Sciencemadness Discussion Board

Calcium Nitrate

madfarmer - 28-2-2004 at 00:02

Hi,

I don't know if this is the place to ask the question, but I am curious with what happens to calcium nitrate [Ca(NO3)2.4H2O] when I spread it through my farm. I noticed the crystals dissolved without me needing to irrigate the fertiliser in.

I read that calcium nitrate is very hygroscopic, so I guess it absorbed moisture from the air. Any way, will the calcium nitrate be available to my trees, or did it disappear, or become unavailable to the plant?

Thanks in advance.

JDP - 28-2-2004 at 02:46

I would imagin that it probably just dissolved in the water formed from due, rain etc. so you have a solution of Ca(NO3), this means it should be perfect for absorbtion into your plants.

[Edited on 28-2-2004 by JDP]

vulture - 28-2-2004 at 02:47

Lol, you should see how we "mad scientists" usually "abuse" your calciumnitrate. ;)

It's indeed VERY hygroscopic. It simply dissolves itself by absorbing moisture from the air and penetrates the soil.

As it is dissolved, it's also dissociated in it's ions, Ca<sup>2+</sup> and NO<sub>3</sub><sup>-</sup>

These can be easily absorbed by the plants.

BromicAcid - 28-2-2004 at 07:40

Remember, the proper term for a solid that absorbs enough water from the air to put itself into solution, e.g. calcium nitrate, sodium hydroxide, etc. is deliquescent. Of course deliquescent chemicals are also hygroscopic, it's just that diliquescence goes one step further in the description.

madfarmer - 28-2-2004 at 07:55

Hi,

Thanks for the replies.

So, now that its been dissociated to Ca2+ and NO3- , can they be affected by our atmosphere and lost to the plant?

Also, if its fine for me to ask Vulture, what do you mean about the abuse?

Thanks again.

chemoleo - 28-2-2004 at 08:20

He means that Nitrates in general can be 'abused' ( I prefer the term 'use';) for the production of nitric acid, other nitrates (which, coincidentially finds use in black powder), and organic nitro/nitrate compounds - which happen to be rather unstable, under certain conditions, and happen to develop a vast amount of rapidly expanding heated gases once those molecules break down...u figure the rest :)

So what happens to the ions (Ca2+/NO3-) once in the soil? well, they are taken up by plants/bacteria/fungi, which convert the nitrate to lesser oxidised forms, which then are used for making protein (mainly) - and no plant could survive without protein of course. The NO3- doesnt evaporate or anything, it is just absorbed by those species that can utilise it. NO3- won't be affected by the atmosphere as such, no. It won't get lost, unless you irrigate the soil too much and the nitrate is flushed into deep layers of the soil where the roots cant reach it, and the groundwater carries it to the river. Hence, never fertilise your trees etc when a rainstorm is due, you might lose most and pollute the rivers/lakes (they will grow excessive amounts of algae)
The calcium, in turn, is of course needed for plants/bacteria/fungi as well, for their survival. Just like humans need calcium - else your nerves will go mad very soon.

madfarmer - 28-2-2004 at 20:02

Thanks heaps for all your information, I was worried when it started to 'melt', you have restored my confidence in the product.

In the research I have done to find stuff about calcium nitrate, I found that some people referred both [Ca(NO3)2.4h2O] and [[5Ca(NO3)2].NH4NO3.10H2O]] as Calcium Nitrate, is that correct?

Also, some calcium nitrate products are marketed as 15.5%N 19%Ca, whilst some are 11.76%N and 23.4%Ca, why would there be such variance in the production of the same product?

Thank you again for your intellectual support.

vulture - 29-2-2004 at 07:02

I found that some people referred both [Ca(NO3)2.4h2O] and [[5Ca(NO3)2].NH4NO3.10H2O]] as Calcium Nitrate, is that correct?

First of all, .H2O is a fancy way of indicating that you're buying stuff with alot of water in it. The first compound is indeed calciumnitrate, the second one is a combination of ammoniumnitrate and calciumnitrate.

The latter has the advantage that ammoniumnitrate has more available nitrogen, but ammoniumnitrate is rather acidic. This is compensated for by the neutral (almost) calciumnitrate.

Ammoniumnitrate fertilizer should not be used in alkaline soil, otherwise the ammonium will be converted to ammoniumgas which escapes into the atmosphere.

madfarmer - 29-2-2004 at 13:44

Thanks Vulture,

So, the latter is not pure calcium nitrate.

