Rotations might be 3 or more years. The quality of the seed is the next consideration. There are many varieties and hybrids of seed which the farmer has to select from each growing season. No single variety is best suited for every soil or growing condition. Farmers try to select varieties which will produce the highest yields.
Most farmers plant certified seed.
This is seed that has been tested and is guaranteed to have a high germination rate, few weed seed, and be free of plant diseases. Before a farmer plants his crop he must decide how and when to till his fields. Tilling or tillage means to prepare the soil and make a good seed bed in which to plant the seed. Tillage normally begins after the last crop is harvested. The farmer uses a disc that he pulls behind his tractor.