Orchardgrass Decline in the Mid-Atlantic

Jarrod O. Miller, Extension Agronomist, jarrod@udel.edu

Orchardgrass decline is an important topic amongst Mid-Atlantic growers, and the overall cause has been elusive. A study from Virginia Tech surveyed farmers and fields in Virginia, Maryland, and Pennsylvania for reduced stand persistence. Surprisingly, neither overall soil fertility nor disease were strong indicators of lower stand persistence. However, higher soil organic matter and manure application were both related to increased stand persistence. Both of these factors could be tied to soil fertility, which may indicate that soil test levels are not great indicators of orchardgrass decline. Another interesting point in the study was that as soil test P increased, stand persistence decreased. Perhaps soils with higher P levels in the Mid-Atlantic were restricted from receiving additional manure applications, which may explain the importance of manure in these fields. This is supported by the orchardgrass biomass results, where biomass increased with soil test P levels. It should be noted that persistence was based on the grower’s perspective of their current stands, while biomass was a direct measurement. The final factor that influenced a decline in orchardgrass stands was the historic maximum temperatures. Further declines in orchardgrass may be observed with future increases in temperature due to climate change.

The study can be found here, but may be behind a paywall: https://dl.sciencesocieties.org/publications/cftm/abstracts/5/1/180003