Paul and Ron et al -- I first ran into the agricultural and manufacturing
schedules while researching general trends in farm size in some of the
upper Shenandoah Valley counties.  The 1885 Historical Atlas of Augusta
County includes a selection entitled, "The Physiography of Augusta County,
Virginia," by Jed Hotchkiss (well known in these parts as surveyor and
cartographer).  The sub-section "Animal and Vegetable Productions" is based
on a comparison of 1850-1880 census data and includes tables that track
changes in types of livestock, cleared and wooded acreage, old fields, cost
of building and repairing fences, bushels of clover seed, pounds of honey,
etc. -- an incredible resource.  I didn't use the primary records (didn't
need to for this very general level of research) and didn't try to find
them, but I was again reminded of the potential goldmine when I came across
similar syntheses for the 1900-1920 period in several publications by the
University of Virginia's School of Rural Social Economics.

I was bowled over when I finally saw an example of the agricultural and
manufacturing census on-line at Edward Ayers' *Valley of the Shadow* web
page.  A study of two counties (Augusta County, Virginia and Franklin
County, Pennsylvania) on the eve of the Civil War, the project is "a
hypermedia archive of thousands of sources", including 1860 census records.
For those of you who have never seen the agricultural and manufacturing
census, I highly recommend a stop at
http://jefferson.village.Virginia.EDU/vshadow2/govdoc/census.html
Included in this section are guides that explain the history of the A and M
census, the enumeration process, the evolution of categories, an
explanation of fields, etc.

Of course, this is well before the time period in which you're interested,
but you might contact Dr. Ayers and ask about availability of these
records.

Carole Nash, Dept. Soc/Anth, James Madison University, Harrisonburg, VA 22807