Repair cross-study and taxon conflations in the Panzhihua causal graph #1676

CommunityMech:000051. The six-node graph conflates 2014 bulk-soil isolates, 2023 nodule isolates, 2018 Sinorhizobium saheli/Leucaena results, an external Polaromonas system and 2024 soil-carbon community measurements. Remove the ungrounded nitrogen/carbon feedback and unsupported vanadium and redundancy nodes. Preserve positive nodulation/N enrichment, isolate metal tolerance and Ochrobactrum IAA/siderophore phenotypes, with explicit strain/species uncertainty and no interbacterial mutualism/cross-feeding claim. Preserve the positive carbon result in an evidence-backed discussion pending community identity repair; do not grant all canonical members carbon activity to conceal disconnected taxa. No new taxon identities. Close only after protected-main merge.

Searched 954 all-state issue titles/bodies; read all five matches (#1077-1079, #497, #258), the previous milk review, and the existing Polaromonas author-request lead. Local hidden/ignored-inclusive search found 64 matching files, excluding .git/docs/site/references_cache. Four whole records and four fresh complete primary main texts/captions read; seven further abstracts checked. No original figure pixels or separate supplements audited. Self-adversarial review, not independent approval.