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Stressed forages need some TLC for a successful 2011 crop

Ag Answers Published on 13 January 2011

The well-being of the 2011 forage crop will depend on whether producers alleviate some of the stresses caused by past management concerns, according to Purdue Extension forage specialist Keith Johnson.

Heavy rainfall in the spring of 2010 delayed hay harvest for many, and dry weather in the late summer and fall may have led producers to allow animals to overgraze pastures.

"The 2010 crop year was stressful to forages because the early spring rains didn't allow producers to get the harvested hay crop out of the field as early as they would have liked and the quality was less than desirable," Johnson said.

"Following that was a very long, dry period. As time went on, producers were stressing pasture crops they did have and overgrazing occurred."

Regardless of weather, forage growers need to take the time to identify the stresses on their hay and pasture crops season to season so they can eliminate some or all of those issues in the best interest of the existing plants.

First and foremost, Johnson said producers need to look at soil types and take soil samples. Those samples should be air-dried and sent to be tested for pH, phosphorus, potassium, magnesium, cation exchange capacity and organic matter. A basic test should cover all of these different measurements.

Any measures of the test that come back at critical levels or less should be given immediate attention - especially pH.

"Different crops have a different pH level at which they grow best," Johnson said. "The cool-season grasses, really ought to be grown in a soil with a pH of 6.2-7. Most of the legumes we grow, such as alfalfa, really need a pH closer to 7."

Having the proper soil pH ensures nitrogen fixation in legumes and affects the availability of nutrients to the forage crop. A pH that is off ultimately could alter the forage composition, and producers could see less desirable forages growing in their fields.

Growers also need to evaluate the stands in their fields. They should look at what is in the pasture and determine whether it's more forages or weeds. If a pasture has been overgrazed and an abnormally large amount of soil is showing, overseeding might be an option.

Other pest stressors to watch for besides weeds are insects and diseases.

"It's the dynamics of growing crops that are important," Johnson said. "Do a good job of scouting. Look at the well-being of the crop as it grows. Understand why the crop might not meet your objective as it grows. Be diagnostic about things and take care of the issues in some fashion so the crop can be as productive as possible."

For farmers unsure of the best process for taking fields or pastures from evaluation to overhaul, Johnson recommended following the Procedural Order for Pasture Renovation:
Assess the need for pasture improvement.

  • Soil test and apply amendments.
  • Control perennial broadleaf weeds.
  • Leave residual growth at less than 4 inches of height.
  • Make seed selections and purchase.
  • Overseed before dormancy breaks.
  • Reduce competition to young seedlings by grazing growth of established forages, or by hay harvest.

—From Ag Answers, January 2010