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Table beets Western Oregon--west of Cascades FG 13 Reprinted January 2000 H.J. Mack, E.H. Gardner, and T.L. Jackson Do you want to print a copy? We recommend downloading the print version (64 K). First download the free Adobe Reader, if you don't already have it. Contents Nitrogen (N) Phosphorus (P) Potassium (K) Sulfur (S) Magnesium (Mg) Boron (B) Lime Good management practices are essential if optimum fertilizer responses are to be realized. These practices include use of recommended varieties, selection of adapted soils, weed control, disease and insect control, good seedbed preparation, proper seeding methods, and timely harvest. Because of the influence of soil type, climatic conditions, and other cultural practices, crop response from fertilizer may not always be accurately predicted. Soil test results, field experience, and knowledge of specific crop requirements help determine the nutrients needed and the rate of application. The fertilizer application for vegetable crops should ensure adequate levels of all nutrients; optimum fertilization is essential for top quality and yields. Follow recommended soil sampling procedures in order to estimate fertilizer needs. The Oregon State University Extension Service agent in your county can provide you with soil sampling instructions, soil sample bags, and information sheets. Recommendations are based on a 24-inch row spacing. Nitrogen (N) Rates of 130 to 170 lb of N/a are recommended. The lower rates of N are used following a good legume crop such as alfalfa or red clover. Highest N rates are suggested following grain or grass seed. Broadcast the N before planting, or apply up to half the N as early-season top dressings. top Phosphorus (P) P is necessary for vigorous early seedling growth, which may reduce damage from "damping off." Band 50 to 70 lb phosphate (P2O5)/a as super phosphate or treble super phosphate 1 inch directly beneath the seed (see Table 1). Broadcast and work the remainder of the P into the seedbed before seeding. Severe seedling burn can result if N-P mixtures or fertilizers containing potassium or boron are banded directly beneath the seed. Table 1.--P fertilization rates for table beets.  If the soil test for P is (ppm) 0 to 25 25 to 50 over 50  Apply this amount of phosphate (P2O5) (lb/a) 20 to 150 70 to 120 50 to 70 top Potassium (K) Broadcast and work K into the soil before planting (see Table 2). Table 2.--K fertilization rates for table beets. If the soil test for K is (ppm) 0 to 75 75 to 150 150 to 225 over 225  Apply this amount of potash (K2O) (lb/a) 20 to 150 80 to 120 60 to 80 0 top Sulfur (S) Plants absorb S in the form of sulfate. Fertilizer materials supply S in the form of sulfate and elemental S. Elemental S must be converted to sulfate in the soil before the S becomes available to plants. The conversion of elemental S to sulfate usually is rapid for fine-ground (less than 40-mesh) material in warm, moist soil. The S requirements of table beets can be provided by: 1. Applying 15 to 20 lb/a of S in the form of sulfate at planting time 2. Applying 30 to 40 lb/a of S as fine-ground elemental S the preceding year 3. Applying more coarsely ground elemental S at higher rates and less frequently Some S fertilizer materials such as elemental S and ammonium sulfate have an acidifying effect on soil. S is contained in several fertilizers used to supply other nutrients. top Magnesium (Mg) To date, no yield response from the application of Mg to beets has been observed in western Oregon. Trial applications of 10 to 15 lb of Mg/a are suggested when the soil test value for Mg is below 1.0 meq Mg/100 g soil. Mg also can be supplied in dolomite, which is a liming material that reduces soil acidity to about the same degree as ground limestone. Mix dolomite into the seedbed several weeks before seeding. top Boron (B) Boron deficiency (canker) in table beets has been severe in some areas. In these areas, foliar applications of water-soluble B materials are needed in addition to soil application. The following B fertilizer programs are suggested: 1. Preplanting treatment: Apply 3 to 5 lb B/a (broadcast and disked in). This rate has been adequate where canker has not been severe. 2. Use the following combination treatment where canker is severe or where beets are held for late harvest. Preplanting application: 3 to 5 lb B/a (broadcast and disked in) Foliar applications: two or three applications of water-soluble B materials. For each foliar application, use 1 lb B/a (in 50 to 100 gal water) at the following times: At time of enlargement (bulbing) of beet roots When beet roots are 1 1 /2 to 2 inches in diameter 10 to 14 days later Lack of moisture will aggravate B deficiency. B should not be banded, but should be applied evenly to the field. top Lime Table beets are less tolerant of soil acidity than bush beans or sweet corn. Make lime applications if the soil pH is 5.8 or below, or if calcium levels are below 7 meq Ca/l00 g soil (see Table 3).  Table 3.--Lime application rates for table beets.   If the SMP buffer test for lime is under 5.2 5.2 to 5.7 5.7 to 6.0 6.0 to 6.3 over 6.3 Apply this amount of lime (t/a) 4 to 5 3 to 4 2 to 3 1 to 2 0 The liming rate is based on 100-score lime. Mix lime into the soil at least several weeks before planting and preferably the previous fall. A lime application is effective for several years. Some soils may have a fairly high SMP buffer value (over 6.2) and a low pH (below 5.3). This condition can be caused by the application of acidifying fertilizer. In this case, the low pH value is temporary, and the pH of the soil will increase as the fertilizer completes its reaction with the soil. This temporary "active" acidity from fertilizer is encountered following recent applications of most nitrogen fertilizer materials. Acidifying fertilizers also have a long-term acidifying effect on soil that is cumulative and leads to lower SMP buffer readings. Sandy soils to which fertilizers have not been recently applied sometimes record low pH and high SMP buffer values. In such cases, a light application of lime (1 to 2 t/a) should suffice to neutralize soil acidity. For acid soils low in Mg (less than 1.0 meq Mg/l00 g soil), 1 t/a of dolomite lime can be used as an Mg source. Dolomite and ground limestone have about the same ability to neutralize soil acidity. top Prepared by H.J. Mack, professor emeritus of horticulture, E. Hugh Gardner, Extension soil scientist emeritus; and T.L. Jackson, Extension soil scientist emeritus, Oregon State University. Revised November 1984. Reprinted January 2000.

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