Like other clovers it has deep roots that penetrate the soil and bulky furry foliage that once dug in helps to improve soil structure.
Crimson Clover is not always winter hardy especially if it is particularly cold, but if it does get frosted just leave the foliage on the soil surface as a mulch, then dig in during spring. If left to flower it will produce lovely crimson flowers that are very attractive and loved by bees and other beneficial insects, it's often use in wildflower mixes. Cut down or dig in before setting seed.
Clover is part of the legume family and fixes nitrogen from the air in its root nodules. When chopped up and dug into the soil the nitrogen store is released fairly quickly.
It can be sown with a ‘nitrogen lifter’ like Italian Rye the nitrogen will be released at a slower rate sometimes up to 6 months later so use will depend on when the following crop will be planted and the nitrogen needed. Sow clover before a brassicas in a crop rotation plan to release nitrogen to the following leafy greens.