Contrary to the regenerative ranching racquet, this meta-analysis further adds to the consensus:

Natural ecosystems contain more stable soil carbon stores than even the best agricultural land, and their preservation (& restoration as best as possible) is therefore crucial.

For so-called marginal land, if its use as agricultural land is necessary, organic amendments (say introducing plant compost or a diversity of nitrogen fixing perennial crops) and even biochar, are far better for soil improvements than grazing cattle:

‘But grazing cattle net stores GHGs and is the best way to protect grasslands’

Nope:

The presence of grazing compared to no grazing decreased SOC by as much as -31% ! (avg -7.1%) (CI -31, -3.9)