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Flint on Crops: Cloudy Weather Affects Crops – Commentary

Ernst Undesser
By Ernie Flint, Mississippi State University July 17, 2017

Flint on Crops: Cloudy Weather Affects Crops – Commentary

Our weather pattern has shifted significantly from almost daily rainfall and overcast conditions to a predominantly sunlight situation with scattered showers punctuated by a few short periods of heavy rainfall that our crops need since their root systems were not built for drought stress this year.

Quite a lot of impact had already been sustained in the way of crop suppression during the long weeks of overcast days. This is especially true for corn since the crop was planted earliest and sustained much of its plant development during the period of low sunlight conditions, and well into its flowering period.

As most of you know, my opportunities to visit fields and evaluate crops myself has been limited this year because of medical issues that I hope will soon be resolved, but I get a lot of phone calls that I greatly appreciate.

One of the main issues that has come up in these phone visits with farmers has been that they have noticed that their corn fields don’t seem to be performing as well as they had expected. This is especially true given the fact that there has been plenty of the one component of corn production that often has the most impact on yields, namely moisture.

There are of course several other factors in addition to moisture that greatly influence the yields of all crops, particularly corn. After all the talk I have done about soil management and fertility most people might expect that I would name this as the culprit, and it can certainly contribute in a major way when there are big problems such as low soil pH, deficiencies of P and K, and especially deficiency of N.

Another major issue that has shown itself to be of special importance this season has been that of drainage. Almost every farm has those areas where soil moisture has remained above field capacity for weeks on end.

In these areas, plants of all crops have failed to develop good root systems, and crops like cotton and corn which are dependent upon applied N have suffered from loss of this nutrient element through denitrification and leaching out of reach of the shallow roots that plants have been able to produce.

There is another major factor that has contributed to the poor performance of corn and also cotton and soybeans as well. This factor is low sunlight or more technically “solar radiation” which is necessary for the miracle of photosynthesis upon which plants of all kinds are dependent for growth and production of yield.

This factor can be responsible for poor development of the basic vegetative structures of the plant, and especially in the case of corn it prevents the plant from assimilating the carbohydrate stores that will later be converted to ears and grain.

A common statement from the growers I have talked with has been that the ears on their corn plants seem to be smaller than normal. This is no surprise, since the plant did not have the raw materials needed to produce the large ears that are necessary for high yields.

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As usual, there will be exceptions since some localities received more sunlight and heat than others so the direct negative impact of solar radiation may not be as great in these areas. Other areas were subjected to almost daily overcast conditions so the impact will be greater. There will almost certainly be some varieties that can tolerate reduced sunlight and heat better than others, and this will likely be reflected in the results of variety trials this year.

And as I usually say, this weather pattern has been a part of the weather our region is famous for. Our climate swings from hot and dry to cool and wet in a cyclic pattern that is probably so long in time that most of us will not be around long enough to realize that the weather is simply repeating itself as it has done for millennia. It’s all part of Nature.

Thanks for your time.

Ernst Undesser
By Ernie Flint, Mississippi State University July 17, 2017