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Forages don’t like wet feet

Spring hay and pasture seedings are normally done from late February through late April in Iowa. The extended period of wet weather and possible flooding in 2010 has many hay and forage producers wondering when they can get their forages planted. Iowa State University Extension forage agronomist Steve Barnhart provides the following considerations and guidelines.

Key Points

• Spring has been wet enough to delay forage planting for some farmers.

• Success of late-summer planting depends on planting window, soil moisture and rain.

• Carryover seed should be stored in a cool, dry place to preserve germination.

What about spring planting?

Can spring forage stands still be successfully planted?

The short answer is yes, into the first 10 days to two weeks of May. The end of the spring forage planting season is limited by seedling development and growth into the summer months.

Most forage seedlings are emerging and growing their root systems into the top 1 to 3 inches of the seedbed during the three to four weeks following germination.

The increasingly dry and hot soil surfaces in late May and June increase the risk that the small forage seedlings will not become establishes. So, the risk depends on rainfall and soil temperatures from those dates on.

If conditions turn normal, or hotter and dryer than normal, the risk of late-planted forage seeding failures increases.

If conditions in late May and early June remain cooler and wetter than normal, then later-than-desired spring forage seedings may survive very well.

Planting forages later than desired adds to vulnerability of erosion and weed competition. Keep cereal companion crop planting rates to half of a full seeding rate or less, and mow or clip new seedlings several times during the early seedling development months to allow light to reach small developing legume and grass seedlings.

Furthermore, be sure to scout for and manage potato leafhoppers in new alfalfa seedings.

Skip spring planting?

What about skipping spring planting and instead planting the new hay and pasture fields in late summer?

The success of planting forages in late summer is set by both the planting window that provides for a six- to eight-week establishment time requirement for seedlings before the first killing freeze of the fall, and the necessity of adequate existing soil moisture and the likelihood of average or better-than-average fall rain.

For alfalfa and other forage legumes, the seed should be planted by Aug. 10 for the northern third of Iowa, by Aug. 20 for the middle third of the state and by late August or the first week of September for the southern third of the state. Cool-season forage grasses can be planted a few weeks later in each of these zones.

The risk of stand failure is high if seed is planted in dry soil, and rainfall patterns for the remainder of the fall season are erratic.

Can seed be carried over?

Can purchased seed be carried over until fall or next spring?

Seed is perishable. Germination declines over extended storage time, and it declines faster if seed storage conditions are warm and in high humidity.

Certainly, you should try to store carryover seed in a cool, dry place. For even better results, try to arrange for storage of seed in a more desirable seed storage facility.

If you do have concerns about the viability of carryover forage seed, have a germination test done before planting it. Then you can adjust your sowing rates to compensate for any germination percentage losses.

Source: ISU Extension

This article published in the April, 2010 edition of WALLACES FARMER.

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