Deficiency · Olive, vine and tomato
Potassium deficiency: confirm before you apply
Potassium shows at the leaf edge and in the fruit. We fly and mark the zones with symptoms, so you confirm them with a test before spending on fertiliser.
We have not flown this problem ourselves yet. We work it out with you, on your field.
The problem
The leaf edge scorches
The leaf yellows and dries from the edge. In vines the leaf margins scorch from mid-summer on; if the deficiency is severe, earlier. In tomato the fruit ripens unevenly. In olive, leaf tips dry out.
It appears when the plant asks for more than the root can take up: heavy crop, little water, poor sandy soils or clays that hold on to potassium. The soil can hold plenty of potassium and the leaf still come up short.
How it works
A flight and a test
1
We fly
When symptoms already show on the leaf: in vines, from mid-summer; in tomato, during fruiting.
2
We send you the map
Zones with less vigour or a paler canopy; the scorched edge can only be seen at plant level. Other deficiencies, drought or diseases look similar.
3
You confirm with a test
Leaf or petiole analysis in those zones before deciding on fertiliser. It is what we do in our nutrient management plan.
Where it shows up
Where it appears
- Olive
- Grapevine
- Tomato for processing
In soils already well supplied with potassium, public trials have often found no response of cereals to an application. Before applying potash, it is better to confirm it is needed.
What farmers ask us
Potassium: field questions
How do I know if I am short of potassium?
Looking at the leaf is not enough. You confirm it with a test; in vines, a petiole test. There are reference values for each stage, which we compare with your results.
I apply potassium and there is no response. Why?
In clay soils, the potassium you apply is first held by the clay. So the response can be slow.
Does foliar fertiliser help?
It can help in the short term, but it is better to confirm the shortage with a test first, then ask your adviser.
Know someone this would help?
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