| Introduction | Meter descriptions | Seed types | Seed meter calibrations | Flexi-coil meter calibrations | Harmon International meter calibration | Morris meter calibrations | New Noble Services meter calibrations | Seed crackage tests | Conclusions and recomendations
Abstract
The purpose of this report was to determine the seed meter rate settings and crackage due to metering, of several speciality crops through pneumatic seeding implements. Four meter systems were used to meter buckwheat, canary seed, caraway, mustard (yellow), pinto beans, safflower and sunflower (oil) seeds. Metering rates were outlined and statistically significant crackage samples noted.
Introduction
With the low price of conventional crops in recent years, farmers on the Canadian prairies have been looking to diversify into alternative crops. Limited farming income has necessitated farmers to using conventional grain equipment for special crop production. Little information is available to farmers on whether special crops can be seeded with conventional seeding equipment. This project outlines the ability of conventional pneumatic seeding equipment to meter specialty crops.
With assistance from the Alberta Wheat Pool, Region 1 Special Crops group of Alberta Agriculture, Flexi-coil Ltd., Harmon International Inc., Morris Industries Ltd. and New Noble Services Ltd., the Alberta Farm Machinery Research Centre (AFMRC) completed meter rate and crackage testing of seven specialty crops grown in the prairie provinces of Canada.
Meter Descriptions
Four seed metering systems used with pneumatic seeding equipment were evaluated for seed metering rate vs. meter revolutions per minute and crackage. The four systems used were supplied by Flexi-coil, Harmon International, Morris Industries and New Noble Services.
The Flexi-coil metering system (Figure 1) tested was a continuous chain ground driven fluted roller type metering system. Seed and fertilizer metering rate was selected by adjusting meter revolutions. Seed was fed by gravity into the meter and then deposited into the primary air line.
The Harmon metering system (Figure 2) was a continuous chain ground drive conveyor type metering system. Seed and fertilizer metering rates were selected using a gate control which adjusted the opening of the meter exposing seed to a conveyor. Once seed was deposited into the conveyor it was placed into the primary airflow line of the system.
The Morris metering system (Figure 3) was a continuous chain ground driven slanted fluted roller type metering system. Seed and fertilizer metering rate were selected by adjusting meter revolutions. Seed was fed by gravity into the metering system and then deposited into the primary air line.
The New Noble metering system (Figure 4) was a continuous chain ground driven auger system. Seed and fertilizer was metered from a storage tank through augers into a primary air line. Seed was fed into the augers using gravity. Seed metering rate was adjusted by changing auger speeds. Once seed went through the auger it was deposited into the primary air line.
Figure 1. Flexi-coil Ltd. Metering System.
Figure 2. Harmon International Inc. Metering System.
Figure 3. Morris Industries Ltd. Metering System.
Figure 4. New Noble Services Ltd. Metering System.
Seed Types
Seven seed types were used in the meter evaluation. The seeds used were buckwheat, canary seed, caraway, mustard (yellow), pinto beans, safflower and sunflower (oil). Typical western Canadian seeding rates are outlined in Table 1.
Table 1. Seeding rates.
| Seed Type | Seeding Rate |
 | lb/ac | kg/ha |
| Buckwheat | 45 | 50 |
| Canary Seed | 30 | 34 |
| Caraway | 10 | 11 |
| Mustard (yellow) | 9 | 10 |
| Pinto Beans | 130 | 146 |
| Safflower | 20 | 22 |
| Sunflower (oil) | 3 | 3 |
.
Tests were completed to measure seed density and seed count. Seed density measurements were done with a standard 0.5 L density test. Seed density tests were repeated 10 times. Seed counts were done by counting and weighing 1000 seeds. Seed counts were repeated five times. Average seed density measurements and seed counts are illustrated in Table 2.
Table 2. Seed density and seed counts.
| Seed Rate | Average Seed Density* | Average Seed Count** |
| lb/bu | g/L | lb/ft³ | seeds/g | seeds/lb |
| Buckwheat | 50.97 | 635.7 | 39.69 | 34.93 | 15843 |
| Canary Seed | 58.05 | 724.1 | 45.20 | 126.61 | 57424 |
| Caraway | 36.12 | 450.5 | 28.12 | 278.11 | 126147 |
| Mustard (yellow) | 56.68 | 731.9 | 45.69 | 179.87 | 81588 |
| Pinto Beans | 61.74 | 770.0 | 48.07 | 2.63 | 1191 |
| Safflower | 43.01 | 536.5 | 33.49 | 23.78 | 10785 |
| Sunflower (oil) | 28.76 | 359.5 | 22.44 | 22.34 | 10133 |
* Average of ten measurements.
** Average of five measurements.
Seed Meter Calibrations
The test facility was made up of a digital scale, seed hopper, seed meter and meter drive. The seed meter drive consisted of a variable speed motor and chain direct drive gear system. Adjustments to meter operating speed were done by varying gear ratios and changing motor speed. The rpm was monitored throughout all tests.
