): 668–76. https://doi.org/10.36103/pnwyex20.

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This study aimed to estimate variability and some genetic parameters for yield and yield components in pea (Pisum sativum L.) genotypes under different phosphorous levels. A field experiment was carried out at the field of Horticulture Department, College of Agricultural Engineering Sciences, Duhok University, on the 1st of November 2021. the experiment unites layout according to split-plot arrangement, the main plots include phosphorus levels (0, 18, 36, and 54 kg ha-1 P2O5 and the subplot represented the thirteen genotypes within RCBD. The results exhibited that phosphorus levels were highly significant for all traits except biological yield, also the genotypes show highly significant the with exception of harvest index, while the interaction between phosphorus levels and genotypes was highly significant for all studied traits except harvest index and pod length. The rate of 54 kg ha-1 P2O5 gave the highest value for the number of pods 281.359), length pod 3.94, 500 seed weight 86.54, biological yield 361.55, harvest index 10.82 and yield seed per plant 23.30. The local variety was superior in leaf area 808.08mm, length pod 10 cm, 500 seeds weight 25.369, also the genotype (1) gave the highest yield per plant 44.0367 kg ha-1 P2O5, for the interaction between genotypes and phosphorus levels of genotype (2).

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Chen, Shengyue, Zhenyu Zhang, Juanjuan Lin, and Jinliang Huang. "Machine learning-based estimation of riverine nutrient concentrations and associated uncertainties caused by sampling frequencies." PLOS ONE 17, no. 7 (2022): e0271458. http://dx.doi.org/10.1371/journal.pone.0271458.

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Accurate and sufficient water quality data is essential for watershed management and sustainability. Machine learning models have shown great potentials for estimating water quality with the development of online sensors. However, accurate estimation is challenging because of uncertainties related to models used and data input. In this study, random forest (RF), support vector machine (SVM), and back-propagation neural network (BPNN) models are developed with three sampling frequency datasets (i.e., 4-hourly, daily, and weekly) and five conventional indicators (i.e., water temperature (WT), hydrogen ion concentration (pH), electrical conductivity (EC), dissolved oxygen (DO), and turbidity (TUR)) as surrogates to individually estimate riverine total phosphorus (TP), total nitrogen (TN), and ammonia nitrogen (NH4+-N) in a small-scale coastal watershed. The results show that the RF model outperforms the SVM and BPNN machine learning models in terms of estimative performance, which explains much of the variation in TP (79 ± 1.3%), TN (84 ± 0.9%), and NH4+-N (75 ± 1.3%), when using the 4-hourly sampling frequency dataset. The higher sampling frequency would help the RF obtain a significantly better performance for the three nutrient estimation measures (4-hourly > daily > weekly) for R2 and NSE values. WT, EC, and TUR were the three key input indicators for nutrient estimations in RF. Our study highlights the importance of high-frequency data as input to machine learning model development. The RF model is shown to be viable for riverine nutrient estimation in small-scale watersheds of important local water security.

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9

Davis, D. A., and C. R. Arnold. "Estimation of apparent phosphorus availability from inorganic phosphorus sources for Penaeus vannamei." Aquaculture 127, no. 2-3 (1994): 245–54. http://dx.doi.org/10.1016/0044-8486(94)90430-8.

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10

Miertschin, James D. "Alternative Methods for Estimation of Phosphorus Loadings." Journal of Environmental Engineering 112, no. 6 (1986): 1153–58. http://dx.doi.org/10.1061/(asce)0733-9372(1986)112:6(1153).

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11

Noor, Hamze, Seyed Khalagh Mirnia, Somaye Fazli, Mohamad bagher Raisi, and Mahdi Vafakhah. "Application of MUSLE for the prediction of phosphorus losses." Water Science and Technology 62, no. 4 (2010): 809–15. http://dx.doi.org/10.2166/wst.2010.092.

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Soil erosion in forestlands affects not only land productivity but also the water body down stream. The Universal Soil Loss Equation (USLE) has been applied broadly for the prediction of soil loss from upland fields. However, there are few reports concerning the prediction of nutrient (P) losses based on the USLE and its versions. The present study was conducted to evaluate the applicability of the deterministic model Modified Universal Soil Loss Equation (MUSLE) to estimation of phosphorus losses in the Kojor forest watershed, northern Iran. The model was tested and calibrated using accurate continuous P loss data collected during seven storm events in 2008. Results of the original model simulations for storm-wise P loss did not match the observed data, while the revised version of the model could imitate the observed values well. The results of the study approved the efficient application of the revised MUSLE in estimating storm-wise P losses in the study area with a high level of agreement of beyond 93%, an acceptable estimation error of some 35%.

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12

Bureau, D. P., and C. Y. Cho. "Phosphorus utilization by rainbow trout (Oncorhynchus mykiss): estimation of dissolved phosphorus waste output." Aquaculture 179, no. 1-4 (1999): 127–40. http://dx.doi.org/10.1016/s0044-8486(99)00157-x.

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13

Shuai, X., R. S. Yost, and O. Wendroth. "State-space estimation of the intrinsic soil phosphorus pools from soil phosphorus tests." Geoderma 214-215 (February 2014): 239–45. http://dx.doi.org/10.1016/j.geoderma.2013.09.006.

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14

Tafesse Tirkaso, Wondmagegn, and Ing-Marie Gren. "Habitat quality and fish populations: impacts of nutrient enrichment on the value of European perch off the east coast of Sweden." Environmental Economics 8, no. 1 (2017): 46–56. http://dx.doi.org/10.21511/ee.08(1).2017.05.

