I want to use different application level of Phosphorous (o kg/ha, 45 kg/ha, 90 kg/ha, 180 kg/ha) as a fertilizer using P2O5. How to manage the application rate ?
Factor P to P2O5 : P X 2.2915
P2O5 to P: 0.4364
Use the above mentioned factor for converting P to P2O5 and P2O5 to P
45 kg.ha P = 103.12 kg.ha P2O5
90 kg.ha P = 206.24 kg.ha P2O5
180 kg.ha P = 412.47 kg.ha P2O5
You can see attached file.
Dear Dr. Israr Khan
In addition to the appropriate answers provided by Dr. Kalaivanan and Dr Vladimir, %P2O5 i.e., I would say that phosphate content in the fertilizer may be required to find out the actual amount of fertilizer to be applied at P rate 0, 45, 90 or 180 kg/ha.
P205 to P = 0.437x AMOUNT P2O5.
Then P to P2O5 = 2.288 x amount of P to be added.
I think you firstly need to check the P2O5 concentration in your fertilizer and then calculate the doses
In addition to the answers provided by Dr. Ahmed Rugheim and , P2O5 concentration in fertilizer can be 14-19% to 42-46%.
Complementing the response issued by Dr. Vladimir, eg triple super calcium phosphate [Ca (H2PO4) 2 • H2O], contains 44 to 48% P2O5. In addition to this percentage, when you make a fertilizer you need to take into account the solubility, why repeatedly fertilizers are chosen. The total P in the super triple calcium phosphate has over 90% solubility in water, making it readily available to plants.
You should take part in lessons of chemistry
I had to do 1 year chemistry only after my study of agriculture.
So a became fit in such questions.
Your W. Roemer
Dear Khan,
First of there is no P2O5 fertilizer as such. The sympol P2O5 is just means of expressing the P content in P fertlizers such as TSP, DAP (NH4)2PO4) etc. Thus the amount of P found in different fertilizers is different or similar and their P content is often expressed as P2O5. For example the P2O5 content of TSP and DAP is 46%. In other P fertilizers the P2O5 content may be greater or lower. Thus if you want to study the effect of different rates of P expressed as P2O5 and your treatments are 0, 45, 90 and 180 kg/ha, the corresponding amount of DAP or TSP will be 0, 97.82, 195.65 and 391.3 kg/ha DAP or TSP. But if you want to use DAP as P source, you have to consider the nitrogen content of DAP as it contains 18 N. Meaning all treatments should receive similar amount of N.
First, I am sure you meant phosphorus, not phosphorous, which refers to phosphite, a less oxidised oxide of P than phosphate.
Second, it is high time we gave up expressing P content as P2O5, which does not exist; instead, we should express it as P content.
P2O5 is the compound that many countries (namely Portugal) use conventionally to express amounts of phosphorus (by extense) or phosphorus content in fertilizers and/or plants and or soil. Nevertheless, as refereed by other colleagues, P2O5 do not exists in fertilizers, soils or plantas.
Other countries use P to express mass of phosphorus.
We should not mix the mass of the element/nutrient (phosphorus by extense) with the units convention as the mass of the element is expressed (P or P2O5)
Atomic weight of P is 30.97 and O is 15 99
Therefore P2O5=141.89
Therefore P= 141.88/61.94=2.29 means P2O5= 2.29 O
P2O5 = 141.88 g/mol (FW)
P = 30.97 x 2 = 61.94 g/mol (FW)
Hence, to convert P to P2O5 = 61.94 x 2.290 (Factor). Why?
Because P2O5 (141.88g/mol) / P2 (61.94g/mol) =2.290 (Factor)
To convert P2O5 to P = 141.88 x 0.4365 (Factor). Why?
Because P2 (61.94g/mol) / P2O5 (141.88g/mol) =0.4365 (Factor)
You don't want to calculate phosphorous, which is a less oxidised molecule of phosphorus than phosphate, but you want to calculate phosphorus. How to do that has been neatly explained above.
From P to P2O5 multiply Px2.2915 and from P2O5 to P multiply P2O5x0.4364
As we want to convert P into P2O5, during calculation why we are deviding by the molecular weight of 2 Phosphorus?
Lambers H and Barrow N J (2020) P2O5, K2O, CaO, MgO, and basic cations: pervasive use of references to molecules that do not exist in soil. Plant Soil 452, 1-4. 10.1007/s11104-020-04593-2.
simply divide all amount by 0.43.
Example 45 Kg/ha P: 45/0.43= 104.65 Kg/ha P2O5
- Badges
- Science topic
- Similar topics
- Biological Science
- Biochemistry
- Biochemical Techniques
- Analytical Chemistry
- pH