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368 Ag Hall OSU Plant & Soil Sciences Department Stillwater, OK 74078 |
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| November 1998 | Volume 22 No. 9 |
NEWS |
CONTENTS OF NEWSLETTER
OTHER LINKS |
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We welcome contributions and suggestions. Comments about and
contributions to the NEWS are welcome and can be submitted to any of the directors. |
| Dry weather this summer and then heavy rains this fall made it very difficult to get a
good stand of alfalfa. First, there was erratic emergence of alfalfa plants in many areas
of Oklahoma, then some washed-out and/or flooded-out areas with more heavy rains in early
November. It is very important to scout your fields as soon as possible to
determine if you have enough alfalfa plants left to have a stand. I discussed how to do
that in the October NEWS, so see those comments for some detailed information. Basically,
if you do not have 10 alfalfa plants per square foot over the entire area, then you do not
have a full stand and will need to try to thicken it up Many new stands that were planted still have volunteer wheat and some cheat in them, and it is very important to control these grasses this fall if they are currently larger than the alfalfa and starting to shade the alfalfa plants. Most weeds emerged at the same time that alfalfa did, and they will continue actively growing until a hard freeze (10o to 15o F). These grasses can still be control this fall with herbicides, providing we get a warm day sometime in November or early December. For best results, spray weeds on a sunny day (shirtsleeve weather). Herbicide choices for controlling volunteer wheat and other grasses in fallplanted alfalfa include fall applications of Poast Plus and Select 2 EC. Select 2EC received label clearance for use on alfalfa for control of weedy grasses on April 6, 1998. Volunteer cereals, some of the bromus species, and ryegrass are listed as controlled with 6 fl. oz/acre when plants are 26 inches tall. We had one experiment where we compared cool-season grass control with Select 2 EC and
Poast Plus. Control of wheat and ryegrass in that study was "good to excellent"
with both herbicides, but control of downy brome was only "fair". Control of
cheat and rescue-grass was "good to excellent" with Poast Plus and only
"fair" with Select 2 EC. I would recommend trying For control of most broadleaf weeds (including seedling dock), use of Butyrac (2,4DB) in the fall is the best choice. However, it is very important to spray weeds in the fall while they are small and in the rosette growth-stage. Many of the weeds are not controlled with spring applications of Butyrac. Shepherd's purse and treacle mustard are seldom controlled with spring spraying of Butyrac, and producers are usually very disappointed with spring spray results. That's why it is so important to examine fall-planted alfalfa now and get them sprayed this fall. See my Guidelines in the September NEWS for recommendations based on Weed Status determined by Scouting for more details on when to spray and not spray. |
--Jim Stritzke |
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This is the final of several brief articles containing information from a study partially funded by AMSUSDA to examine potential markets for alfalfa hay. This newsletter specifically covers the implications for Oklahoma alfalfa producers. Implications for Marketing Alfalfa from Oklahoma The previous newsletter indicated that model results suggest all higher quality alfalfa
produced in Oklahoma should be shipped to Texas and most lower quality alfalfa should be
fed in Oklahoma. We used the model to assess market potential for Oklahoma-produced
alfalfa. First, alfalfa production in Oklahoma was increased 20 percent above the 1995
production level, assuming a constant 33-67 percent split between higher and lower quality
alfalfa, respectively, and no change in demand. This first alternative was to consider a
supply change effect. Second, we considered Results for an assumed 20 percent increase in Oklahoma alfalfa production are interesting in that total exports from Oklahoma increase, but the composition of exports changes. In the base model, Oklahoma shipped 433 thousand tons of high quality alfalfa and 95 thousand tons of lower quality alfalfa to Texas for the Texas dairy demand. Another 1,006 thousand tons of lower quality alfalfa remain in Oklahoma to satisfy the alfalfa demand for non-dairy livestock. With the assumed 20 percent increase in Oklahoma's alfalfa production, Oklahoma ships significantly more alfalfa to Texas, both for the dairy and non-dairy demand in Texas. The model indicates that 572 thousand tons of high quality alfalfa are exported to Texas to satisfy the dairy demand in Texas. Another 823 thousand tons of lower quality alfalfa are shipped to Texas to satisfy non-dairy demand, while 338 thousand tons remain in Oklahoma to satisfy its non-dairy demand for alfalfa. Therefore, a 20 percent increase in Oklahoma's alfalfa production, ceteris paribus, results in more of both higher and lower quality alfalfa being exported to Texas than in the 1995 base model. This suggests that increases in alfalfa production would likely increase alfalfa exports to Texas, but not all at dairy-quality alfalfa prices. Some producers have expressed an interest in exporting Oklahoma alfalfa to Mexico. According to our model results, Oklahoma does not have a comparative advantage to satisfy the Mexican demand for high quality alfalfa. We considered shipping all exported alfalfa through El Paso, Texas and also considered shipping all alfalfa through Laredo, Texas. In both cases, New Mexico is the primary supplier of alfalfa to Mexico. The lead author of this study has worked with alfalfa growers in Oklahoma for about 16 years. During that time, Texas and Oklahoma have been considered the primary markets for Oklahoma-produced alfalfa. Our model results confirm the conventional wisdom. Further, our model suggests Oklahoma could increased the supply of alfalfa and supply a larger percentage of the Texas demand. Opportunities exist in unique situations or under special conditions to market alfalfa profitably to other markets (such as Florida, Tennessee, Ohio, Missouri, and elsewhere) besides Texas and Oklahoma. However, on balance, Oklahoma alfalfa growers should concentrate most on satisfying nearby customers in Texas and Oklahoma. Information from: Clement E. Ward, Solomon Kariuki, Raymond L. Huhnke. "Domestic and International Markets for Alfalfa Hay." Oklahoma State University, Department of Agricultural Economics, Final report to AMSUSDA, January 1998. |
