Sprayer - forgot to change wheel settings. Result?

[Oldmacdonald]

I forgot to change the wheel setting on my sprayer from flotation to rowcrops when applying latest N application.
Flotations are 22.5s, Rowcrops are 28s. Tyre depth roughly the same.

What percentage more or less N have I put on compared with what I intended?

 

[Two Tone]

I forgot to change the wheel setting on my sprayer from flotation to rowcrops when applying latest N application.
Flotations are 22.5s, Rowcrops are 28s. Tyre depth roughly the same.

What percentage more or less N have I put on compared with what I intended?

Disregarding any extra wheel-slip from the row-crops wheels, you will have put on about 80% of what you were planning.
However, it needed to be increased by 25% from your actual setting to achieve what you were aiming for.

 

[Farmer Fin]

Or how many litres did you actually apply?

I forgot to change the wheel setting on my sprayer from flotation to rowcrops when applying latest N application.
Flotations are 22.5s, Rowcrops are 28s. Tyre depth roughly the same.

What percentage more or less N have I put on compared with what I intended?

 

[Flintstone]

@Two Tone is spot on with his sums.

 

[snarling bee]

Really??

I think you need the rolling circumference of each type of tyre not just the rim size.

 

[fudge]

I doubt you will tell the difference at harvest time. I imagine your Nmax audit will show you have followed good practice as well.

 

[Lincsman]

Really??

I think you need the rolling circumference of each type of tyre not just the rim size.

Correct, rim size is irrelevant and only of interest to get the circumference data along with profile and tyre width.

 

[Northdowns Martin]

Must be able to work out from difference between your recorded to actual speed

 

[Chae1]

Surely you would know how much you had left in tank when you finished?

Divide that by ha covered and that's how much you under applied?

 

[Two Tone]

Correct, rim size is irrelevant and only of interest to get the circumference data along with profile and tyre width.

Yes, actually you are correct. Circumference is important.
But the easiest way is not to use circumference but OD diameter, measured parallel, rather than vertical to the ground, then divide the Flotation wheels by the Row crop wheels.

No need to bother with the pi r squared, because it applies to both wheels, so one cancels out the other on each side of the equation.

I had wrongly assumed that the dimensions @Oldmacdonald gave were the OD of the wheels, rather than the OD of the rims.