Leaves thickness and nitrogen tolerant relationship?

[daiviet_nguyen]

Is there the relationship between leaves thickness and nitrogen?

That is, the thicker the leaves the more tolerant to nitrogen heavy feed? The more delicate or thinner the leaves, the less they tolerate heavy nitrogen feeding?

Thanks.

[shibui]

What an interesting theory Daviet, What has caused you to think of this?
I have spent a few minutes pondering and don't think I agree.
For instance grasses generally have similar thickness leaves but some eg phalaris, ryegrass, etc prefer high nitrogen while others, like many of our native grasses prefer lower nitrogen. I know some pasture species tend to disappear when fertility levels are raised but I think that is due more to competition from from the species that grow faster when nutrients are higher rather than the other plants being adversely affected by the nutrients.

For trees I think I could probably safely give my maples similar doses of nitrogen to figs. It might depend more on what form the fertiliser is in rather than just the nitrogen levels??

[daiviet_nguyen]

Hi shibui,

Thank you for the explanations. I have the following problem.

Early Jan, my plum leaves got eaten by a caterpillar. When I found it, I promptly murdered the caterpillar.

Since then this plum has put out beautiful young and delicate leaves. A week or so ago, I put a layer of dynamic lifter onto the soil. Last Sat 4th/Feb/2012, I trimmed off some strong shoots. Monday 6th/Feb, in the afternoon, I noticed some young leaves on the tips had withered and died: no sign of being eaten. The soil was still moist. This morning, some more leaves died of the same "symptom".

The last few days have been in low 20 C. And during the day I keep it sheltered.

This morning 7th/Feb, I have removed all the dynamic lifter from the pot.

I have applied heavy DL to trident maples with young leaves. So far, I have not experienced problem at all. IMHO, plum's young leaves are much more delicate than young trident maples' leaves (?).

Best regards.

[treeman]

A layer of DL!! You may have over done the feeding. Too much DL will lead to ammonium toxicity especially during hot weather. Good that you have removed it. I would be inclined to flush that pot heavily and if you can get it, very fine zeolite dust washed into the p/mix will help absorb some of the excess NH4.( if this is indeed the problem ) Plums are no more sesitive than your average tree.

[daiviet_nguyen]

Hi treeman,

Thank you for replying. I have done what you suggested.

I submerged the pot in water for about 20 minutes. I do not have zeolite dust, so I put a layer of red scoria on top. I will submerge a few more times in the next few days.

Thank you and best regards.

[Tony Bebb]

I would suggest not submerging but running the water through from top to bottom more than you normally would. That will "flush" it through as Treeman said. It will drain after submerging but will still hold that same water in the soil.

[daiviet_nguyen]

Hi Tony,

I put the pot on top of two bricks and drained water through it a few times today. I will do that again in the next few days.

Thank you and best regards.