No, this is certainly meant to depict an arm. Further excavation clearly revealed it ending in a hand above belt and loincloth, thus clearly demonstrating the anthropomorphic nature of these T-Pillars (cf. this 3D scan: //dainstblog.com/wp-content/uploads/2016/05/pfeiler-18-mit-podest-2.jpg).
Is this the representation of a plough on the pillar?
No, it is an arm.
No, this is certainly meant to depict an arm. Further excavation clearly revealed it ending in a hand above belt and loincloth, thus clearly demonstrating the anthropomorphic nature of these T-Pillars (cf. this 3D scan: //dainstblog.com/wp-content/uploads/2016/05/pfeiler-18-mit-podest-2.jpg).