Breaking Yield Barriers in Alfalfa Production
by
Warren C. Thompson
National Forage Specialist:
America’s Alfalfa
Through this series of lectures, I continue to try to report the best information I have accumulated through my own experience and have taught and learned from farmers and professionals for over five decades. My attention has always been directed at how to produce profitable alfalfa and do this year in and year out. I am concentrating on systems that lead to terrific yields, persistent stands and high quality hay, silage and grazing. These systems are research based and have been put to the test and passed these tests with great responses on dairy, beef, and hay producing farms throughout America. I hope you find these ideas work for you.
The following are the basic ingredients to produce top yields of high quality alfalfa. You will not find short cuts, just the facts.
1. Alfalfa is a deep-rooted perennial legume that requires deep, well- drained soils. These soils should allow the roots unrestricted growth to a depth of three feet or more.
2. High pH, phosphate and potash levels are imperative.
3. Select high yielding, persistent varieties that fit your specific area and needs.
4. A ton of alfalfa hay requires four inches of water from all sources.
5. Don’t ever bury seed. Shallow seedings; depth of ¼-½ inch is ideal under most situations and up to ¾ inch in sandy soils.
6. Establish a harvest schedule for quality, yield, and persistence.
7. Scout, identify, and treat yield and stand threatening problems before they become paramount.
8. Control/eliminate broadleaf perennial weeds before seeding.
9. Avoid harvests during the five to six week rest period prior to historic freeze-hard frost dates.
Methods and systems to produce consistent high quality high yielding alfalfa that endures year after year:
1. The roots of 3-5 year old alfalfa often reach depths of four to six feet when unrestricted. I have seen roots as deep as 20 feet when road cuts have been made through old alfalfa fields. It is therefore imperative that alfalfa be grown on the very best drained, deep soils. Avoid seeding in ‘hard-pan’ soils and other impervious conditions such as sub-surface water and/or solid rock formations that are closer to the surface than 3 feet. Should you not have the deep soils, better buy, rent, or lease a suitable site or select different legumes for hay, silage and grazing.
2. Remove pH and fertility as limiting yield factors. The ideal pH level for alfalfa is 6.5-7.0. A ton of alfalfa removes about 100 pounds of lime, 12-15 pounds of phosphate and 60 pounds of potash. So keep in mind that when you remove hay or silage, you remove these minerals and they must be replaced or yields will drop and in time the stands will thin and weeds will invade. On soils that are amended to elevate pH, Boron is usually needed. Two to four pounds per acre are the normal rate, (Check with your University or your fertilizer for the “B” rate in your area). In some areas, depending on current soil and tissue analyses, sulfur and magnesium are recommended-needed to attain top yields. If you want to go for top yield, I suggest you follow your current soil test recommendations for ingredients and ratios before seeding and for follow up topdressing in established plantings. Your best bet is to run soil tests at the end of each production season or at least, every other year. The best time for annual topdressing for most areas is in the fall immediately after the last harvest. For those growers who prefer to fertilize during the production season, the best time is immediately following the first or second harvest. Wheel-track traffic damage by fertilizer spreaders is terrible after seven to eighteen days of plant regrowth. So be sure to apply fertilizers as soon as possible after harvest. When and how much fertilizer? Follow the soil test recommendations for ratios. If you have the pioneering spirit you might want to double back on a portion of a field and count bales and costs/returns or days of extra grazing and evaluate the resulting residual stands at the end of a year or two. I saw this system used several years ago by a top-notch farmer who was dissatisfied with his three and four ton yields and good stands that usually lasted less than four years. What he was shooting for was five-six tons per acre. So he decided to try fertilizing an established alfalfa field at the recommended rate and double back over half of a field. At each harvest and at the end of the year he counted and weighed bales. On the doubled rates his yield jumped to five tons the first year. He tried triple rates but did not get the added yield response he wanted or expected. I wonder what his yield would have been if he had been able to grow AmeriStand 403T or AmeriGraze 401+Z or Affinity+Z instead of the varieties he was growing such as Buffalo, Atlantic, or sometimes Vernal. No question, yields would have been higher and the stands would have been more durable.
