Keith D. Johnson, Forage Specialist
Department of Agronomy, Purdue University
West Lafayette, IN 47907-1150
Situation: Mother Nature wasn't kind to forages grown for the purpose of feeding ruminant livestock and horses in many regions of Indiana this summer.
Response to the situation: What can be done to reduce or alleviate the stress caused by the lack of rainfall?
1. Assess the forage stand. Response to the drought will be quite variable across the state, county, and even within a farm. It is important to put on your walking shoes, or to take a slow ride on your all-terrain vehicle or horse to know what hay field, pasture or paddocks within a pasture are most damaged. Carefully identify the plants that you see and make sure that they are truly forages and not weeds. Web site http://www.agry.purdue.edu/ext/forages/forageid.htm should be helpful in identifying common forage species grown in Indiana.
The forage species in the field at the onset of the dry weather and how they were managed will dictate to a great extent how well they will recover when rainfall does occur. If the pasture today is predominantly Kentucky bluegrass and wild white clover, this is a good indicator that the pasture has been overgrazed over many years and evolved to these species. Location of their growing points permit them to survive close grazing, but the productivity of these pastures is not as great as some other forage species.
I am a stronger proponent of rotational stocking, and alfalfa and low-endophyte tall fescue as components of a pasture system after weather events like this year because they are more drought tolerant than many other commonly grown forage species (e.g. perennial ryegrass, white clover, and red clover). If livestock were removed from the pasture and fed hay in a drylot environment, or restricted to a paddock and not the entire pasture then damage to plants will be minimized.
It is my opinion that the base pasture system for Indiana should be an adapted cool-season grass and legume. If there are fewer than 2 legume plants per square foot in the pasture or the only legume component is wild white clover, then this pasture should be a strong candidate for seeding legumes in the late winter. If the soil surface is visible, then an adapted cool-season grass should be sown, too. As a guideline, an alfalfa hay field should have greater than 40 stems per square foot to be considered economically viable.
2. What is the fertility of the soil? If you don't know, then the soil should be sampled by soil type and management system imposed so the amount of needed nutrients and limestone can be applied. Resist applying amendments without knowing the amount that is needed; one of my "pet peeves" is the recommendation of applying "X" lbs. of triple 12 or triple 16 by fertilizer retail firms. A sound soil fertility program is fundamental to a productive pasture program. If a soil test is needed, get the task completed immediately. Based on an alfalfa fertility research study at the Throckmorton-Purdue Agricultural Center, the best time to assess exchangeable potassium level in the soil is in the summer or autumn. Much potassium is released from potassium-holding clays over the winter months and elevated levels are measured with a late winter or early spring soil sampling.
3. When improving a weak stand, select adapted forage species, best varieties and seed before dormancy break in the spring. Broadcasting seed can be effective if the existing forage residue allows most of the seed to come in contact with the soil. Remember to inoculate legume seed with the rhizobia-specific inoculant. Do not mix red clover and alfalfa seed together. The red clover will be more aggressive as a seedling and will predominate the stand. Do not mix cool-season grasses and legumes in a broadcaster, as the spread pattern will be quite different. Do not try to overseed an existing alfalfa field with alfalfa, as establishment results can be poor because of allelopathy (autotoxicity). Red clover is a viable option if trying to extend the useful life of the hay field for a couple more years. If using a no-till drill, make sure that seeding depth is shallow, less than one-quarter inch.
Another one of my "pet peeves" is use of a prepackaged forage mix that has many forage species in the bag. Resist the temptation of using these mixes as you lose some control of the seeding process (e.g. best species adapted to the site, variety selection, and ratio of species).
4. Rotationally stock (graze) the pasture. Continuous stocking results in inefficient pasture use and can weaken a pasture because of little rest for the forage to recuperate from livestock grazing. Advancements in fencing and delivering water to paddocks should be considered so pasture quality, persistence and utilization can be improved.
5. Winter-annual weed control in alfalfa. If winter-annual weeds become prevalent in an alfalfa hay field this autumn, consider applying a herbicide that will be most effective for the targeted weed pest(s). Most herbicides labeled for this purpose should be applied after the alfalfa is dormant in the autumn and before break of dormancy in the spring.
6. Control alfalfa weevil and potato leafhopper at appropriate times to reduce additional stress to alfalfa. If economic thresholds are reached, then these pests should be controlled with an insecticide or alfalfa harvested if it is past the late bud stage of plant development. Results from a Purdue University Agronomy Research Center trial indicate that lack of control of the potato leafhopper when at a high population in the seeding year can reduce the yield of both susceptible and potato leafhopper resistant alfalfa varieties the year after seeding.
ANSC Beef Page