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Steps to Improve Forage Productivity Following the Dry Summer

The Question

Mother Nature wasn't kind to forages grown for the purpose of feeding ruminant livestock and horses because of droughty conditions during the summer of 1999. What can be done to reduce or alleviate the stress caused by the lack of rainfall?

My Response

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 this autumn 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 winter-annual weeds like chickweed or downy bromegrass.  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 have recovered with some of the recent rainfall.  If the pasture today is predominantly Kentucky bluegrass and Dutch 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 Dutch white clover, then this pasture should be a strong candidate for seeding legumes in the late winter of 2000.  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 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. Winter-annual weed control in alfalfa.  If winter annual weeds are prevalent in an alfalfa hay field, consider applying an 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.

4. Stand improvement. 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 as 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 seed 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). 

5. 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.

6. Control walfalfa weevil and potato leafhopper to reduce 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.

Back to Forage Issues

Keith Johnson
Professor of Agronomy and Forage Crops Specialist
1150 Lilly Hall of Life Sciences
West Lafayette, IN 47907-1150
phone: 765-494-4800
fax: 765-496-2926



For more forage information contact Dr. Keith Johnson: johnsonk@purdue.edu

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