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

Volume 5, Number 2
February 1999


This Month in Ag Connection

image Forage Web Sites:
Mississippi State list  - Great overall site for links to forage and livestock web sites

Alfalfa Council - Good site for alfalfa producers

MU Forage Systems Research Center

Pasture Improvement Strategies
Timing Nitrogen Applications on Pasture
Voice from the Tomb
Swine Enterprise Evaluation Tool
Reducing the cost of Finishing Pigs

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Pasture Improvement Strategies

(Editors note: This article was adapted from the "Forage Systems Update" by Jim Gerrish, Research Assistant Professor, Forage Systems Research Center, Linneus, Missouri. The complete article is available on the Internet at or can be obtained from your local University of Missouri Extension office)

Pasture improvement can be broadly divided into four management areas: fertility, species diversification, weed control, and general grazing management.

Pasture Fertility

Fertility management can be fairly straightforward with single species pastures, but is more challenging in mixed pastures. In a mixed pasture, the fertility level must be adequate to support the desired grass or legume in the mixture with the highest fertility requirement. Native fertility of the pasture may be adequate for all species present, but is frequently below par for the more desirable species.

Most cool-season grasses will persist and be productive at soil pH of 5.5 and P-1 soil test of 20 pounds available P/acre. Most legumes will respond dramatically to higher fertility levels (Table 1). Lime and fertilizer applications benefiting legumes are usually cost effective. A cool-season grass-based pasture with a well-established legume stand (40 to 60% of the annual forage production) will yield as much forage dry matter as the grass alone receiving 100 to 200 pounds of N per acre.

Table 1. Minimum soil test levels used at FSRC for legume establishment and maintenance.

Legume species








Red Clover




White Clover




Birdsfoot Trefoil








Soil testing is a key tool for determining the basic level of nutrients in the soil and is an appropriate starting point for soil nutrient management. Due to the nutrient redistribution patterns of grazing cattle, soil sampling in pastures is not as simple as in crop fields. Avoid testing within 100 feet of water or shade as well as locations where animals tend to loaf due to air drainage or shelter.

Sample the pasture in segments of similar topography to get a true picture of the nutrient status of the pasture. After the fertility status of the pasture has been mapped out, fertilize accordingly.

If the fertilizer budget is limited, target the lowest nutrient areas first. Plant response to fertility is a diminishing curve. The lower on the nutrient availability curve an area of the pasture is, the greater response per unit of applied lime, P, or K.

Pasture Species Diversification

Changing the grass/legume mixture in a pasture can result in increased animal output due to the following:

  • Persistence may be of the greatest economic importance due to the high cost and land erosion potential of reseeding pastures. If a new variety is in fact superior to an existing variety, and is at least as persistent, adding the new variety to the pasture may be cost effective. If a new variety is less persistent than the existing pasture, the improved annual animal performance or production must be significantly better than the older variety.
  • Solar energy collection by a mixed plant species is more effective than by a single species stand. A basic goal of grazing management is to harvest as much solar energy per unit area as possible to maximize the production of quality livestock feed. Grass leaves are typically vertical or steeply inclined, allowing sunlight to penetrate deep into the canopy. A lot of the sunlight reaches the soil and the food production potential of that sunlight is wasted. By adding legumes with more horizontal leaves or grasses with softer leaves, more solar energy is trapped.
  • Production distribution is improved because different species have different growth requirements. Some plants grow better at one time of the year than others. Through diversification, a pasture is more likely to have some plant green and growing, producing quality livestock feed more days of the year.

Weed Control

Weeds are almost always a symptom of inappropriate fertility or grazing management. Weeds do not crowd out pasture plants. The pasture plants are thinned, either through low fertility or improper grazing, and weeds take their place. A healthy, densely growing, vigorous pasture is the best weed control strategy available. However, we should address the symptoms as we try to cure the problem.

For non-woody weeds like pigweed, lambsquarter, and ragweed, heavy concentrated grazing followed by clipping is often the most economical control strategy. One of the greatest concerns about chemical weed control among pasture managers is the loss of legumes from the pasture if broadleaf weeds are sprayed. There are some bio-controls, such as thistle head weevils and a virus in roses, that will greatly reduce the infestation of these weeds. These are usually quite effective in the long haul but may not give the quick-fix that some managers are looking for. Chemical control should generally be used only for those weeds which are truly unpalatable such as thistles and multi-flora rose.

If chemical control must be used, allowing pastures to rest at least 45 days in midsummer will allow clovers and birdsfoot trefoil to set seed. Spraying in the fall while new thistles are in the rosette stage is an effective time for control. If mature legume plants are killed by the herbicide, a seed crop has been produced to allow reestablishment the following spring. Often, rosettes can be sprayed again in the spring before new legume seedlings have emerged.

Broadleaf weeds such as ironweed and goldenrod can be controlled with a sponge or rope-wick applicator when they are above the height of the desirable pasture. Plan to apply herbicide prior to bloom stage of perennial weeds for good control. Follow all label grazing restrictions whenever using a herbicide on pasture.

With any form of weed control, timing is critical. Many weeds have a narrow window of opportunity for control - with or without herbicides. For annual weed management the goal is prevention of a new seed crop. Perennial weeds must either be killed or weakened to the point that they are no longer a problem.

Grazing Management for Pasture Health

The best strategy for improving pastures is to implement a well planned grazing management system that maintains proper stocking rate on the pasture and provides a rest period for individual plants to maintain their vigor. A planned grazing program helps maintain N-fixing legumes in the pasture to supply free N into the system. Manure distribution can also be managed to minimize the needs for purchasing additional P and K.

The healthy pasture will better compete to prevent weed seedlings from establishing in open spots where sunshine reaches the soil surface. Even though this article discussed fertility, diversification, and weed control as separate components, they can be managed most efficiently if considered from the whole pasture- livestock system perspective.

