Some people really have a thing against mulch.
For mulch haters, one option to help out your soil is the humble, average and lowly BEAN.
BEANS:All beans enrich the soil with nitrogen fixed from the air, improving the conditions for whatever crop you plant after the beans are finished. The unscientific synopsis is thus: Nitrogen in the air is not available to all plants and must be "fixed" into Ammonium. Lighting "fixes" nitrogen in the atmosphere and nodules that develop on legume roots do the same. HERE is a really fantastic chart that breaks it all down for you if you are interested in reading further.
In general the legumes are good company for carrots, celery, chards, corn, eggplant, peas, potatoes, brassicas, beets, radish, strawberry and cucumbers. Beans are great for heavy nitrogen users like corn and grain plants because the nitrogren used up by the corn and grains are replaced at the end of the season when the bean plants die back. French Haricot beans, sweet corn and melons are a good combo. Summer savory deters bean beetles and improves growth and flavor. Keep beans away from the alliums. Growing tip: Do not allow beans to mature on the plant, or it will stop producing, and do not pick beans or cultivate when they are wet, or it will spread viral diseases.
Along with humble garden bean, peas, fava beans, chickpeas and any old legume will do the trick! Find the cheapest seed available for this nitrogen-fixing boost instead of the nice, pricey varieties. The 10 cent-25 cent packs at the WalMart and the Dollar store work just fine.