By MICHELE F. MIHALJEVICH
Indiana Correspondent

GRABILL, Ind. — The best way to fight weeds and diseases in forages is to first focus on some basics, a Purdue University forage specialist said last week.

Soil pH, the type of seeds used and the timing of seeding are all important to the successful growth of forages, said Keith Johnson. He spoke during a private applicator recertification program session Feb. 16.

A soil pH of 6.8-7 is best for alfalfa. “A proper soil pH is really essential,” he said. “Farmers who rotate out of corn, soybeans or wheat, will find a soil pH of 6.2 is okay for those. But it’s not okay for alfalfa, so you need to add some lime.”

Soil tests are necessary to know what nutrients are already in the ground and what may be needed, Johnson said. Depending on the results, farmers may opt to add some nutrients soon, or wait and later retest, he added.

Use of seeds that are resistant to pests, including the potato leafhopper, are another key to better overall forage, Johnson said. A few years ago, potato leafhopper-resistant seeds might have been only 25 percent effective, but that has improved to 70 percent, he said.

Yield results for susceptible and no-spray resistant varieties of alfalfa seeds indicates little difference between the two, he said.
“You have to consider the cost of pesticides and the cost of time to apply them. But these (resistant varieties) work well because a lot of farmers don’t spray in a timely manner or don’t spray at all,” he said. “The way to fight diseases is to begin with the genetics in the seed.”

Farmers who seed their forages in the fall will probably not see a good crop, he said.

“In Allen County, the best time to seed is not in October, but probably around August 8, and certainly by August 20,” he explained. “It’s really a late summer seeding and not fall. It’s better to err on the side of being a week early than being a week late.”

Double-cropping is a good way to extend the grazing season, he said. “If you harvest your wheat in July, you have a lot of growing season left. There are several crops that would be ideal as a second crop. I think this will become more common.”

Another way to extend the grazing season is to rotate fields so some are not grazed during the fall, he said. “You can grow grass on those fields to be used in December. It’s a lot cheaper to graze than to harvest.”

When selecting an herbicide, farmers need to think beyond the year for which they’re buying it, Johnson said.

“You need to think through what the rotation will be in 2010 and 2011 before you select the herbicides for this year,” he said. “You have to look at the plantback restrictions and the harvest restriction, which is the number of days that have to pass (after application) for grazing or harvesting of the crop.”

Managing forages correctly takes commitment from the farmer, he said.

“If you’re going to be good at making hay, it had better be the most important thing that you do, next to family and religion,” Johnson concluded.