3. Study yield data released by your University Agronomy Department and the companies you plan to buy your seed from. Then, select top performing varieties for your area and needs. Until 1990, the only alfalfa varieties available were designed for hay and silage harvest. Some farmers did graze residual stands as fields were ready to be plowed and returned to the grain rotation and that was for the most part, the extent of alfalfa grazing until the grazing tolerant varieties came into the picture. Just in the last decade our company, Americas Alfalfa has released varieties that combine grazing and mechanical traffic tolerance, that produce exceptional yields and forage quality that is impeccable. After all of these years in the field, I have yet to see any lineup of varieties that are as good or as promising as those we continue to develop and market. Check the list and see which one(s) best suit your needs.
4. Alfalfa requires four acre-inches of water to produce a ton of hay. In areas where the annual rainfall is 40 inches or less and mechanical or flood irrigation is not available, annual hay yields usually top out at 5-6 tons per acre. Sometimes the yields can be as high as seven tons in wet years. When irrigation is added to the other improved practices this is when the miracle 10+ tons per acre is achieved. Water is especially important when making late summer and early fall seedings. The timing for these seedings particularly in the humid regions coincides with summer droughts periods and often the soils are powder-dry. With winter ‘just around the corner’ plants need to make at least a foot of fall growth before the cold weather onslaught. If there is a chance to lease or rent irrigation units and water is available, irrigation can pay big dividends. A few inches of water can make the difference between marginal and fantastic crops. Early/vigorous survival and growth is directly related to plant health, crop height, stand vigor, winter injury resistance, and resistance to crown and root diseases especially Sclerotonia Crown and Stem Rot.
5. Seeding systems and methods have been argued for as long as I have been around and will continue for years to come. Yet more mistakes are made before and during seeding than at any other time in the life of the alfalfa field. The biggest mistake is placing the seed too deep in the ground. Here is a ‘rule of thumb’. Seed of any species should be planted eight times as deep as the seed is thick. When seeded deeper than this, late emerging, irregular stands (especially small seeded crops such as alfalfa, clovers, grass and the like) will result. The basic rule of thumb for seeding alfalfa is at ¼ to ½ inch on most soils. On sandy soils up to ¾ inch is fine. A firm seedbed helps to maintain a level-shallow seeding profile that helps maintain a uniform seeding depth while maintaining soil-moisture. Seeding on a level, firm, prepared seedbed is a great system for alfalfa on level land that is not subject to sheet erosion. However, in recent years, no-till seeding equipment and improved herbicides have given a whole new, easier approach to successful alfalfa plantings. One of the neatest systems I have seen can be found in detail in our no-till alfalfa seeding section of this web site. Study it and try it, you will like the results. In the Midwest, a 15 to 20 pound seeding rate (mostly 15-18 pounds) is adequate and traditional. In the Southeastern states where the soils are more acid and low in native rhizobia, (native inoculation capability) favorable to alfalfa, a 25-30 pound rate is standard. This same rate is normal in the irrigated far west where much of alfalfa hay is marketed as a commercial crop and the denser alfalfa stand and resulting competition helps to control weeds. What about using a “nurse crop” of small grain on prepared seedbeds? Only where erosion is expected to occur and even then, the planting rate should be kept to a minimum and harvest made as early in the spring as possible to reduce competition between the alfalfa and the “nurse”.
6. What is the best harvest schedule for hay, silage or grazing? Until around 20 years ago, bloom stage was the main harvest signal. Later, a 35-day schedule developed by researchers in Pennsylvania and perfected by farmers all through the Northeast and later copied by growers all around the USA. Persistence was good in both systems and hay quality and yields varied widely but were satisfactory at the time. Crude protein was expected to be in the 14-18% range and digestibility at 50-65%. In recent years harvest systems have been changed again. In many places farmers, especially dairy farmers want higher quality hay and silage and are harvesting on a 28-30 day interval sequence. The increased refinement in plant breeding has allowed farmers to make these more frequent harvests without sacrificing their stands prematurely. The addition of more disease and insect resistance and quicker plant recovery has made the big difference. As a result, hay and silage harvest intervals are more frequent and the feed quality is improved. Timing the first spring/early summer harvest of established stands is the secret to more harvests, increased quality, and higher yields. Top producers are making the first harvest at bud to early bloom. The following harvests then fall into place nicely at a 28-30 day (monthly) schedule. Producers who have historically harvested three cuttings before the late summer rest period now find they can harvest four crops each summer. And growers in warmer climates will now have additional cuts as well. If and when you can afford a temporary drop in quality, allow one crop to go to 35+ days in order to build food reserves during the production season. This trick will aid in persistence. Since there is a definite drop in quality, why not have this rest period occur during the low yielding (mid-summer) season? The harvest schedule for newly established fall seedings that are growing well may assume the same schedule as above. However new spring seedings should grow for at least 65-70 days and be in the bloom stage before the first hay or silage harvest. The second and subsequent harvests may mirror established stands when the regrowth is vigorous. When grazing cattle on ‘grazing tolerant’ alfalfas, the more experienced grazers have moved to more frequent rotation intervals. These new alfalfas are much more resilient than those of the past, but my advice is still don’t push them too far, alfalfa still needs time to build food reserves between harvests and at the end of the season when persistence is important to a producer.
