University of Wyoming's Extension's Barnyards and Backyards webpage
The Colorado State University's Soil-Water-Plant Laboratory analyzes soil, water, plant, sludge, manure and miscellaneous types of samples from farmers, homeowners, consultants, government agencies and CSU personnel, and provides fertilizer suggestions for improving crop growth.
(Takes you to the County Map Server - instructions here)
Grazing on a few acres?
Small acre planning tools (coming soon)