Crop rotation is an important aspect of production that most Pennsylvania corn producers should consider. A carefully planned crop rotation including corn has many advantages over continuous corn. Corn yields often are increased by 5 to 7 percent following soybeans and up to 10 to 15 percent following hay. These “rotational effects” often are enhanced in drought years.
Corn yields in a long-term rotation experiment are listed in Table 1.4-7. Input costs for corn in a rotation often are reduced substantially because of the need for less nitrogen, corn rootworm insecticides, and sometimes herbicides. Crop rotation often facilitates no-till corn production, since soybean stubble and fall-killed sod crops make excellent no-till seedbeds, and rotation reduces the inoculum for diseases such as gray leaf spot, which can be severe in continuous no-till corn. In addition, a diverse crop rotation reduces the risk of yield losses from drought, since more drought-tolerant crops such as soybeans or small grains often are included in the rotation. Rotations also help spread out labor requirements and encourage more timely corn planting and harvesting. Such timeliness can help increase whole-farm corn yields more than just the rotation effect alone. Corn following corn rotations increase risks from drought and pests, but may be profitable on high yielding soils with good management.
In Pennsylvania, crop rotations vary widely across the landscape. An example of an effective grain crop rotation is corn, soybeans, small grain, and double-crop beans. In this rotation, inputs are mini- mized while high yields are still produced.