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Degradation of marine ecosystems through, e.g., eutrophication and climate change is a concern for sustainable fishery management worldwide, but studies on associated impacts on fish populations are rare. This study examines the effects of eutrophying nutrient loads on the economic value of perch populations along the Swedish east coast by estimating the effects of nutrient loads on the population of perch and, then, simulates the harvest value of future perch population under the changes in nutrient loads. A modified Gordon-Schaefer logistic growth model was used for econometric estimation of perch populations based on annual time series data for the period of 1970-2014. Regression analysis using the fully modified ordinary least square (FMOLS) estimator revealed that phosphorus loads had significant effects on the perch population. A 40% decrease in phosphorus loads, as suggested by the international HELCOM agreement, could increase the steady state perch population by 50%. Simple calculations showed that this could increase the total discounted recreational and commercial harvest value of the perch by 30% over a 30 year period.

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De Sisto, Makcim L., and Andrew H. MacDougall. "Effect of terrestrial nutrient limitation on the estimation of the remaining carbon budget." Biogeosciences 21, no. 21 (2024): 4853–73. http://dx.doi.org/10.5194/bg-21-4853-2024.

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Abstract. The carbon cycle plays a foundational role in the estimation of the remaining carbon budget. It is intrinsic for the determination of the transient climate response to cumulative CO2 emissions and the zero-emissions commitment. For the terrestrial carbon cycle, nutrient limitation is a core regulation on the amount of carbon fixed by terrestrial vegetation. Hence, the addition of nutrients such as nitrogen and phosphorus in land model structures in Earth system models is essential for an accurate representation of the carbon cycle feedback in future climate projections. Therefore, the estimation of the remaining carbon budget is impacted by the representation of nutrient limitation in modelled terrestrial ecosystems; however, it is rarely accounted for. Here, we estimate the carbon budget and remaining carbon budget of a nutrient-limited Earth system model, using nitrogen and phosphorus cycles to limit vegetation productivity and biomass. We use eight Shared Socioeconomic Pathways (hereafter SSP) scenarios and idealized experiments with three distinct model structures: (1) carbon cycle without nutrient limitation, (2) carbon cycle with terrestrial nitrogen limitation, and (3) carbon cycle with terrestrial nitrogen and phosphorus limitation. To capture the uncertainty in the remaining carbon budget, three different climate sensitives were tuned for each model version. Our results show that, overall, nutrient limitation reduced the remaining carbon budget for all simulations in comparison with the carbon cycle without nutrient limitation. Between nitrogen and nitrogen–phosphorus limitation, the latter had the lowest remaining carbon budget. The mean remaining carbon budgets obtained from the SSP scenario simulations for the 1.5 °C target in the non-nutrient-limited, nitrogen-limited, and nitrogen–phosphorus-limited models were 228, 185, and 175 Pg C, respectively, relative to the year 2020. For the 2 °C target, the mean remaining carbon budget values were 471, 373, and 351 Pg C for the non-nutrient-limited, nitrogen-limited, and nitrogen–phosphorus-limited models, respectively, relative to the year 2020. This represents a reduction of 19 % and 24 % for the 1.5 °C target and 21 % and 26 % for the 2 °C target for the respective nitrogen- and nitrogen–phosphorus-limited simulations compared with the non-nutrient-limited model. These results show that terrestrial nutrient limitation constitutes an important factor to be considered when estimating or interpreting remaining carbon budgets and that it is an essential uncertainty in the remaining carbon budgets from Earth system model simulations.

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Rasche Alvarez, Jimmy Walter, André Pellegrini, Gilmar Luiz Schaefer, Danilo Rheinheimer dos Santos, and Márcia Luciane Kochem. "Estimation of vulnerability to phosphorus loss by different versions of the phosphorus index method." Investigación Agraria 19, no. 2 (2017): 64–76. http://dx.doi.org/10.18004/investig.agrar.2017.diciembre.64-76.

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17

Nicholls, H. A., A. R. Pitman, and D. W. Osborn. "The Readily Biodegradable Fraction of Sewage: Its Influence on Phosphorus Removal and Measurement." Water Science and Technology 17, no. 11-12 (1985): 73–87. http://dx.doi.org/10.2166/wst.1985.0222.

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Various full-scale studies on the 5-stage Bardenpho process for biological phosphorus removal are reported with special reference to the role of readily biodegradable substrate in phosphorus removal. Results indicated that efficient denitrification was always a prerequisite for good phosphorus removal. The availability of fermencation products could greatly assist both nitrogen and phosphorus removal. Various options for the generation of these products are presented. Methods for the estimation of readily biodegradable substrates, of which fermentation products can be a component, are evaluated.

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Ritvo, G., M. Sherman, A. L. Lawrence, and T. M. Samocha. "Estimation of Soil Phosphorus Levels in Shrimp Ponds." Journal of Agricultural, Biological, and Environmental Statistics 5, no. 1 (2000): 115. http://dx.doi.org/10.2307/1400635.

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Rathore, Indira, and Jagadish Chandra Tarafdar. "Modified Labile Phosphorus Estimation Method for Arid Ecosystem." Communications in Soil Science and Plant Analysis 43, no. 11 (2012): 1542–49. http://dx.doi.org/10.1080/00103624.2012.675391.

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Chen, Yen-Chang, Jih-Hung Liu, Jan-Tai Kuo, and Cheng-Fang Lin. "Estimation of phosphorus flux in rivers during flooding." Environmental Monitoring and Assessment 185, no. 7 (2012): 5653–72. http://dx.doi.org/10.1007/s10661-012-2974-5.

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Jakubus, Monika. "Estimation of phosphorus bioavailability from composted organic wastes." Chemical Speciation & Bioavailability 28, no. 1-4 (2016): 189–98. http://dx.doi.org/10.1080/09542299.2016.1227687.

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John Zeman, L., and H. Olav Slaymaker. "Estimation of phosphorus flux in a regulated channel." Water Research 19, no. 6 (1985): 757–62. http://dx.doi.org/10.1016/0043-1354(85)90123-x.