Author: Jim Gerrish, Research Assistant Professor and Valerie Tate, Research Associate

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Timing Nitrogen Applications on Pasture

Consider a typical N fertilizer program for a cool-season grass pasture —

A common practice is to apply 60 to 80 pounds/acre in early spring and 40 pounds/acre in late summer. This results in excessive spring pasture growth and an early maturing forage pattern. In the best case, we harvest the surplus as hay or clip the pasture. More likely, we falsely believe that the excessive growth can be effectively used later, but this over mature forage has little nutritional value.

An alternative approach may be to graze for a month, clip emerging seedheads early, and then apply 40 pounds/acre of N to stimulate post-heading tillering. The results are more even distribution of yield through the spring and early summer, a higher quality forage in early summer, and less clipping — all for less money spent. The forage dry matter yield response per pound of N to the later 40 pounds may not be as great as it would have been for the earlier application, but more of the yield will be leaf and less stem for the post-heading application. Plus, the economic value of a pound of forage in summer is greater than that of a pound in the spring.

A scenario for grass-legume pastures could be to use 40 to 60 pounds/acre N fertilizer on a quarter of the pasture area to stimulate early growth in part of your grazing system. Use of N on a grass-legume pasture in the spring is not detrimental to the legume if the grass canopy is being grazed off during the early growth flush. Applying the same amount of N to a grass-legume mix in the spring and allowing it to grow to hay stage is usually fatal for legumes.

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Voice from the Tomb

There are a number of versions of a marketing story often referred to as "The Voice from the Tomb." One version concerns a very successful commodity trader. The trader never told his secret and kept it locked away in his safe, but promised his family that they would get it after his death. After his funeral, the heirs gathered and anxiously opened the safe. They expected to find volumes of complicated manuals and formulas. Instead, they were surprised only to find a small slip of paper in the back corner of the safe. Written on the paper were these instructions, "Buy corn in October, January, May and August. Sell corn in December, April, June and September."

Market prices tend to form seasonal patterns that are repeated year after year. The trader simply used this seasonal pattern. Corn prices are typically low at harvest time (October-early November). Prices then usually rally into late November or early December after harvest is complete and end users begin needing corn. Prices often fall in January and February as stored crops begin moving to market. As the market begins to "bid for new crop acres" and planting concerns arise, prices tend to increase in April. Prices then decline as the crop is planted and gets off to a good start in May. Crop problems or dry weather can produce a price rally in late June or early July. Prices typically fall through late July and August as the markets begin to anticipate the coming new crop. A late season rally may occur in September as the market bids for remaining old crop supplies prior to the new crop harvest.

Seasonal patterns are useful for setting time goals in marketing plans. Seasonal patterns provide clues as to when marketing opportunities might occur. They also suggest periods of the year to avoid for making sales. Seasonal patterns occur every year in most agriculture commodities. Unusual events (drought, flood, politics, etc) can distort them, but they are usually still there. Knowing these patterns can help to plan for a time when sales may be made on determining how much longer the crop may have to be stored.

Seasonal patterns aren’t very useful for setting price goals. Price peaks may occur at one of the seasonal highs, but not necessarily. The patterns only suggest that prices may be higher at one time of the year than they are at another time. They don’t suggest how much higher or if that high will be higher or lower than prices were earlier in the year. For example, seasonal patterns don’t necessarily mean that prices in June will be higher than they were in January or April (although they can be). However the patterns suggest that prices in June are often better that they were in late May or will be in late July. In this case, it would be very risky to store corn into July (hoping for higher prices) if the seasonal price trend is down.

Seasonal trends don’t provide all of the answers, but they are useful for making marketing plans for both old and new crops. The trends suggest when pricing opportunities may occur and times when it will probably be best to avoid sales. (Melvin Brees, Farm Management Specialist)

Author: Melvin Brees, Farm Management Specialist

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Swine Enterprise Evaluation Tool

With market hog prices in the trash can, many producers are trying to decide if they are going to continue in swine production. Central Missouri farm management and livestock specialists have a tool which can help producers objectively evaluate the viability of their swine enterprise. An hour or so spent completing this evaluation tool and then discussing the results with your extension specialist could be very helpful as you try to make this important decision.

For more information contact any of the following specialists at the extension office listed after their name: Melvin Brees - Howard, Bill Buehler - Morgan, Cindy DeOrnellis - Osage, Parman Green - Carroll, James Rogers - Benton, Mark Stewart - Callaway, Mary Sobba - Audrain, or Don Utlaut - Pettis.

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Reducing the Cost of Finishing Pigs

One step which some producers may find useful in reducing feed costs for the finishing pig is to sell pigs at the lower end of the packers’ zero sort loss range. If you have typically been marketing 280 pounds, finding shackle space for your pigs when they weigh 240 pounds can save a significant amount of feed.

Feed efficiency for pigs growing from 180 to 240 pounds typically averages 4 pounds of feed per pound of gain. As finishing pigs exceed 240 pounds, feed efficiency drops considerably. Feed efficiency for finishing pigs growing from 240 to 280 pounds averages about 6 pounds of feed per pound of gain. Reducing market weights by 40 pounds should save at least 240 pounds of feed. If your finishing diet is costing you $8 per hundred, then reducing market weight by 40 pounds could result in $19.20 per pig feed savings.

Another step many of you may have taken already is to reduce the quality of your diets (lower quality/lower price). Usually when a lower quality diet is used, pig performance suffers and the length of the feeding period will increase. If this lower quality diet is combined with a lighter market weight, finishing floor space will not become a problem. (Source - Mizzou Pig Pages)

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University of Missouri ExtensionAg Connection - February 1999 -- Revised: April 20, 2004