Available Nitrogen in Soils

S. A. Modena samodena at csemail.cropsci.ncsu.edu
Fri Jun 4 18:20:47 EST 1993

In article <jccahill-040693142032 at mac215.bio.upenn.edu> jccahill at mail.sas.upenn.edu (JC Cahill) writes:
>I am looking for a little help. I need to do a set of soil analyses for a
>current experiment I am involved with.  I need to determine available N, K,
>P - as well as various water measurments.  The literature appears to be
>very unclear as to which procedures are the most reliable.

The chemist-in-charge of any analytical lab must make choices among
available, alternative analytical methods....so often the chemist-in-charge
has the soil chemistry background and calls upon past direct experience.

There are commercial soil testing labs that can quote quantity prices.  Of
course, while they might get spefific about which tests they are
able/advice performing, they are unlikely to give out their lab protocols
and tricks-of-the-trade.

Many labs at public and private institutes are moving toward using
instruments like ICPs.....and since these are general elemental analysis
instruments, there may be one on your campus...and a colleague eager to
offer time on the machine in exchange for some billing.

Of course, your land grant university campuses and your State Extension
Service via your Philadelphia County Extension Office also can offer "free"
nutrient analyses.....and direct contact with their chemist-in-charge must
yield *their* expert recommendation for various protocols.

Another possible source of critiqued and explicit plant and soil chemical
parameter testing, from available N to soil moisture to ozone conc., can be
obtained from the Environmental Protection Agency....since they have
immersed themselves in projects involving monitoring trees and soil at high
altitudes suffering atmostpheric deposition...and low altitude effects of
green house gases....and thus have published and made available detailed
lab protocols that specify QA-able procedures...(using these EPA guidelines
would probably assure immediate technical acceptance by peer reviewers).
You might start your telephone hunt with the EPA Environmental Unit located
in Research Triangle Park, NC.....

One might consider contacting the Soil Science Association located in
Madison WI (I believe), which might be able to lend you a telephone number
of the leaders of their technical sections covering your specific analytical

The various land grant universities all have Soil Science faculties and
undergraduate/graduate courses in the analytical areas you need.  I recall
that when I taught Intro Soil Science lab at UMass/Amherst as a TA, we
had a departmentally authored lab book which contained titration-based lab
protocols that might meet your needs....but that was more then 10 years
ago...but you could give the UMass Dept. of Plant and Soil Sciences a buzz.
(I also taught Plant Propagation lab, so my specific knowledge is

>Like most researchers, resources (financial) are extremely limited - so if
>there are any procedures that can be done with limited funds (ie
>titrations?) that would be great.  I would like to learn how to do most of
>these techniques myself rather then just send them off to some lab.  
>So, what I am looking for are suggestions and comments about various soil
>nutrient measurement techniques.

Good luck....and you might report back later on what you decided on...and
maybe even post a summary of your gathered knowledge!

|     In person:  Steve Modena     AB4EL                           |
|     On phone:   (919) 515-5328                                   |
|     At e-mail:  nmodena at unity.ncsu.edu                           | 
|                 samodena at csemail.cropsci.ncsu.edu                |
|                 [ either email address is read each day ]        |
|     By snail:   Crop Sci Dept, Box 7620, NCSU, Raleigh, NC 27695 |
         Lighten UP!  It's just a computer doing that to you.    (c)

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