I know that nitrates can be leached out of the soil by heavy irrigation, some products use chelating agents to try any bind them to the soil / plant tissue. I buy a liquid fertilizer from a specialist company that use lignosulphonate as the chelating agent. Has anyone heard of lignosulphonate? would it work? Is it possible to chelate the calcium nitrate in a simple way (mix two solutions together)?

Maybe I should start a new thread since it looks like im going off the subject?

Thanks heaps.

vulture - 29-2-2004 at 15:08

No let's keep it in this thread.

Chelating agents normally only keep metal ions from leaching out.

Chelating

madfarmer - 29-2-2004 at 18:51

The company suggests that their whole range of fertilizers are chelated with lignin to improve uptake and have excellent binding properties. So are they chelated? if they are chelated, can the calcium nitrate be chelated?

If you would like to visit there site, go to http://www.sjbagnutri.com.au

Thanks

chelating agents

Magpie - 29-2-2004 at 19:55

As vulture has stated chelants are normally used to sequester or remove heavy metals. However, I believe that there would be an equilbrium in wet soil and if your soil was starved of zinc then a zinc chelate such as zinc lignosulphonate would release soluble zinc to the soil. I did a little searching on Google and both an Australian and a Belgian company make lignosulfonate chelants, so my guess is that this is legitimate.

Lignosulfonate is of interest to me as it was a waste product at a sulfite process pulp mill I once worked for in Minnesota. They gave it away (gladly) for use as a binder to keep down dust on roads. I see that it is now being used for just about everything. As an aside, that pulp mill is now owned by SAPPI, a South African outfit that is a leader in lignosulfonate production.

vulture - 1-3-2004 at 03:40

This thread clearly shows that a little bit of basic chemistry would go a long way in improving the impact of fertilizing and reducing it's effect to the environment.

Too much fertilizer harms the crop just as much as the environment. Excess ammoniumnitrate, for example, will cause the soil to become to acidic.

Governments should send their farmes on chemistry courses instead of imposing strict regulations.

madfarmer - 1-3-2004 at 04:11

I'd be glad if they were still giving the lignosulphonates away, it costs me a fortune compared with standard chemical fertilizers.

Vultures right about making us farmers a little more educated with the products we deal with. We can do a lot of harm to the crops, soil and environment just with a little miss-management.

So, back to using a chelant, would it make uptake of calcium nitrate more efficient? what about other options instead of lignins, I have also used humates, and EDTA would they be more efficient?

How would the process be performed?

I can buy humic acid, i'm not sure where to get the others, if they work and will improve the effectiveness, then I'm for it.

Thanks.

advantage of chelant

Magpie - 1-3-2004 at 19:35

To quote from my freshman chemistry text: "Some complexing groups, when coordinated to certain metals, make the metal more easily assimilated by plants; in other cases, they keep the metal from being effectively utilized by the plant. Hence complexes can be effective in soil treatment."

I can see where a chelant could act as a slow release agent. This would have the advantage of preventing the nutrient from being washed down to the aquifer and away from the root zone where you want it to stay. As vulture says this should reduce chemical usage and prevent polution of the groundwater. Whether this is economical to you, only you can say. The trouble with farming is that your testing cycles are so long, so you have to take a gamble or at best an educated guess, as you are wisely doing. I would think that your govenment agricultural extension agent should be able to give you good advice. But by all means get your own basic education. Then you know the questions to ask and whether the agent sounds creditable.

Answering your specific questions is difficult without being an expert in this area which I am not. The only experience I have is that I used to help my uncle fertilize his wheat fields when I was in high school. For this he used "aqua ammonia" (ammonium hydroxide). He alternated the wheat with peas to fix nitrogen, which was quite effective.

madfarmer - 2-3-2004 at 01:36

Thanks for your inputs,

The way I need the chelant to work is by binding to the soil/plant tissue and to the nutrient, it sound like not every nutrient can be bound by the same chelant.

Anyway, back to calcium nitrate, I was also wondering while I'm on the topic, I should learn how to measure the amounts of nitrogen and calcium that is in the mixture, I just want to check to see if the rates on the label is correct, I think it will be a fun experiment for me to see your science at work. It is possible right? you should be able to precipitate the calcium out?

