How many days does it require for plants to start absorbing fertilizer?

[Bioaga]

If we use fertilizer like urea, calcium ammonium nitrate or ammonium sulfate; in how many days can the plant start to use it or start to absorb it with it's roots? Are the any researches about it?

 

[robs1]

If we use fertilizer like urea, calcium ammonium nitrate or ammonium sulfate; in how many days can the plant start to use it or start to absorb it with it's roots? Are the any researches about it?

Urea has to go through several changes before it become available so needs going on a bit earlier but doesnt leach like AN so that's not an issue, obviously a lot depends on the weather, temperature and moisture have a big effect

 

[Bogweevil]

Nitrate in warm moist aerated soil, pretty quick, urea in cold compacted dry soil mighty slow - it all depends, but generally nitrate almost instantly, urea 10-20 days.

 

[Oldmacdonald]

Nitrate in warm moist aerated soil, pretty quick, urea in cold compacted dry soil mighty slow - it all depends, but generally nitrate almost instantly, urea 10-20 days.

Is it not the ammonium that is getting absorbed quickly there?

Ammonium is used immediately. Nitrate needs converting to nitrite and then to ammonium before getting absorbed and used.

 

[ollie989898]

Is it not the ammonium that is getting absorbed quickly there?

Ammonium is used immediately. Nitrate needs converting to nitrite and then to ammonium before getting absorbed and used.

As I understood it plants could use both ammonium and nitrate ions though with differing pathways and it varied according to species?

 

[Bioaga]

As far as I know plants can take Nitrate (NO3-) directly, some parts of Ammonium (NH4+) can be taken directly too, the other part of Ammonium turns into Nitrate and can be taken aswell.

 

[Steevo]

It's an excellent question! It's surprising that as farmers we don't know this and/or have ready access to knowledge or research on such a crucial process.

I'm guessing many agronomists would give an answer similar to some of the above, but I'm not sure many would have the evidence somewhere to be able to back their suggestions up.

I wonder if NIAB TAG have done research on this. Or ADAS perhaps? @Brid @ ADAS @DanielKindred may know.

 

[Huno]

If we use fertilizer like urea, calcium ammonium nitrate or ammonium sulfate; in how many days can the plant start to use it or start to absorb it with it's roots? Are the any researches about it?

If it bothers you why don't you just foliar feed a highly available Nitrogen straight onto the leaves of the growing plant? If you put nitrogen products on soil its a bit like asking how long is a piece of string and how many balls of string can i afford

 

[Huno]

If you need nitrogen to germinate your plant you soil is either cold or biologically dead in which case you have a much harder question to ask yourself..

 

[whitefox]

If you need nitrogen to germinate your plant you soil is either cold or biologically dead in which case you have a much harder question to ask yourself..

where did Bioaga say anything about needing N to germinate?......or did i miss something

 

[Spencer]

We often here how Urea doesn’t leech.. but how much and how early would you put on , confident it will be not get washed away if you get a wet spell

With the recent trend towards prolonged dry spells in spring and sheds full of Urea, is there any data in this??

 

[robs1]

We often here how Urea doesn’t leech.. but how much and how early would you put on , confident it will be not get washed away if you get a wet spell

With the recent trend towards prolonged dry spells in spring and sheds full of Urea, is there any data in this??

I aim to get at least 25% of my total fert( all straight urea) on by 20th of feb, if its dry and crops need a boost then would give it a little bit early feb, if the forecast is dryish till mid march I would put more on in feb and want all of it on by early April, yields are better here by doing that than waiting and you dont get the rush of N into the plant that AN gives you which I think leads to more disease especially septoria, I've nothing but gut feeling for that but prefer the steady release from urea.

 

[The Gentleman Farmer]

Urea hydrolyses in the soil to ammonia (plus CO2 +H20). The ammonia sits in balance with ammonium, some of which can be lost by volatilisation. The ammonium can be nitrified to nitrate, or adsorbed onto clay particles or SOM or taken up by the crop. The speed at which all this happens is dependent upon many variables including temperature, but it's a continual process that is happening all the time. Nitrate can leach readily, as can potash, ammonium, even phosphate has been shown to leach once concentrations are high enough (amongst other factors). Therefore urea can be leached, in effect, although it will be less than AN applied at this time (Jan) of year I suspect. Also remember that 'leaching' can be the movement of water down a slope as well as through the soil profile. If water is running off the soil surface nitrate will be in solution with it, and most likely clay particles will be carried too onto which ammonium maybe adsorbed. Similarly volatilisation is not solely restricted to warm temps, research in the US has shown that volatilisation can occur on very cool soils.