Seed meter calibration were completed by determining seed metering rate in pounds over a number of meter rpm. From the data points, equations for seeding rate in lb/min vs. rpm were determined. In most cases, r² of above 0.95 were found for regressions between meter rpm and seeding rate. A zero intercept was used for all regressions above an r² value of 0.95. If an r² of 0.95 could not be achieved with a zero intercept, an r² was determined with a calculated intercept. The highest r² equation was used in the final results. Equations, actual data points and statistical results are located in the Appendix of this report.
Data points for metering rate curves were set based on typical prairie seeding rates, 40 ft (12.1 m) of cultivator and a travel speed of 5 mph (8 km/h). Once a typical meter rpm was determined, data was taken to get a representative sample of the metering performance. All equations were calculated using a zero intercept.
Flexi-coil Meter Calibrations
Table 3 illustrates the meter output in lb/min vs. meter rpm. All equations were calculated using a zero intercept. Corresponding meter types are also listed. Meters which would not meter seed at typical product seeding rates were not tested.
Table 3. Flex-coil seed meter calibration.
| Seed Type | Meter Type | Meter Output
(lb/min/run) | r² of Meter Output |
| Buckwheat | Fine
Coarse | 0.17318 x rpm
0.26027 x rpm | 0.9990
0.9989 |
| Canary Seed | Extra Fine
Fine
Coarse | 0.09798 x rpm
0.21240 x rpm
0.31492 x rpm | 0.9974
0.9994
0.9995 |
| Caraway | Extra Fine
Fine
Coarse | 0.04387 x rpm
0.11660 x rpm
0.17479 x rpm | 0.9889
0.9959
0.9997 |
| Mustard (yellow) | Extra Fine
Fine
Coarse | 0.09256 x rpm
0.22583 x rpm
0.33217 x rpm | 0.9970
0.9999
0.9994 |
| Pinto Beans | Coarse | 0.20679 x rpm | 0.8498 |
| Safflower | Fine
Coarse | 0.13929 x rpm
0.21431 x rpm | 0.9997
0.9984 |
| Sunflower (oil) | Fine
Coarse | 0.08241 x rpm
0.12523 x rpm | 0.9994
0.9991 |
.
From the meter output equations (Table 3) constants for calculating meter box setting on the Flexi-coil system were also determined (Table 4). To calculate the required meter box setting, the following assumptions were made: (1) the meter drive wheel circumference is 178 inches (452 cm), (2) the correct drive ratio for the meter is used and (3) the meter displacement corresponds to the test density and equations outlined in Table 4. Flexi-coil meter graphs and data for the crops tested are located in Appendix I.
Table 4. Meter roller displacements.
| Seed | Meter Displacement (ft³/rev/run) |
| Extra Fine | Fine | Coarse |
| Buckwheat | n/a | 0.0043633 | 0.0065576 |
| Canary Seed | 0.0021677 | 0.0046991 | 0.0069673 |
| Caraway | 0.0015601 | 0.0041465 | 0.0062159 |
| Mustard (yellow) | 0.0020258 | 0.0049427 | 0.0072701 |
| Pinto Beans | n/a | n/a | 0.0043019 |
| Safflower | n/a | 0.0041592 | 0.0063992 |
| Sunflower (oil) | n/a | 0.0036725 | 0.0055807 |
.
Using the constants outlined in Table 4, the desired meter setting for the Flexi-coil meter can be calculated using Equation 1.
Equation 1
Meter Box Setting = (F x Rate) ÷ (Density x Displacement)
Where: F = 0.137161 If, Setting < 30 use F = 0.151378
Setting > 30 use F = 0.123853
Rate = Desired Seeding Rate (lb/ac)
Density = Seed Density (lb/ft³)
Displacement = Meter Displacement (ft³ ÷ rev) (Table 3)
From equations similar to Equation 1 and Table 4, curves similar to the manufacturers data tables were developed for the seven crops tested. Data tables are located in Appendix II.
Harmon International Meter Calibration
Table 5 illustrates the meter output vs. rpm equations and corresponding r² for the Harmon meter. Corresponding sprocket configuration rpm's are also listed. Sprocket configurations which would not meter seed at typical product seeding rates were not tested.
