"These are my main objectives:
- Improve the soil
- Prepare the grassland for scything next year"
Those two objectives are still a bit nebulous and I think if you flesh them out further it will help you determine your next step.
What are you defining as "improved"soil? For example are you going to plant a garden or grow crops in the field? What are the needs of your future crops? What is your baseline right now with you current soils?
I have seen a lot of people put a lot of work in for the sake of "improving the soil" just to figure out that they could have been more effective if they spent the same amount of effort with long term planning.
What are you going to be scything next year? Do you plan to cut the field for
hay?
I have cut a lot of
land with a scythe, a brush hog, grazing, and a haybine. Each has its place it just depends on what your long term goals are. The timing of cutting on each and every species of plant will have an impact on its life cycle and influence the composition of the field. Once you know your longer term goals you can work you way backwards and choose each tool that you have appropriately.
My advice would be to not feel guilty if you don't get it done and don't run forward in haste. The plants that exist in the field right now are still playing a role even if they go lignet and set seed. If your next step is
chickens you will see that they love overgrown pastures and they need woody shrubs to get away from aerial predators and to use as shade.
Chickens are also well equipped to pick the seeds off of the over mature grasses and turn them into protein.
Good luck and enjoy the journey!