Soil NPK Indexes

AP2014 · 16-02-2015 06:19PM #1

Alot of threads on soil fertility, testing, silage, fertilisers going around. In one it is mentioned if index is 1 you need 100 units N 30p and 140k for silage. Surely it would be cheaper to feed concentrates nearly than to put out this amount of chem fert to produce silage.

You are looking at a serious cost per acre on fert alone before contractors, plastic etc is taking into account.

Assuming index 3 is the ideal target would it take much to maintain this if taking a cut of silage? What would the maintenance levels be if just grazing?

More importantly for a lot of farms that have low p and k what is needed to move from index 1 to 3 if no grazing or silage was carried out?

ellewood · 16-02-2015 06:33PM

Welcome the world of beef farming where a lot oc things ya do cost more than the return from it :-)

Increasing p+ k is expensive tho and unless stocked high enough I dont think it justifies any more than spreading for little more than maintance

rangler1 · 16-02-2015 06:39PM

AP2014 wrote: »

Alot of threads on soil fertility, testing, silage, fertilisers going around. In one it is mentioned if index is 1 you need 100 units N 30p and 140k for silage. Surely it would be cheaper to feed concentrates nearly than to put out this amount of chem fert to produce silage.

You are looking at a serious cost per acre on fert alone before contractors, plastic etc is taking into account.

Assuming index 3 is the ideal target would it take much to maintain this if taking a cut of silage? What would the maintenance levels be if just grazing?

More importantly for a lot of farms that have low p and k what is needed to move from index 1 to 3 if no grazing or silage was carried out?

If you want to make good silage, you need good quality grass, which you won't get at index I.....Yes, it's expensive to build up fertility, but it's not hard to keep fertility high for silage if you're returning the slurry to the same area as you're taking the silage,

AP2014 · 16-02-2015 07:30PM

ellewood wrote: »

Welcome the world of beef farming where a lot oc things ya do cost more than the return from it :-)

Increasing p+ k is expensive tho and unless stocked high enough I dont think it justifies any more than spreading for little more than maintance

Exactly I don't think it can be justified. Wonder can the tillage guys give us the info that is needed to go from index 1 to 3.

onyerbikepat · 16-02-2015 07:34PM

ellewood wrote: »

Welcome the world of beef farming where a lot oc things ya do cost more than the return from it :-)

Increasing p+ k is expensive tho and unless stocked high enough I dont think it justifies any more than spreading for little more than maintance

I find it very hard to believe that bringing your soil fertility up from index 1 to index 3 is a waste of money. Grass is by far the cheapest feed out there.

Miname · 16-02-2015 07:44PM

The soil ph is critical before you start trying to bring up the indexes. then bringing up the indexes can be done a multitude of ways, bagged manure isnt the only method. pig slurry mushroom compost even throwing meal to cattle on grass helps.

Miname · 16-02-2015 07:52PM

AP2014 wrote: »

Exactly I don't think it can be justified. Wonder can the tillage guys give us the info that is needed to go from index 1 to 3.

if you dont think its justified, everyone better quit spreading compound fertilizer. what you have to realize while you may feel its of no benefit to you, there are plenty of others who can justify it. do you really think that the ground will just keep giving without getting anything back?
in your system you'll get by for a while but thats all.

C0N0R · 16-02-2015 07:52PM

AP2014 wrote: »

Exactly I don't think it can be justified. Wonder can the tillage guys give us the info that is needed to go from index 1 to 3.

If land is the biggest factor in your business ie you can only grow enough grass to support a certain stocking rate, by improving your soil index your able to increase your stocking rate. If you own land at index one, are renting land and aren't actively trying to improve the index of the land own your wasting money in my opinion.

Buford T. Justice XIX · 16-02-2015 08:18PM

AP2014 wrote: »

Alot of threads on soil fertility, testing, silage, fertilisers going around. In one it is mentioned if index is 1 you need 100 units N 30p and 140k for silage. Surely it would be cheaper to feed concentrates nearly than to put out this amount of chem fert to produce silage.

You are looking at a serious cost per acre on fert alone before contractors, plastic etc is taking into account.

Assuming index 3 is the ideal target would it take much to maintain this if taking a cut of silage? What would the maintenance levels be if just grazing?

More importantly for a lot of farms that have low p and k what is needed to move from index 1 to 3 if no grazing or silage was carried out?

A figure that stuck in my mind from last year is that it costs 100 euro a hectare/year to bring P&K levels up over a number of years from the IGA. I'm not sure if that includes the cost of lime also but i imagine it does.

