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Oak Grove, Mn

I am reviewing the my soil test from last fall. The only nutrient that is listed as being low is manganese. I am wondering what the importance of manganese is to giant pumpkins and a method to raise it without adversely affecting the balance of the rest of the nutrients.

3/25/2012 6:54:38 PM

Colorado

You can put in manganese sulfate-a little goes a long ways

3/25/2012 9:56:13 PM

East Jordan, MI

To answer your first question, Manganese plays a significant role in photosynthesis. The formation of free oxygen radicals during water splitting and ultimately the release of oxygen is not possible under Mn-free environments. Mn is the only element that can contribute the necessary electrons for this biochemical process.

What happens when manganese is not available to plants?
The young and recently matured leaves develop chlorosis followed by stippling of necrosis on recently matured leaves. Drastic reduction of shoot and root growth is common. Flowering is strongly inhibited. Environmental factors such as sunny summer months, greenhouses built close to traffic areas and ozonated water used in irrigation/fertigation may contribute to manganese deficiency.

Before changing anything, you have to determine if it is in fact low, and how low is low. I think other than visible signs, the only way to know for sure is with a tissue test.

On my soil test from (A&L Modesto)in the text portion they put the following:
"* MANGANESE: The soil is not a good indicator of deficiency. Maintain a reasonable pH and organic matter status, and follow label directions if applying manganese-containing products.

3/26/2012 5:25:41 AM

East Jordan, MI

There are ratios between manganese and other macro and micro nutrients (these are recommended targets from Western labs) that you can use to determine how low is low.
p:mn 4:1
mn:zn 3:1
mn:cu 7:1
mn:fe 1:1.5-2.5

If it were me, I would first contact an agronomist; the one at your lab would be where I would start. They have always been very helpful (and patient) with me telling me what to do to get where I wanted to be or explaining to me why I shouldn't worry about it.

As to the method to apply, the way I have added micronutrients to the soil is to get a soluble form and apply via a spray, since most often they don’t require very much product and it is very hard to disburse granular evenly in such a small amount. If you can't find a soluble easily, most sulfates are soluble, so you can just mix the granular with water and it will dissolve, strain it to get anything that didn't dissolve (or it will clog your sprayer).

3/26/2012 5:26:06 AM

East Jordan, MI

A couple of good reads:
http://www.spectrumanalytic.com/support/library/ff/Mn_Basics.htm

http://www.incitecpivot.com.au/zone_files/FertFacts/ManganeseFS.pdf

http://www.soils.wisc.edu/extension/pubs/A2526.pdf

3/26/2012 5:33:33 AM

Oak Grove, Mn

thank you for your detailed answer. My ratios are somewhat messed up. I have very high zinc and iron.. mn:zn 1:6 and mn:fe 1:16. What happens if i error and add too much manganese.

3/26/2012 5:52:40 AM

Muddy Waters

Thank you Cecil!

3/26/2012 7:41:13 AM

East Jordan, MI

Too much = manganese toxicity, like cojoe said, go easy a little goes a long way. I still suggest talking to an agronomist they are the experts.

Manganese toxicity is characterised by raised interveinal areas giving a puckered appearance, red, brown
or black spotting of the older leaves and an uneven distribution of chlorophyll. If the toxicity continues, the
plants will wilt and die prematurely.

Effects on plants
affects metabolic processes such as enzyme activities and organic compounds
sterility
symptoms similar to Fe chlorosis
Mn toxicity often occurs with Al toxicity

Signs
yellowish brown spots between leaf veins, extending to the whole interveinal area
brown spots on veins of lower leaf blades and leaf sheaths
drying of leaf tips eight weeks after planting
chlorosis of younger leaves
stunting
reduced tillering
reduced grain yield

3/26/2012 9:04:16 AM

Hinckley MN

Actually amelio, I stated that only minute quantities of neutral molecules can enter a leaf. The rest runs to the ground and is absorbed by the roots. Since manganese doesn't naturally float around in the air, the leaves are not designed to absorb it. The roots are designed to absorb it. Also the micro nutrients must be chelated into a neutral molecule in order for leaf absorbtion to occur.

I did not say foliar feeding was fake stupid and unecessary, I said it was a misnomer. The foliage isn't being fed, the roots are. I even stated that I "foliar feed". I just call it fertigation and know that it is when the water carries the nutrients to the soil that the roots will absorb it and bring it into the plant.

