June 6, 2008

Tornadoes, floods, hail, excessive rain, and other weather calamities are creating crop disasters across the region. In many fields, replanting or delayed plantings are going to be needed. In some cases, planting a grain crop may be nearly impossible due to herbicide carryover, the late planting date, or lack of seed. As a result, annual emergency forage crops might be your only choice.

Before selecting any crop to replant as forage, be sure to check the label of the herbicides used previously. Many herbicides have restrictions and limitations on grazing or feeding forage grown in their presence.

In addition, unless only glyphosate was used, other herbicides can injure forages. Many herbicides for corn and milo will injure pearl millet and foxtail millet. The tolerance of teff to herbicides is not well known but probably similar to the millets.

Sudangrass, forage sorghum, and sorghum-sudan hybrids will tolerate moderate levels of atrazine. Safened seed can be used if herbicides based on metolachlor or s-metolachlor have been applied. These sorghums also tolerate most herbicides labeled for use with grain sorghum. Another possible emergency forage crop is short-season corn as silage or even drilling bin-run corn for late season pasture or hay, especially if corn herbicides eliminate other possibilities.

Soybean herbicides other than glyphosate cause even bigger problems for replanting to forages. All summer grasses are sensitive to most soybean herbicides other than glyphosate. Sunflowers for silage and soybeans for hay or silage are among the few alternatives compatible with soybean herbicide carryover.

In addition to identifying annual forages that will tolerate previously applied herbicides, also consider how you'll use what you plant. For grazing, sudangrass, sorghum-sudan hybrids, pearl millet, and corn often are the best choices. For hay, sorghum-sudan, pearl millet, foxtail millet, and teff are commonly used. Forage sorghum, corn, and sunflowers usually are the better silage options.

A final option is to wait until late July to early August before planting fall and early spring forages. Oats and turnips have little tolerance to carryover herbicides but, if adapted, can produce large amounts of late season forage for grazing; oats also can be cut for hay or silage. Winter small grains like rye and triticale also can be planted early to produce fall forage for grazing and/or abundant early spring forage.

Nobody likes to replant, but if you must, select a forage that is compatible with your herbicides and livestock.

Bruce Anderson
Extension Forage Specialist