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| Young alfalfa plants need time to develop extensive root systems. The root system is
the primary advantage alfalfa has over most other forages, and harvesting new stands too
early can slow the development of the root system. It can be tempting to harvest "rabbit hay" from a new stand in the fall or to graze it. Either of these practices can decrease the productiveness of the alfalfa stand. The most productive stands of alfalfa are generally sown in the fall and harvested about May 1 of the next year. One exception would be grazing weedy areas after a killing freeze (lower than 20o F). This could facilitate removal of weedy grasses which may harm alfalfa by shading. The first flush of growth for first-year plants normally does not bloom. When new growth is initiated from crowns, it is time to harvest. If a severe infestation of weeds exists, then the first harvest should be taken when weeds shade out alfalfa seedlings (normally in mid-April, with cheat). After the first cutting, the stand can be treated as most mature stands. There is little reason to baby or pamper new stands. |
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| For many years we have been told that harvesting alfalfa during the fall is bad. We
believed that stands would decline drastically and the remaining plants would not yield
well. We were told that harvesting alfalfa within a few weeks of the first killing freeze
would be an invitation to disaster. These concepts are correct for northern parts of the U.S. Alfalfa grown in the southern plains is hurt very little (or none at all) by harvesting in the fall of the year O.S.U. researchers have been working with these concepts for 15 years and have identified no particular date that stresses alfalfa any more than others. Frequently it is worth while to harvest late-summer and fall growth. Many fields have 1/2 ton/acre of hay,and some have well over 3/4 ton/acre. There is no reason to waste the forage. Grazing after the first hard freeze is usually the most economical way to utilize fall alfalfa. There is relatively little probability of bloat during this time of year. Generally, alfalfa should be stocked heavily for a short time rather than putting a few animals on a large area for many weeks. The stocking rate should be high enough to clean off all the available forage in 7 to 10 days. Electric fences can be helpful in confining animals to a small area for a few days and then moving them onto an ungrazed area. If cattle are left on an alfalfa meadow for a long time, they start grazing only regrowth from plants that were grazed earlier. This may be about the same (to the plants) as harvesting hay from a meadow every 10 days or so. Some extras come with grazing alfalfa. Perhaps the most important is the removal of stems in which alfalfa weevils lay eggs. If there are no convenient stems for the weevils, they lay fewer eggs and the onset of weevil damage the next spring will be delayed. Grazing may also help clean up fields of weeds. Cattle may kill certain weeds while grazing during the winter or late fall. The act of eating some of the small weeds kills them outright, and cattle hooves tear
up the soil surface enough to destroy others. |
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| A few alfalfa producers plant in mid August and get some nice rains. By mid October
they are tempted to cut or graze the new stands. Generally, this is not worth the risk.
Young alfalfa plants need time to develop root systems. Producers should not abuse young
stands by harvesting or grazing too soon after planting. Being a deep-rooted plant, alfalfa has an advantage of tapping deep moisture supplies, not available to most other forages. Harvesting new stands too early slows development of the root system. In fall it may be tempting to graze or cut "rabbit hay" from a new stand. Either practice can decrease long-term productivity of alfalfa. Most productive stands of alfalfa are generally sown in fall and harvested about May 1 the following year. One exception to this generalization would be grazing weedy fields after a killing freeze (lower than 20o F). This facilitates removal of weedy grasses that harm alfalfa by shading. If weeds are not controlled with herbicides in fall and are "out-growing" or shading alfalfa plants, grazing during winter is an effective way to remove them. In these situations, grazing is less damaging than shading by weeds. The first flush of spring growth on first-year plants does not normally bloom. Harvest should be timed to precede new growth initiated from crowns. If a severe infestation of weeds exists, then first harvest should be taken when weeds become tall enough to shade alfalfa seedlings (normally in mid-April, with cheat). After the first cutting, alfalfa can be managed as a mature stand. The Bottom Line: Harvesting fall-sown alfalfa before spring is a risk. If forage is needed, buy it! It does not make good sense to risk the $150 pre acre, or so, spent on stand establishment for a relatively small amount of forage. For More Information: Alfalfa Harvest Management Discussion with Cost-Benefit Analysis. OSU Extension Circular E-943. -- John Caddel, |
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| Egg lay by the alfalfa weevil typically begins in October of each year after adults
have returned to alfalfa from wooded or weedy areas along field borders and creeks where they spend the summer in an inactive state called aestivation. Eggs are laid in the hollow stems of alfalfa plants that have grown after the last harvest was taken. Numbers of eggs increase throughout the winter until hatching begins in February and March. When stands are cleanly grazed with cattle at relatively high stocking rates (called "flash-grazing") during the period from December to February after foliar growth has been killed by freezing temperatures, 50-70% of eggs may be eaten along with foliar growth. The reduction in eggs often allows a delay of 2-3 weeks in spring before the economic threshold is reached and insecticide must be applied to control larvae. Thus, the numbers of sprays required for weevil control may be reduced, and at times, the need for spraying may be eliminated altogether. --Richard Berberet |
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