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How do plants extract nutrients from the ground?

permaculture.co.uk

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Re: How do plants extract nutrients from the ground?

#31

Post by isbwkisbakadqv »

jedimastert wrote: post #29

This reminds me of my favorite "thought experiment" to poke at intuition: with no other information that what most people learn in elementary/middle school science (or what I would assume is taught, i.e. the water and respiration cycles), where does the majority of a tree's mass come from? First we might look at dirt, but that doesn't quite pan out; where does the mass come from, and how would it be replenished? We d…

Corollary - let’s say I start exercising more and lose weight. I used to eat 100kg now I weigh 90kg. Where did the 10kg go?

Re: How do plants extract nutrients from the ground?

#32

Post by hinkley »

markdown wrote: post #16
thomasfromcdnjs wrote: post #2

I've been doing quite a lot of gardening in the past 3 years. There is a plethora of home gardeners and/or permaculture resources on the internet that generally like as much organic matter as possible. I some of that strategy as it's convenient at home to supply nutrients to plants without much work. But, I can't help but feel it's all sort of wish washy science. https://www.youtube.com/watch?v=KHZHy3_7PPE ^ I found…

> In short, plant roots actually love sand, silt and clay, and actually don't like organic matter around their roots as it causes rot. IMO it really depends on what you're trying to grow. I live in the tropics and there are a lot of tropical plants that do indeed thrive when the soil is heavy on the organic matter. I suspect it depends on how far/long these tropical plants have been bred away from their rainforest or…

Woodland plants also expect organic matter in the soil column. It's one of the complaints about 'modern' forestry practices that leave no mature wood on the ground to decay. Real forests have rotting logs in them.

It's really conventional farmers concentrating on annuals that want something different. They're growing prairie plants.

Re: How do plants extract nutrients from the ground?

#33

Post by social_quotient »

isbwkisbakadqv wrote: post #31
jedimastert wrote: post #29

This reminds me of my favorite "thought experiment" to poke at intuition: with no other information that what most people learn in elementary/middle school science (or what I would assume is taught, i.e. the water and respiration cycles), where does the majority of a tree's mass come from? First we might look at dirt, but that doesn't quite pan out; where does the mass come from, and how would it be replenished? We d…

Corollary - let’s say I start exercising more and lose weight. I used to eat 100kg now I weigh 90kg. Where did the 10kg go?

Fun Ted talk of this point

The mathematics of weight loss https://youtu.be/vuIlsN32WaE

Re: How do plants extract nutrients from the ground?

#34

Post by hinkley »

jspash wrote: post #13

I'm curious what HN thinks about the current trend of root washing when planting trees. From what I've read the science is still out and people tend to be split 50/50. The root washers say that by removing all media that the sapling was grown in will give the roots more "incentive" to move into the native soil and thus it will establish quicker. Whereas the anti-washers say you are slowing the establishment by washin…

I buy bare root plants because tree nurseries repot their seedlings too late, after the roots had already begun circling the pot. The worst one I ever saw had three layers of circling roots. I got it at my favorite froo-froo gardening center. I took it back and showed their plant buyer. He said that's normal. The fuck it is.

Bare root plants never have this problem.

There is definitely a tendency of trees to behave as if they are in a pot when they encounter a huge change in soil medium. The dead tree I dug up this spring had virtually no roots outside of the original cone section of the pot it came in.

The other problem, especially with bushes, is they often put those little plastic time release fertilizer beads into their soil mix and so I'm putting microplastic into my yard. Often the roots are too fibrous to get all of the beads. I sometimes get the smaller plants because of this.

I don't actually 'wash' though, I use a chopstick to tease the dirt away from the roots. They're still coated.

Re: How do plants extract nutrients from the ground?

#35

Post by grumpy-de-sre »

thomasfromcdnjs wrote: post #2

I've been doing quite a lot of gardening in the past 3 years. There is a plethora of home gardeners and/or permaculture resources on the internet that generally like as much organic matter as possible. I some of that strategy as it's convenient at home to supply nutrients to plants without much work. But, I can't help but feel it's all sort of wish washy science. https://www.youtube.com/watch?v=KHZHy3_7PPE ^ I found…

As someone who's done a fair bit of indoor gardening, including hydroponics I have to vouch for the video. Oxygen in the root zone is absolutely critical. Common potting mixes are almost universal terrible. Far too much rotting organic matter.

These days I do all my gardening in a 50/50% volumetric mixture of perlite and coco coir (buffered with calcium and magnesium). With a small amount of pH adjusted hydroponic nutrient and a watering can, the results you can achieve are just incredible, absolutely no comparison. Plus it's completely pest free so you aren't dragging in mite eggs, and fungus gnats.

Never using potting soil again, and anybody still using it should really reconsider. It's insanely counter-intuitive just how well plants can grow in something as inorganic as perlite. It just doesn't look like it should work.

