Best Management Practices For Forage Stands This Spring

Best Management Practices For Forage Stands This Spring

Follow these best management practices to help reduce stress on your alfalfa crop.

Calendars show spring has arrived. Although March and April temperatures have been cool across the Midwest, at least the snow has finally melted. Soon plants will emerge from their winter dormancy, and growers will need to visually evaluate grass regrowth and the vitality of their alfalfa plants.

It's essential to follow best management practices to help reduce stress on your alfalfa crop, says Corey Catt, forage products manager for Latham Hi-Tech Seeds. He provides the following timely guidelines for alfalfa stand evaluation and management.

A STAND WORTH KEEPING?: As plants in pastures and hay fields emerge from dormancy, growers need to evaluate grass regrowth and the vitality of alfalfa plants. Usually at this time of year alfalfa is waking up and ready to stretch from its long winter nap. But this spring could be quite different as last summer's drought may have slowed the plant's ability to adequately build carbohydrates needed to sustain the plant through winter months.

Winter injury -- how to evaluate possible damage, when to replace a stand
Usually at this time of year, alfalfa is waking up and ready to stretch from its long winter nap. But this season could be quite different as last summer's drought could have slowed the plant's ability to adequately build carbohydrates needed to sustain the plant through the winter months. Daytime temperatures fluctuated between above normal to freezing throughout the winter, leaving growers hopeful nighttime temps were cold enough to prevent plants from breaking dormancy. When plants break dormancy early, they're more susceptible to cold crown temperatures.

What are the causes of winter injury? Once alfalfa plants get below 5 to 15 degrees F, water within the plant cells freeze. This forms ice crystals which can puncture the cell membrane, allowing vital water and cell contents to leak from cell walls causing them to die. Another way cells are killed is from extreme dehydration experienced as water is continuously pulled from the cells. It should be noted that various alfalfa varieties have different tolerances to dehydration.

Set The Schedule For Hay Quality. Deciding when to make the first cutting of hay sets the stage for the rest of the year. Download our FREE report 10 Hay Farming Basics: Producing A Quality Hay Product today.

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Additionally, winter ice sheets which prevent air from getting to the alfalfa crowns can cause winter injury or death. This causes toxic metabolites such as ethanol, methanol and lactic acid to accumulate killing the alfalfa plant. Three weeks is the maximum amount of time alfalfa plants can be exposed to this before they are killed.

In addition to temperature and soil moisture, there are actually a number of factors that can affect the likelihood of winter injury in alfalfa stands:
* Stand age:
 Older stands are more susceptible to winterkill.

* Variety: Alfalfa varieties with superior winter-hardiness ratings and a high disease resistance index are less likely to experience winter injury.

* Soil pH: Stands growing on soils with a pH above 6.6 are less likely to experience winter injury.

* Soil fertility: Stands with high fertility, particularly potassium, are less likely to experience winter injury.

* Cutting management: Both harvest frequency and timing of fall cutting affect winter hardiness. The shorter the interval between cuttings, the greater the risk of winter injury.

Diagnosing injury—watch for stands that are slow to "green up" in spring
The most obvious way of knowing your stands are suffering from winter injury is if they are slow to turn green. The easiest way of observing this is if other alfalfa stands in the area are starting to green and yours are still brown. This would be a good time to check more thoroughly whether your plants are suffering from winter injury or death.

Other ways you can evaluate your alfalfa stands are by examining the crown and/or the buds. Normally, buds for spring growth form throughout the previous fall. If a portion of the roots are killed, only the side of the plant which remains living will grow new shoots, making it easy to spot. The buds on the plant crown can also be killed during the winter. Uninjured buds begin growing early, while buds which were killed must be replaced by new buds formed in the spring. The result will be shoots varying several inches in height, also making them easy to identify.

Set The Schedule For Hay Quality. Deciding when to make the first cutting of hay sets the stage for the rest of the year. Download our FREE report 10 Hay Farming Basics: Producing A Quality Hay Product today.

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If you suspect your stands of suffering from winter injury the most conclusive method of diagnosis is digging up the plant 4 to 6 inches to examine the roots. Healthy roots will be white, firm and contain minimum evidence of root rot. Roots suffering from winter injury or that have been killed will be gray and have a water-soaked appearance soon after the soil thaws. As the water leaves the root, the tissue will become brown, stringy and dehydrated. If the root can have water easily squeezed from it than the plant is almost certainly winter killed.

Evaluating stands—consider number of plants per square foot, and age of stand
When evaluating alfalfa for winter injury in early spring, consider both the number of plants per square foot and the age of the stand. Winter-injured plants are often slow to recover in spring, so avoid making a quick decision to destroy a winter-injured stand.

Most agronomists suggest waiting until the spring regrowth is about 3 to 4 inches high, and then selecting random stand count sites. Check at least one, 1-square-foot site for every 5 to 10 acres. Dig up all of the plants in the 1-square-foot area and inspect for new growth, check the crown and buds to determine if the tissue is still alive. Finally, count the number of live plants per square foot. Use the accompanying table, developed by Iowa State University's Department of Agronomy, to begin your rating of the stand.

Visit Latham Hi-Tech Seeds website,or the company's blog for more information.

Set The Schedule For Hay Quality. Deciding when to make the first cutting of hay sets the stage for the rest of the year. Download our FREE report 10 Hay Farming Basics: Producing A Quality Hay Product today.

TAGS: Forage
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