7. Insects and diseases can destroy established alfalfa fields when left uncontrolled. Be sure to study the current publications at your county agricultural agents’ office that originate at your state university for scouting your alfalfa fields. Before and during the hay and silage production and harvest season, WALK, don’t drive your fields at least once a week. That way, you can stay on top and be in control of insect problems and fertility deficiencies and become aware of possible disease problems. Acquire a copy of the color publication “Alfalfa Analyst” that is produced and distributed by the Alfalfa Council. If you would like a copy, call us at 1-800-873-2532 and we will either send you a copy (if we have some on hand) or direct you to the current source where you can order it yourself. This will be one of the best publications you will ever find for use by farmers and professionals alike. Those who already use it call it ‘their alfalfa disease, insect, and fertility bible’. While we are on this subject of scouting, buy a sweep-net and have your agricultural agent or someone else who knows how to use it help you identify the bugs that are giving your alfalfa a ‘fit’. The potato leafhopper will be your prime target most years. In much of the country the alfalfa weevil population has dropped in recent years. But you can never count this one out. Suggestion: you should start looking for the weevil when you see the weevil population building then get on with the treatments that are advised. I have been fighting the weevil since 1963 and the best environmental indicator to supplement field inspection is to watch for apple blossoms. Yes, the blossoms open at about the same time that the alfalfa weevil begins to feed on alfalfa leaves. There must be half-dozen insecticides recommended for control of this weevil. Consult the current list put together by your Entomology Department and available at your County Agent’s office.
8. If the fields you plan to plant to alfalfa are contaminated with broadleaf perennial weeds, bring them under control ahead of seeding. Why? The herbicides that control these weeds will also kill alfalfa. So my suggestion is if you have the problem, take some extra time, maybe a whole crop year to bring them under control. Until recent years, an equal problem or in many instances an even larger problem existed with annual (usually summer) grasses such as crabgrass. But this problem has been greatly reduced with the introduction of grassy weed control herbicides. Pick up a copy of your university’s weed control publication for alfalfa at your county agent’s office and follow the recommendations.
9. Alfalfa is a perennial legume. That is the crown and roots are both perennial, however the top is a portion of an annual depending on how many times it is defoliated (harvested and grazed) in a years’ time. To keep the plants healthy and productive, special care for the underground parts of the plants is necessary. A crucial management system includes a rest period of five to six 6 weeks prior to the historic hard freeze dates (temperatures of 23-24 degrees F for 2 consecutive nights). The temptation to harvest during the period prior to the historic freeze dates especially in years when the growth is exceptionally good and the barns are not full of hay and or hay prices are sky high is real tempting.
Why not wait until the freeze hits if you are determined to make the cutting. After two to four days the crop will wilt then you can more safely make the harvest. The forage may be hard to dry to good hay moisture levels but it does make great silage. The down side is the hay or silage yields the following year will be reduced by about the same amount that you remove during this off-season. Should you decide to graze the residual growth, watch and prepare to control bloat. The same precautions need to be exercised as when grazing as in the early spring/summer. Pre-fill the animals with dry hay and condition them to the grazing by allowing access for short periods until they get accustomed to the feed. This is a great time to also have Poloxolene for them. (Bloat Guard is a product that most farmers are familiar with). Also remember that hungry emaciated cattle and sheep are especially vulnerable.
So now you have it. I have tried my best to touch all of the important phases that lead to consistent high yields. The basic issues are: use good land, elevate pH to 6.5-7.0, remove fertility as a limiting factor, water is so important especially when making late summer/early fall plantings under dry soil conditions and/or when you want to hit the highest possible yields and irrigation is practical and available. Be selective in picking the best varieties for your farm and program, and plant your alfalfa seed shallow and with extreme care and precision. Harvest sensibly to get the highest possible quality without terminating the stand prematurely, control weeds and insects, and pay particular attention to fall management to give roots and crowns favored treatment.