nutrient ratio

[Sylvain]

Since 2008 we recommend the NPK ratio of 5-1-3 and the concentration of 300 ppm of N in the irrigation water.

On the French forum they wonder where it comes from, but I cannot remember.

Could you remind me the origin of these two data?

[millet]

In the book (The Genus Citrus) By Dugo and Di Giacomo on pages 40 - 43 it describes the nutrient up take of citrus being 5-1-3. A yearly loss of the main elements per hectare, in a mature orchard producing 30 tons of fruit, is as follows:  N = 180-220 kg;  P2O5 = 30-40 kg;  K2O = 90-120kg. These are the amounts per hectare that must be replaced by yearly fertilizing.

[ilya11]

I guess much depends on the nature of the substrate, pH and salt compositions.

In a large scale citrus production in soilless substrate the recommended ratios are a little bit different.

link

[Sylvain]

Thank you Millet!
Can you remember "the concentration of 300 ppm of N in the irrigation water"?
I think it was what was used in the green house of a research centre.

Ilya,yes, but you cannot compare.
In the first situation the trees are in ground, in mediterranean conditions and producing harvest. What is near our conditions.
The nutrients ratio are deduced from analyses.

In the second situation we have "rootstocks seedling growth in boxes, in plastic tubes or in bags. For all phases, a complete nutrient solution has been suggested".
The nutrients ratio are suggested!

You can find the original text at: fr1lib.org/dl/1049700/e786d8

[ilya11]

I guess that the soilless fertilization regime,  is closer to the situation of amateur pot culture.

Also, open ground ratios should  depend on the nature of soil, temperature, water regime, etc..

[Sylvain]

Yes, it said in the article. The nutrients ratio must be adapted to the real conditions.

[roberto]

I think in nature nutrition of trees is a very complex process with a lot of players involved -bacteria, mycorrhiza. Justus Liebig made a quite simple question of mathematics out of this complex natural thing. I try to feed my potted trees with organic fertilizer which makes it necessary to keep up the microbiom in my pots. Tricky but it works quite fine. And it has been done like this over hundereds of years. The classic collections of potted Citrus-trees were fed with horse manure...

[Laaz]

I have never followed any ratio. I use Osmocote slow release & have never had any issues whatsoever...

[millet]

Laaz, is it that you use just Osmocote, or Osmocote Plus?

[Laaz]

The pink bag, a handful of epsom salt & that's it a few times a year.

[kelley]

I use FoliagePro and Osmocote Plus, plus Fish fertilizer & epsom (rarely/occasionally). I’ve heard Jacks is great, also.

[millet]

Foliage Pro is a good fertilizer.  The only drawback is that it very expensive to use when you have a lot of trees compared to Jacks .

[kelley]

Agreed, Millet. If I ever end up with more than 50 trees, I will be swapping lol.

[adriano]

I Threw some pelletized cow manure under trees. SLightly Buried it under ground, But did Not Water Them. There is No Rain forecast for next two Weeks. Was the fertilising useless.