Microbial Population Biology

“Across 24 Oregon tall fescue seed fields (stands 2-20 years), total SOC stocks were unchanged by stand age or straw management, but older stands stored more total field-level carbon from greater root inputs and straw retention boosted the labile (particulate) carbon fraction in topsoil along with microbial biomass and respiration. These grass seed fields held less topsoil carbon than nearby natural grasslands but more than arable crop fields, so keeping stands longer and retaining straw supports soil biology even without measurable SOC gains.”

“Leaf-surface bacterial loads and communities shifted strongly by crop and season in Minnesota: corn carried the highest Methylobacterium and total bacterial loads (rising as plants senesced), while the overwintering cover crop pennycress had the lowest loads and most distinct community. Despite these differences, a small core of genera (Methylobacterium, Sphingomonas, Pseudomonas, Massilia) dominated all three crops, pointing to versatile strains that could be developed as plant growth promoters.”