[nafex] Was:Pine needle mulch, now: Blueberries in high pH

Michael Dossett phainopepla at yahoo.com
Thu Dec 20 18:51:09 EST 2012


These are both great points.  I think the same thing Lee said about soybean meal for fertilizing blueberries can be said for organic fertilizers in general (some manures can be an exception) and are not specific blueberry.  They are less prone to leaching and so often need fewer applications, they break down slowly (often temperature dependent rather than moisture dependent) and are less prone to burning the roots, because release is temperature rather than moisture dependent they are also used more or less in synch with plant growth requirements.  Whenever possible I use organic fertilizers for plants in the ground, as I think the pros outweigh the cons in most circumstances. I wasn't trying to imply that ammonium sulfate or urea were the only ways to fertlize blueberries.  If your pH is in the correct range, then your mineralized nitrogen from organic sources will also end up being mostly in the reduced form (ammonium) useable to blueberries.
 
Michael

Michael Dossett
Mission, British Columbia
www.Mdossettphoto.com
phainopepla at yahoo.com

From: Lee Reich <leeareich at gmail.com>
To: Michael Dossett <phainopepla at yahoo.com>; nafex mailing list at ibiblio <nafex at lists.ibiblio.org> 
Sent: Thursday, December 20, 2012 12:57 PM
Subject: Re: [nafex] Was:Pine needle mulch, now: Blueberries in high pH


The advantages of soybean meal over ammonium sulfate or urea for blueberries (and other plants) is that there's less chance of burning the roots (a particular problem with blueberries), the nitrogen is released slowly more or less in synch with plant needs, and only a single annual application is needed. I make one application per year, sometime between late fall and late winter. 

Just one other note to add to Michael's comments on iron deficiency: The symptoms show up first on young leaves. This is important because similar symptoms on older leaves of any plants are a symptom of magnesium deficiency.


Lee Reich, PhD
Come visit my farmden at http://leereich.blogspot.com/
http://leereich.com/

Books by Lee Reich:
A Northeast Gardener's Year
The Pruning Book
Weedless Gardening
Uncommon Fruits for Every Garden
Landscaping with Fruit
Grow Fruit Naturally

On Dec 20, 2012, at 2:19 PM, Michael Dossett wrote:

