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. �