Soil Testing Results in my garden in CA

[Ms. Jitomate]

I had asked earlier about Tracydr's concern about her foundation and sidewalk on her soil in another thread because my garage and a concrete walkway is by a bed I was planning to plant tomatoes. So I decided to get a soil analysis after 28 years of planting various vegetables in this particular bed and I got my results back in one week. I also asked they make a recommendation for my bed for planting tomatoes. This is the first time I have ever seen a soil analysis so it is a bit overwhelming, but the recommendation is to add Dolomite and Sulfur, 70lbs/1000sf and 0.5 lbs/1000sf. These were the comments,

MICRONUTRIENTS: Where levels appear to be high, avoid any further applications for the time being. Very high levels may not necessarily be toxic,but avoid. Maintain correct soil pH. LIME REQUIREMENT: Liming may be necessary if buffer index is less that 6.9. Guidelines are based upon common agriculture lime (70 score) per six-inch depth to raise SOIL pH to about 6.5.

My pH was 6.0 and my Buffer index was 6.7. I have no idea what Buffer index means. Other Very High (VH) items were organic matter, phosphorus, nitrogen, and zinc. Everything else was medium or low.

Now I am trying to find dolomite. Is dolomite the same as dolomite lime?

[Crandrew]

Not sure the definition wasnt clear, but it sounds interchangeable.

Dolomite (pron.: /ˈdɒləmaɪt/) is a carbonate mineral composed of calcium magnesium carbonate CaMg(CO3)2. The term is also used to describe the sedimentary carbonate rock dolostone.
Dolostone (dolomite rock) is composed predominantly of the mineral dolomite with a stoichiometric ratio of 50% or greater content of magnesium replacing calcium, often as a result of diagenesis. Limestone that is partially replaced by dolomite is referred to as dolomitic limestone, or in old U.S. geologic literature as magnesian limestone.

[Ms. Jitomate]

Yet, I found this definition:

Dolomite. A mineral composed of calcium and magnesium carbonates. Pure dolomite contains 40 to 45% MgCO3 and 54 to 58% CaCO3.
Dolomitic Limestone. A material containing MgCO3 in lesser concentrations than found in dolomite. In the aglime trade, a concentration of 15 to 20% MgCO3 is common for material termed dolomitic limestone. Florida law requires that a material "contain a minimum of 36% magnesium carbonate expressed as MgCO3" in order to be sold as "standard dolomitic liming material," and "a minimum of 30% magnesium expressed as MgCO3" to be sold as "dolomitic liming material."

http://hubcap.clemson.edu/~blpprt/acid4.html

[paulgrow]

Buffer index is a soil test measurement that is used to determine the amount of lime required to raise soil pH to the desired level; the buffer index is measured only when the pH of a mineral soil is less than 6.0.
The recommendations are a little confusing. The dolomite will raise the pH while the sulfur will lower the pH.

What type of amendments have you used over the years?

Did they list the levels of the micro nutrients?

The only one I'd worry about is the zinc levels, any idea where it came from?
Nitrogen is usually not listed due to the fact that it freely migrates through the soil and levels are constantly changing.

The ideal pH for growing tomatoes is 6.5-7.0

[Sun City Linda]

Ms Jitomate - What company did you use?

[RayR]

The Buffer Index is based on a lab estimate as to how resistant your soil is to a change in PH.
Since your Buffer Index (6.7) is on the high side, it won't take that much lime to raise your PH to a target PH above 6.0. If your Buffer Index was much lower like 6.2, it might take 3 times more lime to raise the PH to the same target.

The Sulfur recommendation is only 0.5 lbs/1000sf,which isn't enough to make any difference in PH, but they must have determined your availability of Sulfur as a nutrient is low.

[Ms. Jitomate]

The company that I used is A & L Western Agricultural Lab in Modesto, CA. I sent a two cup sample from 4 different parts of the bed. My last vegetable growing there was corn. I cut up the stalks in August 2012 and turned them into the soil. There wasn't any sign of large organic matter in my soil sample. In October 2012 I added chicken manure and some of their bedding. Nothing has been planted in this bed since the corn in the summer. I told the lab I wanted to plant tomatoes this spring 2013.

This is how it reads: (sorry can't attach it because its a PDF with my home address.)
Organic Matter:
% Rating 14.3 Very high
ENR 316 lbs/A
Phosphorus:
P1 (Weak Bray) 203 Very High
(Olsen Method):
92** (unreliable at this soil pH)
Potassium:
262 ppm Medium
Magnesium:
240 ppm Medium
Calcium:
1783 ppm Medium
Sodium:
87 ppm Low
Soil pH: 6
pH Buffer Index: 6.7
Hydrogen:
2.1 meq/100g
Cation Exchange Capacity:
14.0 meq/100g
Percent Cation Saturation (computed):
K = 4.8%, Mg = 14.1%, Ca = 63.4%, H = 15.0%, Na = 2.7%
NO3-N = 80 ppm Very high
So4-S = 16 ppm Medium
Zn = 29.7 Very High
Mn = 3 ppm Medium
Iron = 12 ppm Medium
Copper = 1.2 ppm Medium
Boron = 1.6 Medium
Excess Lime Rating = Low
Soluble Salts = 1.5 mmhos/cm Medium

Could the Zinc be from the concrete and the foundation of the garage?

