Plant wheat following soybeans. A three-year rotation of corn-soybean-wheat appears to be optimum for sustained yield of all three crops. Crop rotation is the most effective method to reduce pathogen populations that affect the three crops in the sequence. The purpose is to provide enough time away from the host plant for pathogens to die out before that crop is planted again. Wheat should never follow wheat or spelt in the rotation sequence.
Soil-borne diseases, like Take-all and Cephalosporium stripe, can cause complete crop failure in non-rotated fields. Foliar diseases, like powdery mildew and Stagonospora glume blotch, may also become more of a problem. Wheat should not follow corn in the rotation because the same fungus that causes Gibberella stalk rot in corn also causes Fusarium head scab in the wheat. Planting wheat into corn residues greatly increases the risk of a severe outbreak of scab in the wheat crop. Wheat also serves as an excellent rotation crop for corn and soybeans, allowing populations of pathogens (like soybean cyst nematode and Sclerotinia) to decline before host crops are again planted in the field.