Agronomy Library > Soil Conservation

Did Your Seeder Do the Job You Expected?
Author: Murray Green, Agricultural Engineer
Date Created: June 06, 2003
Last Reviewed: February 01, 2007

The only way to know if your seeder was adjusted and working properly is to check the job it did, field by field. Take some time between planting and spraying to inspect your fields.
 
As the crop emerges and proceeds through its early stages, a lot can be determined about the performance of the seeder, how it was adjusted, and whether it provided the best possible start for the crop.
 
Emergence of side by side rows
 
Are all the rows emerging at the same time? If not, this is the first indication that there were some incorrect adjustments on the seeder. This observation is best made just as the final plants are emerging. In another week if the plants in the adjacent rows have grow to close to the same stage, the slight variation won’t be a problem. But fine tuning the seeder will ensure uniform maturity.
 
If some rows are delayed:
 
Front rows late: Caused by soil stacking as a result of the adjacent openers throwing soil into the front furrows increasing the depth of soil. The front of the seeder could be set too deep.
 
Rear rows late: The opener wasn’t deep enough to produce sufficient soil cover over the seed leaving the seed in dry soil or even uncovered.
 
Occasional row is late: The shank and opener that planted that row is not adjusted properly and is penetrating too deep. May also be an opener following in a wheel track and not penetrating to moisture, or the soil is working up too lumpy to pack properly.
 
Plants are missing within a row:
 
Long gaps (6 inches or more) in the row: Likely the result of seed being retarded in the seed delivery line or in the seed delivery boot.
 
Small gaps in the row: Some seeds are not sufficiently packed as a result of lumps in the seed bed. It is often difficult to prevent this in clay soils. Unless rain occurs soon after seeding, these missing plants will not likely show up later to interfere with the harvesting. Yields may not be affected by small gaps in the seed row.
 
Irregular gaps, some quite long, in the seed row or even the whole width of the seeder: Most likely the result of poor seed to soil contact and often the result of attempting to plant too shallow which is a common error in direct seeding. These missing plants may show up later after a significant rainfall, and if too late, they may become that dreaded second crop.
 
Plants missing under lumps of soil and residue: Residue conditions often cause straw and eventually soil to drag with the opener. At some point the pile of material rolls off and either falls back on the seed row or onto the adjacent row. Sometimes plants will emerge through the pile but will be later in maturity.
 
Plant population:
 
Plant counts should be made in the two or three leaf stage of cereal crops.
 
Once the first node of a field pea crop has arrived, most plants should be up, as there is little reason to not place all the peas well into moisture while planting.
 
Count canola when one or two true leaves have developed. These are the plants which will produce most of the yield. If a lot of canola plants come later, then there was likely a “seed to moist soil contact” problem. There is often great concern when fewer than the desired numbers of canola plants emerge. Discussion about canola plant populations and yield may be found at www.canola-council.org .
 
Plants should be counted in several seed rows. The average of several counts may be compared to agronomic information available for best plant population per square meter or per square foot. The square foot number is most useful in assessing planter performance since the row spacing of air drills and planters is still quoted in inches or feet. It is necessary to count a specific length of seed row depending on the spacing of the planter openers. If the planting system creates a solid plant stand where individual rows can’t be identified, then a square foot measuring tool is needed.
 
Length of seed row to count for the plant population in ONE square foot at different opener spacing**
 
Opener spacing
Length of row to count
7 in
20.5 in
7.2
20 in
7.5
19.2 in
8 in
18 in
9 in
16 in
9.8 in
14.7 in
10 in
14.4 in
12 in
12 in
14 in
10.3 in
                                         ** Count both sides of a paired row.                     
                               
Not all planted seeds should be expected to make viable plants. But a significant difference between anticipated plant population based on seeding rate and the actual count indicates there is a problem with the planting system.
 
Other situations within an individual seed row:
 
Check the spread of the plant rows.
 
A paired row opener should have two rows of plants either side of the center line of the opener with an inch or two between. If plants are in a solid band instead of rows, then there was too much bounce of the seed due to high air flow and forward speed too fast for the situation. Usually, the plants that are misplaced to the center of a double shoot deep band opener, will come up later as they will have been cover quite deep and will delayed by the concentration of fertilizer. When seeds fall into the center fertilizer band it is actually best if the fertilizer prevents their germination.
 
A spread tip, shovel, or sweep is intended to produce a solid band of seed as wide as the cut off soil underneath. Seeds outside the desired band will not be packed properly but may germinate much later, causing an immature head at harvest. Low air flow or too narrow a seed boot will leave a narrow row which doesn’t utilize the desired seed bed.
 
An erroneous alignment of the openers and packer wheels, or an incompatible opener and packer geometry will also leave much of the seed unpacked. This will produce a situation where some plants come up while others germinate and emerge only after the next rainfall. Two maturity times doesn’t produce a quality sample in the combine hopper!
 
Fertilizer affects. This will be an issue for the emerging crop only if the limits have been exceeding for seed placed fertilizer

Limiting factors are: high rate of nitrogen fertilizer, particularly ammonia, (produced when nitrogen is released from urea, 46-0-0) placed with the seed, dry soil in the seed bed, or narrow seed bands at wide row spacing. The issues described at the beginning of this article should be eliminated before the fertilizer is blamed for poor emergence. The most obvious way to know if fertilizer damage has occurred is to study your check strips. When seed placing fertilizer, particularly if close the limits, one should always turn off the fertilizer for a couple of seconds in an area you can find again. This will be most valuable in diagnosing emergence concerns
 
Generally:
 
Crop up first in wheel tracks:  indicated the seed bed was not packed enough, or the crop was planted too deep.
 
Emergence problems in wheel tracks made before planting:  driving vehicles or even turning the tractor and planter onto unseeded areas will cause soil compaction so that the ground openers cannot form a good seed bed. Moist soil and increasing clay content are most prone to compaction.
 
Other issues: will show up during your inspection that weren’t mentioned here. Hopefully, your really big botch-ups were not next to the main road. But assess them: will they make a difference to yield and grain quality and what could you have done, or what could you do now to fix it for next year?