Table 5. Harmon seed meter calibration.
| Seed Type | Sprocket
rpm | Meter Output
lb/min | r² of Meter Output |
| Buckwheat | 28.70
56.50 | 3.3796 x rpm
6.5278 x rpm | 0.9763
0.9786 |
| Canary Seed | 14.60
28.90
56.50 | 2.2835 x rpm
4.4561 x rpm
8.7500 x rpm | 0.9237
0.9406
0.9804 |
| Caraway | 14.50
28.90 | 1.3212 x rpm
2.5580 x rpm | 0.9671
0.9790 |
| Mustard (yellow) | 5.67
14040 | 0.9087 x rpm
2.2753 x rpm | 0.9306
0.9295 |
| Pinto Beans | 56.90 | 6.0518 x rpm | 0.9864 |
| Safflower | 14040
29.20
57.20 | 1.5329 x rpm
3.0050 x rpm
5.5237 x rpm | 0.9713
0.9784
0.9802 |
| Sunflower (oil) | 5.67
14.40 | 0.3643 x rpm
0.9507 x rpm | 0.9689
0.9988 |
.
From the meter output equations (Table 5), constants for calculating meter openings were determined. Table 6 contains corrected test data constants for determining gate openings. Data was corrected due to variations in meter rpm not corresponding to the set rates of the meter at 5 mph (8 km/h). To calculate meter opening required for seeding rates with the Harmon system the following assumption was made: At a ground speed of 5 mph (8 km/h) the seed meter rotates at 28.4 rpm with the #1 sprocket, 14.2 rpm with the #2 sprocket, 5.4 rpm with the #3 sprocket and 56.8 rpm with the additional #4 sprocket. Harmon meter charts and data for the crops tested are located in Appendix III.
Table 6. Seeding rate constants.
| Seed | Sprocket Configuration |
| #1 | #2 | #3 | Additional |
| A(10-3) | B(10-2) | A(10-3) | B | A(10-3) | B | A(10-3) | B |
| Buckwheat | 3.0206 | 0.0 | n/a | n/a | n/a | n/a | 1.5474 | 0.0 |
| Canary Seed | 2.7568 | 9.7382 | 5.5750 | 1.1291 | n/a | n/a | 1.2858 | 0.518 |
| Caraway | 4.4101 | 6.2383 | 8.7810 | 0.6238 | n/a | n/a | n/a | 0.0 |
| Mustard (yellow) | n/a | n/a | 5.5285 | 1.1372 | 14.2762 | 1.1161 | n/a | 0.0 |
| Pinto Beans | n/a | n/a | n/a | n/a | n/a | n/a | 1.6691 | 0.0 |
| Safflower | 3.4561 | 0.0 | 6.6824 | 0.0 | 1.8416 | 0.0 | n/a | 0.0 |
| Sunflower (oil) | n/a | 0.0 | 10.7745 | 0.0 | 28.5525 | 0.0 | n/a | 0.0 |
.
Using the constants outlined in Table 6, the desired gate opening on the Harmon can be calculated using Equation 2.
Equation 2
Gate Opening = (Rate x Width x A) - B
Were: Rate = Seeding Rate (lb/ac)
Width = Cultivator Width (ft)
A = Constant from Table 6
B = Constant from Table 6
From Equation 2 and Table 6, data tables similar to the manufacturers were developed for the seven crops tested. Data tables are located in Appendix IV and are based on actual data points rather than regression curves.
Morris Meter Calibrations
Table 7 illustrates the meter output vs. rpm equations and corresponding r² for the Morris meter.
Table 7. Morris seed meter calibration.
| Seed Type | Meter Output
lb/min/run | r² of Meter Output |
| Buckwheat | 0.25648 x rpm | 0.9992 |
| Canary Seed | 0.28864 x rpm | 0.9968 |
| Caraway | 0.18954 x rpm | 0.9967 |
| Mustard (yellow) | 0.31020 x rpm | 0.9913 |
| Pinto Beans | 0.39974 x rpm | 0.9933 |
| Safflower | 0.22891 x rpm | 0.9987 |
| Sunflower (oil) | 0.20043 x rpm | 0.9995 |
.
From the meter output equations (Table 7), constants for calculating sprockets in the Morris system were determined (Table 8). To calculate sprockets required for seeding rates with the Morris system the following assumptions were made: (1) at a ground speed of 5 mph (8 km/h) the meter drive wheel rotates at 43 rpm, (2) each full meter shoot represents 10 cultivator shanks, (3) the slow speed drive reduces the meter's speed by a factor of 9.604 and (4) appropriate sprockets are used for the clutch output shaft which corresponds to different shank spacings. Morris meter graphs and data for the crops tested are located in Appendix V.
Table 8. Quick change sprocket changes.
| Drive | Seed | Setting | Constant |
| Slow | Mustard (yellow) | A | 3.10000 |
| Slow | Sunflower (oil) | C | 4.79500 |
| Direct | Canary Seed | A | 0.34722 |
| Direct | Caraway | A | 0.52833 |
| Direct | Safflower | B | 0.43722 |
| Direct | Buckwheat | B | 0.39000 |
| Direct | Pinto Beans | D | 0.25000 |
.
Using the constants outlined in Table 8, the desired quick change sprockets for the Morris meter can be calculated using Equation 3.
