CFAES Give Today
Agronomic Crops Network

Ohio State University Extension


Worried about Fallow Syndrome? Assess the Risk with On-Farm Research

Ohio Prevent Plant Acres 2019

Wet weather conditions last spring prevented Ohio farmers from planting over 1.5 million acres. When fields are left unplanted or fallow, there may be a decline in beneficial mycorrhizal fungi, which is commonly referred to as fallow syndrome. Mycorrhizae are beneficial fungi that colonize plant roots. They aid plants in scavenging for soil nutrients, by extending the root system via thread-like structures called hyphae. In return, plants provide sugars produced during photosynthesis to the mycorrhizae.

Stunting and phosphorus deficiency are common symptoms associated with fallow syndrome.

Purple leaves of corn

The impact of fallow syndrome on crop yields is unclear and the extent that it will occur in 2020 remains a mystery. Ohio State eFields will be running a series of on-farm trials to investigate the yield impacts of fallow syndrome and the efficacy of potential remediation options, such as starter phosphorus applications and microbial inoculants. Information from this trial will be used to improve management recommendations for growers throughout the state.

At each field site, a starter phosphorus fertilizer treatment will be compared to a control with no phosphorus applied. Additionally, growers can include 3Bar Bio-YIELD® microbial inoculant and/or Valent MycoApply® EndoPrime® SC mycorrhizal inoculant in their trial.

If you have fields that were not planted in 2019 and will be planted to corn in 2020 and are interested in being involved in this trial, contact your local Agriculture and Natural Resources OSU Extension Educator. Fields with soil test phosphorus levels <30 ppm Mehlich-3 P, or ideally <20 ppm Mehlich-3P, are preferred.

eFields is a program at The Ohio State University program dedicated to advancing production agriculture through field-scale research. To learn more visit

Crop Observation and Recommendation Network

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.