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Getting the most from drought-stressed forages

Dan Undersander Published on 11 July 2012

The drought has stressed most of the crops we are growing. Most farmers got at least one cutting (and often two). Then stress has reduced growth over the last month.

With the rains we have had most forages will begin to regrow again. The questions we should be considering is how to maximize that growth for good hay, silage or pasture production. Below we will consider the major crops and what actions should be taken.

Much alfalfa has been stunted and is flowering.

1. If stand is over 10 inches tall and flowering, harvest as quickly as possible.

2. If stand is 10 inches or less, leave and let new growth come through (even if short growth is flowering). Mowing will not increase regrowth.

3. Make sure that soil fertility is at optimum levels.

4. New seedings may be harvested in late August if adequate growth is present to harvest. A late-fall cutting may also be taken. The key is to manage so that the alfalfa either has no regrowth at frost or more than eight inches. Six to eight inches of regrowth at frost is the worst possible condition to enter the winter.

Grassy hay fields
Most grassy fields are stunted but are leafy and have few stems.

1. Harvest if tonnage justifies and/or height is over eight to 10 inches.

2. Apply 40 lbs per acre nitrogen to stimulate fall growth if rain occurs before mid-August. This cannot be manure since it will become available too slowly to provide optimum fall growth.

Most pastures are short but are greening up were some rain has occurred.

1. Mow tall weedy or brushy growth.

2. Apply 40 lbs per acre nitrogen to stimulate growth as soon after Aug. 1 as possible.

Corn silage
Many fields are stunted, some have significant firing.

1. Wait to harvest for silage – most plants will put out more growth, all are too wet to ensile now. Check moisture before chopping to ensure excessive moisture does not cause poor fermentation.

2. If grazing, consider nitrate toxicity. This is likely to be a problem if growth was reduced to less than 50 percent of normal and/or high levels of nitrogen were applied.

The nitrate test costs $7 to $10. If above toxic levels feed hay or some other forage in the morning and graze corn a couple hours in the afternoon.  FG

—From University of Wisconsin Cooperative Extension



Dan Undersander
Department of Agronomy
University of Wisconsin