Looking for pasture / land / sod farm to use for training search dogs (dublin / pleasanton / livermore)

Hello! I am looking for land that my search dog training group (mix of SAR and sport dogs) can use either paying a monthly maintenance fee or free (can provide non profit paperwork and will sign waivers.
) We teach working dogs to follow ground disturbance trails, and I am searching for new tracking land (dirt, grass, pasture, just not foxtails as too dangerous) in Pleasanton, Livermore, Danville, San Ramon, Mountain House, etc.
Ideally we need a few acres.
Sod farms work too!