I noticed a reply to a post on growing carrots last week that gave me a reason for what I had believed until then was an old wifes tale, that you should not plant carrots in freshly manured ground. The answer was that it was because the tap roots could hit clumps of muck, and would fang.
That I can understand, especially as I have grown carrots in soil that had well rotted and friable manure manure added to it not long before planting, without any ill effects.
So given the depth of gardening knowledge out there, can I ask for clarification on another old gardening proverb:-
Don't add manure and lime at the same time.
I have never seen a clear explanantion as to why not.Is there a scientific reason for this, or is it another old wifes tale?
Scientific Fact or Old Wifes Tale
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Ian
I believe the advice is due to a chemical reaction that can occur between the two materials resulting in a reduction in nitrigen content in the manure. The lime causes the loss of nitrogen in the from of ammonia gas but I am no chemist!
One thing that strikes is that manure is incredibly variable in nutrient content depending on what produced the manure, how old it is and how it has been stored.
Old manure that has been stored un covered in the open for a few years will have lost a high % of it's nutrients by leaching compared to mature manure stored undercover and I would treat the old manure more as a soil conditioner rather than a manure.
So, not really an answer....sorry!
Jerry
I believe the advice is due to a chemical reaction that can occur between the two materials resulting in a reduction in nitrigen content in the manure. The lime causes the loss of nitrogen in the from of ammonia gas but I am no chemist!
One thing that strikes is that manure is incredibly variable in nutrient content depending on what produced the manure, how old it is and how it has been stored.
Old manure that has been stored un covered in the open for a few years will have lost a high % of it's nutrients by leaching compared to mature manure stored undercover and I would treat the old manure more as a soil conditioner rather than a manure.
So, not really an answer....sorry!
Jerry
Farmers son looking to get back to the land full time one day.....
Holiday in Devon? Come stay with us: http://www.crablakefarm.co.uk/
Holiday in Devon? Come stay with us: http://www.crablakefarm.co.uk/
I seem to remember that I asked this question soon after I joined the forum as I'd inadvertently manured and limed at the same time and was worried about what might happen. Well, nothing did, and everything's growing well so far. Mind you, it was bagged manure from a garden centre and extremely well rotted and friable.
Jude
There are more questions than answers.
There are more questions than answers.
Ian,
As I understand it, Nitrogen exists in many different forms in compost. Depending on what went in to the compost Carbon/Nitrogen ratio will differ significantly. This suggests the concentration of Nitrogenous compounds that might react with the lime will vary.
Lime lasts until it reacts with something. It reacts at differing rates with differing compounds. All reactions will reach a natural equilibrium where concentrations remain constant until an outside agency changes something (i.e. you bunging in more lime/compost)
I have no idea ( I'm not a very knowledgeable gardener) whether the wisdom is to lime first then manure or vice versa. I haven't even tested the pH of my soil and I've been here 3 years!
Chemically speaking it will depend on rates of reaction and equilibria (and I can't find any reseach papers on this yet). pH (parts hydrogen) itself is a result of your soil reaching an equilibrium between molecular water (H20) and Hydrogen ions (H+) and hydroxy ions (OH-) in solution.
My guess would be if your soil has a very low pH then it might be better to lime first to make sure most of lime reacts with the acids, then manure up once the pH is raised, but its a guess! That said, if you did it at the same time I can't see any problem if your soil doesn't reach the right pH, just bung some more lime in!
I would be interested to find out what the anecdotal evidence points to becasue this is an experiment begging to happen!
Right up my alley!
Loz
As I understand it, Nitrogen exists in many different forms in compost. Depending on what went in to the compost Carbon/Nitrogen ratio will differ significantly. This suggests the concentration of Nitrogenous compounds that might react with the lime will vary.
Lime lasts until it reacts with something. It reacts at differing rates with differing compounds. All reactions will reach a natural equilibrium where concentrations remain constant until an outside agency changes something (i.e. you bunging in more lime/compost)
I have no idea ( I'm not a very knowledgeable gardener) whether the wisdom is to lime first then manure or vice versa. I haven't even tested the pH of my soil and I've been here 3 years!
