What the heck is "green manure"? (And why you may want some...)
"Green manure" is really nothing but "cover crop:" typically rye grass, clover, red clover, or horse pasture seed mix. Unlike horse manure or steer manure which may have weed seeds, "green manure" actually helps improve the soil and reduces or eliminates invasive weeds.
The advantage of a cover crop lies in its ability to:
Prevent soil erosion during winter rains
Improve overall soil condition
Serve as a food source for grazing animals
Reduce invasive weeds without herbicides
Improve the look of your property during the fall, winter, and spring
Unfortunately, all cover crops tend to "die off" in July-- when rain water no longer provides needed moisture and summer heat causes die-off.
Other than planting and mowing, there is nothing else to do to improve your pasture and grounds!