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Overman, A. R., and S. R. Wilkinson. "Estimation of phosphorus and potassium concentrations in Bermudagrass." Fertilizer Research 22, no. 1 (1990): 7–14. http://dx.doi.org/10.1007/bf01054801.

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Du, Chenggong, Kun Shi, Naisen Liu, et al. "Remote Estimation of the Particulate Phosphorus Concentrations in Inland Water Bodies: A Case Study in Hongze Lake." Remote Sensing 14, no. 16 (2022): 3863. http://dx.doi.org/10.3390/rs14163863.

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Phosphorus is the most important nutrient associated with lake eutrophication and changes in cyanobacterial blooms, and particulate phosphorus (PP) is the main form of phosphorus found in highly turbid inland waters. Therefore, it is urgent to monitor PP concentrations in inland water bodies. In this study, we take Hongze Lake as the research area and establish a semianalytical model to estimate PP concentrations based on the total particle absorption coefficient (ap); the mean absolute percentage error (MAPE) and root-mean-square error (RMSE) values, which indicate the model accuracy, were 14.90% and 0.009 mg/L, respectively. In addition, the construction process and parameter selection criteria of the remote sensing-based PP concentration estimation model were derived using remote sensing data obtained at different spectral resolutions. Sentinel 3 Ocean and Land Color Instrument (OLCI) and Landsat 9 Operational Land Imager version 2 (OLI-2) data were selected as representatives to verify the accuracy of the model; compared to these two datasets, the MAPE values of the models were 16.32% and 26.84%, respectively, while the RMSE values were 0.010 mg/L and 0.014 mg/L, respectively. Finally, the models were applied to Sentinel 3 OLCI and Landsat 9 OLI-2 images obtained on 16 January 2022. The results show that the spatiotemporal distributions of PP concentrations in Hongze Lake estimated from these two images were relatively consistent, but the OLI data reflected overestimations and underestimations in some areas. These research results provide a new methodology for estimating PP concentrations through remote sensing methods and help to further improve the accuracy of remotely sensed PP concentration estimations in inland water bodies.

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Gatalskaya, E. V., and N. A. Belkina. "FEATURES OF PHOSPHORUS ACCUMULATION IN THE BOTTOM SEDIMENTS OF THE IVANKOVO RESERVOIR." Geopolitics and Ecogeodynamics of regions 6(16), no. 4 (2021): 139–53. http://dx.doi.org/10.37279/2309-7663-2020-6-4-139-153.

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The distribution of phosphorus in the bottom sediments of the Ivankovo reservoir, the forms of phosphorus and its content in different size fractions of the sediment were studied. It is shown that the main part of phosphorus is in mineral form and is contained in the clay fraction of sediment, which increases the risk of secondary pollution of water with phosphorus, due to its flow from bottom sediments in suspended form in the active dynamic zones of the reservoir. The estimation of the diffusion input of soluble forms of phosphorus from the bottom sediments of the reservoir accumulation zones was performed.

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Guse, B., A. Bronstert, M. Rode, B. Tetzlaff, and F. Wendland. "Application of two phosphorus models with different complexities in a mesoscale river catchment." Advances in Geosciences 11 (June 13, 2007): 77–84. http://dx.doi.org/10.5194/adgeo-11-77-2007.

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Abstract. The water balance and phosphorus inputs of surface waters of the Weiße Elster catchment, Germany, have been quantified using the models GROWA/MEPhos and SWAT. A comparison of the model results shows small differences in the mean long-term total runoff for the entire study area. All relevant pathways of phosphorus transport were considered in MEPhos with phosphorus inputs resulting to about 65% from point sources. SWAT focuses on agricultural areas and estimates a phosphorus input of about 60% through erosion. The mean annual phosphorus input from erosion calculated with SWAT is six times higher than the estimation with MEPhos due to the differing model concepts. This shows the uncertainty contributed by the modelling description of phosphorus pathways.

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Lima, Francisco Josivan de Oliveira, Fernando Bezerra Lopes, Daniel Antônio Camelo Cid, et al. "Determination of the Total Phosphorus Decay Coefficient Based on Hydrological Models in an Artificial Reservoir in the Brazilian Semi-Arid Region." Hydrology 12, no. 2 (2025): 36. https://doi.org/10.3390/hydrology12020036.

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Phosphorus input into surface water is a global concern due to its role in eutrophication, which is especially critical in semi-arid regions with their challenging climatic conditions. This study evaluated the best model for estimating the phosphorus decay coefficient (k) in semi-arid lakes, using flows from the Soil Moisture Accounting Procedure (SMAP), model of Génie Rural à 4 paramètres Journalier (GR4J), and reverse water balance hydrological models. Conducted at the Orós reservoir with 37 sampling campaigns from 2008 to 2017, it compared decay rates for temperate, tropical, and semi-arid climates. Some analyses also used phosphorus concentrations measured at the reservoir inlet. Model efficiency was assessed with bias, mean relative error, mean squared error, root mean squared error, and standard deviation. from the best models, water quality classes were classified based on phosphorus concentrations with the use of a confusion matrix to calculate accuracy, precision, recall, and F1 score. The findings demonstrated that the decay rate tailored for semi-arid regions, when combined with GR4J flow data, offered the highest accuracy in estimating phosphorus concentrations (bias = 0.0012, RMSE = 0.0326, EMR = 60.6134, STD = 0.0312). In contrast, the decay rate calibrated for tropical conditions with SMAP-derived flows proved superior for classifying water quality categories (classes defined by CONAMA Resolution 357/05). Therefore, the GR4J model for semi-arid conditions stands out for concentration estimation, while the tropical decay rate with SMAP flows is preferable for effective classification of water quality status.

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Panswad, Thongchai, Napaporn Tongkhammak, and Jin Anotai. "Estimation of intracellular phosphorus content of phosphorus-accumulating organisms at different P:COD feeding ratios." Journal of Environmental Management 84, no. 2 (2007): 141–45. http://dx.doi.org/10.1016/j.jenvman.2006.05.013.