Any fertilizer with a micro nutrient package will have enough Mn to prevent deficency, without much threat of toxicity. Buy a miracle grow hose end sprayer. Make sure it is the kind that has the screw off spray end and both sides of the fertilizer bottle will connect to a hose. Connect it inline in your irrigation system and fertilize through your irrigation water. If you are medium to low on all your micro nutrients (everything except NPK, Ca, S, and Fe) then get a professional fertilizer for peatlite mixes because they have double the micronutrients.

3/26/2012 3:19:33 PM

Oak Grove, Mn

It seems that i have choices to make. Applying manganese sulfate, applying fertilizer with micronutrients or do nothing until a tissue sample. I am leaning towards the manganese sulfate since the rest of my micronutrients are listed in the high to very high range, and i would prefer to be proactive and correct the problem before the plant is growing. I certainly did not want to cause or encourage an argument about this subject. Thank you all for your input.

3/26/2012 6:44:20 PM

Hinckley MN

you might need a few grams of manganeeze sulphate per plant. You really need to weigh carefully and calculate exactly what you need.

3/26/2012 11:25:43 PM

East Jordan, MI

bnot,
Unfortunately that is what this site is becoming, a place for people to get pounced on and ridiculed for asking questions and trying to help each other out. It was not that way as short of a time as 2 years ago. There are still a lot of great people on here that want to both succeed and see others succeed. Don't let a few people make you afraid to ask questions or express an opinion. Keep an open mind, don't believe everything you read, try to get someone with more experience to give their take on things, and you will do well. Ken has put an ignore feature into place to ignore people that continually insist on arguing. Once you add someone to that list (in your user settings) you will no longer see their posts. It is working well for me.

PS, I would still contact an agronomist before adding manganese --lol. We all must make our own choices. Good luck and keep a diary for us to follow your progress. Your decision -- no matter what you decide, might help someone else further down the road that runs into a similar situation.

3/27/2012 5:00:31 AM

Oak Grove, Mn

cntryboy, i was reading the webpages that you posted. On the last one it was saying that Manganese treatment is recommended if the soil tests less than 10 ppm. My soil test shows Mn at 4 ppm. Unfortunately, now i realize that i dont know how to calculate the amount of MnSo4 to add to raise the ppm to a normal level .

3/27/2012 6:01:16 AM

East Jordan, MI

It really depends on the percentage of manganese in the product you get, and how well your soil type reacts to the product being added. The label should tell you how much to apply per acre or 1000 sq ft to raise 1 ppm.

I hate to keep beating a dead horse, but an agronomist can give you the best idea as to what you need to do to change it what you want. And they love to help you, it's their passion, just like growing giants is ours.

3/27/2012 6:55:55 AM

South East

lots of stuff on the net. Generally broadcasting manganese is not recommended. Foliar application with spreader/sticker might work. Like i said lots of info on the net, heres one: www.agtest.com/articles/manganese.pdf

3/27/2012 8:18:02 AM

Omaha, Ne.

c

3/27/2012 8:25:55 AM

East Jordan, MI

very good article Frank, thanks.

3/27/2012 8:57:03 AM

Hinckley MN

maximum recommended application rate for manganese sulphate is 50 grams per 1000 square ft (5 lbs/acre) from the U of Wisconsin extention. disolve in water and spray evenly over your patch. poor drainage (watterlogging), high pH, and high organic matter can also cause Mn deficency in plants.

3/27/2012 9:05:02 AM

Taylorsville, California

Ben- your opinion is fine but when you go giving advice as if it's gospel it can make new growers take your opinion as a fact,possibly causing them to make questionable decision based on your strong opinions. Foliar feeding is something many of us have used with excellent results, regardless of the studies you have read. Not fertigation, foliar feeding with a fine mister resulting in almost zero dripping, or water reaching the root area. Contradicting many HH recommendations isn't helping anyone regardless of whether you believe it works or not. To me the proof is in the pudding

3/27/2012 11:03:59 AM

Colorado

I used manganese sulfate a couple years back.I was very low 4ppm and i placed 1.2 lbs in appr. 5000 sq ft.This shot it up to 60 ppm which is high . So half of my addition would of been better.again a little goes a long ways.I like the suggestion about watering it in-may be a good way to spread evenly-thats the issue when apply ppm doses

3/27/2012 4:55:09 PM

Hinckley MN

Does it really matter if the fertilizer enters through the leaf or through the roots as long as it gets to where it is needed? Everyone is entitled to their opinion. I just prefer the one scientific research supports. The prevailing scientific wisdom has been known to change when better evidence is presented.

3/27/2012 9:51:24 PM