## Metric Problems

Problem: Determine the application rate (kg/ha) for a fertilizer spreader that applied 52.5 kg of material during 15 revolutions of the drive wheel, which has a diameter of 0.53 m. The effective width of the spreader is 0.76 m.

Solution:

525,000 kg t

Problem: Determine the acceptability of the seeding rate for a grain drill when the desired rate is 9.0 kg/ha. The drill has 25 metering units with a 0.20 m spacing. The drive wheel has an effective diameter of 80 cm. During the stationary calibration the

Table 8.4. Data for grain drill calibration in SI units.

Unit 1 2 3 4 5 6 7 8 9 10 11 12 Grams 22.6 22.4 22.0 22.9 22.7 22.6 22.0 22.8 22.8 22.7 22.6 22.8

drive wheel was rotated 50 times. The following amounts of seeds were collected from 12 of the metering units, Table 8.4.

Solution: The seeding rate is determined by calculating the quantity of seed for the area and then converting the results to the desired units. The quantity collected is:

Total = 22.6 + 22.4 + 22.0 + 22.9 + 22.7 + 22.6 + 22.0 + 22.8 + 22.8 + 22.7 + 22.6 + 22.8 = 270.9 g or 0.2709 kg

The area is:

A (ha) = No. Units x w(m) x d(cm) x n x nr m 80 cm x n 1m 1 ha = 12 units x 0.20-x -x 50 rev x -x unit rev 100 cm 10,000 m2

30159.28

1.0 E6 The seeding rate is:

0.2709 kg kg

The acceptability of the drill performance is determined by establishing the upper and lower limits using the 10% rule.

Based on the 10% rule the performance of the grain drill is acceptable because 9.4 > 8.9 > 8.6.

Even though the seeding rate is acceptable, the distribution pattern of the drill should also be checked.

270.9 g

Upper limit = 22.575 x 1.05 = 23.703 ... or 23.7 g Lower limit = 22.575 x 0.95 = 21.44... or 21.4 g

The distribution pattern is acceptable because all of the quantities for each metering unit are within the upper and lower limit.

Problem: Determine the plants per hectare for a row crop planter when the average seed spacing is 11.5 cm in the row and the row spacing is 70 cm.

Solution:

Rl ha

1 ha

70 cm sds

Problem: Determine the seeding rate for a 10.8-m air seeder with 18 cm row spacing when 13 kg of seeds were collected during 50 m of travel.

Solution: Since we have collected seed from all rows we do not need to consider the row spacing.

13 kg

50 m

10,000 m2 ha

10,000 m2 1 ha

Problem: Determine the size of nozzles (L/min) required to apply spray at the rate of 185 L/ha when the nozzle spacing is 0.4545 m and the sprayer will be traveling at a velocity of 4.0 km/hr.

Solution: (L

1 ha

hr 60 min

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