Re: How do plants extract nutrients from the ground?

#36

Post by sgt101 »

thorwasdfasdf wrote: post #27
thomasfromcdnjs wrote: post #2

I've been doing quite a lot of gardening in the past 3 years. There is a plethora of home gardeners and/or permaculture resources on the internet that generally like as much organic matter as possible. I some of that strategy as it's convenient at home to supply nutrients to plants without much work. But, I can't help but feel it's all sort of wish washy science. https://www.youtube.com/watch?v=KHZHy3_7PPE ^ I found…

Charles Dowding, the father of no dig gardening, suggests, you don't need to dig in any compost or ogranic matter, just put it on top, as you've suggested. Apparently, the worms and the microorganisms then get to work and bring all that organic matter into the ground themselves working it into a nice tilth.

Worms! If there are many worms the soil is good. If there are no worms, the soil is bad. Worms like the organic matter and convert it into tiny weeny particles that the plants (bacteria) can absorb, they also open up the soil and create structure so it drains nicely.

Worms!

Re: How do plants extract nutrients from the ground?

#37

Post by sgt101 »

jspash wrote: post #13

I'm curious what HN thinks about the current trend of root washing when planting trees. From what I've read the science is still out and people tend to be split 50/50. The root washers say that by removing all media that the sapling was grown in will give the roots more "incentive" to move into the native soil and thus it will establish quicker. Whereas the anti-washers say you are slowing the establishment by washin…

I think that washing the roots and planting the tree without damaging the roots is a really hard trick to pull off.

I think that you don't want the rootball to be limited to the old pot outline, so opening it up a bit gently (so a few shakes and a little digging around) and encouraging a bit of a spread of the roots is the best way to go.

You might incentivize the tree, you might kill the tree... I don't think that this is a good plan :)

Re: How do plants extract nutrients from the ground?

#38

Post by littlestymaar »

jedimastert wrote: post #29

This reminds me of my favorite "thought experiment" to poke at intuition: with no other information that what most people learn in elementary/middle school science (or what I would assume is taught, i.e. the water and respiration cycles), where does the majority of a tree's mass come from? First we might look at dirt, but that doesn't quite pan out; where does the mass come from, and how would it be replenished? We d…

Edit: this is wrong, see comments below.

The correct answer is water though, not air. Air only accounts for the Carbon content of the tree, which is a big part, but still a minority.

First, a live tree contains a lot of water (30-50%), that's why you need to let wood dry a lot before burning it.

And there's something else:

> Next we might look at water, but water is only made of hydrogen and oxygen, and the oxygen is released.

Not all oxygen is released. All oxygen contained in a plants molecule (mostly cellulose and hemicellulose, which are polymers of glucose, and lignin) comes from water. And there's a lot of it: there's as much Oxygen as Carbon in a glucose molecule.

Re: How do plants extract nutrients from the ground?

#39

Post by muxator »

isbwkisbakadqv wrote: post #31
jedimastert wrote: post #29

This reminds me of my favorite "thought experiment" to poke at intuition: with no other information that what most people learn in elementary/middle school science (or what I would assume is taught, i.e. the water and respiration cycles), where does the majority of a tree's mass come from? First we might look at dirt, but that doesn't quite pan out; where does the mass come from, and how would it be replenished? We d…

Corollary - let’s say I start exercising more and lose weight. I used to eat 100kg now I weigh 90kg. Where did the 10kg go?

Short answer is: it is eliminated through respiration, and becomes CO2

Re: How do plants extract nutrients from the ground?

#40

Post by OrbitRock »

littlestymaar wrote: post #38
jedimastert wrote: post #29

This reminds me of my favorite "thought experiment" to poke at intuition: with no other information that what most people learn in elementary/middle school science (or what I would assume is taught, i.e. the water and respiration cycles), where does the majority of a tree's mass come from? First we might look at dirt, but that doesn't quite pan out; where does the mass come from, and how would it be replenished? We d…

Edit: this is wrong, see comments below. The correct answer is water though, not air. Air only accounts for the Carbon content of the tree, which is a big part, but still a minority. First, a live tree contains a lot of water (30-50%), that's why you need to let wood dry a lot before burning it. And there's something else: > Next we might look at water, but water is only made of hydrogen and oxygen, and the oxygen is…

I’m pretty sure the oxygen comes from CO2.

Plant carbohydrates are made directly from CO2 in the Calvin Cycle.

The Calvin Cycle is the source of all of the carbohydrate building blocks in the plant, and I’m pretty sure that oxygen from H2O does not enter the equation, just CO2 and some enzymes and cofactors.

If so, the vast majority of the mass is from the air.

(H might originate from water but its mass is pretty trivial compared to C and O)

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