Posts By: Midwest AgCenter

We’ve all seen plenty of soybean fields this year and in the past where the soybeans have a burnt appearance. I thought I would dig into this topic a little more to give you an idea of what is going on. Injury symptoms on soybeans that include bronzing, speckling and give soybeans a “burnt” appearance are generally due to the PPO class of herbicides.  Common products that make up this class are Flexstar, Cobra, Blazer,  Cadet, and Resource to name a few.  Many producers use Cobra as a tool for fighting white mold but that is a complex topic that can wait for another day.  This article will focus solely on using PPO herbicides for weed control purposes.  A huge topic of discussion in agriculture today is herbicide resistant weeds particularly to the active ingredient glyphosate, more commonly known as Roundup.  Herbicide resistance has received a lot of press recently so what I want to focus on is weed control, crop injury and how their relationship affects yield.

Soybeans are an amazing plant due to their ability to recover from stresses with little yield loss which is the reason that we can spray them with herbicides that cause crop injury.  When PPO herbicides are applied to susceptible plants, they cause a buildup of specific toxins in plant cells that can be lethal to certain plants and non-lethal to others like soybeans.  Growing conditions and crop growth stage are important to think about when considering yield loss potential.  Crop injury during stressful situations like cold, wet weather or hot, dry weather have a higher chance of reducing yield as opposed to when the injury happens during ideal growing conditions.  Under optimal temperature and soil moisture, crop injury from herbicides labeled for soybeans have a very low probability of causing yield loss as the soybean plants can quickly grow new leaf tissue.  Soybean growth stages are divided into two categories.  Soybeans enter their reproductive (R) growth stages when flowering begins.  Before that, their growth stages are referred to as vegetative (V).  I’ve attached a chart since it’s hard to explain in print.  Leaf defoliation during the vegetative stages causes little to no yield loss but can start to have an effect on yield once a soybean starts reproduction.  This is where we can utilize our PPO herbicides for effective weed control.  Weed control during the development of the first few trifoliate leaves (V1-V3) is critical for protecting yield.  With this logic, it allows us to confidently use PPO herbicides when we are presented with situations involving weeds that are difficult to control with just glyphosate like Lambsquarter or glyphosate resistant weeds like Waterhemp.  If you have questions about your herbicide program, contact your agronomist at WS Ag to start the conversation.

   

-Mark Kendall

In essence, the barrel staves represent plant food nutrients at different levels of availability.

I’m a firm believer in the Law of the Minimum. Over the past 25+ years of scouting crops and troubleshooting problem areas in fields, including alfalfa, corn, soybeans, and winter wheat, I’ve used tissue sampling and soil sampling as my primary diagnostic tools to help fix the problem, or in other words “lengthen the shortest staves.” However, in these situations there has already been some top end yield loss for that year. Which brings up another point: Hidden Hunger.

Hidden hunger is a situation where a nutrient or nutrients are at low enough levels that they are limiting yields, but there are no visual signs of that nutrient deficiency. Sampling can also help to identify these hidden needs.

In closing, ask yourself:

1. Have my yields leveled off the past few years?
2. What changes have I made in my plant food nutrient program lately?
3. Could hidden hunger be leveling off my yields?

Soil sampling and tissue sampling are great tools to help solve problems. If you answered “Yes” to questions 1 and 3 and “none” to number 2, maybe it’s time to take a closer look at the “stave lengths” on your operations, via tissue and soil sampling.

Get a hold of Andy, Mark, Kevin, Tom or myself if you see a need for some sampling to be done. It’s never too early to start planning for next year.

-Dan Langkamp

**Oh yeah, in case you are wondering, Justin Von Liebig was a German chemist from the 1800’s

A large part of the success of any great operation comes through trial and error. The famous story goes, Edison failed to refine the light bulb (one of the few creations he merely refined but did not invent) so many times it took him 10,000 attempts to perfect it. However rather than accepting failure 9,999 times he is quoted as answering questions on his failures as rather: ‘I have not failed. I have just found 9,999 ways that do not work’.

We have all seen tests and results shown to us by sales people that claim their products really work! Just because a product works on one area one year doesn’t mean it will work there or anywhere else on a   different year. We also know that profit comes from having more bushels than expenses at the end of the year, so the question becomes what can we do differently this year to come out better than we have done in the past?

Every year I conduct multiple farm trials to learn how technology and products can benefit customers on their farms. Sometimes I see patterns and consistent results, and other times I don’t see much differences at all. The more trials I do, the more I learn. Technology has really helped gather useful information about these trials. With technology it’s simple to track the trials during the year and see yield differences at harvest.

Here are some of the trials we have going on this year: Nitrogen timing, rates, sources, and stabilizers; planting date trials; row spacing trials; weed control trials; fungicide trials; population trials; seed variety   trials; tillage trials; seed treatment trials; and trials with microbial products. We have already learned a lot this spring from GPS trials comparing the WAAS, TerraStar, and RTK correction systems.  Below are a few pictures of some trials we’re doing, and we look forward to sharing our results with you this fall. If you are interested in trying different products or farm practices on your operation, let us know and we can help you set up your own trials.

In this trial, we are using NK’s S20-T6 variety to compare how row spacing and weed competition affect canopy and yield. We will have weekly photos showing progress, and can already see that the plants are slightly   farther along on the 30” rows than the 15” rows. The 30” row beans were out of the ground a day sooner than the 15” rows, as the 1.5” spacing between plants (150k pop) helped with emergence compared to having 3” spacing  between plants on the 15” rows. The soybeans with the weed competition seem ok but the yield monitor will tell the true story.

This is a trial comparing fall custom applied anhydrous ammonia with spring sidedress urea. The whole field also received 45 lbs UAN with the pre-emerge herbicide program. We were able to track applications    using the AgLeader InCommand 1200 monitor and will be measuring yield with that monitor in a 9500 combine.

Farmers don’t make mistakes, they just leave test areas…or so I’ve been told. We planted this row in our test plot without first priming the meter on the electric drive row unit, so we had several feet of row before corn came out. When we planted soybeans in our plot about a month later we went back and filled in that row, giving us a good trial of corn planted April 25th compared to the same hybrid planted May 23rd. We will find out how planting date affects yield and moisture this fall. Right now that corn is V4 and V8.

– Andrew Tucker