Spring Tillage Lines Still Visible in the Fall

 

All year I've been noticing how many corn and soybean fields even in a dry spring that you could see both wheel tracks and either field cultivator shovel tracks or ripper tracks from the fall before at an angle across the rows early in the season and well into summer.  There is a soybean field that I've watched this on all season long that I just got back from going out to make some observations between the tillage lines vs area in-between.  Here's a shot from about a month ago where you can see the differences in height with the straight lines from the auto steer tillage pass working from the camera vantage point towards the grove across the section. 

 

Here's a shot where you can see the tillage lines tonight with the beans turning colors.  The tillage lines are the greener beans that aren't as mature.

 



When I walked out to look at these specific spots and differences it didn't take long to see that the differences in the beans were significant beyond color variance.  The beans in the tillage line were shorter and greener and had far fewer pods on them in comparison to the soybeans in between.  Those plants were taller, more mature and had much better pod counts on them.  I took a sampling of plants from the field and took them back up to my place to take some pictures and do some pod counts.  Here's what they looked like.



Untracked on the left, beans growing in tillage track on the right

For fun I went and grabbed some of our soybeans across the road from these that were strip tilled and planted the same day as these above.  Here's a pic of our beans vs the untracked beans above.  I don't know what the variety or maturity difference is between these 2 beans but ours are much closer to combining.  A big player I think in the maturity difference is that our beans all emerged within 5 days of planting where these across the road sat in dry dirt for 2 weeks before they germinated.



Strip tilled beans on left - Untracked plants on right

I did pod counts on the 3 samples that I had gathered and found on average the green soybeans grown in the tillage track had on average 10.8 pods, the soybeans that were in between the tillage lines had 18.8 pods/plant and the strip tilled beans across the road had 28.4 pods/plant.  Granted it's a pretty small sample size and not quite scientific but still pretty interesting as it was a pretty representative of what you saw standing in the field.   

 

So what does this all mean? If this translates in yield across a 160 acre 1/4 section assuming that you have these tillage lines every 30" and that they encompass an 8" width for effecting plant growth, you have 60% of yield potential on 47 acres of that 160 acre farm.  Assuming that the untracked beans average 40 bu/A on 113 A and the others yield 24 bu/A on 47 acres.  16 less bu/A on 47 A = about 800 bushels X $17/bu  = $13,600 loss on the farm.  This is making a lot of assumptions but if the actual loss is even 1/2 of this, it's still significant.

 

So what caused this variation?  My best guess is where that the last row of shovels on the field cultivator created a dried out zone that was not leveled out completely by the drag.  This more shallow, dry, compacted zone creating a delay in emergence and prohibited root proliferation which led to these plants being further behind than those plants that grew in between.  My assumption is that there is enough mixing action on the shovels throwing dirt in the rows ahead of the back row that the seed bed is more consistent in between the last row of shovels.  Earlier in the season I thought it could possibly be the old ripper shanks from last fall went where the roots had an easier time of going down and were bigger plants because of it.  However when I saw tonight the plants growing in the lines were smaller and less productive that lessened the chances of that theory holding water. 

 

The thing that gets me is how common you can find this in corn and soybean fields across the country side if you look and what the potential loss is from this is makes a guy think.  What it reinforces with me is that creating a zone free of compaction and planting seed into it without smearing or driving something across that zone has value.  And in a dry year like this one, I'm hopeful that the moisture savings in not tilling our soil will pay dividends. 

 

We will start harvesting corn likely this week as our 98 day corn will likely be 18% or lower by the middle of the week.  All of our corn is standing well and the stalk and shank strength is surprisingly good.  Dad and I spent this weekend getting ready by setting up augers, going through the corn head, combine and hooking up the strip till rig.  I'm excited to dive in to the crop and see what things are going to yield. 

 

So far the harvesting that has happened in our area has had corn yield ranges of 140-200 bu/A which is great considering how dry we were.  Dad said he'd be thrilled if we average 150 bu/A on corn...he's always the pessimist...I think we'll be closer to 170 bu/A if I had to guess today.  The only fields that really worry me is our corn on corn plowing where moisture was short.  Soybeans I'm going to guess we'll average upper 40's to low 50's bu/A.  We'll know how accurate I am in about 10 days as we should be well into harvest by then.  Safe harvesting to all!!!