Ph - To Adjust Or Not To Adjust. The Question.

[we5inelgr]

Hi all,

Got my soil analysis back from Texas A&M (I live near Lodi, CA) and it looks like my pH is a bit too high, at 7.7. Should I try and correct that? If so, with what?

I have relatively compacted clay soil, and according to this article How to Acidify Soil it sounds like I need to stay away from organic materials, as that may make my soil more alkaline.

There seems to be 3 options for lowering pH in clay/compacted clay soils:

• S (elemental sulfur)
• FeSO4 (Iron Sulfate)
• Ammonia Fertilizer.

I will be planting own rooted Cab Sauv and Petite Sirah from UC Davis in a few weeks. What should I use, if anything (at pH 7.7) to make my soil more acidic...and to what pH should it be? Are any more toxic or dangerous long term with vines than the others?


*CL=Critical level is the point which no additional nutrient (excluding nitrate-N, sodium and conductivity) is recommended. **ppm=mg/kg

 

[HillPeople]

Ya- 7.7 is too sweet.
If it's heavy clay I'd try to till in some straw or pine bark to loosen it up and go with a sulfur treatment to get it down to at least 6.0.
This might be helpful:
http://forums.gardenweb.com/forums/load/permacult/msg011105231043.html

 

[we5inelgr]

Ya- 7.7 is too sweet.
If it's heavy clay I'd try to till in some straw or pine bark to loosen it up and go with a sulfur treatment to get it down to at least 6.0.
This might be helpful:
http://forums.gardenweb.com/forums/load/permacult/msg011105231043.html

Great information, thanks!

I'll probably go with a mixture of sphagnum peat moss (for more near term) and sulfur (for more long term).

 

[we5inelgr]

Trying to locate a product to just lower soil pH, that is the least toxic, seems to be fairly difficult.

I want to lower my soil pH from 7.7 to at least 6.7, perhaps 6.5. So at least 1 point.

I think I've settled on using Iron Sulfate over elemental Sulfur, for it's ability to bring the pH down quicker. What do you folks thinkg about Ferrous (Iron) Sulfate for lowering vineyard pH, and what do you think about a water soluble version?

Iron Sulfate Water Soluble Powder Ferrous Sulfate

 

[oregondabbler]

A compacted clay soil (I have one too) isn't going to carry the amendment deeply on its own.

Grapes are very deep-rooted (to 8 ft) and you'll need to do more than till the amendment in. In Oregon we have a different problem but solve it the same way, by amending the soil. The Oregon Extension Agency recommends "ripping" the soil using a special plow that opens the soil in two directions to 24".

Not to derail your thread (but I guess it will a little bit), why are you going with own rooted grapes. Has UC Davis come up with phylloxera-resistant varieties?

 

[we5inelgr]

Not to derail your thread (but I guess it will a little bit), why are you going with own rooted grapes. Has UC Davis come up with phylloxera-resistant varieties?

Because that's what they sell via FPS, and what they recommended (even though I wasn't originally looking for own rooted). Plus, I got the exact clones I wanted.

From what I've heard from them, and what I've read, phylloxera shouldn't be an issue for me in my situation or area and that the clones I've planted come from vineyards with phylloxera "tollerant" rootstock and haven't had an issue themselves for the last few decades at least.

Of course, it's still possible to get a phylloxera infestation, but apparently, we are in a period called the "Post-Phylloxera Era" [1][2]

There is, naturally, no rootstock that is 100% resistant.

For those reasons, I'm not concerned about phylloxera.

Thanks for the reply.

 

[oregondabbler]

Thanks for the information. Resistant or tolerant, it sounds the same to me. Nobody is making claims about Pinot Noir pylloxera-tolerant varieties. It seems that California has found some strains of Cab and Petit Sirah that are.

Have fun and here is wishing you great success establishing your vineyard.

 

[Deezil]

I see what you're going for, by hoping to alter the pH... But..

Trying to move the pH a whole point (6.0 pH is 10x more acidic than a 7.0 pH), feels like it would be an exercise of futility, without some longer-term plan than just amending the field. You could amend the field to get the grapes established, but even then I think you'd be better off with the extra step of grafting your plants onto a rootstock that fairs better in compacted clay soils.

Was the 8ft a typo? Because grape vines dig way deeper than that (80ft might be more correct).

The water-soluble iron sulfate will leach out of the soil just as easily as you apply it; it's water-soluble. So it'll work, until it rains really good - then you'll find a portion of it in the nearest puddle/stream/river/lake.

As for long term plans... You could start some serious composting. You'd want to gather things like leaves, pine needles, bark, wood chips - think "forest duft". Forests are generally more acidic, and grassy plains more basic. Forest duft also takes longer to break down, however, but the process can be sped up with some sort of nitrogen addition.

Much, much easier to put the vines on rootstocks than it is to constantly fight pH fluctuations with inorganic amendments. Just my 2 pennies though.

 

[oregondabbler]

Deezl, the 8 foot number came from an article I read about removing phylloxera-infected roots from the ground. So your question prompted a bit more digging into grape root depth. The Oregon extension site says this:

"Research has shown that grapevine root development is controlled by two factors: the genotype of the vine, i.e. the rootstock or, in the case of ungrafted vines, the scion, and the soil environment. Most roots are found within the top one meter (3 ft), however, a few roots can be found at deeper depths, and rarely roots at extraordinary depths (more than 10 meters, or 30 ft).

http://www.extension.org/pages/45580/how-deep-do-grapevine-roots-grow-down-into-the-soil

It is harder to grow something that doesn't match the natural conditions but we5inlgr's vines can do fine.

Soil pH would not need to be adjusted all the way down to bedrock. Two or three feet would be enough depth to give feeder roots the pH they need to access nutrients. The deeper roots are mostly to get at water during the dry season. Adjusting pH with sulfur will last about 5 years, which will give enough time to build up the acidity of the soil organically. Acidic sources for composting make sense.

 

[we5inelgr]

Soil pH would not need to be adjusted all the way down to bedrock. Two or three feet would be enough depth to give feeder roots the pH they need to access nutrients. The deeper roots are mostly to get at water during the dry season.

From what I've read recently, this makes sense.

The a large portion of the root structure surface area is found within the top ~3 feet, The soil in that "zone" can be pH adjusted more readily and thus enabling all those roots to better absorb the nutrients found within that first 3 feet. The deeper roots are mainly for seeking out water when there is little to none coming through the surface.

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