Sabtu, 23 April 2016

The effects of static magnetic fields on seed germination and plant growth

I have heard anecdotal evidence from people who claim exposing seeds to a static magnetic field increases germination rates and makes seeds germinate a lot faster.  I have heard other people claim that exposing seedlings to a magnetic field increases health of young seedlings.  To be honest I had no idea if this was accurate or not.  If this is true then I want to use magnets in germinating some seeds.

I did some research on the internet and found various papers that have been written on the subject, they appear to have conflicting results and many of the tests were often run is sub optimal conditions (often funded by companies that have a conflict of interest) with far too many variables often in completely non-scientific ways that can not be used to provide unbiased results.  Most (ie all) of the people who I know of that have tried this have not included a control, which in my mind is a waste of time.  I often read statements such as "try this and you will be amazed by the results", so I decided to try it.

To find out for myself if there is truth in this my children and I decided to run a small experiment.  If static magnets do increase the germination rates of seeds (which would be great for old seeds with low germination rates), or decrease the amount of time it takes for seeds to germinate (which would stop weaker seeds from rotting), or increases the vigor of young seedlings (which can die in the first few days while they are tiny) they could be extremely useful for me in germinating difficult seeds or very old seeds of rare varieties.  Lets face it, if this works I have a lot to gain and nothing to lose.
Magnet and seed germination experiment
The three pots, unfortunately one was a different colour
The Experiment
I will probably try to write this up properly some time in the future, include some graphs of the results and try to submit it to some journal for peer review, but I dont have time right now.  For now I will write it up very simply so that you can see what happened and possibly repeat it with your own kids.

This experiment was conducted to determine if a static magnetic field would affect seed germination or the early growth of seedlings.

This study divided wheat (Triticum spp) seeds into three groups.  Each group was comprised of 100 wheat seeds randomly chosen from a sack of feed wheat.  The first group was to germinate in the presence of a strong static magnet field delivered from a Neodymium magnet (approximately 0.6751 tesla).  The second group was to germinate in the presence of a weak static magnet field delivered from a small refrigerator magnet of unknown strength.  The third grew was to germinate in the absence of any added magnetic field to act as a control. 

Several growth parameters were observed throughout the experiment including the germination rate, leaf length, and root length.  In addition the health status of seedlings was measured through observation of leaf color, spots, visual presence of disease, stem curvature, and seedling mortality.  Plant growth was observed continuously for the duration of the experiment.

Three square 10cm plastic pots were filled with potting soil from the same bag to the same depth.  The three pots were watered by submerging the pots in water until the soil was thoroughly soaked.  Each pot was then surface sowed with 100 wheat seeds.  For the duration of the experiment each pot was watered from below once a week so as not to disturb the magnets or the emerging seedlings.  Each magnet was wrapped in a single sheet or 3 ply toilet paper inside a small plastic zip lock bag and placed on top of the seeds.  This was done to protect the magnets from corrosion as well as obscure which magnet was in which group.  To reduce the presence of any variables the control had a small non magnetic stone of similar weight to the magnets, wrapped in toilet paper inside a small plastic zip lock bag.  The three bags were then shuffled and chosen at random to be placed on the seeded pots of soil to ensure a blind test.

The magnets were placed on their side so that some seeds would be close to the North pole, some close to the South pole and others along the edge.  This was intended to show if either pole had a positive or negative effect on germination of the seeds.

After 5 days seeds in all three pots began to germinate.  It appeared as if seeds from all parts of all pots were germinating at the same rate.  It appeared that all three pots had similar germination in terms of the number of seeds germinating, progression of root growth, progression of leaf growth, as well as angle of root or leaf growth.

After 14 days seedlings from all three pots were counted and measured.  Seedlings from all three groups had similar height, similar health as indicated by colour, lack of spots, and visual stem curvature.  All three groups had no seedling mortality throughout the duration of the experiment.

The high magnetic group had 98% germination.
The low magnetic group had 100% germination.
The control group had 99% germination.
The time to germination from all three pots was identical which indicates that magnets have no noticeable effect on germination time.

In addition to the germination rates being similar (98% to 100%), the leaf length, root length and health of seedlings from each batch appeared to be identical.  I had planned on weighing the seedlings from each group to determine fresh biomass but discovered that separating the roots from the potting mix was not possible.
A blind test, I didnt know which pot has the magnet or stone


The results from this small experiment indicate that there is no noticeable effect on the germination of seeds in terms of germination time or germination rate due to either strong or weak static magnetic fields.  It appears that a static magnetic field has no noticeable effect on the vigor/health of young seedlings.  The pots with magnets had similar looking seedlings growing on all areas of the pot which indicates that the polarity of the magnet also had no noticeable effect on germination or early growth.

