Potato fertiliser

[ridger]

I see according to local paper that fertilisers containing p will have to be better justified. I know that is old news but what will happen about potato fertiliser? I tried using zero p back about 8 years ago ( field was index 3) and there was nowhere near enough tubers so I went back to my 8 bags of 8 24 24 again and done mostly ok since. Is it a case of going with 4 ish bags of 22 4 14 and hoping for the best? Hasn't worked in the past anyway

 

[Spud]

I see according to local paper that fertilisers containing p will have to be better justified. I know that is old news but what will happen about potato fertiliser? I tried using zero p back about 8 years ago ( field was index 3) and there was nowhere near enough tubers so I went back to my 8 bags of 8 24 24 again and done mostly ok since. Is it a case of going with 4 ish bags of 22 4 14 and hoping for the best? Hasn't worked in the past anyway

240kgP/ha at index 3? Blimey, I put less than that on at index 1!

Phosphate doesn't move far, so we place DAP (more soluble than TSP) 2" below and 2" to either side of the mother tuber. A bit of micronutrition through the leaf on lazy rooting varieties is usually enough to see them through.
A common feed here is usually:
4-500kg MOP per hectare according to variety, soil index and wether or not fym is present
Anywhere from 100 to 350kg DAP placed at planting
26N37S at 250kg broadcast shortly after planting
The balance of N usually applied as liquid mixed with the herbicide - which helps weed control efficacy too.

I'm of the veiw that P makes nothing like as much difference to tuber number as things like apical dominance, but they do need fresh P to produce and support shoots and stems.
The majority of our potatoes are on rented land, so I tend to apply to replace off take - in practice though, potatoes remove very little p (but quite a lot of k)
FYM would reduce P application significantly.

 

[Sonoftheheir]

We’re on 15.5/15.5/23.5 at 850kg ha where muck has been applied and 1000kg ha where it hasn’t this year. Our land is mostly in the 3’s.

We have found low P in tubers that have problems with frying (going black one end) this is on rented land that generally doesn’t have the high fertility like ours does.

We need to put more Phosphorus on to try and help with that problem. Trouble is liquid P is at very high volumes and I don’t really want a huge tank on the front of the tractor. I guess I could put granular dap on? Would just need to sort an applicator.

What machine do you use @Spud?

 

[Flat 10]

I’m not a potato grower but my omex man was suggesting that the local spud men are putting down serious amounts of K as they are seeing yield increases at rates above those traditionally recommended.

 

[ollie989898]

Spuds love potash but I would not want to see them short of P.

In fertile land they are nearly a laugh to watch grow, they seem able to get the goods at leisure.

Foliar nutrition definitely works, used to feed mine about once a fortnight, in with the blight sprays, you could see where the odd plant didnt get any!

 

[ridger]

I need to do something to get more numbers. Currently planting seed at 7 inches and still too many big potatoes. And can't burn down early because need dry matter

 

[Spud]

I need to do something to get more numbers. Currently planting seed at 7 inches and still too many big potatoes. And can't burn down early because need dry matter

7"spacing? What's the variety?

 

[ridger]

Kerrs pink

 

[ridger]

They say phosphorus gives you numbers so don't want to cut it down much

 

[Mr chips]

They say phosphorus gives you numbers so don't want to cut it down much

We give our Royal liquid phosphate through the sprayer at Rosetta stage . This does boost tuber numbers. Backfired last year with the drought. Too many small tubers. We find liquid placed does utilise all fertiliser especially in dry springs. And the blend can be specific for each field. We use between 600 and 1200 litres per ha . With the extra K been granular applied in the next month. We are also trying Polysulphate as a split with the K to get extra Mag and Sulphur.

 

[ridger]

I've no access to liquid fertiliser over here, are any of the products to on with sprayer any good, used a lot of maxi crop this year and haven't much faith in it

 

[Mr chips]

I've no access to liquid fertiliser over here, are any of the products to on with sprayer any good, used a lot of maxi crop this year and haven't much faith in it

We find half a litre of Phorse during tuber initiation boosts numbers . We do our own trials and it’s very conclusive it works. And we don’t sell it .