Chemically speaking it will depend on rates of reaction and equilibria (and I can't find any reseach papers on this yet). pH (parts hydrogen) itself is a result of your soil reaching an equilibrium between molecular water (H20) and Hydrogen ions (H+) and hydroxy ions (OH-) in solution.
My guess would be if your soil has a very low pH then it might be better to lime first to make sure most of lime reacts with the acids, then manure up once the pH is raised, but its a guess! That said, if you did it at the same time I can't see any problem if your soil doesn't reach the right pH, just bung some more lime in!
I would be interested to find out what the anecdotal evidence points to becasue this is an experiment begging to happen!
Right up my alley!
Loz
The action of lime will be to react with ammonium compounds which are one form of captive nitrogen and turn them into calcium compounds, then the ammonia being a gas will escape and no longer be available for the soil life to turn into nitrates or nitrites for uptake by the plants. No serious damage, just waste of plant food.
Allan
Allan
When you get a delivery of fresh manure it contains a lot of Urine, especially from a Bull pen,
and the reason that you store it is to wait until it has lessened in strength. As it lessens in strength it converts to a different form of ammonia which is more readily accepted by plant life. When it is fresh it is said to cause burning or manure scorch.
This is why fresh manure should not be used when sowing Carrots. The Carrots hit fresh maure and the growing root tip is destroyed. After a while growth will continue but nature being what is it Mutates and gets two growing points which is what we term as forking. This can also occur to a Carrot when the growing tip hits a stone. Sometimes it is able to push the stone aside but again if in trying to do so this the growing point is damaged the same forking occurs. The use of very well rotted manure, where it has all but converted to soil will, if well dug in, not harm but will help Carrots.
If you manure, with fresh manure and Lime at the same time all you are in fact doing is to reduce the overall potential of adding Nitrogen into the soil.
The Old Wives Tale bit is when they say that you should never use manure on Carrots as it always used to be said "You should never manure with Fresh
manure to grow Carrots." To newcomers this is very confusing and they generally understand that Carrots do not need any feeding which is entirely wrong.
and the reason that you store it is to wait until it has lessened in strength. As it lessens in strength it converts to a different form of ammonia which is more readily accepted by plant life. When it is fresh it is said to cause burning or manure scorch.
This is why fresh manure should not be used when sowing Carrots. The Carrots hit fresh maure and the growing root tip is destroyed. After a while growth will continue but nature being what is it Mutates and gets two growing points which is what we term as forking. This can also occur to a Carrot when the growing tip hits a stone. Sometimes it is able to push the stone aside but again if in trying to do so this the growing point is damaged the same forking occurs. The use of very well rotted manure, where it has all but converted to soil will, if well dug in, not harm but will help Carrots.
If you manure, with fresh manure and Lime at the same time all you are in fact doing is to reduce the overall potential of adding Nitrogen into the soil.
The Old Wives Tale bit is when they say that you should never use manure on Carrots as it always used to be said "You should never manure with Fresh
manure to grow Carrots." To newcomers this is very confusing and they generally understand that Carrots do not need any feeding which is entirely wrong.
JB.
Thanks for that - two old wives tales that actually have some foundation in science, albeit they have become a little bit distorted in the telling.
Anybody else got any other old wives tales that need a bit of chemical analysis?
Anybody else got any other old wives tales that need a bit of chemical analysis?
Allan wrote:then the ammonia being a gas will escape and no longer be available for the soil life to turn into nitrates or nitrites for uptake by the plants.
Allan
This happens without the lime aswell!
Not a lot you can do to stop it I'm afraid. In addition..........
AT pH 7 (pure water) about 99% of ammonia (NH3) will be protonated by water to form the NH4+. NH3 and NH4+ are not as soluable as the nitates (and 'trites) but will be trapped by clay particles and be available for nitrifying bacteria as a source of energy whereupon they will be converted to 'trates n trites. Unfortunately there are snipers about, bacteria that denitrify, converting these to N2O and N2. They then get washed away (leached). Mainly sucked down rather than drifting up!
Sad, but there ya go!
Loz