Metals in Soil: Benefits for Plant Growth?

[pivoxa15]

I heard that it's good to put metals like steel in the soil in which the plants grow in. Is that true? How does it help the plant? Does it act like a source of minerals?

 

[Moonbear]

Minerals are metals. But, I'm not sure they'd be in any useable form in something like steel. Where did you hear that?

The best approach is to have your soil tested, and then use minerals, fertilizers, etc., to adjust the balance of nutrients to what is appropriate for the plants you want to grow. The nutrients that one plant requires in high concentration may kill off another plant, so it's best to check on the requirements for the types of plants you're trying to grow. If you're growing multiple types of plants together (such as in landscaping), you should check that they are compatible for the same soil types, and that your soil meets those requirements. If you have knowledgeable employees at your local gardening center, they can help with that, as can your county agricultural extension office (if you're in the US). Both are also good resources for finding out what types of plants will grow easily in your climate, and which will require a lot of extra care.

 

[pivoxa15]

Minerals are metals. But, I'm not sure they'd be in any useable form in something like steel. Where did you hear that?

The best approach is to have your soil tested, and then use minerals, fertilizers, etc., to adjust the balance of nutrients to what is appropriate for the plants you want to grow. The nutrients that one plant requires in high concentration may kill off another plant, so it's best to check on the requirements for the types of plants you're trying to grow. If you're growing multiple types of plants together (such as in landscaping), you should check that they are compatible for the same soil types, and that your soil meets those requirements. If you have knowledgeable employees at your local gardening center, they can help with that, as can your county agricultural extension office (if you're in the US). Both are also good resources for finding out what types of plants will grow easily in your climate, and which will require a lot of extra care.

From my uncle (a novice). Are nails made from steel? Steel is just iron. Do plants need large quantities of iron?

 

[gravenewworld]

Try putting a small hole in a tree and inserting a piece of copper wire hehe.

 

[pivoxa15]

Try putting a small hole in a tree and inserting a piece of copper wire hehe.

What would that do?

 

[Ouabache]

Steel won't do very much towards benefiting plant health.
Here is a nice general http://www.agr.state.nc.us/cyber/kidswrld/plant/nutrient.htm of nutrients required by plants. You will see that iron (Fe), the largest component of steel, is a micronutrient and needed only in very small quantities. Same goes for copper (Cu). Best absorption is via the roots.

Bio-availability of these nutrients will vary depending on such variables as soil pH, soil texture, moisture & temperature.

 

[jim mcnamara]

Okay. From the top.

It is correct to note that some micronutrients can introduced into the plant's environment in some inventive ways. Apple orchards in iron-rich acidic peaty soils sometimes have Zinc deficiency problems. In the 1960's the standard treatment for this was to drive a galvanized (Zinc plated) nail into each tree. Worked great. Sandy coastal plain soils in Eastern Maryland have become deficient in Boron. The solution years ago was to put out small mineral blocks made of borax (as in 20 mule team Boraxo), about 10-20 per acre.

Now, all of this kind of thing is done commercially through chemigation - adding chemicals to irrigation water.

Simply adding chunks of iron or cobalt or whatever element strikes your fancy is not a good idea for a variety of reasons. Ouabache mentioned bio-availability, but there are also problems with toxicity, especially when micronutirents are concerned. A little is great, too much is deadly.

Greenhouses and hydroponic farms use fertilizer products that are part of irrigation - they contain very small amounts of macronutrients like Nitrogen and Potassium, and incredibly tiny amounts of metals like Boron. The fetilizer powder is mixed into the water - it normally has color added so that you don't confuse fresh water with fertilizer water.

You can do the same at home. These products are already balanced for safe use. And they don't cause plant damage when used per the label.

No steel.

 

[pivoxa15]

What about adding Mg in vast quantities since it is a standard metal solid. However from http://www.agr.state.nc.us/cyber/kidswrld/plant/nutrient.htm it seems that inserting metals in vast quantities is unnessary if the soil already contains these nutrients when bought.

 

[jim mcnamara]

Consider that growing plants to eat is a business. Even you if have a small garden, you have to consider cost/benefit ratios. Unless you're a student at an Ag college doing massively over-funded research...

Would you go out and fill your gas tank and let the tank overfill and spill out onto the ground for hours because you think it is a good idea? No. Why?
Because you are literally spilling money onto the ground. Not to mention polluting the ground water for the next 10000 years.

Ditto your question.

This is the what-if game. The answer is: just because you can do something does not mean doing it makes any sense whatsoever.

Your turn: how much does Mg cost per Kg? So, now work out how much it costs to put 1cm of Mg powder on a hectare?

 

[pivoxa15]

From here http://pubs.acs.org/cen/80th/magnesium.html

"...has forced magnesium prices down to nearly those of aluminum ($1.60 per kg)."

So about $2/kg

What is 1cm of Mg powder? I need a volume in order to work out the total cost.

Do soils usually provide all the micronutrients plants need?

Your point is worthwhile.

 

[jim mcnamara]

100 cubic meters of finely ground Mg metal. You could assume it's one big sheet 1cm thick if that makes it easier. Next, you need the density of Mg.

 

[jim mcnamara]

Using $1.60/Kg I get $2,784.00

Not a cheap solution.

 

[pivoxa15]

The plants I am considering were home grown. So maybe add some metals to a pot or two of plants. I don't think 100m^3 of Mg is necessary nor fit the pots. But I take your point. Maybe adding metals to plants in bulk is some sort of 'human' thing where you can claim that you have 'metal plants' which makes your plant seem 'good'. But it is possible to add soil to plants that lack metals couldn't it? How common is this?

 

[chroot]

Why do you think your houseplants need "vast quantities" of any metal at all?

- Warren

 

[pivoxa15]

My uncle obserbed that after putting metal into his plants, they grew a lot. And 'metal plants' by inserting metal into the soil of plants are popular.

 

[Ouabache]

What about adding Mg in vast quantities since it is a standard metal solid. However from http://www.agr.state.nc.us/cyber/kidswrld/plant/nutrient.htm it seems that inserting metals in vast quantities is unnessary if the soil already contains these nutrients when bought.

If you are concerned about Mg soil concentrations, I would have it tested by a competent soils lab, as Moonbear also described. Deficiencies occur most commonly in sandy soils, where this macronutrient can be leached out. A typical symptom of Mg deficiency is interveinal chlorosis (loss of green color between leaf veins).

Here is an example on tomato, and in http://www.hbci.com/~wenonah/min-def/plate039.jpg . Magnesium is a necessary element in the synthesis of chlorophyll which explains why a deficiency would give a chlorotic symptom.

The best way to replenish Mg in deficient soils and improve availability to plants, is in salt formulation (magnesium sulfate = epsom salt, magnesium carbonate = dolomitic lime, and potassium magnesium sulfate. http://web.missouri.edu/~umcsnrsoilwww/313_W2004/mg_2004.htm . Metallic Mg in powder or solid form, would not be easily taken up by plants.

As I mentioned earlier, soil pH affects bio-availability of plant nutrients. In soils lower than pH 7 (acidic), will lower Mg availability to plants and result in deficiency.

 

[pivoxa15]

So lack of Mg results in badly (brown) looking plants rather than stunted or slow growing plants.

 

[Ouabache]

Since the leaves become deficient in chlorophyll (where photosynthesis takes place in these plants), what do you think, would be the impact on overall plant growth?