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Zhu, Cheng Yi, Jun Liu, Guang Qiang Li, and Zhao Ping Chen. "Dephosphorization Ability Estimation of Fe_tO-Rich Demanganization Slag during Hot Metal Pre-Treatment." Advanced Materials Research 560-561 (August 2012): 1027–34. http://dx.doi.org/10.4028/www.scientific.net/amr.560-561.1027.

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In order to find out the optimum thermodynamic conditions for hot metal dephosphorization and predict phosphorus content after demanganization pretreatment, thermodynamic equilibrium experiments between CaO-FetO-SiO2-MnO-P2O5 slag and silver/solid iron were carried out in an iron crucible at different temperature under pure argon atmosphere in an electric resistant furnace. The results indicate that phosphorus distribution ratios increase with an increase of basicity in the slag at the experiment temperature, and then they decrease with an increase of basicity at 1573K and 1623K. The phosphorus distribution ratios decrease with an increase of FetO content in the slag at 1573K, while they increase with an increase of FetO content in the slag and then decrease with an increase of FetO content in the slag at 1623K. The results indicate that the maximum phosphorus distribution ratio between slag and hot metal is 92.4 when basicity of the slag is 1.7 and FetO content in slag is 49.75 mass% at 1623K, and the correspondent phosphorus content in the carbon saturated iron is 0.019mass%. Dephosphorization is easier under low temperature. The equilibrium quotient of phosphorus obtained in the present work is formulated as a function of slag compositions and temperature using the multiple regression method which is used to predict phosphorus content equilibrium with the demanganization slag and optimum conditions needed for ideal phosphorus contents in demanganization pretreatment.

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Chandniha, Surendra Kuman, Harshit Chouskey, S. K. Khunte, Muskan Sharma, and Harithalekshmi V. "Estimation of Soil Nitrogen, Phosphorous and Potassium Using IoT Based Sensor." Journal of Experimental Agriculture International 46, no. 8 (2024): 557–64. http://dx.doi.org/10.9734/jeai/2024/v46i82735.

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This study developed a sensor system to measure soil Nitrogen (N), Phosphorus (P), and Potassium (K) levels. Using an Arduino-based setup, the sensors were installed at different soil locations to provide real time nutrient data. The collected data was analyzed to determine nutrient levels, and the results were visualized using ArcGIS and the IDW method. The analysis showed significant variability in soil nutrient levels. Nitrogen levels were low in many locations, indicating a need for nitrogen fertilization. Phosphorus levels were mostly high, suggesting that additional phosphorus fertilization is not needed in most areas. Potassium levels were low in some locations, indicating the need for potassium fertilization in several locations. These findings helped to understand of nutrient dynamics in agricultural soils and underscore the role of IoT technology in precision agriculture for improving nutrient management strategies.

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Jun, K. S., J. W. Kang, and K. S. Lee. "Simultaneous estimation of model parameters and diffuse pollution sources for river water quality modeling." Water Science and Technology 56, no. 1 (2007): 155–62. http://dx.doi.org/10.2166/wst.2007.447.

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Diffuse pollution sources along a stream reach are very difficult to both monitor and estimate. In this paper, a systematic method using an optimal estimation algorithm is presented for simultaneous estimation of diffuse pollution and model parameters in a stream water quality model. It was applied with the QUAL2E model to the South Han River in South Korea for optimal estimation of kinetic constants and diffuse loads along the river. Initial calibration results for kinetic constants selected from a sensitivity analysis reveal that diffuse source inputs for nitrogen and phosphorus are essential to satisfy the system mass balance. Diffuse loads for total nitrogen and total phosphorus were estimated by solving the expanded inverse problem. Comparison of kinetic constants estimated simultaneously with diffuse sources to those estimated without diffuse loads, suggests that diffuse sources must be included in the optimization not only for its own estimation but also for adequate estimation of the model parameters. Application of the optimization method to river water quality modeling is discussed in terms of the sensitivity coefficient matrix structure.

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Pathak, Arvind, Tara Limbu Ijam, Akrasha Tamang, and Manoj Nidhi Wagle. "Estimation of nitrogen and phosphorus in fertilizers found in Nepalese market and some soil samples." Scientific World 17, no. 17 (2024): 66–70. http://dx.doi.org/10.3126/sw.v17i17.66437.

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Soil fertility is the basis for agriculture, soil acts as a crucial reservoir of plant micronutrients including the major elements such as nitrogen and phosphorus which largely determine plant health and crop productivity. The availability of nutrient absorption largely depends on the soil pH and soil moisture content as it affects the soil’s chemical, physical, and biological properties and plays a key role in agricultural productivity. In this study, 15 soil samples were collected from Thecho, Gokarna and Pathivara Yangwarak to measure moisture content, soil pH, nitrogen and Phosphorus content and 6 samples of fertilizers from the Nepalese market were selected for their nitrogen and Phosphorus content. Soil moisture was found in the range of 16.57 – 28.40 % and soil pH was found in a slightly acidic to nearly neutral with pH value in the range of 6.5 – 7.0. Nitrogen content was estimated by the Kjeldahl method and phosphorus content was estimated by Olsen's method. Among 15 soil samples, phosphorus in 11 soil samples were found high value, 3 soil samples were found medium value and 1 soil sample were found low value and nitrogen in 5 soil sample were found high, 5 soil samples were found medium and 5 soil samples were found low value. In most of the fertilizers, nitrogen and phosphorus content were found much lower than labeled in the packet.

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Rajbhandari, Ajay, Rajendra Kumar Agrawal, Anil Baral, Anil Pokhrel, Dineshwori Shrestha, and Rajani Hada. "Estimation of Serum Vitamin D, Calcium and Phosphorus in Chronic Kidney Disease." Medical Journal of Shree Birendra Hospital 16, no. 1 (2017): 30–36. http://dx.doi.org/10.3126/mjsbh.v16i1.17266.

