Importance of planter calibration
In dry land farming, maize, soya and dry beans are major crops produced by the majority of farmers on a commercial or smallholder scale. Whether using no-till or conventional farming methods, the productivity and hence the profitability of the grain crops will largely depend on planter performance.
Malfunctioning of a planter during the critical planting season can easily cost up to 10% of production in terms of reduced yield or additional seed and fertilizer cost and time spent. Planter performance is especially critical in no-till farming because of the high penetration resistance with crop residue at the soil surface, and the surface being rough as well. Inadequate planting will result in uneven seed depth and plant spacing.
Planter calibration must be done properly before planting because without calibrating the planter correctly, the correct crop seed population and thus optimal crop yield are just not achievable.
The planter calibration usually includes calibrating both the seed and fertilizer. The planter calibration as discussed in this article is based on a typical mechanical chain-sprocket/gear driven maize/soy planter with seeding disk/plate inside seed hoper.
Know your farm plan
The following information is needed before you do calibration of a planter:
- Target seed population per hectare.
- Advised amount of fertilizer application in kilograms per hectare for your soil.
- Average row distance in meters.
- Crop cultivar seed to suit your soil and target yield.
Know your planter
- Thoroughly read the operational manuals and understand the recommended calibration instructions of your planter.
- Check drive gears or sprockets and know the gear ratios from drive wheel to seed and fertilizer hoppers.
- Select correct seeding plate/disk which has proper size of holes along disk circumference to give a seed drop with a minimum of doubles or skips.
- Count the number of the circumferential holes.
- Understand the adjustment mechanism for fertilizer when necessary.
- Combining drive gear ratios and number of holes on seeding disk/plate should give pre-set estimated seed population and spacing.
Seed calibration in field
- Bring your planter with tractor to field side.
- Measure a 10m distance and mark with two easily identified markers.
- Load minimum seeds into a side unit of the seed hoppers.
- Take the rubber/plastic seed pipe from the seed boot so that the seeds can be planted on soil surface and easily seen.
- Run the planter and tractor as normal planting over the 10m distance.
- Check the furrow opening, planting depth, soil cover and soil press to satisfaction. Make adjustment if necessary.
- Count the number of the seeds planted over the 10m distance and check any doubles or skips.
- The seed population per hectare can be calculated by the following equation:
N=1000 x n/d
Where N=planting seed population per hectare
n=seed number counted over 10m distance
d=average row distance in meters
If the row distance is 0.9m and the seeds planted are counted as 33 over 10 meters, the planting seed population per hectare is calculated as:
N=1000 x 33/0.9=36667 plants per hectare.
Compare the calibrated results with your planned target seed population per hectare. If necessary, make adjustment by selecting different seed disk/plate or different gear ratio and repeat the above procedure.
- Bring your tractor with planter to your field side.
- Measure a 10m distance and identify with two easily observed markers.
- Load minimum fertilizer into a side unit of the fertilizer hoppers.
- Take the rubber/plastic fertilizer pipe from the fertilizer boot so that the fertilizer will be planted and easily collected by a container.
- Run the planter and tractor as normal planting while collecting the fertilizer by a container over this 10m distance.
- Get the weight of the fertilizer planted in grams over the 10m distance.
- The fertilizer amount applied can be calculated by the following equation:
Where W=fertilizer applied in kilograms per hectare
w=fertilizer weight in grams planted over 10m distance
d=row distance in meters
If the row distance is 0.9m and the fertilizer planted is collected and weighted as 140g over 10 meters, the fertilizer to be applied per hectare is calculated as:
W=140/0.9=155.6 kg per hectare.
Compare the calibrated results with your planned target fertilizer application in kilograms per hectare. If necessary, make adjustment and repeat the above procedure.