By Darren Hefty

Brian and I get questions all the time about what a difference we think planting population and picking the right variety can make in terms of yield and profitability.  The answer to both questions is “a big difference.”  This is why we are so excited to be varying the seeding rate AND changing varieties on the go as we put our wheat and soybeans in the ground this year.  We invested in a new drill and air cart for our farm this spring.  We’ll be set up with 10-inch rows for both crops and will also use tramlines to control our traffic patterns in the field. Here are some of the biggest reasons you may consider doing the same thing.


  1. Plant thicker in high pH zones.  Soybean roots excrete organic acids to help bring nutrients into the plant.  More roots means more acid production which is a great thing in high pH soils.  We see less iron deficiency chlorosis (IDC) symptoms and typically higher yields.
  2. Plant a different variety in stressed areas of the field.  Think about planting a racehorse yielder in the good areas of the field; using a defensive bean to fight phytophthora root rot in pothole areas; an IDC bean in high pH areas; or even potentially a nematode-resistant bean for soybean cyst nematode pockets in the field.


  1. Plant a high-yielding variety in the best areas of fields.  Plant a stress-tolerant variety in the tough areas.
  2. Vary population by soil type to maximize yield and control seed cost.

You may not have the capability to switch varieties on the go right now, but I strongly encourage you to use the technology that you already have (and have already paid for) to vary the planting population as you cross at least one of your fields.  Last year in corn, we saw a 6% boost in yield by varying our seeding rate by management zone.  Sure, you don’t know exactly which populations to use for each soil type because you have no idea what the rainfall will be like this year (on dryland production anyway).  Use common sense and set up a plan that makes sense for you.  Maybe 150,000 is your normal soybean population.  Try varying from 130,000 in the lighter soils to 170,000 in the high pH areas of the field, for example.  Then, leave a few check strips in the field at your standard 150,000 rate.  I’ll be shocked if you don’t learn something.  Next year, you can start doing this on more acres; and before you know it, you’ve added 5% to 10% to your bottom line without spending any more money.

This may seem crazy, but Brian also plans to seed up to 50 acres of corn with the drill and tramline system.  I’ve been trying to talk him out of it all winter because we all know corn is much more fussy about having seed singulation and an even planting depth.  Brian’s argument is that it is only 50 acres, and it is just to show people that variable varieties can be planted in corn.  Plus, even though yield could suffer a little due to planting depth, the parallel linkage on the new drill should really help that.  Spacing doesn’t have to be as accurate either when you drop a single seed every 15 or 18 inches in a 10-inch row compared to every 5 or 6 inches in a 30-inch row.  We have some fields with heavy soil that also have sand veins running through them.  Imagine a drought-tolerant hybrid in the sand and a racehorse in the good ground.

Regardless of the crop you plant, variable variety and variable rate planting appears to be a technology that will be quickly adopted due to its yield and economic benefits.