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Introduction: Abnormalities in mineral metabolism are invariable with progressive deterioration of kidney function in chronic kidney disease (CKD). These abnormalities are documented in CKD on dialysis in our population but not on pre dialysis. So, present study aims to estimate serum vitamin D, calcium and phosphorus in CKD stage 3-5ND. Methods: It was a cross sectional study of established new CKD patients not on dialysis, vitamin D, calcium, phosphate binders and corticosteroids therapy. Blood sample was drawn for estimation of serum vitamin D, creatinine, calcium, phosphorus and albumin and CKD staging done by KDIGO (2012) criteria. SPSS software version 19 was used for data analysis and chi-squared and ANOVA test was applied as the test of significance.Results: Sixty six (51 male and 15 female) CKD patients with a mean age of 54.3±14.8 years were studied. Hypovitaminosis D (<30 ng/ml) was present in 84.8%, with deficiency (<20 ng/ml) in 50% and insufficiency (20-30) ng/ml in 34.8%. Other abnormalities observed were hypocalcemia (60.6%), hypercalcemia (1.5%) and hyperphosphatemia (63.6%) with no difference of corrected calcium, significant difference of serum phosphorus (p<0.001) with hyperphosphatemia in stage 4 and 5 CKD and vitamin D insufficiency in stage 3b, deficiency in stage 3a, 4 and 5 CKD. There was no correlation of serum vitamin D with calcium and phosphorus in different stages of CKD.Conclusion: Present study concludes that hypovitaminosis D, hypocalcemia and hyperphosphatemia is common in our pre-dialysis CKD patients and serum phosphorus raises more with reduction of GFR.

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Yamamoto, K., and T. Suetsugi. "Estimation of particulate nutrient load usingturbidity meter." Water Science and Technology 53, no. 2 (2006): 311–20. http://dx.doi.org/10.2166/wst.2006.065.

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The “Nutrient Load Hysteresis Coefficient” was proposed to evaluate the hysteresis of the nutrient loads to flow rate quantitatively. This could classify the runoff patterns of nutrient load into 15 patterns. Linear relationships between the turbidity and the concentrations of particulate nutrients were observed. It was clarified that the linearity was caused by the influence of the particle size on turbidity output and accumulation of nutrients on smaller particles (diameter &lt;23 μm). The L-Q-Turb method, which is a new method for the estimation of runoff loads of nutrients using a regression curve between the turbidity and the concentrations of particulate nutrients, was developed. This method could raise the precision of the estimation of nutrient loads even if they had strong hysteresis to flow rate. For example, as for the runoff load of total phosphorus load on flood events in a total of eight cases, the averaged error of estimation of total phosphorus load by the L-Q-Turb method was 11%, whereas the averaged estimation error by the regression curve between flow rate and nutrient load was 28%.

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Larose, A., and S. B. Jørgensen. "State estimation for a biological phosphorus removal process using an asymptotic observer." Water Science and Technology 43, no. 11 (2001): 205–13. http://dx.doi.org/10.2166/wst.2001.0684.

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This study investigated the use of an asymptotic observer for state estimation in a continuous biological phosphorus removal process. The estimated states are the concentration of heterotrophic, autotrophic and phosphorus accumulating organisms, polyphosphate, glycogen and PHA. The reaction scheme describing the process was simplified from a combined ASM1-Delft model. Three examples were investigated: operation at steady state, operation at steady state with a random white-noise in the measurements and operation with a ramp disturbance. In each case, the estimation was quite accurate even if the convergence, driven by the dilution rate, was slow (from 15 to 60 days). The propagation of the measurement noise and a bias in the estimation of glycogen and PHA could be the result of the high condition number of one of the matrices used in the algorithm of the asymptotic observer for the aerated tanks.

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C, Sushmitha, Chikkalingaiah, Fatima Sadatulla, and S. Chandrashekhar. "Estimation of Biochemical Constituents in Leaves of Elite Mulberry Hybrids." Journal of Advances in Biology & Biotechnology 27, no. 10 (2024): 469–78. http://dx.doi.org/10.9734/jabb/2024/v27i101470.

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Mulberry silkworm Bombyx mori nourishes its nutrition from its sole food plant Morus spp. Various biochemical techniques have facilitated the sericulture’s in identifying the most nutritive mulberry variety for obtaining eminent silk. A deficiency of certain nutrients or an imbalance of nutrients in leaves causes some changes in the composition or metabolic activity of larval body. Eight mulberry hybrids and two commercial check varieties were analysed for Nitrogen, Phosphorus, Potassium, Calcium, Magnesium, Sulphur, Ash, Crude Fibre, Carbohydrates, Proteins, Phenol, Sugar and Amino acid contents. The result revealed that hybrids, ME-65 × V1 recorded highest nitrogen content (3.47%), Potassium content (2.15%), calcium content (0.64%), Magnesium content (0.45%), Sulphur content (0.30%), Ash content (12.92%), Phenol (3.99 mg) and sugar content of (12.66%) compared to check variety V1 and S-36. Whereas ME-146 × MI-66 recorded highest total amino acid (8.37 mg/g). Similarly, biochemical constituents viz., phosphorous (0.55%), Crude Protein (18.81%), Carbohydrate (22.8%), crude fibre (9.89%) were recorded highest in the check variety V1.

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Henson, Eleanor, Abbie Lasater, and Brian E. Haggard. "Reducing Dissolved Phosphorus in Stream Water May Not Influence Estimation of Sediment Equilibrium Phosphorus Concentrations." Agrosystems, Geosciences & Environment 2, no. 1 (2019): 1–5. http://dx.doi.org/10.2134/age2019.05.0037.

