You can certainly use the same soil as last year but go ahead and improve it by adding a few inches of compost on top of the old soil and then mixing this into the top few inches of old soil with a hoe or rake. If you don't have compost use steer manure or purchase bags of compost from the garden store. Vegetables suck nutrients from the soil plus they are heavy feeders so you will also want to fertilizer your plants. I use a combination of compost, slow release Osmocote and sometimes an application of liquid fertilizer to jump start plants that look slow to grow. Keep improving the soil every year and you'll reap the rewards. Keep growing, Marianne Binetti