Fields of Yellow When They Should Be Green

it's past the Fourth of July, and very few corn fields around here are meeting the "elephant's eye" height test.  That's because it's been a really lousy summer growing season.

We had a dry Fourth of July, and the rain yesterday and today is the first in a week, but boy, June was soggy. Especially near the end of the month, when we had 12 straight days of rain. 

"The corn, as wet as it’s been, has not rooted as deep as it normally would have at this point in time or the root system's not growing," said Mark Badertscher, chief educator for agriculture and natural resources at The Ohio State University Extension Office in Hardin County.   The result has been a lot of fields with yellowing corn.  And I don't mean yellowing in the good way, as in, plump yellow kernels.   The yellow is showing up on the leaves.

Yellowing leaves are a sign of nitrogen deficiency.  Corn feeds heavily on nitrogen, one of the Key Three plant nutrients (Remember your high school biology?  Nitrogen, potassium, phosphorus).  The rain is messing up the corn's intake of nitrogen in two ways.  First, Badertscher said the rains have leached a lot of nitrogen out of the soil.  Farmers haven't been able to get into their mucky fields to apply more.  Second, the corn itself is having a hard time getting to whatever nitrogen is there.


"What happens is that the corn gets so saturated that the roots do not grow," Badertscher explained.  "When the roots do not grow, they’re not bringing up nutrients like they normally would.  The farmers who put nitrogen on their corn, the roots haven’t grown enough to access it."

 "Where you see fields of dark green corn, that's due to high land, good tile drainage, or a soil that drains better than others.  They’re able to get to that nitrogen."

Not yet elephant-eye high.  Maybe elephant-knuckle.  A corn field along Route 103, between Ada and Arlington.

Not yet elephant-eye high.  Maybe elephant-knuckle.  A corn field along Route 103, between Ada and Arlington.

Size matters, too, when it comes to weathering storms like the kind we've been having, over and over and over again.  "When you have corn that has reached that V6 stage, it can withstand more water than if it hasn’t reached that V6 stage," said Badertscher.

V6?  Sounds like he's talking about an engine.  Well, he is, in a way.  What Badertscher is referring to is a method of calculating corn's growth stage based on the number of leaves.  Leaves are the engines of the plant; they convert carbon dioxide and water into glucose through photosynthesis.  

Yeah, I know you know this, but I loved biology and botany classes and I get into this stuff.  Stay with me.

Not all the leaves are counted in the V-method.  Just the ones with visible collars on them.  What's a leaf collar?  Check this out:

Betcha didn't know THAT.  Or that there's a second way of counting leaves, called the "droopy leaf" method, which a Purdue University agronomist says is the "preferred method of crop insurance adjustors."  I'm guessing they prefer it because it means lower claims.  Corn leaves, droopy or otherwise, are often stripped away by a damaging hail storm, while the sturdier stalks and their tell-tale leaf collars remain.

I decided to play crop insurance adjustor and assess the water damage to the sweet corn in my garden.  I've got lots of yellow leaves on stalks at the V5 stage.  I bought some fish emulsion and blood meal, organic sources of nitrogen, to put down. So, no payouts just yet, but I could have a claim to make by season's end.  

My nitrogen-needy sweet corn.

My nitrogen-needy sweet corn.

As for local farmers, Mark Badertscher at the Hardin County Extension Office said farmers won't know until harvest time how much their yield was diminished by the rain.  There's still time for a turn-around. "We need the soil to dry out and to get warm temperatures," he said.