## Mobile Calibration

Mobile calibration methods are the same for air seeders as for grain drills. One difference is the number of rows that must be collected. Air seeders are so large that it is not practical to collect all of the rows. Recommendations for the number of rows that should be collected vary, but 25% is a general recommendation. The appropriate number of seed hoses are disconnected from the individual seed tubes and connected to a bag or other collection device. The seeder is driven a fixed distance, 100 to 200 ft and the material is weighed from each bag. With this information and knowing the effective width of each shank the seeding rate or application rate can be calculated.

Problem: Determine the seeding rate (lb/ac) for a 50-ft air seeder with a 10.0 inch spacing. The following quantities of seeds were collected from every 4th shank on a single row during 200 ft of travel, Table 8.3.

Solution: The first step is to determine the total amount of seeds collected.

Total Pounds = 0.34 + 0.33 + 0.33 + 0.36 + 0.34 + 0.35 + 0.35 + 0.33 + 0.34 + 0.34 + 0.35 + 0.35 + 0.33 + 0.34 + 0.34 = 5.12 lb

The next step is to determine the area: [Note: For calibration purposes the effective

 Collector lb 1 0.34 2 0.33 3 0.33 4 0.36 5 0.34 6 0.35 7 0.35 8 0.33 9 0.33 10 0.34 11 0.34 12 0.35 13 0.35 14 0.33 15 0.34 16 0.34

area is the number of shanks times the spacing between shanks.]

Area (ac) =-x , x 16 row x 200 ft x row 12 in 43560 ft2

32000

522720

The air seeder applied 5.45 lb of seeds in 0.61 acre. The last step is to determine the pounds of seed per acre.

Pounds 5.12 lb lb

Acre 0.061 ac ac

The air seeder is applying seeds at the rate of 83.9 lb/ac. It is up to the owner/operator to determine if this is an acceptable level of performance.

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