The 5 most likely ways to end up with a less than desirable corn and/or soybean stand
By: Mike Toohill, AgVenture WSC
Bloomington, IL
As we get closer to planting, the following 4 scenarios are always in the back of my mind as I watch the planters roll.
(1) The planting into warm soils that get a heavy, COLD rain within 48 hours of seeding scenario.
Believe it or not, over my years some of the worst stands occurred when planting on some of the best late April weather days. In this situation, seed rapidly begins to germinate and then the soil temperature drops significantly with a cold front and rain. This often causes corn imbibitional chilling/ “cold shock” resulting in weakened seedlings with highly variable emergence. Soybeans are not prone to chilling/shock but soil crusting is also very likely in this scenario.
Recommendation: Stop the corn planter (and maybe the bean planter) a few days before a sharp cold front with accompanying heavy rain is expected.
(2) Soil crusting after a heavy COLD or WARM rain.
Soil crusting from heavy rains is always worse in tilled soils and we all know which soil types on the farm are more prone to getting hard after a heavy rain. The less time between the tillage tool and the planter increases crust risk. Every hour between completing planting and the heavy rain is beneficial to stand establishment. Hoeing crops when crusting is probable seems to be a lost art, but it can still be effective especially if soils are damp during the hoe pass. I do not like to hoe when the seedlings are close to the soil surface.
What I've seen people do when this happens: Some growers have gone to running the planter shallow back over the crusted row with good results (as long as the seed development is well below where the planter runs). More common now a days it seems, is do nothing and hope for a shower to “rain up” the crop.
(3) Long duration cold, wet, saturated low oxygen soil conditions.
Since forecasts often lose their “accuracy” more than 5 days out (why the 6 to 10 and 8 to 14 days become an outlook), trying to manage the weather maps more than a week in the future is difficult at best. Marginal soil conditions at planting always add to the impacts of cold and wet in my experiences.
My general thoughts on this risk: A very cold and wet forecast in early April is more likely to slow or stop my planting operations than a cold and wet early May forecast. Once mid-May rolls around, its GO time for me regardless of the forecast. All assume good soil conditions when the seed is going in the ground.
(4) Not watching planting depth close enough on warm, windy, low humidity days.
The last few springs being dry (with few “fixing” rains) has added to the acres of poor emergence due to dry soils. If I was running the planter, I would check moisture at seed depth at least every hour or two on days when the wind and temperature is high and the humidity low. Tilling soils ahead of the planter on hot, dusty days adds to seed in dry soil risk. Increased time between the tillage tool and planter also adds to top soil dry out issues. Heavily traffic areas are usually the most problematic. In marginal seed moisture situations, I always error on going down an extra notch/setting granting that increased seed depth makes it tougher for seedlings to emerge through a crust.
(5) The seed goes in great, soils stay warm, the crops come up fast BUT a frost/freeze event occurs after emergence.
In this situation, no-till and heavy residue fields are the most likely to be impacted by sub-freezing temperatures. Often just a day or two delay in planting date can make a HUGE difference in cold weather injury. Contrary to what most of the agronomic research says, corn is never quite right after a freeze event even after a “full” recovery. This is most likely due to a significant increase in plant to plant variability after the frost/freeze event/s. If the early April forecast indicates that 7 to 10 day or so corn and soybean emergence is possible, maybe it’s best to wait at least a few days (especially in high residue situations)?
In closing, keeping the above situations in the back of your mind when making planting decisions can minimize a lot of stand issues and worry. If you ever have a question about the forecast and/or weather impacts to stand establishment on your farm, feel free to contact Mike Toohill.
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