Should Soybean Lodging and Shattering Be a Concern for Producers?

Lodging and shattering of soybean in the Midsouth has been a concern in the past. However, is that still the case, and should producers be cognizant of these traits in the varieties that are now grown?

The concern about these two traits is rooted in the past history of soybean production in the Midsouth for two reasons.

•     When MG’s V-VII were being grown in the old “conventional” system–i.e., May and later planting dates–they routinely got very tall (>36 in.) and fell over or lodged before harvest. Often, this led to reduced yield since the lower part of the stems were on the ground and did not set pods.

•     When MG IV’s were introduced into the Midsouth in the early days of the ESPS, varieties that were available came from more northerly latitudes; i.e., they were not adapted to Midsouth conditions. The mature pods of these varieties would often dehisce at maturity because of the hot, dry conditions during this time. The seed from these burst pods would then shatter and fall to the ground. I can remember being in plots during this period and the shattering was so pronounced that it sounded like popcorn being popped. It was a disheartening sound, as you might imagine.

So, in my opinion, scoring of today’s varieties for lodging and shattering is a holdover from the past when these traits were often consequential. But are these ratings/scores or consideration of them necessary today? The following presentation will help you decide.

In the below table, I have entered the average values for these two traits along with plant height at maturity from selected Soybean Official Variety Trials (SOVT) that were conducted in Arkansas in 2016.

As the tabled data indicate, average lodging scores did not exceed 1.4 in any of the early-planted tests, and only exceeded 2.0 in the full-season test on the silt loam site at Stuttgart, where average plant height was as much as 43 in. A perusal of the Mississippi and Louisiana SOVT reports shows the same result; i.e., lodging score of the vast majority of tested varieties was 1, and only rarely did any variety receive a score of 2.

It is known that plants of varieties growing in later plantings on a silt loam soil such as that at Stuttgart likely will reach a height that will be conducive to lodging, and this should be considered when planting during this timeframe on loam soils. Click here for an example of this occurrence.

Average shatter scores rarely exceeded 1.0 in any of the tests shown in the table, which means that there was essentially no shattering of seed from pods of any of the tested varieties no matter if planted early or late at any of the locations.

So what does this mean? Simply stated, producers should not be concerned about lodging and shattering when deciding on a variety to plant early. These two traits are just not important selection criteria for today’s varieties when planted during this preferred timeframe.

Does this mean that the coordinators of state SOVT’s should not waste their time taking these ratings? Probably so. But if there is a variety or varieties that stand out as being affected by either of these conditions in a particular test, then those varieties can be flagged in the tables that present their data. That way, if this unlikely occurrence happens, it can be recorded as such without consuming time collecting these data for other tests or varieties in a test. In tests that have no lodging, simply stating this without the time-consuming process of assessing individual varieties is sufficient.

These data indicate with certainty that recording shatter ratings is apparently unnecessary and therefore a waste of time. Today’s varieties apparently are not prone to shattering.

I would be greatly surprised if a released variety, when grown in its intended environment, is subject to either lodging or shattering. The parties that release new varieties today likely ensure that those that are released do not lodge or shatter in the environment for which they are intended.

Composed by Larry G. Heatherly, Dec. 2016, larryheatherly@bellsouth.net