Yes, it takes a while to build up to that. The current estimate of the science community in a publication that was just released last Friday says we could get up to 78 million tonnes per year by 2030, and it will take the next nine years to build up to that, with a lower than 78 million tonne average.
The thing that's really interesting is that the theoretical capacity for us to store incremental carbon in our soils is about equal to what our current estimates of the soil organic carbon stocks are. In theory, you can't build up soil carbon stocks faster than nature is willing to, but that capacity to sequester an incremental 70 million to 80 million tonnes per year persists for hundreds of years.