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Pant, Hari K. "Estimation of Internal Loading of Phosphorus in Freshwater Wetlands." Current Pollution Reports 6, no. 1 (2020): 28–35. http://dx.doi.org/10.1007/s40726-020-00136-6.

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Qiao, Baiyu, Xiongkui He, Yajia Liu, et al. "Maize Characteristics Estimation and Classification by Spectral Data under Two Soil Phosphorus Levels." Remote Sensing 14, no. 3 (2022): 493. http://dx.doi.org/10.3390/rs14030493.

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As an essential element, the effect of Phosphorus (P) on plant growth is very significant. In the early growth stage of maize, it has a high sensitivity to the deficiency of phosphorus. The main purpose of this paper is to monitor the maize status under two phosphorus levels in soil by a nondestructive testing method and identify different phosphorus treatments by spectral data. Here, the Analytical Spectral Devices (ASD) spectrometer was used to obtain canopy spectral data of 30 maize inbred lines in two P-level fields, whose reflectance differences were compared and the sensitive bands of P were discovered. Leaf Area Index (LAI) and yield under two P levels were quantitatively analyzed, and the responses of different varieties to P content in soil were observed. In addition, the correlations between 13 vegetation indexes and eight phenotypic parameters were compared under two P levels so as to find out the best vegetation index for maize characteristics estimation. A Back Propagation (BP) neural network was used to evaluate leaf area index and yield, and the corresponding prediction model was established. In order to classify different P levels of soil, the method of support vector machine (SVM) was applied. The results showed that the sensitive bands of P for maize canopy included 763 nm, 815 nm, and 900–1000 nm. P-stress had a significant effect on LAI and yield of most varieties, whose reduction rate reached 41% as a whole. In addition, it was found that the correlations between vegetation indexes and phenotypic parameters were weakened under low-P level. The regression coefficients of 0.75 and 0.5 for the prediction models of LAI and yield were found by combining the spectral data under two P levels. For the P-level identification in soil, the classification accuracy could reach above 86%. These abilities potentially allow for phenotypic parameters prediction of maize plants by spectral data and different phosphorus contents identification with unknown phosphorus fertilizer status.

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Manpreet, Kaur, Kaur Maninder, Kaur Jaspinder, Seema, Chopra Sunny, and Kaur Supreet. "To Evaluate the Levels of Serum Calcium, Magnesium and Phosphorus in Hypothyroid Patients." International Journal of Pharmaceutical and Clinical Research 16, no. 8 (2024): 53–57. https://doi.org/10.5281/zenodo.13380841.

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Background: Hypothyroidism is one of the most prevalent forms of thyroid dysfunction in which the disease causes generalized slowing of metabolic processes. Thyroid dysfunction frequently disturbs mineral metabolism. The aim of the present study was to evaluate the levels of serum calcium, magnesium and phosphorus in patients with hypothyroidism. Materials and Methods: We conducted the present study on 100 lab-diagnosed cases of hypothyroidism based on the thyroid profile. 50 healthy controls were included in the study. We estimated serum calcium, magnesium and phosphorus in both cases and controls. Results: This study found that in people with hypothyroidism, the mean levels of calcium and magnesium in blood were significantly (p value<0.001) lower than in controls, while the levels of phosphorous were significantly (p value<0.001) higher. We found a significant negative correlation between both serum calcium and magnesium and serum TSH levels, and a significant positive correlation between serum phosphorous and serum TSH levels. Conclusion: The current study concluded that hypothyroidism alters the metabolism of minerals. Estimation of these minerals in hypothyroid patients will be of great benefit in the prevention and treatment of subsequent clinical manifestations.

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He, Haifeng, and Xing Xu. "Effects of Phosphorus Addition on Inorganic Phosphorus Fractions and Phosphorus Accumulation in Alfalfa in Alkaline Soils." Agriculture 15, no. 9 (2025): 973. https://doi.org/10.3390/agriculture15090973.

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Distribution and availability of soil inorganic phosphorus fractions significantly influence plant phosphorus uptake and crop yield, particularly in alkaline soils, where phosphorus availability is often constrained by soil chemical properties. This study investigated the contribution of different phosphorus fractions to phosphorus uptake and yield of alfalfa by applying four phosphorus addition levels: 0 kg/hm2, 50 kg/hm2, 100 kg/hm2 and 150 kg/hm2, designated as P0, P50, P100, and P150, respectively, over two consecutive years. Correlation analysis and multiple linear regression analysis were employed to analyze the data. The results revealed that in alkaline soils, inorganic phosphorus fractions were dominated by aluminum-bound phosphate (Al-Pi) and decacalcium phosphate (Ca10-Pi), with storage contribution rates of 33.92% and 37.11%, respectively. In contrast, the cumulative storage contribution rates of dicalcium phosphate (Ca2-Pi), octocalcium phosphate (Ca8-Pi), iron-bound phosphorus (Fe-Pi) and occluded phosphorus (O-P) accounted for 28.97%. Although the storage contribution rate of Ca10-Pi was relatively low, its output contribution rate was high, rendering it easily absorbed and depleted by plants, thereby serving as an important source of soil phosphorus availability. Among these fractions, O-Pi was identified as the primary source of phosphorus for alfalfa, playing a critical role in P nutrition. Furthermore, Ca8-Pi exhibited a significant positive correlation with phosphorus uptake in alfalfa (R2 = 0.98, p < 0.05) and was identified as a key factor influencing alfalfa yield, making it a reliable predictor for yield estimation.

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Silva, Samuel de Assis, and Julião Soares de Souza Lima. "Spatial estimation of foliar phosphorus in different species of the genus Coffea based on soil properties." Revista Brasileira de Ciência do Solo 38, no. 5 (2014): 1439–47. http://dx.doi.org/10.1590/s0100-06832014000500009.

