Click on a thumbnail picture below to see the full size version. 1 Entries. Sunday, January 12 View Page First Bioassay results to test manure based compost for residual herbicide. JC stands for the source(Johnson County Topsoil). Peas look vigorous and leaves are not cupped. I’ll be proceeding with using it. Also of note, JC Soil + Alfalfa did poorly. Also had a few other things growing in there since I had the seeds laying around.