Any thoughts?

vulture - 2-3-2004 at 03:30

Ca(NO3)2 + XSO4 ---> CaSO4 + X(NO3)2

Where XSO4 is any soluble sulfate salt.
CaSO4 will precipitate.

I can't name any easy nitrogen determination methods off the top of my head.

chemoleo - 2-3-2004 at 18:14

Ok, as to the choice of chelating agent, I would definitely go for the most natural one - lignosulphonate. There are bound to be pathways for the uptake of polysaccharides/polyphenols (which is what lignin is), or degraded products thereof, and much less so for less natural agents such as EDTA. I am speaking from a theoretical viewpoint here, as I have no quantitative data to back it up with.
Besides this, using lignosulphonates are bound to be more environmentally friendly than EDTA and similar.

As to the detection and quantification of NO3- there is this reaction:

NaNO3 + 4Zn (or Al) + 3 NaOH + 6 H2O --> 4 Na[Zn(OH)3] + NH3

I am sure Ca(NO3)2 can be used too.
The NH3 can be detected by smell of course, and there are ways to quantify the nascent gaseous NH3 with transition metals (i.e. by spectral absorbance, precipitation and such).
Of course there are better ways to do this, such as with organic dyes - but I doubt anyone's got Lunges reagent, or Brucin...
Besides this, there are reasonably insoluble alkaline Hg and Bi -nitrates, which could be used for quantification. But not everyone's got Bi or Hg I believe...

madfarmer - 2-3-2004 at 19:37

Thanks, I'll give those a try (If I can find the chemicals to use)

Chemoleo, so you say lignin is probably the best way to go, how would I go about chelating the calcium nitrate with the substance?

Do I just mix the two together?

chemoleo - 2-3-2004 at 20:25

Yes, I *guess* you'd have to mix those two together. Make sure it's aqueous (in water), else the ions wont dissociate and mix (i.e. bind to the chelator).
Personally I think best would be to simply spread your nitrate fertiliser during a period of draught (or, when the weather forcasters say there wont be rain for the next three days). The moisture in the air will be enough to dissolve the hygroscopic nitrates, and after a few days at most, most of the nitrate should have been absorbed by the plants/trees. Hence no leaching of fertiliser. Probably much cheaper than using chelators...

calcium nitrate

Magpie - 2-3-2004 at 21:01

You already know that calcium nitrate is very soluble in water. So it would leach down to the aquifer after so much rain has occured. I suspect that the lignosulfonate is only good for chelating metals, that is the nitrate may be unaffected, as it is not a metal. If it is the nitrate that your plants are after then this chelant may not be any good for that.

madfarmer - 3-3-2004 at 00:17

So then the company marketing the products as chelated with lignosulfonate is not accurate. The link below is to a image of the label that is on one of their products:

http://www.sjbagnutri.com.au/biglabels/vigor-ligplusbig.jpg

What do you make of it? They aren't all metals are they?

madfarmer - 3-3-2004 at 00:31

I think I might understand now, in the case of calcium nitrate, the calcium is Ca++ whilst the nitrate is NO3-. The + can be chelated, the - can't. Is that right?

Is it possible to put nitrogen in a form that is +?

zestywesty - 3-3-2004 at 01:02

actually, by oxidation state, the nitrogen atom in NO3- has a +5 charge.

vulture - 3-3-2004 at 01:55

True, but it doesn't behave as a positive ion in solution, so no use chelating it.

Theoretic - 3-3-2004 at 05:20

"Is it possible to put nitrogen in a form that is +?"
Yes, the ammonium ion NH4+ has a +1 charge, it's present in ammonium salts (duh :D), and ammonium nitrate does fall into that category, so the chelating agents that this company sells will retain some of the nitrogen in case of [[5Ca(NO3)2].NH4NO3.10H2O]].

Magpie - 3-3-2004 at 19:58

I think you've got the right idea now about the positive ions being capable of being chelated. With NO3- (nitrate) this nitrogen containing ion is not shown chelated with the lignosulfonate. But, if the nitrogen is contained in the NH4+ (ammonium) ion then then it is chelateable. All the chelated ions shown are positive ions. Most are metals but there are some exceptions like NH4+.

madfarmer - 3-3-2004 at 23:28

Thanks heaps!!!

I feel like my understanding of the way calcium nitrate and chelating agents work. This site is so handy.

I wish you well in your future discussions, and if you need a hand in growing citrus, especially navels - leave a message and I'll try to help.