Ag Connection
Your link to the Universities for ag extension and research information

This Month in Ag Connection
How to Re-Do Pasture or CRP Land
Tiller Dynamics
Grazing Schools in Central Missouri
ALS Resistant Foxtail Found in Minnesota — Missouri Could Be Next
Cool Season Vegetable Crops Training Session
May 1997
Volume 3, Number 5

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Publishing Information
Ag Connection is published monthly for Central Missouri Region producers and is supported by University Extension, the Commercial Agriculture program, the Missouri Agricultural Experiment Station and the College of Agriculture, Food and Natural Resources, UM-Columbia. Editorial board: Maryann Redelfs, Managing Editor; Parman Green, James Rogers, Mark Stewart, Melvin Brees, Don Day and Ron Alexander.

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Please send your comments and suggestions to Maryann Redelfs, Agronomy/Information Technology Specialist, University Outreach and Extension, 608 E. Spring Street, Boonville, MO 65233, call 660-882-5661, or send messages by e-mail to:

To send a message to an author, click on the author's name at the end of an article.

How to Re-Do Pasture or CRP Land

Does your pasture give out when you need it most? Does it fall short on quantity or maybe quality too? Want to avoid losing a season’s grazing during renovation? If you tore up the sod, would the top soil wash away? You can “have your cake and eat it too.” Sure, Mother Nature has to cooperate with a little rain — just like any new seeding.

Here is the recipe:
- Take a soil sample now
- Harvest hay or pasture short (2 to 4 inches) by May 20
- Wait for 2 to 3 inches of new growth
- Apply 1 quart of Roundup or 1 quart of Gramoxone
- Apply fertilizer and especially agricultural lime
- Plant a smother crop immediately, for pasture use a summer annual
- Begin grazing when 16 inches tall
- Rotational graze for the summer
- Apply 1 quart of Roundup or 1 quart of Gramoxone on September 20
- Plant alfalfa or your favorite grass and legume

It takes about 4 to 6 months for the limestone to react with the soil, so it is important to make the correction, if needed, well ahead of legume planting. By pasturing up to mid-May or mowing for hay, most of the cool season grass production is completed. This allows time for planting soybeans or grain sorghum if a grain crop is desired, or sorghum-sudan if pasture is your choice.

A grain crop probably means forage seeding will be delayed until the next spring. Just plant wheat in the fall and plant the forage in the spring. The May 20 date keeps the grass seed from maturing and shattering — causing recontamination.

The smother crop is important. It will help the Roundup or Gramoxone burndown and reduce infestation of undesirables. The regrowth will provide new tender material to absorb the burndown chemical. A surfactant must be used with both the Roundup and the Gramoxone. Lorsban 15G, used at 6.7 pounds per acre, has been proven to increase the viability of the new forage seeding. The best way to incorporate the Lorsban into the soil is to simply mix and plant with the seed. This will complicate calibrating the planting rate but can be done. No-till drills have worked very well in the past. Be sure to inoculate the legume seed.

Forage Renovation on Video
To borrow a copy of the video "No-Till Forage Establishment", contact your University Extension Center.

This procedure needs only slight modification to adapt to spring planting. The burndown herbicide should be applied near the end of October. Cool season grasses such as fescue are easier to kill in the fall, but must not have reached winter dormancy. One to 1 pints of the burndown material will be sufficient. When planting time arrives in the spring, reapply the burndown herbicide to control newly emerged winter annuals and any plants surviving the fall application.

Renovating CRP into more productive and profitable forages, such as pure alfalfa, requires the same procedure. Again, using the no-till drill will be most satisfactory. The accumulated growth and deadfall from past growth will need to be removed to allow soil penetration of drill coulters and give good seed-to-soil contact.

Author: Ron Alexander, Agronomy Specialist

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Tiller Dynamics

"Manage for maximum leaf production to maximize forage quality." This rule of thumb has been used for years. The principles that make this true are really quite simple and worth a short discussion.

The basic unit of forage production is a tiller, which is composed of leaf blades and leaf sheaths, stem, and sometimes a seedhead. Most tillers originate from the crown of the plant (near the soil surface), and new leaves are pushed up through surrounding sheaths of older leaves. Most forage grasses will produce between 5 and 10 leaves per tiller. The last leaf to emerge is the flag leaf. The flag leaf precedes the emergence of the seedhead and is recognized by its peculiar orientation, generally parallel to the ground.