 

[ridger]

Who makes it? I'll need to get it ordered to have it ready

 

[AndrewB]

I've no access to liquid fertiliser over here, are any of the products to on with sprayer any good, used a lot of maxi crop this year and haven't much faith in it

I use Headland Hi phos in with blight spray at hook/ tuber initiation, @ 5 l / Ha normally for two sprays. All seed and salad crops so tuber no. Is very important. N and P placed with planter, K broadcast on ploughing.

 

[Mr chips]

Who makes it? I'll need to get it ordered to have it ready

Not sure. I will look tomorrow and let you know.

 

[Spud]

We’re on 15.5/15.5/23.5 at 850kg ha where muck has been applied and 1000kg ha where it hasn’t this year. Our land is mostly in the 3’s.

We have found low P in tubers that have problems with frying (going black one end) this is on rented land that generally doesn’t have the high fertility like ours does.

We need to put more Phosphorus on to try and help with that problem. Trouble is liquid P is at very high volumes and I don’t really want a huge tank on the front of the tractor. I guess I could put granular dap on? Would just need to sort an applicator.

What machine do you use @Spud?

We first got into fert placement with an Agroband back in 1999 iirc. Ok but struggle to drop the fert in the right place with anything like a side slope, without the back of the planter being out of line.
Graduated to an accord hopper blowing to 8x30mm pipes at the back, two tines in front and two behind the openers - much better accuracy, but struggled to get rid of the air.
In 2011 we bought a new Standen SP200 planter, and by now Horstine were making fert legs to fit. 4x60mm pipes from the accord hopper straight to the openers from the front mounted mushroom certainly improved things. Its flaws? Back pressure at higher rates or higher speeds, and fast wearing rotors.

We've dabbled with suspension fert but struggled with inconsistent product, and poor results. Prefer to have control of application when we plough just in time too.

Looking for the next upgrade now - probably switch to a belt planter, which will dictate an upgrade in fert kit at the same time. Liquid looks good, but is more expensive logistically than the current system. At an average rate of say 300kg/ha, we only need three 600kg bags across the seed trailer to last all day. At the thick end of 1000litres of liquid/ha, we'd need a yard tank and bowser - neither of which we currently have - our bowser is busy enough feeding water to the potato washer unless its a late time. I guess liquid kit will cost similar money to replacing the dry fert kit. Not an easy one. Currently considering a Horstine Airstream (not cheap) of Agrisem equivalent, or going liquid.

 

[Sonoftheheir]

Thanks for that @Spud very interesting!

What granular product do you use?

 

[Spud]

Thanks for that @Spud very interesting!

What granular product do you use?

Used to use MAP mostly for it's solubility, but swapped to DAP to get more N in the seed bed to get the plants up and away. 18%N46%P
MOP spun onto stubbles pre cultivation, Kieserite too if mg levels dictate
We experimented last season with a liming product applied post ploughing as an aid to skin finish - I was very sceptical but it worked, so we'll do some again this time, maybe applying at the same time as the MOP/KS for easiness, it was a pain putting the spinner on every time we got a field ploughed last year

 

[Sonoftheheir]

Thanks @Spud Looks like MAP might be better for us on our black Fen soils as it’s better in higher ph soils. I think we’d spin it on once the baselier has been through, prior to planting. Might be a faff though, but only 120 acres to do, so not sure if it’s worth buying a Horstine?

 

[Farmergrum]

Thanks @Spud Looks like MAP might be better for us on our black Fen soils as it’s better in higher ph soils. I think we’d spin it on once the baselier has been through, prior to planting. Might be a faff though, but only 120 acres to do, so not sure if it’s worth buying a Horstine?

Id say it would be... ours was second hand, now 20 years old, means the p is close to root system as they start to grow....
We use a blend DAP +AM Sulphate