Straight p fertiliser

[35x]

What straight phosphate fertiliser are people using ? Years ago, (last used around 1988) we put down Basic gafsa from Adam Lythgoe, a long gone Name. My uncle swore by it. I can see the red and white bags now.3 or 4 bags to the acre every 3 years, on grazing ground. I think it was 35% P.
Thanks.

 

[pgk]

Used triple superphosphate to top dress some low index clay soils, did same last year but with P K mix, P was index 1 or -1, clover this year is a sight to behold. Never used much but now dont use bag N at all only used 20-10-10 till 4 years ago but correcting P K levels and lime has produced better results.

 

[35x]

Used triple superphosphate to top dress some low index clay soils, did same last year but with P K mix, P was index 1 or -1, clover this year is a sight to behold. Never used much but now dont use bag N at all only used 20-10-10 till 4 years ago but correcting P K levels and lime has produced better results.

How much Tsp per acre did you use ? Thanks.

 

[pgk]

Worst field 80kg/ac remainder which also had single hay crop last year 50kg.
We have taken to small top up annually, notable where fym applied in past indices much better.

 

[john432]

Think the closest type of phosphate to gasfa commonly used now is fibrophos. It should be readily available,as the plants have already absorbed it from the soil once at least. I was told that banging on a lot of triple super, more than the current crop needs led it to becoming trapped in a none available form. Some thought that there is usually plenty of insoluble locked up phosphate in our soils, and it needs plenty of available calcium for soil microbes to break down and release the phosphate. Wish I knew the truth!

 

[livestock 1]

Father improved acres of poor pasture land with tsp and lime. The land has no resemblance to what grows over the wall now an unbelievable change. Used ground rock phosphate which was a waste of time in my opinion. Map and Dap seemed better. Lime man recommends slag or fibrophos but maybe that’s because he will be spreading it

 

[livestock 1]

Think the closest type of phosphate to gasfa commonly used now is fibrophos. It should be readily available,as the plants have already absorbed it from the soil once at least. I was told that banging on a lot of triple super, more than the current crop needs led it to becoming trapped in a none available form. Some thought that there is usually plenty of insoluble locked up phosphate in our soils, and it needs plenty of available calcium for soil microbes to break down and release the phosphate. Wish I knew the truth!

@Kiwi Pete talks about this. Ph correction leads to using existing nutrients which are currently unavailable. Which is what I’ve experienced here

 

[john432]

Could you @Kiwi Pete possibly explain more, any links to trials done , I use a lot of steel works slag, same price as ground limestone here, think it makes the clover thrive. Thanks

 

[Kiwi Pete]

@Kiwi Pete talks about this. Ph correction leads to using existing nutrients which are currently unavailable. Which is what I’ve experienced here

It's rare to find soil with low total P but common to find soil with low available (soluble) P
A lot is stored in organic matter and this is what can cause an apparent "low P level" - it's a sign of low microbial activity which is insufficient to meet the needs of the plants, brought about by the plants not meeting the needs of the microbes, because someone is applying 'fresh phosphate'

...so you see how the merry go round begins...

the problem with TSP is the sulphuric acid isn't all removed during manufacture, now here is a substance that certainly doesn't need microbes to get to work on your soil.
Unfortunately (as aluminium is the most abundant element in the Earth's crust, as alumnosilicates) the sulphuric acid basically breaks the bonds and allows the Al ions to float around in the soil solution as a toxin, antagonising (or bonding to) other bits you may need

There is a phenomenon referred to as a "chemical pan" whereby the Al layer basically provides a barrier to microbial life (which is why many deodorants, for example, have aluminium in them) and therefore roots do not penetrate it.
Thus, no more or very little P can be pulled out of the available pool at depth by microbial activity, effectively meaning the crop can only access what is supplied each year, regardless of hundreds on tons per acre being present.

Calcium hydroxide doesn't have enough free silica to remediate TSP damage to soil, all it does it reduce acidity which by itself isn't enough to affect phosphatase levels.

And that's just one element's efforts to lock up P anions, most salts in excess will do the same (zinc, iron, etc).

The problem with most of the "industrial byproduct so-it's-affordable-enough-for-farmers" fertilisers is that they have these unfortunate impurities in them, heaps of heavy metals in some cases compound the damage began by the acid base.

Puts me in an "interesting" job really, I spread this stuff all around the district knowing full well that what I am applying is bad news.... but they moan if you're late, so... silica is what is needed, crazy that it's the second-most abundant thing behind the aluminium under our feet yet it (low available Si) causes all these other "deficiencies" that they can sell you stuff for.

That's where the rock dusts and volcanic sand and guano/RPR type fertilisers the organic folks use are better value than anything else on the market IMO, because they can address the real issue behind unavailable nutrients.
No point being thirsty in the middle of a lake.

 

[deleted user 837354]

Need to soil test first or you are going totally blind and guessing.

I would use TSP generally but would depend on what K indices were, could use 0.24.24 to solve both if needed.

Correcting just the P is not really the name of the game.

pH needs to be right to begin with or it's a waste of time.

 

[Sharpy]

Pretty sure Gafsa phosphate is available as a straight, it is a powder though. I spread thousands of acres with it up till about 15 years ago (contracting).

 

[Macsky]

What rates

Pretty sure Gafsa phosphate is available as a straight, it is a powder though. I spread thousands of acres with it up till about 15 years ago (contracting).

did you spread the gafsa at? Any opinions on it for low p grassland?

 

[Derrick Hughes]

If you have ho ochre content in the soil it won't work Gafsa that is ,locks up

 

[Macsky]

If you have ho ochre content in the soil it won't work Gafsa that is ,locks up

Ho ochre?

 

[Derrick Hughes]

We did Trails back I'm the 80ts on soils high in iron ocher ,quite common in these parts. The brown stuff you see in drains
The only product that worked was water soliable phosphate, the Gafsa locked up and became unavailable

 

[Sharpy]

What rates

did you spread the gafsa at? Any opinions on it for low p grassland?

Anywhere from 1 to 3 cwt acre (125kg to 375kg per hectare).
Good product, handy trace elements, slow release.
IIRC works best on soil with an acid pH, doesn't work on alkaline soils.

 

[Macsky]

Anywhere from 1 to 3 cwt acre (125kg to 375kg per hectare).
Good product, handy trace elements, slow release.
IIRC works best on soil with an acid pH, doesn't work on alkaline soils.

Acid soils is something I can provide

How long would you expect an application to last?

There used to be recommendations on the old scotphos website I’m sure but it’s gone now, and I can’t find anything else anywhere

 

[Sharpy]

Acid soils is something I can provide

How long would you expect an application to last?

There used to be recommendations on the old scotphos website I’m sure but it’s gone now, and I can’t find anything else anywhere

We were doing annual applications from October onwards, sometimes blended with muriate of potash depending on requirements. This meant the farmer only needed to apply straight N the next growing season.

 

[Macsky]

I’m sure I remember larger rates for 5 yearly ‘corrections’ recommended on the old website. Got to be someone out there still using it

 

[Derrick Hughes]

Fresh Poultry muck if you could get it
Is best option