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Information underlying analyses of coffee fertilization systems should consider both the soil and the nutritional status of plants. This study investigated the spatial relationship between phosphorus (P) levels in coffee plant tissues and soil chemical and physical properties. The study was performed using two arabica and one canephora coffee variety. Sampling grids were established in the areas, and the points georeferenced. The assessed properties of the soil were levels of available phosphorus (P-Mehlich), remaining phosphorus (P-rem) and particle size, and of the plant tissue, phosphorus levels (foliar P). The data were subjected to descriptive statistical analysis, correlation analysis, cluster analysis, and probability tests. Geostatistical and trend analyses were only performed for pairs of variables with significant linear correlation. The spatial variability for foliar P content was high for the variety Catuai and medium for the other evaluated plants. Unlike P-Mehlich, the variability in P-rem of the soil indicated the nutritional status of this nutrient in the plant.

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Tuladhar, ET, V. Pant, B. Aryal, et al. "Does serum magnesium analysis need to be a part of routine dyselectrolytemia investigation?" Journal of Institute of Medicine Nepal 39, no. 2 (2017): 52–55. http://dx.doi.org/10.59779/jiomnepal.927.

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Introduction: The fourth most abundant cation in the body and the second most prevalent intracellular cation, magnesium (Mg) is a co-factor for over 300 enzymes. Though magnesium abnormalities frequently accompany other electrolytes abnormalities, during electrolyte investigation, magnesium estimation is often overlooked. This study aims to investigate the occurrence of magnesium abnormalities in serum samples sent, for routine electrolyte measurement like sodium, potassium, calcium and phosphorus, to the biochemistry laboratory of Tribhuvan University teaching hospital. Methods: Serum magnesium measurement was done in 799 serum samples ordered for various electrolyte estimation. Magnesium, Calcium and phosphorus present in sample was analyzed by BT 3500 machine spectrophotometrically. Sodium and potassium ions were analyzed by direct ion selective electrode method. Results: Only 14(1.75%) samples were requested by physician for magnesium estimation out of total 799 samples sent for various electrolyte estimation. When all 799 samples were analyzed for magnesium level, magnesium abnormalities were identified in 76(9.5%), out of which hypermagnesemia was found in 22 (2.75%) and hypomagnesemia in 54 (6.76%) samples. Conclusion: Since, significant numbers of patient's serum sample, sent for estimation of various electrolytes, are found to have magnesium abnormalities, we recommend routine measurement of this analyte along with other electrolytes.

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Shrestha, Shashi, Sadikshya Thapa, and Sanjay Kumar Jha. "Nutrient Analysis of Selected Wild Edible Mushrooms Collected from Thulo Ban Community Forest, Myagdi District, Nepal." Journal of Plant Resources 21, no. 1 (2023): 13–20. http://dx.doi.org/10.3126/bdpr.v21i1.57197.

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The study analyzes the nutrient content of three wild edible mushrooms Cantharellus cibarius, Laccaria laccata and Scleroderma cepa commonly consumed by the local people of Arjam, Myagdi district. Thirteen parameters were analyzed such as ash, carbohydrate, fat, moisture, protein, manganese, zinc, magnesium, potassium, iron, copper, phosphorus and calcium. The test methods used for ash, fat, moisture, protein and phosphorous content were ignition, soxhlet extraction, oven dry method, kjeldahl digestion method and spectrophotometric method respectively. Carbohydrate content was determined by calculation method and iron, manganese, copper, zinc, calcium, magnesium and potassium content estimation were done by AAS method. All macro and micronutrient compositions were determined on a dry weight basis. Ash, carbohydrate, fat, moisture and protein are ranges from 7.05-13.38%, 61.89-71.37%, 0.78-1.94%, 12.37-13.66% and 16.18-24.47% respectively, whereas calcium, magnesium, phosphorus and potassium ranges from 0.13-0.15 µg/g, 0.09-0.11µg/g, 0.25-0.37 µg/g and 1.41-3.40 µg/g respectively. Similarly copper, iron, manganese and zinc ranges from 2.40-30.94 µg/g, 0.08-0.20 µg/g, 7.22-16.06 µg/g and 45.70-77.35 µg/g respectively.

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Wang, Zhen, Yunqi Wang, Zhiyi Yan, et al. "Estimation of phosphorus input on county-based scale is more appropriate to formulate phosphorus management policies." Ecological Indicators 166 (September 2024): 112541. http://dx.doi.org/10.1016/j.ecolind.2024.112541.

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Coates, D. B., and J. H. Ternouth. "Phosphorus kinetics of cattle grazing tropical pastures and implications for the estimation of their phosphorus requirements." Journal of Agricultural Science 119, no. 3 (1992): 401–9. http://dx.doi.org/10.1017/s0021859600012247.

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SUMMARYTwelve yearling Droughtmaster heifers were grazed on a tropical grass/legume pasture in north-east Australia for 1 year in four paddocks, each of 4 ha. One paddock was fertilized annually with 10 kg P/ha (treatment HPF). The other three paddocks had low soil P and low pasture P status. In one of the low soil P paddocks, P was added to the drinking water (treatment HPS) but no supplement was provided in the other two paddocks (treatments LP1 and LP2). In February, May and August 1989, the P kinetics of the heifers were monitored following oral administration of ruminal chromic oxide capsules and i/v injection of 32P. At the same times, oesophageal-fistulated steers were grazed in the paddocks to obtain extrusa samples to estimate the P content and digestibility of selected forage.The liveweight gain per heifer was higher in the HP treatments (196 kg) than in the LP treatments (152 kg). The intake, absorption and excretion of P were closely related but the faecal excretion of P relative to P intake was less in heifers with than without P supplement. The P intakes of the LP heifers were about half the quantities recommended in the nutrient feeding standards for the observed food intakes and weight gains. The coefficients of P absorption in the LP heifers in May and August were high (> 0·8) and did not decrease with age or liveweight. The coefficients of P absorption of heifers given supplementary P were as high as those for LP heifers, but those of heifers on the fertilized pasture were significantly lower in May and August. The endogenous faecal excretion of P was related to P intake but more closely to dry matter intake and plasma inorganic P together. The reasons for the difference between observed P intakes of LP heifers and recommended requirements are discussed in relation to the assessment of P requirements of grazing cattle. The results from this experiment suggest that recommended P requirements are higher than necessary to sustain the measured liveweight gains of cattle on grass/legume pastures in the tropics.