Equation 3
Quick Change Sprocket = (MSS/25) x Constant x Rate
Where: MSS = The number teeth on the meter shaft sprocket
(Standard = 25 teeth)
(Low Rate = 40 teeth or 35 teeth)
(High Rate = 15 teeth)
Constant = Value from Table 8
Rate = Seeding Rate (lb/ac)
From Equation 1 and Table 8, curves similar to the manufacturers curves were developed for the seven crops tested. Curves are located in Appendix VI.
New Noble Services Meter Calibrations
Table 9, illustrates the meter output vs. equations and corresponding r² for the New Noble meter. Corresponding augers are also listed. Auger configurations which would not meter seed at typical product seeding rates were not tested.
Table 9. New Noble Services seed meter calibration.
| Seed Type | Meter Type | Meter Output
lb/min | r² of Meter Output |
| Buckwheat | Fine
Course | 0.10439
0.09675 | 0.9931
0.9962 |
| Canary Seed | Fine
Course | 0.13845
0.15437 | 0.9977
0.9996 |
| Caraway | Fine | 0.07237 | 0.9992 |
| Mustard (yellow) | Fine | 0.12389 | 0.9993 |
| Pinto Beans | Course | 0.98972 | 0.9897 |
| Safflower | Fine
Course | 0.09326
0.08930 | 0.9993
0.9952 |
| Sunflower (oil) | Fine | 0.05641 | 0.9964 |
.
From the meter output equations (Table 9), constants for calculating sprockets in the New Noble system were determined (Table 10). To calculate sprockets required for seeding rates with the New Noble system the following assumptions were made: (1) at a ground speed of 5 mph (8 km/h) the soft trac meter drive wheel rotates at 40 rpm, (2) each tooth on the driver sprocket represents one shank, and (3) shanks are spaced at 14 in. New Noble meter graphs and data for the crops tested are located in Appendix VII.
Table 10. Sprocket selection constants.
| Seed Type | Auger Flyting |
| Double | Triple |
| Buckwheat | 0.09675 | 0.10439 |
| Canary Seed | 0.15437 | 0.13845 |
| Caraway | n/a | 0.07237 |
| Mustard (yellow) | n/a | 0.12389 |
| Pinto Beans | 0.14770 | n/a |
| Safflower | 0.08930 | 0.09326 |
| Sunflower (oil) | n/a | 0.05641 |
.
Using the constants outlined (Table 10), the desired sprocket on the New Noble air seeder can be calculated using Equations4 through 9.
Where: Rate = Seeding rate (lb/ac)
Constant = Value from Table 10
If required sprocket is not available use higher range.
Equation 4
Range 1 Sprocket = Rate ÷ (1.243 x Constant)
Equation 5
Range 2 Sprocket = Rate ÷ (2.486 x Constant)
Equation 6
Range 3 Sprocket = Rate ÷ (6.629 x Constant)
Equation 7
Range 4 Sprocket = 6788.57 x Constant ÷ Rate
Equation 8
Range 5 Sprocket = 13577.14 x Constant ÷ Rate
Equation 9
Range 6 Sprocket = 27154.29 x Constant ÷ Rate
From Equations 4 through 9 and Table 10, data tables similar to the manufacturers tables were developed for the seven crops tested. Data tables are located in Appendix VIII.
Seed Crackage Tests
For crackage tests, seed was passed through the meter at 130 percent of the recommended seeding rates. If the metering system could seed at the 130 percent rate with different combinations of drives or meter sizes, the system using the greatest meter speed or causing the greatest damage was used for the test. Seed crackage tests were consistent for all meters.
The percent crackage was determined by the difference in the results between a new untouched seed sample and the sample which is passed at 130 percent of the recommended rate. Seeding rates were based on a 40 ft (12.2 m) seeding implement operating at 5 mph (8 km/h).
Each crackage sample was analyzed three times against samples of unmetered seed. A one way t-test was applied to the results to determine if the crackage was statistically significant. A p-value of 0.05 was used to determine significant crackage.
Of the seven seeds tested only pinto beans caused significant crackage with any of the meters. The pinto bean crackage was 0.3, 6.2 and 0.4 percent for the Flexi-coil, Harmon and New Nobles meters, respectively. The 6.2 percent crackage of pinto beans caused by the Harmon may have been reduced by dropping the slide plate on the meter. The Morris system did not show any significant crackage for any of the seed tested.
Conclusions and Recomendations
All metering systems tested provided adequate metering capabilities for the seven seeds tested.
While, the metering rate tables and graphs provided can be used to help select meter settings. Calibration tests should be performed with the seed and system to determine actual meter settings.
Minimum crackage occurred with all meters and all systems tested. Only pinto beans caused significant crackage in the meters.
Future testing should include the effect of pneumatic conveying and distribution on seed crackage and germination.
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