Hi friends,
Sorry to bother you all once again. Just that I am new to the field and need to confirm my calculations with all elite experienced researchers out there. It gives me lots of confidence.
My question is:
Say we have a potassium based fertilizer salt, like K2SO4 or K2CO3.
When we solubilize them in water, than
K ppm is around 9000 ppm
HCO3- around 20,000 ppm,
Ca - 500 ppm,
Mg- 400 ppm, Cl- 600 ppm....
I suppose one should consider only cations for purity analysis. Kindly correct me If I am wrong.
Also do we have to take total weight of the cations and than calculate the % purity of K or should we be taking the moles into consideration.
Kindly help me to clear my doublts
Thank You
Tanuja
Dear Tanuja,
The basic concept is that only water soluble materials are absorbed and utilized readily by plants.
Therefore this would not exclude anions into a purity analysis in my opinion.
Take Sulfate an anion is of fertilizer value and interest it would be dangerous not to consider it. Sulfur is a plant essential nutrient and can lacking in many instances. Anions are important too and as such should not be neglected and our interest is the soluble cations and anions which favor the plant. are all of importance and interest.
When we solubilize them in water, than
K ppm is around 9000 ppm
HCO3- around 20,000 ppm,
Ca - 500 ppm,
Mg- 400 ppm, Cl- 600 ppm....
Potassium, Calcium, Magnesium, and Chloride are all known as essential nutrients and in this case they are all soluble in water and therefore available.
In the case of Potassium sulfate for instance both Cation and Anion are of fertilizer value and become soluble and are readily absorbed and utilized.
Even the case of carbonic acid HCO3 component it might have utility for the mobilization of nutrient particular in alkaline soil condition that can immobilize nutrition.
I could argue that too should be included as potentially useful in the formulation and purity analysis.
From a fertilizer perspective I would take all the components of utility and interest and express that in percentage.
While the molecular concentration makes sense for chemists it is less useful for the fertilizer industry and farmers.
Fertilizer people and client farmers are using percentage because it is your better expression for the ease of their understanding.
For most farmers in North America at least if you say mole they will check the soil for burrowing animal in their fields and gardens.
Some thoughts.
Thanks for a detailed analysis of the problem and your perspective Reed.
Thanks for your valuable time
I appreciate the detailed and good comments of Dr.Hepperly. The Ministry of agriculture fixes certain criteria under Fertilizer Quality Control Order which the fertilizer industry and fertilizer marketing agencies need to follow. FAO has also established similar quality standards for common fertilizers. In case of potassic fertilizers(all other fertilizers) for quality assessment apart from nutrient cations and anions,the fertilizers contain moisture,certain impurities like Na and Cl.The nutrient K is expressed as K2O and the particle size of fertilizer is also important.The standard purity criteria for K2SO4 according to FAO is :moisture percent by weight,Max.1.5,potassium content as K2O percent by weight,min. 50,Total chloride as Cl percent by weight,max 2.5, sodium as NaCl percent by weight,max.2.0 and sulphur as S percent by weight ,min 17.5 .FCO also has similar criteria.The following references give provide the quality standards fixed for different fertilizer materials.
Anonymous.2006 Fertiliser control Order.Published by FAI ,New Delhi.One can get information on similar line from
http://www.fao.org/Landandwater/ag11/minfertspecs.stm
- Badges
- Science topic
- Similar topics
- Geoscience
- Asia
- India