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SOYBEAN SEEDING RATES AND ASSOCIATED COSTS
Soybeans can be planted at varying seeding rates because growers know that different rates within an acceptable range can be used without affecting yield potential. Seed of today’s biotech varieties often cost more than $30 per 50 pounds. Thus, the seeding rate decision now has significant economic implications.
Information in the accompanying table can be used to determine how much a particular seeding rate will cost, and how much a change in seeding rate will affect cost. For instance, if seed costs are $30 per 50 pounds, increasing seeding rate of a 3000-seeds-per-pound variety from 120,000 to 160,000 seeds per acre will increase cost $8 per acre when 50 pounds are planted. If there is no agronomic reason to use the higher seeding rate, this extra seed cost will reduce net return. On the other hand, producers may decide that the extra cost is worth the peace of mind gained from planting on the higher end of the range to ensure an acceptable stand in a planting environment that is less than ideal.
Planting the same number of seeds per acre of comparably performing varieties with a different number of seeds per pound will affect cost. For instance, planting 140,000 seeds of a variety with 3000 seeds per pound will cost over $4.50 per acre more than planting the same number of seeds of a variety with 3600 seeds per pound. If the two varieties are comparable in performance, then this higher cost will reduce net income.
Producers should use their prior seeding rate experience to make an economical seeding rate decision.
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Number of seeds per foot of row for soybean seed of varied size planted at different seeding rates in five row spacings.
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Row spacing--in.
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Seed size
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Seeding rate
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7
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15
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20
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30
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40
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No./lb.
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seeds/acre
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lb./acre
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----No. seed/ft. of row------------
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2800
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100,000
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35.7
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1.3
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2.9
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3.8
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5.7
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7.7
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120,000
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42.8
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1.6
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3.4
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4.6
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6.9
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9.2
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140,000
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50.0
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1.9
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4.0
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5.4
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8.0
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10.7
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160,000
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57.1
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2.1
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4.6
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6.1
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9.2
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12.2
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180,000
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64.3
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2.4
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5.2
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6.9
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10.3
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13.8
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200,000
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71.4
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2.7
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5.7
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7.6
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11.5
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15.3
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3000
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100,000
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33.3
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1.3
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2.9
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3.8
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5.7
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7.7
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120,000
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40.0
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1.6
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3.4
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4.6
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6.9
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9.2
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140,000
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46.7
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1.9
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4.0
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5.4
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8.0
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10.7
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160,000
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53.3
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2.1
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4.6
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6.1
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9.2
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12.2
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180,000
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60.0
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2.4
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5.2
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6.9
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10.3
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13.8
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200,000
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66.7
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2.7
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5.7
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7.6
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11.5
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15.3
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3200
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100,000
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31.2
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1.3
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2.9
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3.8
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5.7
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7.7
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120,000
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37.5
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1.6
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3.4
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4.6
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6.9
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9.2
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140,000
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43.8
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1.9
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4.0
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5.4
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8.0
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10.7
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160,000
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50.0
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2.1
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4.6
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6.1
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9.2
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12.2
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180,000
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56.2
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2.4
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5.2
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6.9
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10.3
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13.8
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200,000
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62.5
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2.7
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5.7
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7.6
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11.5
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15.3
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3400
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100,000
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29.4
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1.3
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2.9
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3.8
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5.7
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7.7
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120,000
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35.3
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1.6
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3.4
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4.6
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6.9
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9.2
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140,000
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41.2
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1.9
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4.0
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5.4
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8.0
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10.7
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160,000
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47.0
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2.1
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4.6
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6.1
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9.2
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12.2
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180,000
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52.9
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2.4
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5.2
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6.9
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10.3
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13.8
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200,000
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58.8
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2.7
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5.7
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7.6
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11.5
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15.3
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3600
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100,000
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27.8
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1.3
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2.9
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3.8
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5.7
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7.7
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120,000
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33.3
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1.6
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3.4
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4.6
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6.9
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9.2
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140,000
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38.9
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1.9
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4.0
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5.4
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8.0
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10.7
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160,000
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44.4
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2.1
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4.6
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6.1
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9.2
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12.2
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180,000
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50.0
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2.4
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5.2
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6.9
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10.3
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13.8
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200,000
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55.6
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2.7
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5.7
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7.6
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11.5
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15.3
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Cost per acre for soybean seed of varied size and cost planted at different seeding rates.
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Cost/50 lb. seed
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Seed size
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Seeding rate
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$20
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$30
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No./lb.
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seeds/acre
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lb./acre
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-----$/acre-----
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2800
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100,000
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35.7
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14.29
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21.43
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120,000
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42.8
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17.14
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25.72
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140,000
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50.0
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20.00
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30.00
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160,000
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57.1
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22.86
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34.28
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180,000
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64.3
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25.71
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38.57
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200,000
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71.4
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28.57
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42.85
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3000
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100,000
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33.3
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13.33
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20.00
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120,000
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40.0
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16.00
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24.00
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140,000
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46.7
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18.67
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28.00
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160,000
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53.3
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21.33
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32.00
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180,000
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60.0
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24.00
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36.00
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200,000
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66.7
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26.67
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40.00
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3200
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100,000
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31.2
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12.50
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18.76
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120,000
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37.5
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15.00
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22.50
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140,000
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43.8
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17.50
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26.25
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160,000
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50.0
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20.00
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30.00
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180,000
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56.2
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22.50
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33.76
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200,000
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62.5
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25.00
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37.50
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3400
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100,000
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29.4
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11.76
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17.66
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120,000
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35.3
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14.12
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21.18
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140,000
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41.2
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16.47
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24.71
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160,000
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47.0
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18.82
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28.24
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180,000
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52.9
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21.18
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31.77
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200,000
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58.8
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23.53
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35.28
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3600
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100,000
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27.8
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11.11
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16.66
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120,000
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33.3
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13.33
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20.00
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140,000
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38.9
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15.56
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23.33
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160,000
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44.4
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17.78
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26.67
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180,000
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50.0
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20.00
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30.00
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200,000
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55.6
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22.22
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33.33
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