how many acres do you have? Is it already tillable? Are you planning on doing a soil sample ? Where do you live and what does the farms around you already have planted?
All these matter before you decide. If i had 2 acres or more i would either do alfalfa or soybeans depending on what you want to spend and if you are looking for annual growth.
If you got enough funds, soybeans are excellent. The leaves are tasty treats for the deer and then the fall beans are great food. It is a great all around plot but you need to protect the young plants until they are "brows proof" or they will never amount to anything because they will get eaten up before they get big enough to withstand the munching.
The roundup ready beans are a great way to go, just plow, disk em in lightly, and when the plants and weeds get about 10" tall spray them all with roundup. everything will die but the beans. then the beans will grow more and shade out any new weed growth.