You can grow grass at a cost of 6c/kg DM but you buy concentrates at a cost of c.30c/kg DM.

On maintainence levels at grazing, it would depend on the level of sales ie milk/cattle/grain you are taking off. Someone here will have Teagasc figures on that, i imagine.

ellewood · 16-02-2015 09:03PM

onyerbikepat wrote: »

I find it very hard to believe that bringing your soil fertility up from index 1 to index 3 is a waste of money. Grass is by far the cheapest feed out there.

I never said it was a waste of time increasing p+k But ehat I did say thats its un ecomical to do it if ya havent the sr to use the extra grass grown
Like some one else said there are lads paying 200/acre to rent extra ground and if they spent that on their own ground, grew more grass dropped the rented ground thed be better off

AP2014 · 16-02-2015 09:23PM

Miname wrote: »

The soil ph is critical before you start trying to bring up the indexes. then bringing up the indexes can be done a multitude of ways, bagged manure isnt the only method. pig slurry mushroom compost even throwing meal to cattle on grass helps.

I heard meal was getting cheaper alright but jesus surely it's not this cheap :eek:

Greengrass1 · 16-02-2015 09:36PM

We leased grassland last yr.
Best thing we did gave our home farm a break.
Have loads of silage this yr and I'll be able to run a proper grazing system.

It was going to be spent on meal if not.

Were spending a lot if money on p and k here though

farawaygrass · 16-02-2015 10:35PM

The way I'm looking at it but not saying im right, I could go out and spend my money on all meal, and do the same next year, and the year after and for as long as I'm farming. Or I could spend money on getting soil fertility right, which seems dear in the short term, but when I get it right I'll only have to maintain it. Spending money on lots of meal year in year out is giving your merchant options to grow his business, spending money on soil fertility is giving yourself options to grow your own business.
*no doubt it costs a lot, it does either way.

AP2014 · 17-02-2015 12:05AM

Miname wrote: »

if you dont think its justified, everyone better quit spreading compound fertilizer. what you have to realize while you may feel its of no benefit to you, there are plenty of others who can justify it. do you really think that the ground will just keep giving without getting anything back?
in your system you'll get by for a while but thats all.

farawaygrass wrote: »

The way I'm looking at it but not saying im right, I could go out and spend my money on all meal, and do the same next year, and the year after and for as long as I'm farming. Or I could spend money on getting soil fertility right, which seems dear in the short term, but when I get it right I'll only have to maintain it. Spending money on lots of meal year in year out is giving your merchant options to grow his business, spending money on soil fertility is giving yourself options to grow your own business.
*no doubt it costs a lot, it does either way.

Ignore my system, this question is just based on some posts recently here as I said in my opening post. The general consensus I am getting here is that it is worth doing. The amazing thing is no one seems to be able to cost or determine quantities that are involved in moving from index 1 to 3 in npk. Also to maintain ground at 1 or 3 when taking silage or just grazing.

Greengrass1 · 17-02-2015 12:09AM

AP2014 wrote: »

Ignore my system, this question is just based on some posts recently here as I said in my opening post. The general consensus I am getting here is that it is worth doing. The amazing thing is no one seems to be able to cost or determine quantities that are involved in moving from index 1 to 3 in npk. Also to maintain ground at 1 or 3 when taking silage or just grazing.

To maintain soil index at 3 with stocking rate of 2.7lu/ha you need 16u P and around 30 K
Takes 100 units of P to lift from index 1 to index 3 and then your maintaince figure on top of that

Buford T. Justice XIX · 17-02-2015 12:13AM

AP2014 wrote: »

Ignore my system, this question is just based on some posts recently here as I said in my opening post. The general consensus I am getting here is that it is worth doing. The amazing thing is no one seems to be able to cost or determine quantities that are involved in moving from index 1 to 3 in npk. Also to maintain ground at 1 or 3 when taking silage or just grazing.

Maintenance and improving the indexes depends on stocking rate and also soil type. There is no easy '5 bags of 10:10:20' answer.

Send a sample in to see the P&K and lime requirements and then adjust for stocking rate and soil type.

AP2014 · 17-02-2015 12:21AM

Buford T. Justice V wrote: »

Maintenance and improving the indexes depends on stocking rate and also soil type. There is no easy '5 bags of 10:10:20' answer.

Send a sample in to see the P&K and lime requirements and then adjust for stocking rate and soil type.

Thanks, lets say no stock though. Would 90N, 30P and 140K bring me to index level 2. And the same again the following year push me to index 3.

