[Market-farming] Easy soil fertility test

Bill Shoemaker wshoemak at illinois.edu
Sat Oct 30 15:52:10 EDT 2010

I usually look at my crops, and the weeds. If they look healthy, the fertility is good. Not being sarcastic, just realistic.


---- Original message ----
>Date: Fri, 29 Oct 2010 14:14:22 -0500
>From: Nan Hildreth <NanHildreth at riseup.net>  
>Subject: [Market-farming] Easy soil fertility test  
>To: Market Farming <market-farming at lists.ibiblio.org>
>How can you tell if your soil building is working?   Do this quick 
>and dirty soil fertility (biology) test.
>To summarize the below:
>Get a shovel and dig a two inch slice, count worms in slice.
>2 worms                 not dead soil
>4 or 5 worms            fairly decent soil
>7 or 8 worms            great soil will grow heavy feeder veggies
>20 worms                especially fabulous soil
>If needs improvement, add organic matter and inoculate with soil 
>biology by a compost tea.
>At 12:25 PM 10/29/2010, Philip Bogdonoff wrote to soil-age at googlegroups.com
>>An  'optimally inaccurate indicator' (OII) is usually a quick and low-
>>cost method for estimating a trait you wish to measure.
>>Here's one for soil fertility posted by "Honyocker" to the
>>greenwizards.org/ website recently launched by John Michael Greer):
>>Soil Fertility
>>Wed, 10/27/2010 - 10:26
>>I recently found a simple method of estimating soil fertility that
>>seems to be pretty accurate, at least in the fields and gardens where
>>I've tried it. The theory is that natural soil fertility depends on
>>activity of the soil bacteria, fungi, insects, etc. (biota) that work
>>the soil and release nutrients from the inorganic and organic
>>materials in the soil. It assumes that earthworms are the peak
>>organism in the soil biota and, if you have a sufficient quantity of
>>earthworms, the remainder of the soil biota is probably in good
>>To estimate the number of earthworms, take a shovel and dig up one
>>shovelfull of soil. Then take the shovel blade and dig it in to the
>>top of the blade again about 2 inches back so that you end up with a
>>slice of soil 2 inches thick and the width and depth of the shovel
>>blade. Count the number of earthworms in the slice of soil. Then
>>repeat the process in a grid pattern around your garden or field and
>>calculate the average number of earthworms that are found in a slice
>>of soil. Take the average and multiply by 100,000 to get an estimate
>>of the number of earthworms per acre.
>>In general, you need a minimum of 250,000 earthworms per acre to have
>>enough natural soil fertility to grow crops, although you probably
>>will still have shortages of some nutrients. 400,000 to 500,000 will
>>allow you to grow most crops that aren't heavy feeders. 700,000 to
>>800,000 is a good range to be in, but more is always better.
>>Organically managed, deep topsoils in the American Mid-West can have
>>in excess of 2,000,000 earthworms per acre.
>>If you're short of earthworms, first try adding more organic material
>>to the soil by digging it or tilling it in. Also use organic mulches
>>around your plants. If that doesn't bring up the earthworm numbers,
>>trying adding organic compost or compost teas. In most cases, your
>>soil fertility can be increased by these methods.
>># # #
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>>For more options, visit this group at 
>Nan Hildreth, Houston   713-842-6643
>Make Soil, End Global Warming
>"We could end global warming if we restored the fertility in the 
>soils in the state of California."  Dr. Elaine Ingham, www.soilfoodweb.com
>"...global warming can be reversed by restoring biodiversity in the 
>soils and in the ocean.  ... There is enough land to sequester this 
>carbon and it could be done in a decade or two. ... Now that the Oil 
>Age is coming to an end, we are entering the Soil  Age. 
>"  http://groups.google.com/group/soil-age
>"... a 1.6% increase in organic content of soils humans manage would 
>restore atmospheric carbon dioxide levels to normal." says Allan 
>Yeomans in 
>http://www.youtube.com/user/AllanYeomans1#p/a/u/0/-o2N6vJDLpE Free 
>download of his book http://www.yeomansplow.com.au/priority-one-contents.htm
>"Soil is the new frontier" Eaarth by Bill McKibben  
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William H Shoemaker, UI-Crop Sciences
Sr Research Specialist, Food Crops
St Charles Horticulture Research Center
535 Randall Road  St Charles, IL  60174
630-584-7254; FAX-584-4610

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