Re: Would the zinc in soil be attracted to a magnet planted in the soil?

First, congratulations for your interest on the science methods; there's 
no doubt in my mind, that you will be a good scientist in the future. Well 
for you! and for our society.

And now, going to your question:

Because of the many factors involved in plant growth and the element 
bioavailability is difficult to assess the effect of the magnet on plant 
growth with a single experiment like the one described by you. I think that 
your approach may be correct, but I there are not enough elements to 
demonstrate your hypothesis, yet. Let me explain why.

The zinc is a non-ferrous metal, it can not be atracted to the 
magnet. Also, The uptake of zinc by plants is related to the concentration 
of bioavailable metal in the soil. Bioavaliable refers to the zinc readily 
available for uptake by the plant, that is, zinc in a dissolved form.

There is a difference between the total zinc concentration
and the dissolved zinc concentration in water. There is no relationship
between total zinc concentration and the uptake of zinc by organisms. 

However, many other factors such as temperature, water hardness, pH, and 
dissolved organic carbon content, in fact determine the bioavailability of
zinc in water. In the soil, zinc is bound to the soil complex (clays, 
organic matter, ...) depending on different physicochemical soil factors 
such as pH and organic matter content.

These factors determine the solubility of the zinc contained in soil, and 
consequently, its bioavailability for uptake by organisms. Changes in soil 
pH, for example, dramatically alter the bioavailability of zinc in soil.

Organisms take up the essential elements they need from their environment, 
that means directly from air, water, soil, and from food. When their 
cellular requirements for these elements are satisfied, growth and 
development are optimal. When uptake is too low, deficiency occurs and 
adverse effects can be observed. On the other side, uptake of too much of 
an essential element can lead to toxicity.

Between these two extremes, each organism has a concentration range for 
each essential element within which its requirements are satisfied. Thus, 
an Optimal Concentration Range for zinc exists for each living organism, 
including man. Indeed, there is an Optimal Concentration Range for 
Essential Elements for each essential element and each living organism

On the other hand, I think that the particles that you see atached to the 
magnet after the washout, were diverse iron particles, the 
orange colour that you seen is due to the oxidation of iron in contact 
wiht oxygen dissolved on the water.


There's a link on the internet that is sure to be of interest to you. It refers 
to the periodic table of elements:

www.webelements.com/webelements/elements/text/Zn/biol.html


Thanks for your interest.


Luis E. Castro-Solís, M.Sc.
Environmental Engineer