By Zachary Curtis and Andrew Frankenfield et.al
After stretches of droughty weather, producers might wonder if their forages have died or gone dormant to save themselves. From the road, fields might appear to be a total loss. Taking time to scout fields and carefully inspect plants will tell us whether fields have been lost.
Make Sure You Know What You're Looking At
This may sound redundant, but properly identifying forage species and weeds in our fields is the first step to determining the viability of a stand. If a field was recently planted to common forages like orchardgrass, tall fescue, alfalfa, or small grain, make sure that the plants that look dead are desirable forage species. A large patch of dead material may actually be foxtail, nimblewill, wirestem muhly, or other weedy species common in hayfields or pastures. In that case, we'd expect them to die in late fall. This Forage Identification and Use Guide from the University of Kentucky contains pictures and descriptions that are helpful in identifying most of our common forage species.
Dig Up and Inspect Forages
Once you've identified the species that should be present, take a trowel and dig up individual plants. Carefully inspect the leaves for signs of green, living tissue. Look for living tissue at the crown, stem, and root of the plant - living tissue should appear firm, have a bright white color, and fully occupy the space within the crown or root. Dead or dying tissues will have a mushy, limp, or crispy appearance, may appear yellow or brown in color, and may have voids in the crown where tissue has been rotting. For alfalfa stands, the same principles in Winter Injury and Spring Assessment of Alfalfa can be used to determine if drought-stressed alfalfa crowns are still viable.
For many of our forage crops, the crown contains meristematic cells responsible for producing new stems or tillers at the beginning of the next growing season. A healthy crown can also grow new roots or rhizomes to help replace structures that may have died from drought stress. Look for living tissue that will support regrowth after moisture returns and the plants break dormancy.
Conduct a Bag Test
If you're still unsure if the plant is alive, you can conduct a simple viability test with a plastic bag and a little water. Dig plant samples and rinse roots clean of soil. Trim any existing stem or leaf tissue to about one inch above the crown, and trim off all the root material. Moisten the plant with cool tap water. Place several trimmed plants in a plastic bag and store them for 2-5 days at room temperature and out of direct sunlight. If the crown is still viable, you should see new root and stem tissue emerge within several days. If there is no new regrowth after 6 days, the plant has died.
Make Contingency Plans
Hopefully, after going through this process, you will find some plants in your stand that are still viable and can provide good growth next season. However, if you've found that a significant part of the stand has died, begin planning to reseed that field or rotate it to another crop. Stands that are thin can leave room for weed infestation and reduce the profitability of harvesting that field. This would be a good time to consider reserving replacement seed, planting equipment, burndown herbicide, or other materials needed to replant a damaged stand.
During and following drought, fertility and crop quality concerns can arise. Consult Forage Fertility and Quality Issues During Spring Drought for management guidelines in these situations.
If you've noticed a long-term decline in the productivity of a forage stand, review good management practices that support economical yields. Successful Forage Crop Establishment is a good review of practices vital to establishing a competitive forage crop.
If fall and winter losses are a concern, review How Late Can Cool-Season Perennial Forages Be Planted? for some considerations on planting deadlines for the following spring. Be cautious in managing pasture and grazed crops -Evaluating and Maintaining Pastures in Dry Conditions provides good principles for pasture management in dry situations.
Source : psu.edu