I guess it's too late to sleeve the posts with PVC pipe. Along the mudflap idea of RStringer's...conveyor belting would work well, but it's expensive to buy new. If you know someone that works in a factory that uses belt conveyors you could get some used for nothing before it goes to the dump.

Maybe for a cheap temporary fix...black corrugated drain tile...split down the side and pop-wrapped around the pipes and hose clamped at the top.

Fish on!,
Noel