Cowboydoc, do you composte the shavings/manure before you spread it or do you spread it right out of the barn? Most of the nitrogen that the horse gives up is in the urine. That is lost pretty quickly as it turns to ammonia and evaporates. The shavings use up a lot of nitrogen as they decompose.
From UMontana....
"Sawdust and wood shavings are rich in carbon like wood chips, and they have more surface area for bacteria to work on than chips do, so these materials tend to rob more nitrogen from the soil or compost initially. Sawdust should be aged/weathered before adding it to the compost pile. To balance the demands of one cubic yard of fresh sawdust, add 3 1/2 pounds of actual nitrogen (17 lbs. Ammonium sulphate, 15 lbs blood meal, 11 lbs. ammonium nitrate, or 8 lbs urea)"
Umontana
Another is the "bible" for berry farmers...
The Backyard Berry Book by Stella Otto. On page 66, she says: "One important point to remember when using any natural plant matter as mulch, is the need to provide extra nitrogen to the garden. Soil organisms that break down these mulches use considerable nitrogen in the process. If additional nitrogen is not supplied to them through supplemental feeding, they will compete with the fruit plants to use what is already in the soil."
Hope that helps. I try to composte mine for a year before I spread it.
