I agree with above respondent. But I suggest for site specific nutrient management based on soil testing and integrated approach of nutrient management.

You can look at this paper:

Neri, Ulderico & Diana, Giampietro & Indiati, Roberto. (2005). Change Point in Phosphorus Release from Variously Managed Soils with Contrasting Properties. Communications in Soil Science and Plant Analysis. 36. 2227-2237. 10.1080/00103620500196556.

and others of the author Roberto Indiati that you can find in ResearchGate.

Best regards

Please find enclosed few papers in this line for estimation and similar studies.

The slow movement of P by diffusion is frequently ascribed to the tortuosity of the pore system. However, the reactive sites for P adsorption on soil minerals lining the sides of the pores can also retain phosphate ions, temporarily or permanently, slowing or preventing their movement along the pore. The slow reaction between phosphate and soil was attributed to the diffusive penetration of adsorbed phosphate ions into soil components. One potential option is to use a slow-release P fertilizer in these situations; a second option is to try to increase soil organic matter but this is not easy on coarse-textured soils. The soil amended with bio solids released more P at a higher rate than vermicomposting amendment, even though bio solids added less P than vermi compost. This is consistent with bio solid P released more readily which could impair water quality (Penn and Sims 2002), particularly beyond 16 mg P kg-1 soil. The slow P release with vermicompost amendment may help prevent erosion washing or leaching losses of this nutrient. The probable reasons for slower P release in vermicompost amendment were threefold. Firstly, it might be attributable to earthworm casts that retain their porosity and structure and contain more water-stable aggregates than surrounding soil, probably due to polysaccharide gums produced by earthworm intestinal bacteria and proliferation of fungal hyphae on the surface of casts. Secondly, phosphatases are produced in the gut of earthworms in response to a need for P by microorganisms suggesting a P release partly regulated by enzymatic processes. Thirdly, vermicompost-amended soils contain more organic matter which enhance nutrient retention, as well as humic acids, fulvic acids and humans which regulate the release of nutrients. Slow P release most likely originates from diffusion from interior sites inside soil solid phases, aggregates or slow dissolution of amorphous or crystalline solid phases of P. The gradual reduction in P release rate over time may result from decreasing surface charge and decreasingly interacting adsorbed phosphorus ions. Maximum amendment doses identified for wastewater and solid waste reuse. P release in soil with bio solid and vermicompost initially rapid and subsequently slowed down, which corresponded to a fast initial and then prolonged fertilizing effect.

When producers pay special attention to managing phosphorus (P), it can lead to profitable crop production. The best way to use fertilizers to meet P requirements changes with crop, soil properties and environmental conditions.

Inorganic commercial P fertilizers have evolved over the last several decades into a refined, predictable product. Plus, there are the organic P sources closely associated with livestock operations or with proximity to major metropolitan areas.

There should be no difference in P fertilizer sources, as long as nutrient analysis differences are taken into account. While there are certain situations where one product performs better, phosphorus fertilizer recommendations are the same regardless of the phosphate fertilizer source.

Use of slow release P fertilizers is gaining importance for crop production, compared to inorganic P fertilizers. However, the release P from slow release fertilizers in soil is affected by the composition of coating material. Slow release of P from coated P fertilizer, increases the P availability, P uptake and P use efficiency of crop plants. Inorganic fertilizers may be more favorable for P uptake and plant growth at initial stage of crop growth, whereas slow release fertilizer show greater effect on late plant growth stages.

Slow release fertilizer promote AMF richness and its diversity in soil

For quantification please go through the following article

J. Soil Sci. Plant Nutr. vol.16 no.4 Temuco dic. 2016

http://dx.doi.org/10.4067/S0718-95162016005000081 

I agree with above respondent. But I suggest for site specific nutrient management based on soil testing and integrated approach of nutrient management.

The usual problem with such studies is discriminating between P from the fertiliser and that from other sources.

Crop demands increase over time to a maximum then decline

Dear fellow researchers, thank you indeed for your invaluable feedback and suggestions. Really appreciate it. I will read through the papers and summarize soon. Thank you Paul Milham Suresh K Malhotra Sunita Gaind Mukul Barwant Prem Baboo Claudio Beni Prem Baboo Surendran Udayar Pillai ...

Regards,

Jaya

Paul, i agree with your comments..Unfortunately , such studies carried out in - vitro do not stand in -vivo because of the obvious reasons of three dimensional movement of solute particles. Old concepts of lysimetric studies , use of 32P fertililizers are no longer so authentic due to concerned environmental studies. How do we use the response curve of phosphorus vis'a- vis crop production using P- uptake studies..

probably by estimating different P pools after a set of time. In case of K we use Q/I relationship.

Isotope study using phosphorus isotope enriched P fertilizers may serve the purpose. It will exactly provide the contribution form fertilizer P. The release pattern from fertilizer can also be studied under various conditions either in a laboratory or in a pot/field experiment.

First you should select a sandy soil prone to phosphorus leaching and apply the activated phosphate rock with different dosages in a pot trial and compare with a fully soluble phosphorus fertiliser such as ammonium phosphate. You should compare the P-uptake of plants seeded in the pot trial (for example a grass or an alternative crop with rapid growth rate) after a definite growth period by taking plant samples for chemical analysis. Further you should take soil samples to measure plant available P from the SRF and the soluble P fertiliser.

Thank you for your valuable inputs indeed Alvin Alexander Satish Bhagwatrao Aher Owais Ali Wani & Anoop Kumar Srivastava , It helps me a lot.

A new article has just been published on this issue. Please, read:

Fertahi S, Bertrand I, Ilsouk M, Oukarroum A, Zeroual Y, Barakat A (2020). New generation of controlled release phosphorus fertilizers based on biological macromolecules: Effect of formulation properties on phosphorus release. Int J Biol Macromol 143 153–162. DOI: 10.1016/j.ijbiomac.2019.12.005

Professor, Amaral Chibeba ,Thank you very much for your recommendations. This helps a lot.

The release of phosphorus will depend on the type of soil, its structure, temperature and moisture content.

My suggestion here would be to time the release of P in conjugation with the crop/plant requirement stage prior to your study because as an example. ..the release of P at a stage when it us not actually required as compared to flowering or fruiting stage would dampen the overall goal of your study

Article EFFECT OF BIO FERTILIZER IN ADDITION WITH PHOSPHORUS ON THE ...

Pot cultivation may be conducted at first with loose soil applying easily soluble phosphatic fertilizers. Phosphorus isotopes or spectrophotometer can be used to determine phosphorus after preparing soil samples.