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Last week, I told you some observations about my corn harvest. So this week, I thought I would change gears and give you my insights on our farm’s soybean harvest.
The biggest issue that I notice this year was where I post-applied my glyphosate in Roundup Ready soybeans compared to where I did not post-apply any glyphosate.
My burndown program consists of 3 ounces of Valor XLT along with 12 ounces of 2-4,D E-99 in the spring with a crop-oil concentrate 1 to 2 weeks ahead of planting. The soybean crop was planted from April 22 to May 4, so we actually had a good jump on the calendar this past year.
The crop emerged quickly with plenty of moisture and heat. From mid-May to July 1, we had constant rains that actually slowed the soybeans down, but still a lot of my residual Valor herbicide was holding its own along with the help of a good canopy. With that, I decided not to spray 25% of my soybeans with the post application of glyphosate.
During August, I had some weed escapes, but nothing that I thought would hurt yields too much. I somewhat make a rule of thumb to put away the sprayer after July 1 because I would likely do more harm than good.
To my surprise at harvest, I’m glad I did put away the sprayer. What I saw with the yield monitor was something that really shocked me.
My yields where I sprayed my post application of glyphosate averaged 59 bushels per acre. With the somewhat weedy part of the field in spots right next to where I post applied my glyphosate, my yields averaged 65 bushels per acre! This field was planted the same day with the same variety with the same soil types and same planter.
The question is why the difference? Could it be that the glyphosate post-applied has something to do with the yield reduction? Is this why our soybean yields have not increased dramatically for the past 10 years, but our corn yields have exploded with our superior hybrids. Surely there has been research done for this, or maybe this is just a coincidence. It sure was not due to wheel tracks from the sprayer because my tires were in-between my 15-inch rows where I applied glyphosate at the R2 stage.
Last year, I had a suspicion that something was going on where I noticed a 5- to 8-bushel-per-acre increase in yield where I post-applied Select and Flexstar on my Roundup Ready 2 soybeans in comparison to where I post-applied the glyphosate. Hopefully, you blog readers can give me some insight to this because I am surely not the only one that has noticed this. Your thoughts are appreciated.
Sir, I am seeing the same thing in our operation. Something is going on here. We were taking a several bushel per acre “Yield Hit” w/ RR Soybeans for 3-4 yrs. & 2 yrs ago, we quit RR Soybeans completely. We were using some lines that were common to several seed companies, so our genetics were surely not that bad. We are using some older & 1 newer variety conventional soybeans & were beating the RR soybeans badly. We just need some newer varieties of conventional soybeans & we could literally “Smoke” the RR lines. Are we getting old Genetics in the RR varieties, or is there something else going on here? We are seeing it in Irrigated & Dryland fields. Add up the Royalty cost, the yield hit, & now lack of control on marestail, velvetleaf, & various species of pigweeds & I have to wonder why anyone is still planting RR soybeans. I have not tried the RR 2 lines & @ this time probably will not do so, @ least until I can see something different. The Liberty Link program has its limitations, but they have beat the RR lines in most fields in this area where fair comparasons have been made. The LL’s have been about equal to the conventional lines for us the last 2 years. There is a professor back east that is convinced that RR ties up some micro-nutrients, but I do not know much about his work. I had a college agronomy professor tell me about 3-4 yrs ago that the RR lines are really not new, but only “Warmed-over” varieties, as He put it. I am really beginning to wonder now. We should be getting yield increases now after 15 years of developing RR Genetics, not lower yields. Any other thoughts on this subject out there? You are certainly not the only one seeing this. We have several seed customers seeing this & are trying conventional soybeans & are happy. We have others who are not even trying the Conventionals. What are we doing wrong, if there is not a “Yield Drag” from something in that program? Thanks for the opportunity to share my thoughts.
Comment by Grant Corley — November 19, 2010 @ 7:47 pm
Spend some time on the net and read Don Huber’s work on glyphosate. He presented at the Innovative Farmers conference in Ontario in 2010. I spent several days going through his citations and researching the subject. Not everyone agrees with his positions but he never misquoted anybody.
The original patent on glyhosate was as a mineral chelator so it is very good at tying up zinc, manganese, etc. This happens when you spray the soys so they suffer for a period of time. Also, RR plants do not break down glyphosate. It is diluted as the plant grows and some is exuded through the roots where it can affect the root ecology, sometimes for the worse. One paper claimed a reduction in root nodules and mass but no yield decrease. Possibly the biggest concern is the side effect the RR gene had on the early varieties. Even without glyphosate, they had reduced nutrient levels. The owner of the lab that I use told me that all RR soy varieties he tested were Manganese deficient.
I love glyphosate as no-tiller but I wish I had this information a long time ago. Use it wisely and test your plants nutrient levels to modify your programme.
Comment by Don Ready — December 30, 2010 @ 7:13 pm