With regard to plant uptake and use, plants take up nitrate primarily via water uptake and this cannot be controlled as the nitrate is in solution, whereas ammonium is taken up by exchange. The conversion of nitrate to nitrite and on to amide is done within the plant and is quite energy intensive. Some research claims this process is 15% more energy inefficient than utilising ammonium.

To answer the OP's question my understanding is if the plant is growing, nitrate (of the AN or urea) will be taken up most quickly. As most ammonium within the soil is nitrified to nitrate quite rapidly I would suggest this is the form taken up in the largest amounts and therefore most likely utilised.

 

[yellow belly]

It's an excellent question! It's surprising that as farmers we don't know this and/or have ready access to knowledge or research on such a crucial process.

I'm guessing many agronomists would give an answer similar to some of the above, but I'm not sure many would have the evidence somewhere to be able to back their suggestions up.

I wonder if NIAB TAG have done research on this. Or ADAS perhaps? @Brid @ ADAS @DanielKindred may know.

Time ing trials have been done
subscribe to niab and the results will be available

 

[Huno]

Urea hydrolyses in the soil to ammonia (plus CO2 +H20). The ammonia sits in balance with ammonium, some of which can be lost by volatilisation. The ammonium can be nitrified to nitrate, or adsorbed onto clay particles or SOM or taken up by the crop. The speed at which all this happens is dependent upon many variables including temperature, but it's a continual process that is happening all the time. Nitrate can leach readily, as can potash, ammonium, even phosphate has been shown to leach once concentrations are high enough (amongst other factors). Therefore urea can be leached, in effect, although it will be less than AN applied at this time (Jan) of year I suspect. Also remember that 'leaching' can be the movement of water down a slope as well as through the soil profile. If water is running off the soil surface nitrate will be in solution with it, and most likely clay particles will be carried too onto which ammonium maybe adsorbed. Similarly volatilisation is not solely restricted to warm temps, research in the US has shown that volatilisation can occur on very cool soils.

With regard to plant uptake and use, plants take up nitrate primarily via water uptake and this cannot be controlled as the nitrate is in solution, whereas ammonium is taken up by exchange. The conversion of nitrate to nitrite and on to amide is done within the plant and is quite energy intensive. Some research claims this process is 15% more energy inefficient than utilising ammonium.

To answer the OP's question my understanding is if the plant is growing, nitrate (of the AN or urea) will be taken up most quickly. As most ammonium within the soil is nitrified to nitrate quite rapidly I would suggest this is the form taken up in the largest amounts and therefore most likely utilised.

And the higher your SOM in a balanced system the bigger your plants grow as 12 or 6 to 1 is the magic water soluble number! 6 to 1 is hardcore and 20 to 1 is Carbon locking N

 

[Brid @ ADAS]

It's an excellent question! It's surprising that as farmers we don't know this and/or have ready access to knowledge or research on such a crucial process.

I'm guessing many agronomists would give an answer similar to some of the above, but I'm not sure many would have the evidence somewhere to be able to back their suggestions up.

I wonder if NIAB TAG have done research on this. Or ADAS perhaps? @Brid @ ADAS @DanielKindred may know.

Sorry for the delay, I checked with Roger Sylvester-Bradley, (our head of crop performance) about relevant research. The answer for ammonium nitrate is “within one day”, as shown in the attached paper (see Fig 3 & 4). He strongly suspects that ammonium sulphate & CAN would be just as fast. Urea would possibly take a day or two longer to get started, because it needs to be hydrolysed. Overall, the speed will all depend on the moisture content of the topsoil .. it will generally be fast, and will only be slower if the topsoil is either very dry (like last year) or waterlogged.

 

[Steevo]

Sory for the delay, I checked with Roger Sylvester-Bradley, (our head of crop performance) about relevant research. The answer for ammonium nitrate is “within one day”, as shown in the attached paper (see Fig 3 & 4). He strongly suspects that ammonium sulphate & CAN would be just as fast. Urea would possibly take a day or two longer to get started, because it needs to be hydrolysed. Overall, the speed will all depend on the moisture content of the topsoil .. it will generally be fast, and will only be slower if the topsoil is either very dry (like last year) or waterlogged.

Thank you.

I’m impressed by that. It seems a lot quicker than has been suggested by TFF members.

 

[Bioaga]

I have found a very informative and short video on Youtube about this topic.

 

[robs1]

I have found a very informative and short video on Youtube about this topic.

Not sure that's made by an independent source

 

[czechmate]

Thank you.

I’m impressed by that. It seems a lot quicker than has been suggested by TFF members.

i put some urea on barley early as it was going yellow, early feb on a hard frost. Obviously the bags didn’t exactly fit so I ran the machine out on the triticale next to it.
Even in a cold early February I could pick out where I went very easily in 10 days