September 4, 2006

 

Cloudy August conditions not seen impacting US soy yields

 

 

The recent spate of cool weather and plenty of moisture has some industry analysts wondering if too much of a good thing could curb US soybean yield potential.

 

A few crop observers acknowledge the benefits of moisture for filling soybean pods, but also point out the lack of sunshine that has accompanied August rains limits the natural growth of plants. However, agronomists are downplaying this notion, pointing to beneficial weather as more of an influence on yields than cloudy conditions.

 

Sunlight is of particular importance in June and July during the flowering stage, as this is the period when plants need good light and moisture for rapid growth, said Palle Pedersen, extension agronomist with Iowa State University in Ames, Iowa.

 

By August, the soybean plant's nodes and leaves are already developed and by Aug 15 to Aug 20 plants usually stop adding nodes and leaves, Pedersen added.

 

A lack of sunshine could impact yields, but the Midwest has not had enough cloud cover to reduce solar radiation so appreciably that it would it affect soybean yields, said Dale Hicks, agronomist with University of Minnesota in St Paul, Minn.

 

Wet weather patterns across the US Midwest during the key pod-filling stage of soybean development has changed market perspectives in the past couple of weeks. Timely rains have fed beliefs that soybeans have the potential for optimal yields in many Midwest areas in 2006.

 

In Minnesota, soybeans will fare much better than corn as timely rains have revived the soybean crop, Hicks said. There are areas with short beans, but short beans don't mean low yields, Hicks adds.

 

Emerson Nafziger, extension agronomist at the University of Illinois in Urbana, said he doesn't think cloudy conditions in August would poise a big problem for crops, as there is always some sunlight that follows storms. Cooler temperatures would do more to slow down growth, but once the sun emerges the crop would be off and running again.

 

Moreover, no clouds and no rain would be a worse condition than clouds and rain in August, Nafziger added.

 

Meanwhile, Pedersen said all the rain the crop has absorbed in August opens the up the potential for maximum soybean seed size in pods, but does acknowledge because of stressful temperatures in July, the heat may limit the number of seeds not their size.

Looking at Iowa, 11 counties in the dry western part of the state received rains recently and they should have decent size seeds based on the timely rains, as many observers just need to look back to Illinois in 2005, when 2 inch rains in August improved yields from 30 bushels an acre to 40 bushels an acre in certain areas, Pedersen added.

 

Soybeans are on target to be very good in many areas of Minnesota, Hicks said. It's true we had some cloudy days, but we also had some fantastic weather for filling soybeans, Hicks added.