Jim Morrison, retired University of Illinois Extension educator, talks about soil fertility and forage crop varieties during the Overcoming the Challenges of 2012 meeting.
Jim Morrison, retired University of Illinois Extension educator, talks about soil fertility and forage crop varieties during the Overcoming the Challenges of 2012 meeting.

DIXON, Ill. — Taking a soil sample is the first step producers should take to evaluate their drought-stressed pastures.

“It starts with knowing your soil,” said Jim Morrison, retired University of Illinois Extension educator. “You do the same thing with corn and soybeans. There’s no reason why you shouldn’t implement a regular soil testing program for your pastures and hayfields.”

Ideally, producers should take a soil sample every 2.5 acres, 6 to 7 inches deep, every four years.

“If you have to put on lime, the applications are usually structured over a four-year application period,” Morrison explained at the Overcoming the Challenges of 2012 meeting, sponsored by Sauk Valley Community College, Whiteside County Cattlemen’s Association and the U of I Extension.

Although grid sampling can be used for pastures, the educator said, producers also can sample by management zones.

“Sample the bottom ground, the side slopes and up on the hill to give you an idea of the differences across the pasture,” he said. “The soil sample should be taken six months prior to seeding in case you need to apply lime.”

The minimum pH levels are 6.0 for grasses, 6.5 for grass-legume mixtures and 6.8 for mixtures with alfalfa.

“The reasons why pH is so important is it impacts the availability of nutrients in the soil, it is needed for the nodulation process and it affects the yield of legumes,” Morrison said.

The pH is on a logarithmic scale from zero to 14.

“Because of the logarithmic scale, a pH of 5 is 100 times as acid as a pH of 7,” the specialist explained. “And a pH of 6 compared to 7 is 10 times more acid.”

One tool producers can use to evaluate their pastures is a pasture condition scorecard.

“It is available on the Internet through (Natural Resources Conservation Service) offices, and it is a subjective evaluation of 12 to 13 items you rank as you walk across your pastures,” Morrison said.

“You need to realize there’s no silver bullet. All grasses and legumes have strong points and disadvantages,” he noted. “Not all of them are adapted to all growing conditions.”

Morrison is a big proponent of grass-legume mixtures in pastures.

“The pasture needs two or more legume plants per square foot to supply the nitrogen for the grass,” he said. “We know the price of nitrogen fertilizer, so if we have legumes at the recommended level in our pastures, we can avoid applying nitrogen.”

The educator discussed a research project that evaluated the importance of keeping a legume in the pasture. By applying 180 pounds of nitrogen to a tall fescue pasture, forage production totaled 5 tons per acre.

“When 6 pounds of red clover was added to the tall fescue, forage production was over 11,000 pounds of dry matter,” Morrison said. “They got over 1,000 pounds more by adding red clover to a tall fescue pasture as compared to adding 180 pounds of nitrogen. You can buy a lot of red clover for what it would cost you to put on 180 pounds of nitrogen.”

Producers should buy inoculated seed.

“The inoculants have a shelf life so make sure you know the plant by date,” Morrison advised. “Buy certified seed and stay away from variety not stated because you don’t know what you’re getting.”

For frost seeding a pasture, the two main candidates for legumes are red clover and white clover, the specialist said. “Frost seed the legumes and grasses separately because they have different seed densities, and if you mix them together, you won’t have a very uniform spread pattern.”

Following the drought of 2013, if a farmer is establishing perennial forages this spring, Morrison recommended taking the first two harvests as a hay crop.

“Be aware of the autotoxicity in alfalfa,” he said. “The drought had no effect on autotoxicity — it will still be a problem.”

If a producer had to sacrifice an area of the pasture during the drought, that area can be seeded with oats and a perennial forage mix by May 1.

“Or you can wait until about June 1 and seed some annual crops like sorghum/sudan, Teff or turnips,” Morrison said.

The educator listed several advantages for rotationally grazing pastures, including providing an opportunity for forages to rest and re-grow, increasing the utilization of the forages and improving the distribution of manure across the pasture.

Ergot can be a common disease for a wide variety of grasses and cereal grains.

“It is somewhat weather related, so for dry years, it shouldn’t be a problem,” Morrison noted.

The ergot body will take the place of a kernel on seed heads.

“The easy way to avoid this problem is don’t allow the crop to produce a seed head,” Morrison said.

The best way to control rust on orchardgrass is to buy a variety with resistance.

“Rust is not toxic, but it is a palatability problem,” the specialist said.

“If you’ve had winter annual weeds in your alfalfa fields, the best way to control them is with a dormant application of an herbicide,” he said. “And watch for poison hemlock because it is toxic, and it can be confused with Queen Anne’s Lace.”