Winged Effect

Pioneer's 2013 Agronomy Sciences Research Summary is out.  It is a great publication that addresses some pertinent agronomy issues.  Because real winter is here it is a good time to stay inside and review some of the articles.

One study that caught my eye was the reported variability in yield across the width of very large planters.  This study was done on farms in Minnesota using three planter configurations.

• 36 rows, 22 inch spacing, centre fill
• 36 rows, 20 inch spacing, centre fill
• 48 rows, 20 inch spacing, row unit boxes

Corn yield from the outside one-third of the planter was compared against the middle one-third.  It has been well documented that compaction from wheel traffic beside the row has a negative effect on yield.  Heavier planters and the corresponding tractor necessary to pull the planter increases the potential compaction effect, especially if the soils are damp. 

Twelve locations were harvested and the average yield on the outside third of the planter was 11 bu/acre higher than the inside third.  There was significant difference between the outside third and the middle third in 9 out of the 12 locations.

While there is not much a grower can do to change his planter configuration being aware of the compacting effect is useful knowledge.  Keep in mind there is sometimes a trade off between timely planting and less than perfect soil conditions. 
One last consideration is the row effect on hybrid evaluation.  This is something I have been guilty of doing.  As an example, I have taken a 12 row planter and split it into three 4 row plots.  Splitting a planter into more than two equal halves could unfairly bias hybrid performance.  The outside rows would have an automatic advantage.