Are you noticing emergence problems in your corn?

Good field emergence ensures that the desired plant density is achieved. And in this way an even development is guaranteed. Unfortunately, in the period following sowing, there are a number of factors that can drastically disrupt the germination process and field emergence. Only a timely field check can help identify the cause of poor field attendance.

As is customary in arable farming with beets and onions, it is important to assess the field emergence of maize in good time and not to wait until the weeds in the field are controlled. The maize should preferably have emerged within fourteen days after sowing. If this is not the case, then there is the option of overseeding. If a poor emergence is found later, overseeding or overseeding is almost pointless and leads to disappointing results.

If problems with field emergence are observed, it is important and necessary to make a distinction between turnout problems that occur locally or in full fields.

Spot by bad field attendance:

• Corn seed quality problem very unlikely
• Soil problems due to, for example, wet spots, compaction and/or driving tracks
• Large temperature differences on drier, light soils resulting in too low a germination temperature
• Differences in water availability in the seedbed (capillarity)
• Bird damage from crows, jackdaws, pigeons, pheasants
• Wire damage. Damage caused by wire ropes is increasingly being observed. This is mainly due to a too slow youth growth as a result of cold, drought and/or insufficient effect of the anti-chickener agent with which the seed has been treated. Young plants are particularly affected, as the budding larvae are small and their jaws or chewing parts do not allow chewing of coarse material. When a plant remains in the germination stage for a long time due to circumstances, the wireworm has longer to feast on the young crop. Only larvae in the third and fourth year of life (in the last phases just before the actual insect, the longhorn beetle, emerges) are able to eat coarser material. Anyone who has collected a lot of organic material in the field over the years offers a suitable source of nutrition for young wireworms.

Full Field Turnout Problems
In principle, there is an unsatisfactory field emergence if more than 15% of the seedlings are missing. The damage picture and the causes can be very diverse:

1. Seeds not found

• Wrong coulters used
• Strippers on the coulter set incorrectly
• Wrong air pressure

In all these cases corn seed is left after sowing!

2. Seedlings are missing

• Salt damage (burning) due to inaccurate application of starter fertilizers during row fertilization (incorrect setting, blunt, bent fertilizer coulters)
• Seed picked by pheasants, geese, pigeons or crows (typical holes in the bottom). After the disappearance of Mesurol as a maize seed treatment against bird feeding, KWS introduced the seed treatment Initio Bird Protect. Initio Bird Protect combines effective protection with the right ingredients for a smooth germination. It promotes root health and phosphate uptake and reduces cold stress symptoms. All this results in a rapid rapid growth to the 4-6 leaf stage without plant losses. More information about Initio Bird Protect is here to find. 

• Damage caused by hoeing and/or weeding (too deep, wrong time)
• Flooding, rotting of the seed in excessively compacted ruts

• Seeds placed very superficially (more often when sowing in green manure, inaccurate depth control of the coulter)

3. Wave-shaped emergence, irregularly developing seedlings

• Uneven seeding depth (driven too fast, blunt coulters)
• Not level seedbed due to incorrect seedbed preparation
• Irregular moisture supply in the seed bed (sowing depth insufficient)

4. Seedlings developed very differently

• Seedbed that is too loose, resulting in a poor germ water supply
• Clumpy seedbed with the 'result' of a disrupted water connection

• Seeds sown too deeply (deeper than 7 centimeters)
• Seeds covered, for example by silting up sowing trenches that are too deep
• Air or oxygen deficiency after clogging and/or flooding
• Food damage to the seeds by, for example, wireworms, centipedes and/or snails
• Mold formation (more often with long emergence times after early sowing and no or insufficient protection of disinfectants)
• Long lay time of non-germinated or germinating grains in wet, cold soil
• Lots of weak double plants and gaps after seed rolling (row speed too high, stubby coulters)

5. Non-germinated seeds, abnormal seedlings

• Unfavorable germination conditions such as drought and/or cold. In 2019, this has been a major problem in many places. A good and airy seed bed helps, but can't change anything if the ambient temperature and thus germination temperature are too low
• Coarse seedbed due to a disturbed water connection. The seedlings have to travel a long way before they emerge.
• Interruption of the germination process by a cold wave gives aggressive soil fungi a greater chance.

• Too little sprouting water in case of insufficient capillarity of the root bed and/or drought
• Wrongly stored leftover maize seed from the previous year used (stored under unfavorable temperature and/or humidity). In addition, remember that the maize seed treatment, especially after long-term storage, can have a (very) negative influence on the germination rate
• Lack of germination capacity of the seed
• Deficient germination percentage of the seed

Problems that may be due to the maize seed can only be checked if one knows which maize seed lot is involved. Therefore, always keep the labels of the used seed until the end of the season.

The field emergence (emergence of all sown seeds) is easy to check by randomly fitting 13,3 meters at a number of places in the sown field in one row, counting the number of plants over this distance and multiplying this by 1.000. The loss of plants and/or seeds that have not germinated should not be a problem as long as it is a 'regular irregularity'. The image in which a plant is missing here and there. It is not necessary to switch to overseeding or overseeding too quickly because this entails additional costs and it is not said that this will be recouped through a higher yield and/or better quality.

If in doubt about field attendance, consult your regional KWS advisor. You can find his contact details here find. 

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