A prospective Iowa farmer wrote to the Agricultural Experiment Station for advice on what crops to grow on a 120-acre farm near Fort Dodge. It is unwise to plan a definite farm program without a thoro understanding of the farm conditions and the ability and resources of the farmer. However, in our reply to this farmer and to others with similar difficulties, we have tried to give suggestions which would help in solving their problems. This bulletin is our answer, not only to this farmer, but to all others who care to think with us in planning their cropping systems.