compacted hay field

i have a hay field that is around 280 on penetrometer in first 6 inches. it is low land and very heavy soil, high water lin emaybe  a foot below surface, it is reed canary grass which my grandfather seeded 40 years ago. (said was the only grass that would grow well there and hold up the machinery) where it is growing well the root mass is about 6 inches deep and where it is not growing well and more compacted the roots only go down 2 inches. my question is....what type of tool should i run through it? a rolling type aerator with the spade like things, or a ripper type with coulters leading them. i am also looking into drilling radishes in early fall. .....open to other suggestions as well. ..... i do have a 2 shank subsoiler already 4ft on center and will need to rent or buy anything else. thanks

compacted hay field