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NEWS |
CONTENTS OF NEWSLETTER
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OTHER LINKS |
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We welcome contributions and suggestions. Comments about and
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If your fields do not have soil test readings of near 65 ppm for phosphorus, 350 ppm for potassium, and 7.0 for soil pH, lime and fertilizer should be applied at least one year before establish alfalfa. High yielding alfalfa removes large amounts of nutrients from the soil. For best results, both lime and fertilizer should be incorporated into the upper six inches of soil before stand establishment, then monitored by soil testing every year. Before sowing, apply enough lime to neutralize the soil and enough phosphorous to satisfy the crop's needs for at least three years. Annual applications of potassium are recommended for deficient soils. This is a good time to check the fertility for next year’s plantings. If essential nutrients become deficient, or if the soil becomes excessively acidic, yields decrease and the alfalfa stand life may be shortened. Problems with weeds increase on nutrient-deficient soils because of reduced alfalfa competitiveness. Herbicides can control weeds, but alfalfa yields remain low due to soil fertility problems. Liming: It is important to realize that fields with a history of high production of other crops, such as wheat, may not be well suited for alfalfa. For example, wheat grows well at soil pH 5.5, but alfalfa production may be reduced to 50 percent of normal at pH 5.5, and stand failure is likely at soil pH of 5.0.Lime deficiencies can not be corrected after planting because the lime should be thoroughly soil incorporated with the soil. It is necessary for the soil to have in reserve about three to five tons of lime, in order to meet the needs of a five-ton yield for six to ten years without a drastic decline in soil pH. The need for reliable soil testing is obvious, and a program of regular testing cannot be overemphasized. Additional information on soil fertility, sampling procedures, and photographs can be obtained through the Oklahoma Alfalfa Calendar on the world wide web at (alfalfa.okstate.edu). Gordon Johnson, Soil Fertility Specialist, OSU
For Fall-Planted Stands: Hopefully most of you controlled weeds in your new alfalfa this fall while they were small and actively growing. Cold weather has stopped growth of weeds, so it is too late now to control most weeds in stands planted this fall. Some winter weeds can be controlled again this coming March when they start growing. Examples would be cutleaf eveningprimrose with BUTYRAC and ryegrass with POAST PLUS or SELECT. However, do not expect to control shepherdspurse and most of the other broadleaf weeds with BUTYRAC or most of the winter grasses with POST PLUS or SELECT applied in March. If you did not do a good job of weed control while it was warm, you will need to cut weed-infested fields early in the spring to minimize the weed shading damage to the alfalfa. Established Stands: One of the positive things that a number of producers are now doing to increase their profitability is to graze-off fall growth of alfalfa. So, if you haven’t grazed your fall regrowth, then you need to graze it off this winter. If your fields are dry, then get it grazed off in December. If your fields are wet, then you will need to graze it off when the soil is frozen, or wait until it dries up. Grazing off the fall regrowth in the winter will reduce the number of seedling weeds and weevil eggs in fields, and can delay and/or decrease the number of insecticide treatments required. It also removes old growth so it is not a component of first-harvest hay. If stem density is 20 to 30 stems/sq. ft. and there were more than 5 % weeds in your first cutting last year, then control of weeds with herbicides needs to be considered. This fall was dry in many areas, so weeds may not be a big problem. However, it is important to scout the fields now to see if there are any emerged weeds. If weeds have emerged, then you should control them if you want weed-free hay. The most profitable thing to do is control the cool-season weeds in thinning stands by spraying with a herbicide such as SINBAR and VELPAR. You need to spray sometime in January or February when the field is dry enough to support equipment. If you have a thin stand (less 20-stems/sq. ft), and have livestock, then you should consider spring grazing. We have data from three sites that indicate that March grazing and not using any pesticides could be the most profitable option in thinning stands with less than 20 alfalfa stem/sq. ft. if the site is infested with a cool-season grass like rescuegrass. High quality forage production can be utilized from these grass-infested fields by grazing in March and April, and bloat problems are reduced because of the grass component. Disking and planting oats is another management option in these thin stands with less than 20-stems/sq. ft. It is best to use a small diameter disk set at sight angle to minimize damage to alfalfa crowns. We also recommend 100 lb/acre of 18-46-0 down the drop-tube as a starter fertilizer. Success of this overseeding is dependent on: good moisture in soil profile at over-seeding and good rainfall during March and April. On the down side, we have noted that disking will result in a lot more summer weed problems. This is a good way to increase forage production if you are planning to graze in the summer, but summer weeds will prevent getting any high quality alfalfa hay to sell.
Check out Oklahoma Alfalfa on the web for new items on alfalfa weeds. Several new items have been added recently. A link to Pesticide Labels and MSDS Sheets was added at several spots. This includes nearly all the agricultural chemicals you use.
– Jim Stritzke
 At the Board of Directors meeting in October new officers were elected for the Oklahoma Alfalfa Hay & Seed Assoc.
There will be an election at the Annual meeting in January for Directors and for Officers of the Board. I was Secretary since early 1992, longer than anyone else in one stretch. I will continue to do the newsletters and anything else the Board wants. We need some new people involved and I think Jim Stritzke will do a good job. --John Caddel
Just a couple of observations related to Frequently Asked Questions #1 I have been watching a stand of alfalfa that was planted in mid September in a good but dry seed bed. We had temperatures below 20oF in early October before there was enough rain for germination. Then it warmed and rains came in mid October. The alfalfa has been growing since about October 20 and has 2 or 3 true leaves now. About 25% of the plants have died. The plants that are living, look bad. Many of the living plants do not have enough root to hold them in the soil. I doubt there will be enough plants there next April to call it a stand, even though it started out with more than enough plants. #2 Normally alfalfa does not have dangerously high nitrates. A sample came to the Forage Lab at OSU and tested 9500 ppm nitrates (and 33% crude protein), very dangerous if that is the main part of the diet. I harvested some very lush alfalfa that had been regrowing since mid October with adequate moisture, and it tested 900 ppm nitrate (and 25% crude protein). This level of nitrates is not dangerous , but it is much higher than "normal" for alfalfa. We should watch out and have some of the very lush, leafy alfalfa tested for nitrates before grazing. --John Caddel, Forage Agronomist |
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Anyone wanting to list alfalfa meetings may contact John Caddel with the particulars. His mailing address and phone are listed below. Fax 405-744-0354. Email-caddel@okstate.edu |
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