This is a blog post for fertiliser nerds only. Later on this morning am going to a Syngenta technical update about Nemathorin. If you are really well-behaved then I might write a post for Potato Cyst Nematode nerds a bit later.
Yesterday I was pondering over potato fertiliser rates.
Our soil indexes for Phosphate and Potash are solid 3's and 4's. Most of our potato crops are following at least one crop of brassicas and, since we have had exceptionally dry weather, it stands to reason that the levels of soil Nitrogen will possibly be high and at least 1.
This makes fertiliser maths quite complicated. I want to keep our costs as low as possible and I have a strong moral objection to using more fertiliser than a crop absolutely needs. Nitrous oxide emissions and the leaching of phosphate and nitrate into watercourses are pollutants which cost farmers money. There is nothing to be gained from over-using N and P.
I consider it terribly mealy-mouthed when people say "on the other hand" but, "on the other hand," it is foolish to go to all of the trouble, cost and diesel use of producing an area of potatoes and then losing yield because you have under-fed it. In theory we need very little fertiliser to grow a good crop but my experience dictates that this would be a foolish omission to make.
For all of the great advice that is offered, fertiliser recommendations are not a perfect science. We often use more inputs than a crop theoretically requires; this is because the cost of a crop failure always outweighs a small saving in production costs.
I am going to draw up two recommendations for our potato crops. I will personalise them by giving each one a name. I'm calling one "Bells and Whistles" and the other one "Ebenezer."
When I get time I will put them both up on here and we can do a vote on it.
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