Why do fruit trees generally prefer more acidic soil than vegetable plants?

[emma69]

Hello guys,

I have been wracking my little brain with this one. Why do fruit trees generally prefer a more acidic soil than vegetable plants. Veg plants like 6-7ph (except potatoes - why again !) Fruit around 5-6pH. Thanks in advance :)

 

[phinds]

I don't know but my guess would be because fruits evolved to have some acid in them (think lemons "citric acid") and veggies did not.

 

[Borek]

Never heard about it.

And no, I doubt it has anything to do with the pH of the fruit.

 

[256bits]

Different nutrients are available, or more easily available, from the soil with different pH levels.

I guess one would have to go into the chemistry of it all, and how the plants do the uptake in different acidic, or alkaline soils.

 

[tom aaron]

Different nutrients are available, or more easily available, from the soil with different pH levels.

I guess one would have to go into the chemistry of it all, and how the plants do the uptake in different acidic, or alkaline soils.

More 'trees' evolved in acidic soils. Greater turn over of organics in soils. Usually wetter conditions...partly why grassland soils tend to be less acidic. The largest terrestrial ecosystem ( coniferous forest) raises PH of soils. Ecosystems shift over time leaving these soils.

However, lots of fruit evolved fine as bushes in alkaline soils. I'm going out today to collect Saskatoon berries. These taste and look look like blueberries (but unrelated).

 

[emma69]

Thanks for your replies, but I think my question is a long way from being resolved.

Re: Saskatoon - what do they taste like, never heard of them.

 

[Borek]

Thanks for your replies, but I think my question is a long way from being resolved.

Problem is - in the first place it is not clear whether the question is valid and well defined. What and why is classified as fruit (where the common market definition and the biological definition are different things) and what is classified as a vegetable? Then, do they really need different pH? I mean - sure, different plants do prefer different pH of soil, but is the correlation you have mentioned real, or is it just a coincidence occurring for a small subset of the most common plants?

And if it is, it would make sense to check if the low pH is preferred by the fruit trees, or the trees in general (in which case it is not a question about "fruit trees" and "vegetables" but a much wider question about different types of plants).

 

[emma69]

Hi Borek, its not necessary for me to be more specific, my question is intentionally general. If you disagree with my statement (common fruit trees vs common vegetables pHs), go and get a basic knowledge of horticulture and get back to me. Questioning the premise of my question is a blind alley, better try to address the question please. However your observation regarding fruits trees vs just trees is valid. Thanks.

 

[Borek]

You are missing the point I am afraid.

You want to know the explanation for a fact. That's OK. But you can't ask for an explanation of a fact without showing that the fact is real. That's simply not how the science works. If someone asks "Why some unicorns are pink" the valid answer is "show me a pink unicorn and we will start from there".

Besides, this is not a chemistry question - this is a biology question.

 

[emma69]

Hi, I am afraid it is you Borek that is missing the point and forcing me to digress. To continue with your analogy, you my friend are pursuing your argument in a world without "pink unicorns", when everyone else with a basic knowledge of horticulture sees 'pink unicorns" everyday and have moved on... Secondly I place no restriction on the discipline or disciplines yourchoose to address my question only that you do not waste my time with pedantry.

 

[Cumberland]

More 'trees' evolved in acidic soils. Greater turn over of organics in soils.

And fulvic and humic acids constitute the major portion of the decayed organic soil component, correct?

 

[Cumberland]

Also, I believe humic acids and fulvic acids interface with plant roots to deliver ions such as potassium and calcium to the plant. So, is it possible that fruit plants have a greater need for those nutrients?

I'm not a botanist or soil scientist, but I had to read a lot of literature on organic soil matter for my organic chemistry class.

 

[emma69]

Just to clarify Borek, I am talking about the ph of the soil sir, not the fruit ! Yes Cumberland fulvic and humic acids are at least an important part, but not sure its the major part, in all cases as soil can be quite variable. I wondering if the trees are more linked to fungal organisms in the soil and the veg is more linked to aerobic bacteria most of which can't handle more acidic conditions so well (eg <5.5 pH)

 

[Almeisan]

Agree strongly with Borek.

If you want an answer to have any value, you need to be sure of the question and what types of answers that question has.
If the premise of the question is wrong or vague, so will be the answer.

Do you want a wrong answer? I can make one up for you. Surely horticulture people have all kinds of theories, as they like to make them up on the spot..

Even the concept of soil pH is where this whole endeavor can get off track.

But surely the acidity of the soil has nothing to do with the acid molecules in culinary fruits.

 

[emma69]

Hi Almeisan, you have gone off on the wrong track. Ph in fruit is Borek's fantasy, if read the other comments rather than making a knee jerk reaction you would know that . To clarify we are talking about soil pH, if you don't understand what that is, don't bother commenting.

 

[Almeisan]

rofl

Do enlighten me. What is soil pH?

 

[Borek]

Ph in fruit is Borek's fantasy

Please show me where I referred to the fruit pH, I don't think I ever did. Could be my English failed me and there was some ambiguity in my posts, but if so, please show the quote.

 

[Cumberland]

I think Borek was asking if it's agreed upon by the scientific community that fruit trees do prefer more acidic soil than do vegetables plants. Also, what plants specifically constitute fruit trees and vegetable plants? What did you mean by prefer?

