Fallow syndrome

Fallow syndrome is when a crop has insufficient nutrient uptake due to the lack of arbuscular mycorhizae (AM fungi) in the soil following a fallow period. Crops such as corn that are prone to fallow syndrome should not follow a period of fallow, but instead should follow a cover crop which is a host for AM fungi, such as oats or other small grain crops. The presence of any plant roots, including weeds, can reduce occurrence of fallow syndrome.