CALIBRATING your planter MAXIMISES THE YIELD

October 2024

PIETMAN BOTHA, INDEPENDENT AGRICULTURAL CONSULTANT

EVERY PLANTER SHOULD BE CLEANED IN PREPARATION TO HEAD BACK TO THE FIELD EACH SEASON. HOWEVER, GETTING A PLANTER READY FOR OPTIMUM PLANTING IS MORE THAN JUST CLEANING. PLANTER CALIBRATION MUST BE DONE PROPERLY BEFORE PLANTING TO MAXIMISE THE YIELD.

A planting mistake can influence the final yield drastically. A too high or too low plant population will cost you money, so it is best to plant adequate seeds to ensure that the final plant stand is optimum for the desired yield. Obtaining an optimum yield depends on how you prepare and set your planter. Adjusting the planter to plant a specified number of seeds per metre or row is important in obtaining a proper stand. 

A CHECKLIST FOR PLANTERS
Use the owner’s manual extensively for calibration and check the following to ensure the best stand for your crops: 

1. Ensure that the drive trains are not rusted or stiff. 
2. Shaft bearings and sprocket bearings should be well lubricated and in good condition. 
3. Chemical meters on the planter that are used for seed treatments must be cleaned and inspected. 
4. Opener blades must not be worn. 
5. Ensure that the sprocket teeth are not worn. 
6. Make sure that the right tray has been selected for the specific seed size when using tray planters or vacuum planters with trays. The correct vacuum delivery for vacuum planters should be checked. 
7. Finger-wheel planter dispensing mechanisms should be serviced and in perfect working condition.
8. If equipped, make sure the vacuum meter system is clean and seals are not worn to ensure proper metering. 

In the field, dig to expose seeds in the row to make sure the planter is operating correctly. This may help to avoid an erratic stand after emergence. Confirm the desired seed depth and seed-to-soil contact. 

It is important to measure the distances between the pips.

During the planting season it is important to either store the planter inside overnight or to cover it to prevent moisture accumulation in the material storage hoppers.

SETTING A PLANTER FOR THE DESIRED PLANTING RATE 
Suppose the desired maize stand is 40 000 plants per hectare. Assuming there will only be 90% of surviving, healthy plants, the planting rate (PR) can be calculated by the following equation: 
PR = Plants per hectare desired/emergence percentage 
PR = 40 000/0,90 
PR = 44 444 seed/hectare 

Seed per metre or row required for planting
Convert the planting rate to reflect the row spacing in use. In this example, a 90 cm row spacing is used to do the calculations. One hectare is 100 m wide and 100 m long – or 10 000 m².

To calculate the distance between the seeds:

1. Calculate the number of rows per 100 m. This is done by dividing 100 by the row in this example: 100 m ÷ 0,9 m = 111 rows. 
2. Divide the planting rate (PR) with the number of rows, for example 44 444 (PR) ÷ 111 (rows per 100 m) = 400 pips per 100 m row.
3. Divide a 100 m row by the pips per 100 m to calculate the interplant spacing. Example: 100 ÷ 400 = 0,25 m apart. 
4. This means that in 1 metre, 4 pips must be planted. Example: 1 ÷ 0,25 m = 4 pips per metre.

With this knowledge, the planter can be taken to the land to measure the plant density.

The Farmer Development Programme offers an intensive training course on planter- and boom sprayer calibration.

If you open the row where seed has been planted, put the removed soil to the side. Make sure that the row marker is set correctly that the inter row distances are always the same.

Seed dispensing can be done as follows:

1. Mark out a distance of 10 m in the field.
2. Set the plant depth so that the seed is placed on the soil.
3. Plant at the normal plant speed over the measured distance of 10 m.
4. Count the number of seeds delivered in a row over the distance of 10 m.
5. Divide 10 by the number of pips counted. 
6. This gives you the interplant spacing.

If the plant population must be changed, change the gear combinations as indicated on the calibration table of the planter. If there are many double seed deliveries or seed is not delivered at all, make sure that the right tray has been selected for the seed size for tray and vacuum planters. The correct vacuum delivery for vacuum planters should be checked. Make sure finger-wheel planter dispensing mechanisms are working correctly.

Remember a mistake at planting cannot be corrected without replanting, so make sure that everything is working correctly. Compare the number of bags of seed planted against the bags needed for the field on a regular basis. Check the planting distance regularly.

Publication: October 2024

Section: Pula/Imvula