Fully understand there are variables in soil etc, just looking for approx figures here. I realise I am over simplifying.

rangler1 · 17-02-2015 12:34AM

AP2014 wrote: »

Thanks, lets say no stock though. Would 90N, 30P and 140K bring me to index level 2. And the same again the following year push me to index 3.

Fully understand there are variables in soil etc, just looking for approx figures here. I realise I am over simplifying.

Are you referring to fertilising requirement for silage

AP2014 · 17-02-2015 12:38AM

rangler1 wrote: »

Are you referring to fertilising requirement for silage

Initially looking at what is required to go from index 1 to 3 as this is the index for optimum grass growth from what I am told here. Lets say no silage or stock on land.

Then when at index 3, what is required for for one cut of silage or grazing with medium stocking levels and maintain fertility at index 3.

onyerbikepat · 17-02-2015 10:05AM

See page 8 of the attached.
Don't confuse Units of fertiliser with KG/Ha. A unit refers to one % of a CWT ("hundred weight" - old units), and one CWT is 50.8Kg. So for example a 50Kg bag of 18.6.12 would contain;
9Kg of N,
3Kg of P
and 6 Kg of K.

AP2014 · 17-02-2015 01:59PM

onyerbikepat wrote: »

See page 8 of the attached.
Don't confuse Units of fertiliser with KG/Ha. A unit refers to one % of a CWT ("hundred weight" - old units), and one CWT is 50.8Kg. So for example a 50Kg bag of 18.6.12 would contain;
9Kg of N,
3Kg of P
and 6 Kg of K.

Super stuff, thanks.

Miname · 17-02-2015 02:53PM

I've brought ground from low index 1 to mid 2 over 3 years using pig slurry on top of fertiliser. I'm going with a coat of mushroom compost this year which is supposed to be good at holding a consistent supply of p. My main issue is all my k's are high index 3s so I'm trying to find a balance without bringing tetany into the equation.

AP2014 · 17-02-2015 03:08PM

Miname wrote: »

I've brought ground from low index 1 to mid 2 over 3 years using pig slurry on top of fertiliser. I'm going with a coat of mushroom compost this year which is supposed to be good at holding a consistent supply of p. My main issue is all my k's are high index 3s so I'm trying to find a balance without bringing tetany into the equation.

Mushroom compost hard to get out? Do you hire a contractor?

onyerbikepat · 17-02-2015 05:08PM

If your K is high, you could use a fertiliser with a different P/K ratio.
Gouldings for example, make a 15.10.10 fertiliser.

Anyone ever take this approach?

onyerbikepat · 17-02-2015 05:09PM

15.10.10

Miname · 17-02-2015 08:03PM

onyerbikepat wrote: »

15.10.10

I'm going with 25-4-0 on some ground. Mushroom compost needs to be spread with either a dung spreader at a minimum of 4 ton per acre to get any kick I'm told

smokey-fitz · 17-02-2015 08:26PM

onyerbikepat wrote: »

If your K is high, you could use a fertiliser with a different P/K ratio.
Gouldings for example, make a 15.10.10 fertiliser.

Anyone ever take this approach?

Thats what I am at, my p's are index 4 and k's are 1 and 2's so I go with 19.0.15 with intentions of going with murate of potash over the next few years too.

Green farmer · 17-02-2015 08:44PM

Got my soil test results back. 5.9 ph and p & k both index 1. Any ideas of fertiliser type to use to gradually bring up over a year or two. Was thinking of something like 18.6.12 little and often in addition to lime. Just sheep farm here so no slurry option etc.

Miname · 17-02-2015 11:38PM

Green farmer wrote: »

Got my soil test results back. 5.9 ph and p & k both index 1. Any ideas of fertiliser type to use to gradually bring up over a year or two. Was thinking of something like 18.6.12 little and often in addition to lime. Just sheep farm here so no slurry option etc.

Lime first then with 18-6-12 you won't go too far wrong

mauser77 · 18-02-2015 09:19AM

If you're ph was 5.3 and you spread lime at 2 ton to the acre how far up the ph scale would you move

onyerbikepat · 18-02-2015 09:50AM

mauser77 wrote: »

If you're ph was 5.3 and you spread lime at 2 ton to the acre how far up the ph scale would you move

I had fields come back at 5.1 (water PH) and FBA recomended 12.5 Tonnes/Ha. Thats 5 tonne /Acre.
So at a guess you will only get about half way to the 6.3 PH target with 2 tonne/acre.

Soil NPK Indexes

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