P on Potatoes

[Secret Agronomist]

What levels do you usually apply? We have soils that are moderate to high and put on 100Kg/ha and sometimes more. could I get away with less for 1 year?

 

[jpd]

do a soil test
it will give you rates for various crops

 

[Secret Agronomist]

We obviously do that! But potatoes need luxury P early then they don't remove much of it, so how little luxury can I get away with?

 

[Nitrams]

How available it is will be key. Dont know much about it but there is a product called phosphate liberator i think.

 

[cricketandcrops]

I would say depends on a number of factors eg rented land? indices? target yield? placed or broadcast? variety type and length of season? some of my customers we were down around 60 kg P placed where indices were high on rented land......then top up with foliar P during season (eg Magphos K)

 

[Secret Agronomist]

Owned land, mostly M to M+, some M- and H (Scottish Scale), all P placed as liquid. Maris Piper targeting 62t/ha. I usually use about 100Kg. The only other crop that gets artificial P is the carrots and both those and spuds leave a lot behind. I top up with chicken litter as and when I get it, that's on a rotational basis as we get limited tonnes of it so I put it on the field that needs it the most.

 

[Secret Agronomist]

Comparing it to the K map certainly shows where straw has been used on the carrots in recent years.