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Musilova, A., M. Lichovnikova, L. Kupcikova, and V. Anderle. "Effect of suboptimal levels of non-phytate phosphorus and exogenous phytase on precaecal digestibility of phosphorus and calcium in laying hens." Czech Journal of Animal Science 62, No. 11 (2017): 473–81. http://dx.doi.org/10.17221/16/2017-cjas.

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The precaecal digestibility of phosphorus and calcium in laying hens was evaluated at two dietary levels of non-phytate phosphorus (NPP; 1.58 and 2.03 g/kg) and two levels of exogenous 3-phytase (F; 0 and 300 phytase units (FTU)/kg). A total of 192 ISA Brown hens were used for the study, and were housed in enriched cages (8 per cage). At the end of the experiment, which was the peak of the egg production, the content of the posterior half of the ileum from each hen was collected. The lower level of NPP significantly (P &lt; 0.05) improved the precaecal phosphorus digestibility coefficient. There was no significant difference in the amount of absorbed phosphorus between the lower and the higher level of NPP. The level of NPP with supplementation of exo-genous phytase had a significant effect (P &lt; 0.001) on the concentration of phosphorus in ileum, while the higher level of NPP increased phosphorus concentration in the ileum and phytase decreased phosphorus content in the ileal digesta. The phytase had no significant effect on phosphorus precaecal digestibility. There was no significant effect of the both factors, level of NPP, and exogenous phytase on the daily calcium intake, the amount of absorbed calcium, the content of calcium in ileal digesta, and on the precaecal digestibility of calcium. However a significant effect (P &lt; 0.05) of the interaction between NPP and phytase was observed on the amount of absorbed calcium and on the precaecal digestibility coefficient. It can be concluded that the estimation of phosphorus ileal digestibility depends on the level of dietary phosphorus.

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Weaver, DM, GSP Ritchie, and RJ Gilkes. "Phosphorus sorption by gravels in lateritic soils." Soil Research 30, no. 3 (1992): 319. http://dx.doi.org/10.1071/sr9920319.

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The effect of sesquioxidic gravels (>2 mm size fraction) on phosphorus sorption by two gravelly lateritic soils was investigated by phosphorus sorption experiments, X-ray diffraction, autoradiography and electron microscopy.In one soil the abundance and size of gravels decreased downslope. As the gravel content of both soils increased (13-61%), the proportion of large (>8 mm) gravels increased (0-70%). Phosphorus sorption increased in the order: (>2 mm fraction) < (whole soils) < (<2 mm fraction). Phosphorus sorption on lateritic gravels (>2 mm) decreased with increasing gravel size and increased with increasing time. Phosphorus sorption by whole soils decreased with increasing gravel content. Phosphorus sorption by the >2 mm fraction was principally by the external surfaces of the gravels. The estimation of phosphorus application rates for lateritic soils depended on the amount of phosphorus required by the plant and the gravel content of the soil. The former is the important factor at low soil gravel contents whereas the latter becomes more important as the gravel content increases. The implications for fertilizer management on the soil with consistent relationships between landscape position, gravel content and subsequent P sorption properties of whole soils are discussed.

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Lin, Y. C., and J. J. Kao. "Effects of seasonal variation in precipitation on estimation of non-point source pollution." Water Science and Technology 47, no. 7-8 (2003): 299–304. http://dx.doi.org/10.2166/wst.2003.0702.

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The extent of nonpoint source pollution (NPSP) generated from upstream catchment areas of a reservoir is normally estimated based on a design rainfall. However, rainfall generally varies in different seasons. This seasonal change may significantly influence the estimation of runoff volume and associated NPSP arising within a reservoir watershed. The NPSP management, reservoir operation, and water treatment operation strategies developed based on the estimation will also be altered. This study analyzes the effects of monthly and seasonal variation in precipitation on the estimation of pollution levels from non-point sources in a reservoir watershed. The area studied is the Derchi reservoir watershed located in central Taiwan. This watershed is subdivided into twenty-six sub-watersheds, and the Thiessen method is used to determine the rainfall intensity in each sub-watershed. Runoff pattern and NPSP contributions for each sub-watershed are estimated using the AGNPS model. Results show significant seasonal variation in precipitation; estimated NPSP loads likewise vary significantly over time. Seven- to one hundred-fold differences among monthly and seasonal estimations of phosphorus and sediment loads are observed.

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Paul, Anamika Sikdar, and Bruce Anderson. "Phosphorus removal by blast furnace slag and cement clinker – flow cell studies for estimation of sorptive capacity for use with constructed treatment wetlands." Water Quality Research Journal 46, no. 4 (2011): 300–311. http://dx.doi.org/10.2166/wqrjc.2011.112.

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Blast furnace slag and cement clinker were explored in long-term flow cell experiments for estimation of their phosphorus (P) removal efficiencies. A local gravel, typically used in constructed treatment wetlands, was used as a control medium. The experiments examined the removal of phosphorus from a solution initially containing 4 mg P/L. The slag and clinker were nearly 100% efficient due to very high sorptive capacities. The control gravel medium removed 50% of the influent phosphorus. Results from this study indicate that the use of blast furnace slag in constructed wetlands or filter beds is a promising solution for P removal via sorption mechanisms.

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Journal articles on the topic 'Phosphorus estimation'

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