Lee is right, Gypsum (calcium sulfate) is a neutral salt and in most circumstances has no effect on soil pH.  There have been some reports of it raising pH in soils that are high in aluminum, but this is attributed to increasing the solubility of aluminum in these soils. Gypsum can be beneficial or detrimental depending on your soil, but it is often most useful for breaking up heavy clay soils and displacing sodium (by replacing it with calcium) in soils with excess sodium. Depending on the composition of your soil, it may in fact lower pH very slightly but this is also specific to certain soils and generally it must be applied at high rates to have this effect.
> 
>Blueberries need acid soils (pH 4.5-5.5) for two reasons.  One is because they have poor nitrate reductase activity.  As soil pH is reduced, nitrogen is more commonly found as ammonium, which blueberries are able to take up and utilize.  At higher pH, soil nitrogen is oxidized into nitrates, which blueberries are very inefficient at utilizing for growth.  If using conventional fertilizers for blueberries (i.e. if NOT using soybean meal as suggested earlier) then one should use either ammonium or urea, depending on your objectives. The other reason why blueberries need low soil pH is also because they often have problems with iron deficiency in higher pH soils.  As soil pH rises, iron becomes less bioavailable (as do zinc and manganese, although these are less problematic in blueberry).  Blueberries grown in soil that is too high in pH usually develop iron deficiency before they experience nitrogen deficiency.  Iron deficiency in blueberries
>manifests itself as a yellowing of the leaves with some green retained at the midvein and in some of the other leaf veins, leading to what many people refer to as a "Christmas tree" pattern.  Google "Blueberry iron deficiency" and you will see many good pictures.  Many people see this yellowing and assume it is nitrogen deficiency so they never really fix the problem, or worse, they burn the plants by giving them too much or the wrong kind of nitrogen, as blueberries are very sensitive to high EC.
> 
>Adding elemental sulfur about 6-12 months before planting is the best way to lower soil pH (the rate is dependent on the amount of lowering needed and your soil type).  This is because soil microbes break down the sulfur over time and it gets converted into sulfuric acid.  The effect is temporary, so you should monitor soil pH every year or so to make sure it stays in the proper range.  Fertilizing blueberries with Ammonium Sulfate provides the correct form of nitrogen and has the effect of lowering pH slightly at the same time (although to a lesser extent than adding elemental sulfur).  This is the recommended nitrogen source for established blueberry plantings where the pH has started to creep upward.  Urea has less effect on soil pH and is the preferred nitrogen source for blueberries where the soil pH is already in the correct range.  There is some evidence that high organic matter and mycorrhizae may help to mitigate nitrogen issues when soil
>pH is higher than optimal, so that blueberries can get sufficient nitrogen.  Unfortunately, this doesn't fix the iron deficiency that occurs in many soils when pH is too high, so it can't be counted on as a way to grow blueberries in higher than optimal soil pH at every site.
> 
>Of course everything I just said mostly applies to growing blueberries in the ground.  If you grow in pots or bales of peat, there may be other issues with the soil chemistry which affect how well blueberries perform.
> 
>Michael
>
>Michael Dossett
>Mission, British Columbia
>http://www.mdossettphoto.com/
>phainopepla at yahoo.com
>
>From: Lee Reich <leeareich at gmail.com>
>To: nafex mailing list at ibiblio <nafex at lists.ibiblio.org> 
>Sent: Thursday, December 20, 2012 7:20 AM
>Subject: Re: [nafex] Was:Pine needle mulch, now: Blueberries in high pH
>
>Gypsum does not raise pH. 
>I wouldn't worry about the microorganisms.
>
>Lee Reich, PhD
>Come visit my farmden at http://leereich.blogspot.com/
>http://leereich.com/
>
>Books by Lee Reich:
>A Northeast Gardener's Year
>The Pruning Book
>Weedless Gardening
>Uncommon Fruits for Every Garden
>Landscaping with Fruit
>Grow Fruit Naturally
>
>On Dec 20, 2012, at 9:47 AM, Andrew Hahn wrote:
>
>
>Thanks for the amendment suggestions, I hadn't though of soybean meal as
>>
>being particularly good for acid loving plants and avoided Gypsum so as not
>>
>to rais the pH. Probably time to test the soil again to see what it needs.
>>
>
>>
>I had wondered why naturally occurring fungi would not be picked up and
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>couldn't find much about how common thy were. It is pretty likely my soil
>>
>has at least some, while I don't know of any ericaceous plants here in the
>>
>plains, 20 miles away the mountains have serval species.
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>
>>
>Very helpful, thank you.
>>
>
>>
>Andy
>>
>
>>
>On Wed, Dec 19, 2012 at 10:01 AM, <nafex-request at lists.ibiblio.org> wrote:
>>
>
>>
>An excellent, inexpensive, and organic (especially if non-GMO) source of N
>>>
>for blueberries and other acid-loving plants is soybean meal. Good for any
>>>
>plant, in fact.
>>>
>
>>>
>I did graduate research involving ericoid mycorrhiza and found no effect
>>>
>from inoculations. In fact it was hard to keep control plants from picking
>>>
>up inoculum as a general contaminant. The only exception would be places
>>>
>where blueberries or ericaceous plants are naturally absent and plants are
>>>
>raised without any source of contamination -- in Australia, for instance.
>>>
>
>>>
>
>>
>
>>
>
>>
>-- 
>>
>"The trouble with being poor is that it takes up all your time." - Willem
>>
>de Kooning
>>
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