12/29/2012 7:00 AM
By Charlene M. Shupp Espenshade Special Sections Editor
GRANTVILLE, Pa. — Orchardgrass stands failing after one year? It’s a question that Les Vough, a forage agronomist from Southern Maryland RC&D, has been reviewing.
Vough said he believes pest pressures and heat stress from the past two summers have played a part, but that they were just the “final straw that broke the camel’s back.”
They are not the primary cause, he said. The real problem is management.
Vough spoke Dec. 18 at the Keystone Crops Conference at the Holiday Inn in Grantville. He said there are a variety of management issues that can cause stand problems.
Orchardgrass started having problems with the introduction of the disc mower, Vough said, recalling that he heard one farmer call the mower a “land-leveling device.” Stands were being cut or grazed too short, he said, leaving the plant vulnerable.
Vough told of being called out to an organic farm where the owner was perplexed as to why one square in a field was greener than the rest. He discovered that the greener patch was near a groundhog hole where the farmer had raised the mower to clear the debris, then lowered it to continue cutting.
Nutrient reserves are stored in the lower stem of an orchardgrass plant. If cut too short, plant reserves are depleted and the orchardgrass has to recover its reserves as well as grow. And in times of plant stress, it could become too much to handle.
“If it’s dry, the plant has to survive on its reserve, if one-half to two-thirds of the reserve is taken it’s hard to survive,” he said.
Research has shown that orchardgrass production is affected by the interaction of nitrogen and potassium. If potassium is limited, it limits the nitrogen uptake of the plant. Orchardgrass that is cut at 2 inches needs additional potassium to make up for what was lost in the cutting or stand viability begins to decline.
In contrast, cutting at 4 inches does not increase potassium needs, Vough said. This is also more economical than applying additional fertilizer.
A Mid-Atlantic soil survey of commercial forage fields indicated they were low in potassium, and Vough credits the finding to the rising costs of fertilizer. The survey also found that dairy farms tended to be more in balance because of their use of dairy manure.
The timothy rust mite had forced farmers to rotate to another grass variety in their forage production. Farmers selected orchardgrass as the alternative. But, was it the right choice?
“Where are we trying to grow orchardgrass? Are Maryland growers planting it where it is not designed to persist?” Vough asked.
Orchardgrass and timothy have different characteristics. Orchardgrass works “more like alfalfa” for the soil type, drought tolerance and nutrient needs, Vough said. Timothy can work better in drier conditions and wetter soils, two