However, not all tillers become reproductive and produce a seedhead. Seedhead production varies from species to species and seasonally within species. Tall fescue makes a good example. Most spring growth tillers, in response to temperature and day length, produce seedheads. Fall growth tillers generally remain vegetative. In some cases there are also varietal differences in seedhead production within a species, as common verses Coastal bermudagrass.

New tillers originate from basal buds, a form of specialized plant tissue. If growing points are removed by grazing or cutting, no more tillers are produced. Many of the forage grasses have growing points at or slightly below the soil surface; most notably bluegrass and tall fescue.

Individual tillers are relatively short-lived, even on the perennial forage plants. Individual tillers often live for only 5 to 10 weeks, then die. A corn tiller (stalk) is an easy to visualize example. The tiller grows, producing leaves, then turns reproductive, produces a seedhead, matures the seed, then the tiller dies. A bermudagrass, switchgrass, or tall fescue tiller does the same thing, with the exception that some of the tillers die without becoming reproductive. This gives rise to another management principle — "Use it or lose it."

Influence on Forage Quality

As the grass tiller changes from vegetative growth (leaf production) to reproductive growth (seedhead production) the plant goes through rapid physiological changes. Typically seedheads are located high on the plant which allows seeds to be dispersed over a wide area. Plants evolved with this characteristic. It allows them to reproduce more effectively as the wind, birds and animals help disperse the seed. This is seen as the stem elongates, called jointing in small grains. To hold the seedhead up the stem must become more rigid, stronger, stiffer, or tougher. These words should be telling you that digestibility or forage quality is decreasing. Fibers in the stem are converted from more digestible material to lignin, which is very indigestible. This general process of fiber conversion is occurring in all forages as they mature or age, even if the individual tiller does not become reproductive.

If the tiller is producing a seedhead, several other changes are occurring in the plant. The nutrients to fill the seed are translocated (moved from) the leaves on the tiller. These nutrients include protein, minerals, and carbohydrates such as starches and sugars. The bottom, or oldest leaves on the tiller are the first to have nutrients translocated to the seedhead. When producing a grain crop, such as grain sorghum or wheat, we speak of the bottom leaves "firing." That means the leaves are senescing or dying.

The translocation of nutrients is a great process when producing grain such as corn, wheat, or grain sorghum. However, most grass seed, including grain sorghum and the small grains, but especially the forage grass seeds, are relatively indigestible when fed whole and are generally passed through the grazing animal and consumed by birds!

This gives us two management principles to help keep forage quality high, although they are almost the same. First is to harvest (graze or cut for hay) before seedheads are produced. The second is to utilize the forage in a way that maximizes the leaf:stem ratio. This simply means to maintain a greater proportion of leaves compared to stem.

Influence on Forage Quantity

On a per tiller basis, forage quantity (tonnage) increases as new leaves emerge. In general, maximum dry matter yield per tiller will occur somewhere between flag leaf and flowering (keep in mind that the plant must flower before the seed is formed so we are talking about the time before grain filling, soft dough, etc.). However, maximum digestible nutrient yield almost always occurs at or before flag leaf.

Yield per acre increases as tillers grow, but mainly yield increases as the number of tillers per acre increases. New tillers are produced in response to several actions. Generally, removal of top growth will stimulate tillering, as long as the basal bud is protected. Proper fertility is needed for maximum tiller development, as is reasonable moisture.

Energy is used by the plant to develop new tillers. This energy comes from carbohydrates stored in roots and the lower stem bases. The new tiller uses this stored energy to ‘feed’ the new growth until it develops enough leaf area to produce its own energy or food from the sun by photosynthesis. At that point the depleted root energy is replaced.

Depleted root energy reserves slow new tiller development. Therefore, proper defoliation management to keep root energy reserves replenished will maximize new tiller development and increase yield per acre.

In most forage grasses some sunlight needs to strike the basal bud to initiate new tiller development. This principle is the reason yield per acre can actually decrease if the defoliation period is too long. The grass actually mulches itself so to speak. Heavy growth does not allow sunlight to the growing points, bottom leaves are senescing, seedheads are forming, and with no defoliation and removal total yield per acre decreases; and forage quality has already gone to pot.

This knowledge gives us two management principles to increase yield. Do not defoliate so frequently that root energy reserves are not replenished; stated another way, allow the forage plant time to grow with no grazing so that energy is moved to and stored in the roots. The second principle is to defoliate before the plant becomes decadent and few new tillers are being produced. This usually coincides with seedhead formation, and/or when a good percentage of the bottom leaves are senescing. This is the primary principle that rotational grazing is based on.