[Sun City Linda]

Thanks. I think I will get my soil tested soon!

[habitat_gardener]

Using the Acid Soil worksheet from

http://soilanalyst.org/soil-analysis...nt-dense-food/

it looks like your K, Na, and Zn are high. (But the worksheet is based on using Logan Labs, and they do note that another lab they use, Spectrum, gives different results
http://growabundant.com/organicalc-f...tic-goes-live/
so it's possible the worksheet is not compatible with your lab.)

I read the book, too, and they recommend calculating all the sulfates (Fe, Mn, Cu) first, which also gets you the S component. (But another soils book I'm reading now, Building Soils Naturally by Phil Nauta, barely mentions Fe, Mn, Cu, and Zn! He says these are trace metals important only to advanced gardeners.)

Nauta cautions against using dolomite lime for gardens (in any amount, ever) because he says it's too high in Mg for the amount of Ca it contains, and excessive Mg will compact the soil. Instead, he prefers calcitic lime (also called calcium carbonate or aragonite). iirc, Solomon says pretty much the same thing, but he calls it agricultural lime. Gypsum is their second choice, assuming you need the S it contains.

For boron, the amount Solomon recommends based on your soil is 2 teaspoons of (laundry) borax per 100 square feet.

I've been planning to get a $20 soil test from Logan ever since I read the Solomon book, but haven't gotten around to it yet, and it doesn't look like I'll have any spare time for at least another month.

Maybe the zinc is from galvanized metal?

[habitat_gardener]

Hydrated lime can burn your plants and your skin, and it's not approved for organic gardens.

[Ms. Jitomate]

So if I want to plant tomatoes in a higher pH than 6.0 this month, it's useless to add Dolomite Lime because it won't use it until way late in the season. One of my nurseries said leave it at 6.0. I haven't planted tomatoes in this section in over 3 years, so I want to include this bed because of crop rotation and limited amount of space.

My Magnesium is fine so I don't want to add Dolomite Lime if it is going to add more Magnesium and compact my soil. How about hardwood ashes? It was suggested in this website, http://www.grow-it-organically.com/c...html#alternate. But it doesn't say how much it is going to change the pH. They also suggest oyster shells and eggshells but I also have enough Calcium. What can too much Calcium do to my soil? And how much will oyster shells and eggshells change the pH?

[habitat_gardener]

Originally Posted by Ms. Jitomate

...How about hardwood ashes? It was suggested in this website, http://www.grow-it-organically.com/c...html#alternate. But it doesn't say how much it is going to change the pH. They also suggest oyster shells and eggshells but I also have enough Calcium. What can too much Calcium do to my soil? And how much will oyster shells and eggshells change the pH?

iirc, Solomon discussed other sources such as wood ashes and oyster shells and said to avoid them because of possible heavy metal contamination or other negative effects on soil.

Both authors advise working on improving the fertility of the soil and balancing the nutrients, rather than adding things to bump the pH one way or another, which is counterproductive.

Both of the soils books I mentioned recommend agricultural lime (=calcitic lime) as the best source of Ca. Based on your soil test results, it looks like 1 pound per 100 square feet would be a good amount for your soil. The right amount of Ca increases the availability of other nutrients and microbial activity. Physical signs of Ca deficiency, according to Nauta, are grassy weeds, dandelions, and thick woody stems. Nauta says too much Ca can create too much air space in the soil so that it's hard to keep wet.

If I wanted to bump up the pH, I'd just add compost and let the soil microbes do the work. Nauta recommends no more than a 1/4 inch layer. You can add some kelp meal for trace minerals -- 1/3 to 1 lb. per 100 sq. ft.

[Ms. Jitomate]

Any ideas where I can get more info to interpret this info? If I add Dolomite Lime now will it be available immediately for the tomato plants ? Is there another option to raise the pH to 6.5?

[Sun City Linda]

Dolomite lime can take several months to be available to plants. Hydrated lime is readily available but may pose a handling problem. If you have any good nurserys near you (not big box stores) maybe someone there could help you.

[Sun City Linda]

I live in SoCal too. We are right on top of our gardening season. I think it may be unreasonable to effect some of the changes in your dirt that quickly. Some of the additives are going to take a while. I would imagine you could purchase a fast acting soluable fert or additive to raise PH. Seems to me I have seen them. This is your backyard right, and not a huge plot of land?

Eggshells will not breakdown by NEXT year, much less this year.