Forensic Agronomy

ReachOut: Forensic Agronomy from Central Valley Ag on Vimeo.

by Mike Zwingman

by Mike Zwingman

The last few weeks we have been talking about why you and your Central Valley Ag Field Sales Agronomist should be out walking your corn fields prior to harvest. We have talked about doing this as a way to work out some of your harvest logistics and minimizing your harvest loss. This is a great use of your time and a good way to make decisions about hybrids for your next cropping year. But, what if I told you this is one more chance to do some evaluation of the performance of your planter. Yes, you all are witnessing me writing a pre-harvest article all about your planter.

I know, I know I encouraged you to do this in Late May and Early June, but that was so you could see what happened in the field first hand.  This trip is where we are going to see the effect of those planter and emergence issues and how they may or may not have impacted your yields. This is important because we have talked a lot about things like meter testing, and downforce and what trials have shown as a return on investment. Doing this with your FSA or one of your ACS specialists will help you rebuild the scene. Use all the evidence and start to see what corrections we need to make to your planter for next year to lessen the probability of this happening again.

Randomly go out to different spots of your field and step off your needed feet for 1/1000th of an acre and count your final population, and then in the same spot count out 100 plants. Once you have determined your plant population and identified 100 consecutive plants we go to work and rebuild what happened with your planter.  First thing walk through those 100 plants and count all the skips and doubles and write that down. The second thing I want you to pay attention to is ear height and consistency of stalk diameter. These are an indication of emergence timing, count all the ears that are at least 8-12” lower than average and write that number down.

Close up Cob SS

To determine what the effect of these issues are, we are going to have to do a few things. Picking of ears, counting of kernels and calculations on what your yield is and what your yield may have been if everything was a bit more consistent. First, pick five random ears out of the section of those 100 plants where ear height and plant spacing is rather consistent. Then pick five ears from where you have doubles, and five from where the ear height is considerably lower than average.

Count and average the kernels for each one of those groups of ears, and what I want you to notice is how the kernel count changes between each one of those groups. Then use the average kernel counts of the 15 ears combined to calculate your yield using the formula Yield= [(Kernels per ear*harvest populations)/85,000]. This is the effect those changes have had on your final yield. Now look at the percentage of times you either have skips, doubles or inconsistency in ear height. Replace the kernel count of the percent of inconsistent ears with the kernel count of where things were good and recalculate your yield. Take the difference between the two and multiply that times a realistic corn price and that is the profit loss that planter issues have caused. Multiply that by the number of acres you are going to plant over the next 1-3 years, and that is the amount of money you could quickly recover if you invested in upgrading your planter before 2016.

Blue-Box-e1409667504172This reconstruction is an important process for you to be able to improve your profitability through consistency.  With lower commodity prices the expendable income may not be there for planter upgrades, so we need to do our homework to make sure that investment is going to create return and is justified. So let’s put our boots on and look one last time.