This was a blind test and it was not until after the seedlings were counted and measured that I opened the little zip lock bags to discover which pot had which magnet.  I figure if this was worth doing it was worth doing properly.


My thoughts
While I was kind of disappointed by this result in hindsight it is not overly surprising.  If any positive difference would be seen then seed magnetisation would be used by commercial farmers.  Farmers have tight profit margins and often grow in hostile environments, they are willing to do whatever it takes to make their crops thrive and magnetisation would be reasonably cheap and simple to apply.  The fact that seed magnetisers are only seen being sold by a few sketchy online sellers and are not seen in rural stores or used by many commercial farmers hints that it may not be all that useful.  It was still worth testing to see for myself.

I have already started to run a similar experiment again and changed some of the parameters, the use of sand instead of soil will allow me to weigh the fresh or dry biomass and see if there is any difference there.  An extra 100 seeds in each group is only going to make the data better.

I am using seeds from a dicot instead of a monocot to see if that makes any noticeable difference.  Doing this experiment using seeds with naturally high germination rates as I did possibly obscures the results as germination rates could not really get any higher.  The seeds in the second test are older and have lower germination rates so I should be able to see if the magnets make any noticeable difference on germination rates that are not close to 100%.

I am also planning to grow seedlings for a longer time to see if any noticeable difference is made as they get larger, in the future I may even grow them to maturity to determine if any difference is made to overall yield or time to maturity (Micro Tom tomatoes seem like a great choice for this).  There are also a few other things that I may considering trying in the future that may make the experiment a little more robust.
Micro Tom tomatoes, tiny plants with a short lifecycle makes them ideal for experiments
When I conclude this second experiment I plan to post the results (or a link to the results) here.

If you also try this little experiment please ensure you are removing as many variables as possible and do it as a blind test with a control so that the results are accurate.  Feel free to let me know your results.

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I repeated the experiment using some old cress (Lepidium sativum) seeds that would have a lower percentage of germination and I grew them out for a bit longer.  Again I used 100 seeds per group but this time all of the pots were exactly the same.  

The time to germination was identical in all groups.  The plants in all groups looked similar in terms of height, number of leaves, colour, angle of leaf growth etc.  The motality rate was identical in all three groups (4 seedlings germinated then died in each group).  I did not weigh the seedlings as I assume they would weigh less than 1 gram collectively and my scales are not accurate enough to record any differences.  Due to less than ideal conditions all 3 groups then started to grow mould which infected all seedlings similarly and all plants are succumbing at a similar rate.  I am going to let this continue to see if there is any noticeable difference in the groups but at this stage that looks unlikely.

The percentage germination was the only area where I could see even a slight difference.  The control group had 24 seeds germinate, the strong magnet had 22 seeds germinate and the weak magnet had 30 seeds germinate.  

This is certainly not the miracle difference in growth and/or germination that I had hoped for, it is not going to be the magic bullet to help germinate tricky or weak seeds.  The difference between 24% germination of the control and 30% germination for the weak magnet is not enough for me to think that the magnets are creating a difference of any kind.

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If it is worth doing it is worth doing right. 

Some people have asked me why I only have 100 seeds in each group.  The answer is because if I have any more seeds they are too far from the magnet to experience the magnetic field.  I agree this test would be more valid with larger numbers, to help overcome this I have run the experiment several times using several different species to see if I obtain any significant difference.

I repeated this again with some older garlic chive (Allium tuberosum) seeds that I had left in a paper bag.  As the seeds were aging I had expected germination rates to be low. 

I used 100 randomly chosen seeds in each pot and used three identical pots filled with sand.  Again I used the strong magnet, the weak magnet and the non magnetic stone as a control.  As before I did not know which group was which until after I had counted the seedlings.

The time to germination was identical in each pot, the health and size of seedlings in each pot was also identical.  The early growth rates of the seedlings was identical.  I tried to weigh the seedlings after the experiment but my scales were not accurate enough to record any differences.

The control group had 64 seeds germinate, the weak magnet had 61 seeds germinate and the strong magnet had 65 seeds germinate.

Just like the previous experiments I am far from amazed by these results.  Their seems to be little to no effect of a static magnetic field, either strong or weak, on seed germination and early plant growth.

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From here I want to run this little experiment again using the Micro tomatoes from planting the seeds until maturity so I can count and weigh the fruit to see if there is any improvement in crop yield.  I will probably only be able to grow 3 seeds of each in this experiment as I do not have enough magnets to grow larger numbers. 

Due to moving etc I may not get around to this for some time though, if I do I plan to post the results here or if the results are interesting I may write another post and link to it from here.

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