The following recommendations are from Keith D. Johnson, Purdue Forage Specialist.
The following are tips to consider as you assess forage needs and forage crop health. Feel free to contact me with questions or concerns. Check with your crop insurance and Farm Service Agency personnel to see if it permissible to seed corn/soybean flooded spots in a field with annual forages if the feed is needed.
If seeding is permissible, review labels of the herbicides applied to confirm what can be seeded without concern of carryover effects.
If soil conditions will not allow seeding flooded spots by late July, I would defer from seeding warm-season grasses like sorghum-sudangrass, sudangrass, pearl millet, foxtail millet and teff to a mid-August seeding of spring oat. Inclusion of a forage turnip might be considered if the acreage will be grazed.
In the above list, teff and foxtail millet are more likely able to be dried for hay. It is difficult to make dry hay in the fall because of shorter days and cooler temperatures. Bale silage could be an alternative storage method to consider if a bale wrapper or in-line tuber is owned or arranged for.
Assess pasture and hay fields for plant damage caused by saturated soils. Dig up several forage plants, especially those challenged by water and assess the wellbeing of the roots and crown by cutting through the tissue. If there is little browning and the integrity of the roots are firm, these would be a good signs.
Also, take note of hoof action (pugging) damage to forages in pastures. Reduce further damage if possible by grazing better drained pastures and paddocks first. Come back to hoof-damaged areas in the field often to assess if forage recovery is occurring. If permanent damage has occurred, plan on reseeding or renovating the field.
Keep in mind, that some alfalfa yellowing may be caused by the insect potato leafhopper and not totally attributed to saturated soils.
If grasses are nitrogen deficient, apply approximately 50 pounds of nitrogen per acre. If the nitrogen fertilizer is applied to cool-season grass dominant pastures by late August this should stimulate grass growth and provide more late-in-the-year grazing days.
Sample stored forages, hay and silage, for quality. Forage quality will likely not be excellent for most this year, because of delayed harvest. Send the samples to a forage testing laboratory and provide the results with a trained nutritionist so rations can be formulated for your livestock. Details about forage testing can be found at www.foragetesting.org.