How to count fungi more accurately with the excel spreadsheet!!

[jamesdpinner]

Dr. Ingham asked that I talk about this because she didn't have much time to explain the spreadsheet in class. 

The spreadsheet we use assumes a fungal strand is as long as the diameter of the field at a 400x total magnification.

So if the strand is:

a quarter of the diameter count it as 0.25 

a half of the diameter count is as .5 

and so on...

Each branch of the fungi is considered another strand on the excel spreadsheet. 

Remember with fungi the average diameter needs to be included in the calculation in order to get a more accurate fungal biomass value. Be sure to weight the averaged. For example if you have:

1 strand the full length of the field that is 5um diameter

1 strand that is the 0.4 of the field that is 4um diameter

2 strands that are full length of the field and are 8um diameter

(1 x 5um) + (0.4 x 4um) + (2 x 8um) = 6.2235 Average diameter

(1) + (0.4) + (2)

6.2235 can be rounded to 6 um then copy and paste the value associated with 6um average diameter.

One more thing!!

Check for consistency your standard deviation should be no more than 20% of the mean. A quick check I use is to multiply the standard deviation by 5 and if that number is higher than my mean than my standard deviation is more than 20% of my mean.  

If your standard deviation is greater than your mean than the amount of organisms you found were not significantly different that zero.

So if you have

0.15 fungal strands with a standard deviation of 0.2 than you should state that there is no fungal biomass. 

[ednaknightlora]

Thanks, James. This clears things up.

[Ingham, Elaine]

Here's another thing to think about -

When you are not getting alot of fungi in your soil or compost, and you are having a hard time seeing fungi, or protozoa, or even nematodes in that 1/5 dilution, or even a 1/2dilution, let the sand, silt and clay settle for a good 30 seconds before pulling a sample into your pippetter. That way, you may lose a tiny bit of the organisms if they settle with the mineral material, but most organic matter floats, so youwill get the fungi on that in the sample.

Then without all that interference from the mineral materials, seeing the fungal strands should be easier.

If you still do not see fungal strands,or if the mean value of fungi in the sample is less than the standard deviation, you really have to conclude that fungi in the sample are not distinguishable from zero. You really have no significant level of fungal biomass present.

Am I saying this in a way that makes sense?

Elaine R. Ingham
Chief Scientist
Rodale Institute

-----Original Message-----
From: ednaknightlora [mailto:ednakni...@gmail.com]
Sent: Sat 11/3/2012 8:23 AM
To: lifein...@googlegroups.com
Subject: Re: How to count fungi more accurately with the excel spreadsheet!!

Thanks, James. This clears things up.

On Monday, October 22, 2012 9:48:14 PM UTC-4, jamesdpinner wrote:
>
> Dr. Ingham asked that I talk about this because she didn't have much time
> to explain the spreadsheet in class.
>
> The spreadsheet we use assumes a fungal strand is as long as the diameter
> of the field at a 400x total magnification.
>
> So if the strand is:
> a quarter of the diameter count it as 0.25
> a half of the diameter count is as .5
> and so on...
>
> Each branch of the fungi is considered another strand on the excel
> spreadsheet.
>
> Remember with fungi the average diameter needs to be included in the
> calculation in order to get a more accurate fungal biomass value. Be sure
> to weight the averaged. For example if you have:
>
> 1 strand the full length of the field that is 5um diameter
> 1 strand that is the 0.4 of the field that is 4um diameter
> 2 strands that are full length of the field and are 8um diameter
>

> *(1 x 5um) + (0.4 x 4um) + (2 x 8um)* = 6.2235 Average diameter

> (1) + (0.4) + (2)
>
> 6.2235 can be rounded to 6 um then copy and paste the value associated
> with 6um average diameter.
>
> One more thing!!
> Check for consistency your standard deviation should be no more than 20%
> of the mean. A quick check I use is to multiply the standard deviation by 5
> and if that number is higher than my mean than my standard deviation is
> more than 20% of my mean.
>
> If your standard deviation is greater than your mean than the amount of
> organisms you found were not significantly different that zero.
> So if you have
> 0.15 fungal strands with a standard deviation of 0.2 than you should state
> that there is no fungal biomass.
>

--

[Elsa]

Absolutely clears things up.  Thank you Elaine.