Water and wind erosion claimed too much top soil and threatened to reduce the yield potential of our fields. Water quality of the streams and lakes also suffered. As we change our tillage systems to reduce erosion, we need to ask how this will change the whole system. The purpose of this fact sheet is to focus on how wheat diseases might be affected by reduced tillage practices and what we might do about it. The main way that reduced tillage affects disease is by increasing the amount of inoculum.
Inoculum is a term for the pathogen propagules that initiate an epidemic.
Tillage reduces crop debris that serves as a refuge for many pathogens. It also destroys volunteer plants that serve as a reservoir of pathogens, such as viruses or rusts, that require a living host. Another way that tillage can affect diseases is through changes in the microenvironment. Reduced tillage, for example, tends to increase soil moisture and decrease soil temperature. These changes suppress some diseases such as dryland foot rot or common root rot.