I understand what you meant by your question. If it's true that fruit trees do prefer more acidic soils, could it be that trees, being generally much larger and more complex organisms than vegetable plants, require a soil that is richer in organic matter to flourish? Since the organic soil component is primarily composed of fulvic and humic acids, would that be a reasonable assumption of why a tree would prefer a more acidic soil?

 

[Almeisan]

Trees that drop fruits do so right on top of the soil where they have roots. That surely isn't going to make the soil more basic. And it is not like dropping leaves since the tree is much more active when it drops fruit.

 

[256bits]

Hi Borek, its not necessary for me to be more specific, my question is intentionally general. If you disagree with my statement (common fruit trees vs common vegetables pHs), go and get a basic knowledge of horticulture and get back to me. Questioning the premise of my question is a blind alley, better try to address the question please. However your observation regarding fruits trees vs just trees is valid. Thanks.

Point is:
The words vegetables and fruits are used as the everyday culinary description of plant material that we eat, and can come from many different varities of plants.
Vegetable is not a real scientific designation.

Defining a "vegetable" is hard because so many different parts of a plant are consumed as food; roots, tubers, bulbs, https://www.physicsforums.com/wiki/Corm , stems, leaf stems, leaf sheaths, leaves, buds, flowers, fruits and seeds. The broadest definition is the word's use adjectivally to mean "matter of plant origin" to distinguish it from "animal", meaning "matter of animal origin". More specifically, a vegetable may be defined as "any plant, part of which is used for food",[4] a secondary meaning then being "the edible part of such a plant".[4] A more precise definition is "any plant part consumed for food that is not a fruit or seed, but including mature fruits that are eaten as part of a main meal".[5][6] Falling outside these definitions are mushrooms and other edible fungi which, although not parts of plants, are often treated as vegetables.[7]

In everyday language, the words "https://www.physicsforums.com/wiki/Fruit " and "vegetable" are mutually exclusive. "Fruit" has a precise https://www.physicsforums.com/wiki/Botany meaning, being part of a plant that developed from the https://www.physicsforums.com/wiki/Ovary_(botany) of a https://www.physicsforums.com/wiki/Flowering_plant . This is considerably different from the word's culinary meaning. While https://www.physicsforums.com/wiki/Peach , https://www.physicsforums.com/wiki/Plum , and https://www.physicsforums.com/wiki/Orange_(fruit) are "fruit" in both senses, many items commonly called "vegetables", such as https://www.physicsforums.com/wiki/Eggplant , https://www.physicsforums.com/wiki/Bell_pepper and https://www.physicsforums.com/wiki/Tomato , are botanically fruits.

https://en.wikipedia.org/wiki/Vegetable


Legume, on the other hand, classifies a certain type of plant.

A legume (https://www.physicsforums.com/wiki/Help:IPA_for_English or https://www.physicsforums.com/wiki/Help:IPA_for_English ) is a https://www.physicsforums.com/wiki/Plant in the family https://www.physicsforums.com/wiki/Fabaceae (or Leguminosae), or the https://www.physicsforums.com/wiki/Fruit or https://www.physicsforums.com/wiki/Seed of such a plant. Legumes are grown agriculturally, primarily for their https://www.physicsforums.com/wiki/Food_grain seed (e.g., beans and lentils, or generally https://www.physicsforums.com/wiki/Pulse_(legume) ), for https://www.physicsforums.com/wiki/Livestock https://www.physicsforums.com/wiki/Forage and https://www.physicsforums.com/wiki/Silage , and as soil-enhancing https://www.physicsforums.com/wiki/Green_manure . Legumes are notable in that most of them have symbiotic nitrogen-fixing bacteria in structures called https://www.physicsforums.com/wiki/Root_nodules . Well-known legumes include https://www.physicsforums.com/wiki/Alfalfa , https://www.physicsforums.com/wiki/Clover , https://www.physicsforums.com/wiki/Pea , https://www.physicsforums.com/wiki/Bean , https://www.physicsforums.com/wiki/Lentil , https://www.physicsforums.com/wiki/Lupin , https://www.physicsforums.com/wiki/Mesquite , https://www.physicsforums.com/wiki/Carob , https://www.physicsforums.com/wiki/Soybean , https://www.physicsforums.com/wiki/Peanut and https://www.physicsforums.com/wiki/Tamarind .

https://en.wikipedia.org/wiki/Legume

In which case, the relevance of soil acidity is a direct result of the livelyhood of bacteria in the soil, particularily the bacteria Rhizobium in soil. Rhizobium prosper best in low acidity soils for nitrogen fixation.
http://www.csun.edu/~hcbio027/biotechnology/lec10/lindemann.html

A tuber vegetable may have different requiremens than say a leafy vegetable, even though they are both vegetables, but not in a similar botanical family. Fungi, such as mushrooms, as classified as a vegetable, are no way similar to other vegetables in our garden.

 

[256bits]

Trees that drop fruits do so right on top of the soil where they have roots. That surely isn't going to make the soil more basic. And it is not like dropping leaves since the tree is much more active when it drops fruit.

Soil acidity is a function of the pH level in the soil. Would dropping fruit, while re-adding some biomass back to the soil, have a significant effect on soil pH?

 

[Almeisan]

Don't think it will. Seems it will be quite negligible. More important would be all other plantlife around and whatother affects the nature of the soil.

Also don't think that soil acidity is a function of pH level.