Those of you about to opt for SFI NUM3(legume fallow) or AHL1&2(pollen & nectar/winter bird food) need to consider the management consequences. Black grass, ryegrass, bromes, thistles and ragwort can become quickly established. Clovers and other legumes are swamped in year one but do establish in year two. Think carefully what your objectives are. One-year rotational options may be better in terms of preventing the return of weed seeds and managing the return of a field to the arable rotation.
Winter bird food field after 2 years of an annual bird food mix sown every year.
Winter Bird food field after 2 years of a 2-year mix including kale.
Legume fallow 18 months following establishment and multiple topping! Plenty of grass weeds.
Legume fallow. Patchy thistles but some good clover in patches as well 18 months after sowing.
The correct mix of species and how you manage these SFI options will be critical going forward to avoid storing up trouble for future years.