There are two main differences between Northern and Southern agriculture that we can identify. One was connected to the types of crops grown while the other had to do with the size and labor force of the agricultural producers.
In the South, agriculture revolved around the planting and raising of staple crops. It was largely a monocultural system. Southern agriculture consisted of growing tobacco or rice or indigo or, later on, cotton. This was not largely for local consumption. Instead, it was to be exported. In the North, there was less monoculture. More farmers planted various kinds of crops. The crops were often used for personal or local consumption.
Of course, the two regions differed in the size of their farms. The South was dominated by large plantations while the North was more oriented towards small farms worked by individual families. This led to the most famous difference between the North and the South which was the nature of the labor force. Southern plantations needed large numbers of workers and that workforce quickly came to be made up of slaves. In the North, farms were more usually worked by members of one family with occasional help from neighbors, particularly at busy times like harvest time.