The Compromise

From the above discussion it should now be obvious that you cannot have both MAXIMUM yield and BEST quality. However, the fact that yield increases with time (maturity) and forage quality decreases with time does give us a management principle to meet livestock nutrient requirements. A dairy cow producing 50 lbs milk/day, or stocker steers gaining 3 lbs/day must be consuming immature vegetative forage to meet these production goals, and you will not be able to produce maximum tonnage of forage.

At the other end of the spectrum are your out of breeding season bulls, and that slightly overweight pleasure horse. These animals can do just fine on older more mature pastures, or hay that was cut late. The nutrient requirements of these classes of livestock are lower and therefore the pasture can be managed for a higher yield; or as may often be the case, the low quality hay can be fed to these animals.

Understanding tiller growth and development is the key to proper defoliation management. Pastures should be grazed and hay should be cut to produce the desired or needed forage quality, with an understanding of the influence that defoliation has on forage yield. It is also important to try to provide the best quality forage to animals which have the highest nutritional requirements.

A final admonishment:  there is never a good reason to manage your pastures and hay fields at the extremes. In very immature stands, do not cut or graze before root energy reserves are replenished; and further, do not let stands become so mature that yields are not increasing or even worse, have started to decline.

James Rogers, Livestock Specialist, Source: Bruce Pinkerton, Extension Agronomist, Clemson University

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Grazing Schools in Central Missouri

Location Date Contact
Mexico June 26-27 Mary Sobba (573) 581-3231
Russellville June 2-3 Gary VanDeVelde (573) 893-5188
Higbee June 9-10 Cheryl Livingood (573) 875-5269
Hillsboro September 9-10 Franklin Co. SWCD (314) 789-5391
Salem June 26-27 Jim Freeman (573) 729-3196
Marshall May 28-30 James Rogers (660) 438-5012
Boonville June 24-25 James Rogers (660) 438-5012
Lafayette Co July 8-9 James Rogers (660) 438-5012
Sedalia August 5-6 James Rogers (660) 438-5012
Lincoln August 26-28 James Rogers (660) 438-5012

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ALS Resistant Foxtail Found in Minnesota — Missouri Could Be Next

Foxtail biotypes, including Giant Foxtail, resistant to the ALS inhibiting herbicides Accent and Pursuit, have been found in Minnesota and have the potential to become a problem in Missouri. We use many of the same herbicide programs and rotations.

Weed management strategies need to be deversified to prevent herbicide resistant weed problems. In soybean, if you favor total postemergence herbicide programs, change your soybean grass herbicide program to another mode of action (e.g. Roundup Ultra with Roundup Ready Soybeans or the lipid synthesis inhibiting post grass herbicides).

If you find the total postemergence option less than desirable, consider using a preplant incorporated herbicide such as Treflan, Prowl or Command and then follow with an appropriate postemergence program.

In corn, total postemergence options may involve some of the new herbicide tolerant crop technologies such as Liberty Link or Sethoxydim Resistant Corn.

Another option would be to use a preplant incorporated or preemergence grass herbicide (i.e. any of the acetanilide herbicides and/or cyanazine ) followed by an appropriate postemergence program.

For both corn and soybean, consider integrating your herbicide program with inter-row cultivation or altering the crop rotation to crops that are less dependent upon ALS chemistry (e.g. alfalfa). Both the alfalfa rotation and including cultivation are useful because they prevent a lot of weeds that escape initial treatment from going to seed.

Although only some of the possible alternative weed management practices are listed here, diversifying weed management practices is the key to preventing and dealing with herbicide resistant weed problems. For more information, request Herbicide Resistant Weeds NCR 468, from your local University Extension center.

Authors: Bill Johnson, Extension Weed Specialist, Commercial Agriculture and J.L. Grunsolus, Extension Agronomist, Minnesota

For more information, go to International Survey of Herbicide-Resistant Weeds Web Site at

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Cool Season Vegetable Crops Training Session

Saturday, May 31 — 9:00 a.m. to 3:00 p.m.
Evans’ Funny Farm — 1995 Halifax Road, Holts Summit

Field demonstration and hands on exposure with raised beds (22,000 square feet) intensive production, interplanting, harvesting and marketing of cool season vegetable crops. Visit with a local chef and grocery chain produce manager.

No course fee. Lunch provided.
Registration required and limited to 25 participants.
Register with the MO Alternatives Center at 800-433-3704.

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University ExtensionAg Connection - May 1997 -- Revised: May 9, 1997