Tissue test results

[Jo28]

Could someone interpret tissue tests on oilseed rape done at the start of flowering so I can see what the values should be for optimum yield.

Nitrogen 4.4%
Phosphorus 0.36%
Potassium 2.4%
Sulphur 0.76%.

Cheers

 

[Brisel]

This was taken in mid March, just before the green bud fungicide and final dose of N+S to see what I needed to add to the tank. Boron is consistently low here. K is always low but it is for everything I've tested during rapid stem extension.

 

[snarling bee]

BH Is your rape flowering already!!

 

[Jo28]

cheers surprised our k is low, our soil is high in k.

 

[Brisel]

If you really want to make your head spin, analyse this instead!

This is why you can't take one nutrient in isolation. Just because a lab test says it's in good supply in the soil doesn't always make it available to the plant when needed.

Is the low K because the test isn't quite right? Has the large dose of N still being drawn on at flowering masking the K? Is something else in excess antagonising the K uptake? How do you apply K? Muriate of potash which is potassium chloride which is a basic salt, temporarily toxic in large doses.

I think there was some YEN work done on good responses to freshly applied K in most crops.

 

[Warnesworth]

cheers surprised our k is low, our soil is high in k.

Have you got a recent soil analysis of the same field you could post?