thats not a bad idea , ill check craigslist for a cheap one and just leave it out there, its just to throw some dirt a couple times and probably never use it again or often.. thanksStandard disclaimer:
Make sure you have permission before you do any repairs or building on trails.
That being said, if you're building berms and step-ups or even small "humps" you're going to find using an entrenching shovel to be very slow and laborous. You'll be better off strapping a full size shovel to your bike and just taking it easy when you ride in. You won't need to carry it with you every time you ride. If you have lots to do, stash it out there. You can buy a long handled shovel for $15. You can even carry a D-handled shovel in your pack, watch for low branches though.
By "fix" do you mean do basic maintenance like clearing drains, de-berming critical edges, etc? Or do you mean constructing "features" where none currently exist? Clearing drains and such can be done with a relatively small folding saw, moving and shaping lots of dirt takes a more substantial tool.i was thinking of getting a shovel to fix some of my local trails, just for personal satisfaction..berms, humps etc.. any suggestions? thanks