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Oklahoma State University Stillwater, OK |
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Oklahoma Alfalfa |
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Oklahoma State University Stillwater, OK |
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Oklahoma Alfalfa |
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ALFALFA FERTILITY REVIEW Any alfalfa field that has not been soil tested in the last three years should be sampled before next season. Problem fields, especially those with a history of low soil fertility, should be sampled more frequently. This is a good time to sample, and needed fertilizer can be applied during the fall or winter. Following recommendations for fertilizer application will pay off during next growing season. Areas of most concern are soil acidity and deficiencies in phosphorous (P2O5) and potassium (K2O). Low pH or deficiencies in phosphorous and potassium result in lower yields and tend to allow broadleaf weeds and weedy grasses to encroach into fields earlier than fertile fields. Alfalfa looses some of its competitiveness under those conditions. Alfalfa takes a lot of nutrients out to the soil. Continuous high production of alfalfa is one of the most acid-causing cropping systems. One ton of alfalfa removes about 125 pounds of lime (or lime-like material) from the soil. Soil pH should be above 6.5 for efficient alfalfa production and stand longevity. A pH of 7.2 is ideal for alfalfa. If a field is producing reasonably well but is found to be acidic, and lime incorporation is not feasible, broadcasting lime on top of the soil is better than not applying it at all. Many alfalfa fields become deficient in phosphorous and potassium after a few years of high production. A ton of alfalfa removes the equivalent of about 14 pounds of phosphorous (P2O5) and 70 pounds of potassium (K2O). Good alfalfa stands that become deficient in these nutrients will respond to broadcast applications, even though incorporation before stand establishment is much more effective. Assistance in planning soil testing and forwarding samples
for laboratory analysis is available through the Oklahoma Agricultural Extension Service
represented by your County Extension Agricultural Agent. |
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| Gordon V. Johnson Former Nutrient Management Specialist Department of Plant and Soil Sciences Oklahoma State University |
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